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  • Articles  (1,021)
  • Springer  (1,021)
  • 2020-2020
  • 1970-1974  (989)
  • 1945-1949  (32)
  • 1973  (535)
  • 1970  (454)
  • 1948  (32)
  • Architecture, Civil Engineering, Surveying  (1,021)
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  • Articles  (1,021)
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  • 2020-2020
  • 1970-1974  (989)
  • 1945-1949  (32)
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  • 1
    Electronic Resource
    Electronic Resource
    Reaching decisions about technological projects with social consequences: A normative model (1973)
    Springer
    Transportation 2 (1973), S. 1-24 
    Details
    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Among the crises facing our society is the public's loss of confidence in technical professionals and their ability to make decisions about large-scale projects (such as highways) in the public interest. To overcome this crisis of confidence, this paper hypothesizes a model for the role of the technical professional in the process of reaching decisions about public actions. In evaluating technological projects with social consequences, one key issue is the differential incidence of impacts. Typically, some groups are hurt in order that others may benefit. Social equity must be considered explicitly. Such presently-used techniques as benefit-cost analysis and point-rating schemes are unsatisfactory. New techniques are needed, reflecting a more comprehensive model for the role of the technical team in the political process. A normative model is outlined. First, the objective of the technical process is defined: to achieve substantial effective community agreement on a course of action which is feasible, equitable, and desirable. Second, a process for achieving this objective is proposed. A key element of this process is a four-phase strategy of technical and community interaction activities to achieve the objective. The basic premise of this approach is that the role of the technical team is to clarify the issues of choice, to assist the community in determining what is best for itself. This theoretical model has resulted in several practical products. A procedural guide for use by highway and transportation agencies has been prepared, and a number of specific operational techniques have been developed and are included in the guide. The procedural guide is now being field-tested in several state highway departments. The theoretical model has already been useful in identifying, in one highway department, opportunities for significant changes in the agency's mission, organization and procedures to enable it to be more responsive to public concerns. The theoretical model also has served as the basis for the development of federal guidelines for consideration of social, economic and environmental factors in highway planning and decision-making, in all of the state highway departments in the U.S.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172613
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  • 2
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    Some evidence of transit demand elasticities (1973)
    Springer
    Transportation 2 (1973), S. 25-52 
    Details
    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract This paper draws together empirical evidence from a variety of sources about the magnitudes of transit price elasticities and cross-elasticities. A number of different practical measures of demand elasticity are first defined and some expectations about magnitude are discussed. Evidence is then collated from the analysis of transit operating statistics, from experience in demonstration projects and from attempts to develop cross-sectional models of demand and modal choice. In general, all of the limited evidence available suggests that transit demand is inelastic with respect to money price. Typically, ridership is significantly more sensitive to changes in the level of service (particularly door-to-door journey time) than to changes in fare, although service elasticities also are usually numerically less than unity. In broad terms, short-run direct fare elasticities are characteristically observed to lie within the range of -0.1 to −0.7. A more precise value in a particular instance will depend on a variety of factors in ways which largely support a priori notions. Thus in very large cities, central city areas, at peak hours, and in other circumstances where the prices of alternative modes are high, transit fare elasticities are usually numerically at the lower end of the range. Estimates of cross-elasticities (representing the volumes of transit traffic diverted to other modes by transit price increases) are much harder to come by, and in fact only a few very uncertain estimates are presented here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172614
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  • 3
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    An analysis of the 1968 rapid transit vote in Los Angeles (1973)
    Springer
    Transportation 2 (1973), S. 71-86 
    Details
    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Analysis of the results of past mass transit bond issues can aid transportation planners in understanding and anticipating voter behavior. This paper reports the results of an analysis of the 1968 rapid transit bond issue vote in Los Angeles, California. The simple relationships of the vote to a variety of possible explanatory variables are first examined. An attempt to assess the relative independent importance of these variables and to offer a partial explanation of the vote using multiple regression analysis is then presented. Variables found to have had the greatest impact on the vote are proximity to the proposed transit system, income-level, and ethnicity. Variables found to have had little or no effect, on the other hand, are population density, age, partisanship, and election turnout rate. The analysis indicates that the frequently used “mood-of-the-electorate” explanation of bond-issue failures in general, and transit proposals in particular, underestimates the quality of the electoral decision. The electorate does make rational distinctions, and future bonding attempts will confront voters capable of perceiving the utility to them of proposed transit systems and voting accordingly. The policy implications of this analysis suggest that the design of future mass transit proposals should, firstly more explicitly attempt to incorporate the preferences of middle-income voters, and secondly, be part of a comprehensive transit plan for the entire metropolitan area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172616
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  • 4
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    Errata (1973)
    Springer
    Transportation 1 (1973), S. 475-475 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172393
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  • 5
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    Planning for implementation (1973)
    Springer
    Transportation 1 (1973), S. 419-453 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Although the urban transportation planning process has evolved into the most sophisticated of all urban planning processes, the increasirig difficulty in implementing long-range transportation plans in urban areas today suggests basic questions concerning the process which deserve critical examination. Planning for implementation of urban transportation programs, particularly during periods of rapidly changing human values, requires a continuing re-evaluation of both technical and organizational strategies and their interrelationships. This paper raises some fundamental questions about the traditional activities and relationships that have characterized most urban transportation planning programs in the past. It also suggests a number of strategies, both technical and organizational, that may contribute to the implementation of plans and programs resulting from the transportation planning process. The first portion of this paper discusses the implications of not providing transportation services to match metropolitan growth. The experience of the Washington Metropolitan Area over the past decade is used to illustrate these implications. A discussion of organizational and institutional constraints upon the planning process follows. Then, the implications for the planning process are explored, and the scale of planning is reviewed as well as the need for monitoring the performance and impact of facilities. Next, the paper deals with the need to broaden the range of solutions to transportation problems, including consideration of economic and land development policies to reduce travel demand, as well as the provision of new facilities. Finally, techniques for involving decision-makers in the planning process are discussed. Examples of special project activities in the Washington area are used to illustrate these techniques and their value.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172390
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  • 6
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    News (1973)
    Springer
    Transportation 2 (1973), S. 97-110 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172618
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  • 7
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    Comments (1973)
    Springer
    Transportation 2 (1973), S. 111-117 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172619
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  • 8
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    Communication innovations, urban form and travel demand: Some hypotheses and a bibliography (1973)
    Springer
    Transportation 2 (1973), S. 153-193 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Hypotheses are developed about the effects of telecommunication advances on urban growth patterns and urban travel demands. It is suggested that CBD (central business district) office employment might decentralize if telecommunications could effectively substitute for short inter-office business trips and that job decentralization would alter journey-to-work patterns and the viability of certain public transit systems. Major research questions are raised and keyed to an extensive bibliography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02428557
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  • 9
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    Trip characteristics of selected israeli cities (1973)
    Springer
    Transportation 2 (1973), S. 313-319 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Over the last 15 years travel patterns were investigated in 15 urban settlements in Israel. The results indicate an unusual combination of high trip generation by dwelling unit and low motorization rates. The diversity of socio-economic characteristics of population groups, as well as that of city size distribution, are reflected both in motorization rates and in trip generation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243359
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  • 10
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    An analysis of gravity model distance exponents (1973)
    Springer
    Transportation 2 (1973), S. 299-312 
    Details
    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract This study examines variations in the basic parameter of the gravity model: the distance or travel time exponent. In a conceptual examination of the exponent under ideal conditions, it is noted that the exponent will be low if either production or consumption of the phenomena is geographically concentrated. It is further noted that if all regions produce and consume the phenomena, this generally implies a large number of substitute regions, and therefore a large exponent. These three variables are made operational and related to a set of eighty exponents for 1967 commodity flows in the United States. A multiple regression model is derived and utilized to estimate the exponents. The latter are then used to reestimate the flows. The root mean squared errors are quite similar for the fitted and estimated exponents. Implications of the research appear to be consistent with variations of the exponent in the urban context.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243358
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  • 11
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    Evaluation of road-rail interaction in Thailand (1973)
    Springer
    Transportation 2 (1973), S. 281-298 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract The main line of the State Railway of Thailand to serve the Northeastern region of the Kingdom was built in 1900 to the town of Korat and subsequently extended to its northern extremity at the Laos border. The Friendship Highway, a modern highway parallel to the railway and serving the same transportation corridor, was completed in 1958 as far as Korat. In 1965 the northern extension of the Friendship Highway was opened to Nong Khai, the northern terminus of the railway. The effect of the nearby and parallel highway on freight traffic - for upland crops, vegetables, rice, kenaf, and forest products - is shown in terms of tonnages dispatched by the railway and in relation to the production of those commodities. Passenger traffic originating on the Northeastern railway line is analysed. Statistics indicating the shift in modal split between road and rail, for both freight and passengers in the Kingdom, are presented for a six-year period. An estimate of the loss in revenue for the Korat-Nong Khai segment of the railway has been made for both originating passengers and certain classes of freight traffic. Clearly demonstrated is the unceasing trend toward road haulage of freight and the use of highway buses by intercity passengers. This paper is intended to draw attention to the magnitude of the problem rather than to suggest definitive solutions.
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    URL: http://dx.doi.org/10.1007/BF00243357
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  • 12
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    Book reviews (1973)
    Springer
    Transportation 2 (1973), S. 337-339 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243361
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  • 13
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    News (1973)
    Springer
    Transportation 2 (1973), S. 341-345 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243362
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  • 14
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    Abstracts (1973)
    Springer
    Transportation 2 (1973), S. 347-349 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243363
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  • 15
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    A technique for the investigation of scheme benefits in large-scale transport networks (1973)
    Springer
    Transportation 2 (1973), S. 321-335 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Existing methods of evaluating large-scale transport networks involve the use of mathematical models of traffic flow which are generally both large and complex. However, the time and cost involved in the use of these models normally restricts their use for the detailed forecasting of traffic flows and costs to the assessment of a relatively small number of alternative patterns of overall investment. In order to evaluate the individual projects and groups of projects which go to make up an overall investment plan, it is, therefore, usually necessary to make simplifying assumptions about the influence of any one project on the overall traffic pattern, so as to isolate it from the influence of neighbouring projects. These assumptions generally result in the loss of a certain amount of the detail normally available from a standard model, and the task of assessing the relative value of different projects and the amount of interaction between them is made more difficult. This paper describes a new technique, designed to permit the evaluation of individual projects whilst still retaining the level of detail available from a full-scale mathematical model. The aim has been to produce a cheap and easy-to-use technique, capable of producing substantially the same results as a standard model. The technique uses newly developed computer algorithms which short-cut the full-scale model by forecasting the changes in an existing travel pattern resulting from the influence of a particular project. Initial tests suggest that approaching the problem in this way can save up to 70% of the computing time and costs involved in the use of a standard model for the evaluation of individual projects. The technique as described here is envisaged as a tool for aiding strategic investment decisions. It can, however, provide data for more detailed investigations, and could, with modifications, carry out these investigations on smaller problems than those for which it was originally designed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243360
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  • 16
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    Urban traffic studies from aerial photographs (1973)
    Springer
    Transportation 2 (1973), S. 373-389 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Two problems concerning the use of aerial photographs for conducting traffic studies in urban areas are considered in this paper: (1) Suitable procedures requiring simple equipment and methods and the appropriate formulae for determining the traffic characteristics of density, volume, traffic count, speed, composition; (2) Problems relating to flight planning for traffic surveys from the points of view of duration of photography and the scale of the photography from considerations of the reliability of the determined traffic characteristics, vehicle identification, and also economy. The conclusions concerning the flight planning were applied in a test flight from which traffic data were determined as illustrated in a sample calculation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00837899
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  • 17
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    Psychological theory applied to mode choice prediction (1973)
    Springer
    Transportation 2 (1973), S. 391-409 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract In an effort to improve transit ridership prediction, this manuscript proposes a conceptually unique mode choice model derived from the field of experimental psychology. The “psychophysical“ model, as it is called, differs from earlier modal split models in its substantive use of psychological theory. The result is a modal split model with a sound behavioral foundation. The psychophysical model is tested using data from the recent demonstration of dial-a-bus in Columbia, Maryland and found to be a marginal predictor of modal split. It is noted though that the difference between actual and predicted ridership may be accounted for in a second generation model. This will employ individual rather than aggregate data, incorporate the concept of adaptation-level, and refine the decision-making process.
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    URL: http://dx.doi.org/10.1007/BF00837900
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  • 18
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    Problems of the carless in the United Kingdom and the United States (1973)
    Springer
    Transportation 2 (1973), S. 351-371 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract An examination of current population statistics shows that in the U.S. more than half of the population is without immediate access to a car, and in the U.K. more than three-fifths of the population is without access to a car. This phenomenon has been accentuated by national investment in both countries in major highway programs. The term carless refers to more than just households that own no cars. It extends, in households with cars to those without licenses (old and young), the handicapped, and even the licensed drivers who have no access to the family car when it is in use elsewhere (e.g. at work). The most severely effected are those in urban areas and especially the urban poor. Transportation expenses are limited for the poor when other family expenditures (food, shelter) take a high priority. Once the work trip has been satisfied, money for other trips, for the poor, is not always available. One solution to cost-free travel is pedestrianism (walking), but this too is difficult in urban areas where the pedestrian has been overlooked in favor of the car. Solutions to problems of the carless include dial-a-ride, better public transit, and better design of urban form.
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    URL: http://dx.doi.org/10.1007/BF00837898
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  • 19
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    Beirut travel characteristics — A comparative study (1973)
    Springer
    Transportation 2 (1973), S. 411-430 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract This paper reviews the results of an origin-destination survey conducted in Beirut, Lebanon. The survey was conducted according to the techniques developed and used in the U.S.A. There has always been some doubt that methodologies and techniques, namely dwelling unit interviews, developed for use in U.S. cities would work in cities of developing countries. The results of the study indicated that such methods proved to be useful and effective. In spite of the higher residential density and lower level of car ownership, trip rates in the city of Beirut were within the ranges observed in U.S. cities. The comparison of travel parameters acquired from various cities around the world might show that the regularities and trends in urban transportation are universal.
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    URL: http://dx.doi.org/10.1007/BF00837901
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  • 20
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    Book reviews (1973)
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    Transportation 2 (1973), S. 431-442 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00837902
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  • 21
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    Abstracts (1973)
    Springer
    Transportation 2 (1973), S. 453-454 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00837904
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  • 22
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    News (1973)
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    Transportation 2 (1973), S. 443-451 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00837903
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  • 23
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    Home-based trip end models — A comparison between category analysis and regression analysis procedures (1973)
    Springer
    Transportation 2 (1973), S. 53-70 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract The trip end models which have been used in past transportation studies are briefly summarised. Problems associated with the use of zone-based models are outlined and reasons are given to support the development of models at the household rather than zonal level. It is suggested that recent developments which have taken place in household-based models have not been entirely logical. In particular, arguments between regression models and category analysis models have been confused with the use of aggregate (zonal) as against disaggregate (household) data — regression models being associated with the use of zonal data and category analysis models with household data. Misunderstood arguments and false notions regarding sample sizes have directed attention from the regression analysis approach. A detailed comparison of the category analysis and regression analysis methods for developing household-based trip end models is given. Both methods have been applied using data from the Monmouthshire Land Use Transportation Study. The regression results reported are from a very preliminary analysis and contain a number of anomalies, although it is thought that sufficient work has been done to provide an objective evaluation of the two methods. It is recommended that the household regression approach should be further investigated since it has advantages as a modelbuilding procedure and makes better use of sample data. A certain amount of categorisation of household types is necessary and the investigations would attempt to determine the best balance between categorisation and regression fitting. Further development will be restricted if the trend towards minimum sample sizes of about 1000 households is continued. Larger samples should be taken in certain circumstances to pursue development work.
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    URL: http://dx.doi.org/10.1007/BF00172615
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  • 24
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    Reviews (1973)
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    Transportation 2 (1973), S. 87-96 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172617
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  • 25
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    Book reviews (1973)
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    Transportation 2 (1973), S. 219-236 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02428559
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  • 26
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    Consequences of service reduction in municipal transit: San Francisco’s muni (1973)
    Springer
    Transportation 2 (1973), S. 195-218 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Urban transit in the United States is going through a crisis of rising costs, increasing fares, falling patronage, and concomitant service reductions; typical of the pattern is San Francisco’s Municipal Railway, the agency in charge of all the City’s transit. From a basic fare of 15c in 1969, two increases brought the fare to 25c by 1972, and cut sharply into a previously stable patronage. The “Muni”, in an effort to reduce costs and meet its budgeted deficit, attempted to reduce service by ten to fifteen percent. From an analysis of the data which could be obtained, it appears that neither efficiency not equity in the City would have been served by the proposed cutbacks. The analysis draws from a variety of sources and methods in exploring the interactions within the transportation system and within the city budget.
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    URL: http://dx.doi.org/10.1007/BF02428558
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  • 27
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    A direct demand model for downtown work trips (1973)
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    Transportation 2 (1973), S. 121-152 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract This article documents the development of a direct travel demand model for bus and rail modes. In the model, the number of interzonal work trips is dependent on travel times and travel costs on each available mode, size and socioeconomic characteristics of the labor force, and the number of jobs. In estimating the models’ coefficients constraints are imposed to insure that the travel demand elasticities behave according to the economic theory of consumer behavior. The direct access time elasticities for both transit modes are estimated to be approximately minus two, and the direct linehaul time elasticities approximately minus one. The cross-elasticities with respect to the travel time components are estimated to be less than the corresponding direct elasticities. In general, the time cross-elasticities are such that rail trip characteristics but not car trip characteristics affect bus travel, and car trip characteristics but not bus trip characteristics affect rail travel. The cost elasticities lie between zero and one-half. Thus, the success of mass transit serving a strong downtown appears to depend on good access arrangements. This success can be confirmed with competitive linehaul speeds. The cost of travel appears to assume a minor role in choice of mode and tripmaking decisions. In the paper, a comparison is also made between the predictive performance of the models developed and that of a traditional transit model. The results indicate that the econometric models developed attain both lower percent error and lower variation of the error than the traditional model.
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    URL: http://dx.doi.org/10.1007/BF02428556
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  • 28
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    News (1973)
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    Transportation 2 (1973), S. 237-242 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02428560
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  • 29
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    Communication innovations, urban form and travel demand: Some hypotheses and a bibliography (1973)
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    Transportation 2 (1973), S. II 
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    ISSN: 1572-9435
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Hypotheses are developed about the effects of telecommunication advances on urban growth patterns and urban travel demands. It is suggested that CBD (central business district) office employment might decentralize if telecommunications could effectively substitute for short inter-office business trips and that job decentralization would alter journey-to-work patterns and the viability of certain public transit systems. Major research questions are raised and keyed to an extensive bibliography.
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    Consequences of service reduction in municipal transit: San Francisco’s muni (1973)
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    Transportation 2 (1973), S. II 
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    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Urban transit in the United States is going through a crisis of rising costs, increasing fares, falling patronage, and concomitant service reductions; typical of the pattern is San Francisco’s Municipal Railway, the agency in charge of all the City’s transit. From a basic fare of I 5c in 1969, two increases brought the fare to 25c by 1972, and cut sharply into a previously stable patronage. The “Muni”, in an effort to reduce costs and meet its budgeted deficit, attempted to reduce service by ten to fifteen percent. From an analysis of the data which could be obtained, it appears that neither efficiency not equity in the City would have been served by the proposed cutbacks. The analysis draws from a variety of sources and methods in exploring the interactions within the transportation system and within the city budget.
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    A direct demand model for downtown work trips (1973)
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    Transportation 2 (1973), S. I 
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    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract This article documents the development of a direct travel demand model for bus and rail modes. In the model, the number of interzonal work trips is dependent on travel times and travel costs on each available mode, size and socioeconomic characteristics of the labor force, and the number of jobs. In estimating the models’ coefficients constraints are imposed to insure that the travel demand elasticities behave according to the economic theory of consumer behavior. The direct access time elasticities for both transit modes are estimated to be approximately minus two, and the direct linehaul time elasticities approximately minus one. The cross-elasticities with respect to the travel time components are estimated to be less than the corresponding direct elasticities. In general, the time cross-elasticities are such that rail trip characteristics but not car trip characteristics affect bus travel, and car trip characteristics but not bus trip characteristics affect rail travel. The cost elasticities lie between zero and one-half. Thus, the success of mass transit serving a strong downtown appears to depend on good access arrangements. This success can be confirmed with competitive linehaul speeds. The cost of travel appears to assume a minor role in choice of mode and tripmaking decisions. In the paper, a comparison is also made between the predictive performance of the models developed and that of a traditional transit model. The results indicate that the econometric models developed attain both lower percent error and lower variation of the error than the traditional model.
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    Approaches to dynamic transport planning (1973)
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    Transportation 2 (1973), S. 245-280 
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    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Dynamic transport planning refers to the analysis of the problem of choice of implementation date of the construction or improvement of transport facilities. This analysis may also include consideration of stage construction or progressive improvements in quality and/or capacity over time, beginning from some relatively low standard. A transport facility is defined as a vehicle (e.g., automobile, airplane) or a supporting facility (e.g., highway, port). There appears at present to be a serious lack of any truly comprehensive evaluation of the essentials of the problem of choice of implementation date. It is the intent of the ensuing presentation to help to rectify that situation by introducing new concepts which structure the timing problem. The concepts are based on a suggested classification of future traffic and definitions of independent and indivisible facilities. In addition, volume of traffic and benefits of a transport facility are recognized to be dependent on calendar time and the facility's age. Presently, no uniform theoretical framework exists for establishing the optimal time for constructing new facilities or improving existing ones. A framework based on the aforementioned concepts is introduced. It distinguishes between the phasing of projects through time in the absence of budget constraints and this phasing in the presence of such restrictions. The specific procedures suggested in this paper for the analysis of the problem of choice of implementation date apply to any individual transport facility and tend to unify the concepts involved in dynamic transport planning. The article concludes with a survey of current approaches to dynamic transport planning and discusses these in the light of the above framework.
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    Editorial note (1973)
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    Transportation 1 (1973), S. 357-357 
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    Pocono conference — A step forward (1973)
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    Transportation 1 (1973), S. 359-363 
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    Appropriate relationships between comprehensive planning and transportation planning for the 1970s (1973)
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    Transportation 1 (1973), S. 403-418 
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    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Transportation planning and comprehensive planning have evolved as separate and frequently conflicting fields of professional activity. Current relationships between both types of planning are characterized by increasing frustration and declining effectiveness in the national pursuit of public development policy objectives. At the federal level, ambivalence toward comprehensive planning has hampered the development of planning capacity among state, metropolitan, and local agencies, while unquestioning pursuit of federal-aid highway construction has produced a monolithic transportation planning establishment operating at a single level of government and dominated by a single mode. The results of the current separatism characteristic of comprehensive planning and transportation planning are apparent in a pattern of local injunctions against highway projects, belated analyses of a comprehensive range of environmental and socio-economic factors inherent in highway construction, and widespread public demand for a reassessment of the true costs and benefits of highway systems. Organizational and structural prescriptions are offered to achieve more appropriate relationships between transportation planning and comprehevensive planning institutions in order to achieve the potential benefits of both through integrated action.
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    News and comments (1973)
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    Transportation 1 (1973), S. 455-455 
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    The state-of-the-art of “comprehensive” planning (1973)
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    Transportation 1 (1973), S. 365-377 
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    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract “Planning” occurs as a part of governmental operations wherever “decision-making” happens. For US metropolitan areas, the locuses of decision-making are multiple, ranging in scale from very small jurisdictions up through the hierarchy to state and federal levels, and in function from general governments to many special-purpose agencies — transportation, health care, education, etc. Almost all might affect or be affected by urban transportation decisions and actions. Since no one of these units of government is comprehensive in authority and activity, there is no single, centralized planning operation that is truly “comprehensive.” “Pluralistic planning” is increasingly trying to foresee and to accommodate the interactions among the various levels and functions. Instead of fragmenting, with the fragments pulled apart and insulated, we need to move toward partitioning, not merely to delimit boundaries but also to identify interfaces. This movement is hampered by the differentials in the development of the “state-of-the-art” of the technical planning process now used by the several levels and functional units of government. This is most advanced, and most effective, for small, homogeneous suburban jurisdictions primarily concerned with guiding and controlling physical development; it is in disarray in central cities trying to cope with social and economic problems as well as with physical deterioration; at the metropolitan scale it is highly developed technically but not very influential. There is a trend toward a network of planning activities that recognizes and facilitates interrelationships and interactions, both vertically among functional boundaries and horizontally across geographical-scale distinctions — a trend toward the “comprehensive” —but we have a very long way to go.
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    The state-of-the-art in urban transportation planning or how we got here (1973)
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    Transportation 1 (1973), S. 379-401 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract This paper traces the development of urban transportation planning in the United States, focusing particularly on the influence that three previous conferences -Sagamore (1958), Hershey (1962), and Williamsburg (1965) - have had on the course of this development. Included also are comments on the current state of the art of urban transportation planning and observations as to its future direction. The Federal-Aid Highway Act of 1934, which authorized the use of “1 $${\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}$$ percent funds” for highway planning is identified as the progenitor of urban transportation planning in the U.S., and two reports based on information developed by the highway planning surveys first funded under the 1934 Act, “Toll Roads and Free Roads” (1939) and “Interregional Highways” (1944), are credited with preparing the ground for much of the urban transportation planning that was to follow. The rapid development of home interview survey techniques in the late 1940's and the full-scale introduction of computer technology in the Detroit Area Transportation Study are noted, as is the work of the National Committee on Urban Transportation, which was initiated in 1954 under sponsorship of the Automotive Safety Foundation. In addition to its substantial technical contributions, the NCUT, through its success in mobilizing the cooperative efforts of virtually every major group concerned with urban transportation, stimulated significant gains in Federal-State-local relationships and paved the way for increased Federal aid to cities in solving their local transportation problems. The impact of the 1956 and 1962 Federal-Aid Highway Acts on urban transportation planning is assessed. The substantial contributions, of the Hartford, Sagamore, Hershey, and Williamsburg conferences are discussed, as are their shortcomings. It is noted that many of our present concerns — environmental impacts, relationships between transportation and land use, need for cooperation among all levels of government, the multi-modal nature of urban transportation, and the need for citizen involvement, to name a few — were incorporated in the provisions of either one or another of the Federal-Aid statutes in the 1950's and ‘60's or appear in the recommendations of the several conferences. That these matters still concern us today is given as evidence that planning has not fully lived up to its promise and responsibility, that more rather than less planning is needed, and that, above all, new leadership to pick up where the old has left off must soon assert itself.
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    Reviews (1973)
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    Transportation 1 (1973), S. 461-474 
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    Zum Aufsatz K. W. John: Ein Ingenieurverfahren zur rechnerischen Abschätzung von Festigkeit und Verformbarkeit regelmäßig geklüfteten Felsens, erschienen in Vol. 1, No. 4 (1969) (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 61-64 
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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    Book reviews (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 71-74 
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    Ausbesserung und Umbau von Eisenbahntunneln während des Betriebes (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 112-116 
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    ISSN: 1434-453X
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Summary Repair and Reconstruction of Railway Tunnels During Traffic Maintenance The reconstruction and repair of railway tunnels on lines of the Czechoslovak State Railways (CSD) requires — especially on main lines with high traffic density — special kinds of solution. New, progressive methods enable a considerable increase in efficiency and much shorter working times. The method of tunnel reconstruction during railway traffic maintenance is based on a modification of the ring tunnelling system. This system takes advantage of the natural properties of the rock mass for the stabilization of the expanded tunnel tube. For a successful application of this kind of renovation a profound knowledge of the laws of origin and effects of rock pressures (their magnitude and direction) is absolutely necessary, and also an exact geotechnical prospection to reliably ascertain the properties of the rock mass. The article is dealing with the reasons for renovations, with a new working method for tunnel reconstruction and its techniques. A completely mechanized working train can be applied for the renovation works.
    Notes: Zusammenfassung Ausbesserung und Umbau von Eisenbahntunneln während des Betriebes Die Ausbesserung und der Umbau von Eisenbahntunneln auf den Strecken der Tschechoslowakischen Eisenbahnen (CSD) erfordert, namentlich auf Strecken mit hoher Verkehrsdichte, Lösungen ganz besonderer Art. Neue, fortschrittliche Methoden können dabei eine wesentliche Leistungssteigerung und erheblich kürzere Baufristen ermöglichen. Die hier behandelte Methode der Tunnelerneuerung unter Aufrechterhaltung des Betriebes beruht auf einer Modifizierung des Ringausbausystems. Diese Bauart nützt die natürlichen Eigenschaften des Gebirges zur Stabilisierung des aufgeweiteten Tunnelhohlraumes aus. Voraussetzung zur erfolgreichen Anwendung dieser Erneuerungsart ist eine gründliche Kenntnis der Gesetze der Entstehung und Wirkung der Gebirgsdrücke (Größe, Wirkungsrichtung) und eine genaue geotechnische Aufnahme, welche die Eigenschaften des Gebirges verläßlich feststellt. Der Aufsatz behandelt die Gründe für Erneuerungsarbeiten, eine neue Arbeitsmethode zum Tunnelumbau und deren Techniken. Bei den Erneuerungsarbeiten kann eine komplett mechanisierte Arbeitsgarnitur auf Waggons angewendet werden.
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    Book reviews (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 120-122 
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    Spannungserscheinungen über Stollen in vorgepreßten sandigen Kiesen (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 173-175 
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Summary Stress Phenomena over Galleries in Prestressed Sandy Gravel The outlets of an airraid shelter in prestressed gravel have been observed to widen like a trumpet due to the spalling of stressed shales. Distressing at the tunnel outlet can lead to dangerous collapse of the tunnel entrance.
    Notes: Zusammenfassung Spannungserscheinungen über Stollen in vorgepreßten sandigen Kiesen Die Ausmündungen einer Luftschutzanlage, die in vorgepreßten Kiesen angelegt war, erweitern sich durch das Abplatzen von Entspannungsschalen trompetenförmig. Die Spannungen, die am Stollenmundloch herrschen, führen oft zu Zusammenbrüchen am Stollenbeginn.
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    Book reviews (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 177-180 
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    An experiment proving that dilatancy is a pervasive volumetric property of brittle rock loaded to failure (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 181-188 
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Experimenteller Nachweis zur Dilatanz als volumenbezogene Eigenschaft spröder, bis zum Bruch belasteter Körper. Dilatanz, d. h. relative Volumenvergrößerung im Vergleich zur elastischen Zusammendrückung, ist ein Phänomen, welches häufig bei der Druckbeanspruchung von Gesteinen beobachtet werden kann. Diese Erscheinung ist für das Verständnis der Bruchvorgänge von Gesteinen und deren Anwendung auf geologische und technische Probleme von beträchtlicher Bedeutung. Ein Großteil der bisherigen Untersuchungen zu dieser Frage wurde an kleinen zylindrischen Probekörpern mit großem Verhältnis von Oberfläche : Volumen durchgeführt. Bei diesen Versuchen wurden meist Dehnmeßstreifen an die Oberfläche der Probekörper geklebt. Demnach kann die Möglichkeit nicht ausgeschlossen werden, daß die beobachtete Dilatation infolge abnormaler Oberflächenverformungen ein Oberflächenphänomen ist. Messungen der Dilatation an der Innen- und Außenseite eines hohlen zylindrischen Probekörpers während der Druckbeanspruchung in einem homogenen Spannungsfeld bilden eine Möglichkeit, diese Ungewißheit zu beseitigen. Im Falle einer oberflächengebundenen Dilatation würde es zu einer relativen Verkleinerung des inneren Querschnittes des hohlen Probekörpers kommen, während die Dilatation der Außenseite mit der Verformung anwachsen würde. Demgegenüber würde es im Falle der Dilatation als einer volumetrischen Eigenschaft zu einer ähnlichen relativen Vergrößerung des inneren Querschnittes des hohlen Probekörpers und des Probekörpers selbst kommen. Die Experimente an hohlen zylindrischen Probekörpern aus Quarzit zeigen, daß die Dilatanz ein volumetrisches Phänomen ist.
    Abstract: Résumé Expérience prouvant que la dilatance est répartie dans tout le volume des roches fragiles chargées jusqu'à la rupture. La dilatance, c'est-à-dire l'augmentation de volume par rapport à la déformation élastique en compression, se manifeste souvent quand on comprime des échantillons de roche jusqu'à la rupture. Ce phénomène a une importance considérable pour la compréhension des processus de rupture des roches, et pour les applications aux problèmes géologiques et géotechniques. La plupart des essais ont été faits à ce jour sur de petits échantillons cylindriques, dont la surface est grande par rapport au volume, le plus souvent au moyen de jauges à résistance collées sur la surface de l'échantillon. Il reste la possibilité que la dilatance mesurée ne soit qu'un phénomène superficiel, dû à des déformations anormales de la surface. Pour lever cette incertitude, on peut mesurer la dilatance à la fois sur la surface externe et sur la surface interne de cylindres creux soumis à des contraintes homogènes: une dilatance superficielle produirait une diminution de la section du trou et une augmentation de la section totale, tandis qu'une dilatance répartie dans tout le volume produirait des augmentations de section similaires. Les essais sur cylindres creux de quartzite montrent que la dilatance est un phénomène réparti dans tout le volume.
    Notes: Summary An Experiment Proving that Dilatancy is a Pervasive Volumetric Property of Brittle Rock Loaded to Failure. Dilatancy, that is, volumetric expansion relative to the compression resulting from elastic deformation is often observed in the compression of rock specimens to failure. This phenomenon is of considerable importance to the understanding of the processes of rock failure and in their application to geological and engineering problems. Most of the observations to date have been made on small cylindrical specimens of rock, with a high surface area to volume ratio; frequently by means of resistance strain gauges cemented to the surface of the specimen. The possibility of the measured dilatancy being a superficial phenomenon due to anomalous surface deformations cannot be excluded. Measurements of dilatant deformation on the inside and outside of hollow cylindrical specimens during compression under homogeneous stresses provide a means of resolving this uncertainty. Superficial dilatancy would result in a relative diminution of the cross-section of the hole as that of the outside of the specimen increases with deformation; whereas pervasive volumetric dilatancy would result in similar relative increases in the cross-section of both the hole and the specimen. Experiments on hollow cyclindrical specimens of quartzite show that dilatancy is a pervasive volumetric phenomenon.
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    Aufgaben der Felsmechanik bei neuzeitlichen Tunnelrekonstruktionen (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 245-248 
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    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Summary The Function of Rock Mechanics in Modern Tunnelling. For modern methods of tunnel driving it is necessary to apply new procedures of geological investigations including large-scale rock mechanics tests. This view holds equally for reconstruction projects. In addition to the mechanical properties of the rock masses it is necessary to determine the intrinsic stresses in the rock and in the tunnel lining, the thickness of the inelastic (relaxed) zone around the tunnel, as well as the possibility of grouting and anchoring.
    Abstract: Résumé Application de la mécanique des roches aux méthodes modernes de construction et de reconstruction des tunnels. Dans la technique moderne des tunnels il est nécessaire d'appliquer de nouvelles méthodes de reconnaissance comportant davantage d'essais de mécanique des roches. La même exigence est valable pour la reconstruction des tunnels. Outre les propriétés mécaniques du massif rocheux, on déterminera aussi les contraintes dans le rocher et dans le revêtement, l'épaisseur de la zone décomprimée et même les possibilités d'injection et de boulonnage.
    Notes: Zusammenfassung Aufgaben der Felsmechanik bei neuzeitlichen Tunnelrekonstruktionen. Für die neuzeitliche Tunnelbauweise müssen neue Erkundungsmethoden mit erweitertem Umfang felsmechanischer Prüfungen angewandt werden. Diese Forderung soll ebenso bei Rekonstruktionen erfüllt werden. Außer den mechanischen Eigenschaften werden auch die innere Spannung im Felsmassiv und in der Ausmauerung, die Mächtigkeit der gelockerten Zone sowie die Injektions- und Verankerungsmöglichkeit bestimmt.
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    A theory for the shear strength of rockfill (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 205-222 
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Eine Theorie für die Scherfestigkeit von Gröbstkornschüttungen (Steinbrockenschüttungen). Das vorhandene Wissen vom Wesen der Scherfestigkeit von Gröbstkornschüttungen sowie davon, wie und warum sie verschieden groß ist, ist unzulänglich. Es wird gezeigt, daß die Scherfestigkeit durch den entscheidenden Reibungswinkel von Gestein auf Gestein (Φ u ), den Hohlraum-Quotienten (e) und den Bruch von Teilchen (B) bestimmt wird, und daß sie von dem Quotienten aus größter und kleinster Hauptnormalspannung abhängt. Bei der Anwendung statistischer Methoden, welche mit einigen einfachen, auf Versuchen beruhenden Annahmen kombiniert werden, können Formeln für die Scherfestigkeit von Gröbstkornschüttungen abgeleitet werden. Theoretische Ergebnisse werden mit den Ergebnissen von Triaxialversuchen im Labor verglichen.
    Abstract: Résumé Une théorie pour la résistance au cisaillement des enrochements. Les connaissances actuelles sur la signification de la résistance au cisaillement des enrochements, et sur le pourquoi et le comment de ses variations sont insuffisantes. On montre que la résistance au cisaillement dépend de l'angle de frottement élémentaire rocher sur rocher (Φ u ), de l'indice des vides (e) et de la rupture des blocs (B), et qu'elle varie avec le rapport des contraintes principales extrêmes. Grâce à des méthodes statistiques et à quelques hypothèses simples basées sur un travail expérimental, on obtient des formules donnant la résistance au cisaillement des enrochements. Les résultats théoriques sont comparés avec les résultats d'essais triaxiaux au laboratoire.
    Notes: Summary A Theory for the Shear Strength of Rockfill Existing knowledge of the meaning of the shear strength of rock fill, and of how and why it varies is inadequate. Shear strength is shown to be controlled by the basic angle of friction of rock on rock (Φ u ), the voids ratio (e) and the particle breakage (B) and to be dependent on the ratio of major to minor principal stresses. Using statistical methods combined with some simple assumptions based on experimental work formulas are derived for the shear strength of rock fill. Theoretical results are compared with the results of laboratory triaxial tests.
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    Determination of the post-failure behavior of brittle rock using a servo-controlled testing machine (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 189-204 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Bestimmung des Verhaltens von sprödem Gestein nach dem Bruch mittels eines servogesteuerten Prüfgerätes. Es wird über ein neues Verfahren berichtet, den Bruch spröden Gesteins zu kontrollieren, nachdem seine maximale Bruchlast überschritten ist. Dieser Bereich ist im allgemeinen der Untersuchung nicht zugänglich, da bei der Verwendung herkömmlicher Belastungs-Maschinen vom Belastungs-System ein Überschuß an Energie frei wird, der für eine explosionsartige Zerstörung des Gesteins verantwortlich ist. Bei dem hier beschriebenen Verfahren wird das Freiwerden der im System gespeicherten Energie durch ein hochfrequentes, elektronisch geregeltes Servo-System in Verbindung mit einer Hydraulik mit kurzer Verzögerungszeit kontrolliert. Es wird dabei der Gesteinsprobe zu jedem Zeitpunkt nur so viel Energie zugeführt wie zur Aufrechterhaltung für den stabilen Bruch notwendig ist. Die theoretische Betrachtung des Systems zeigt, daß die Bedingung für den stabilen Bruch entlang der Post-Failure-Charakteristik durch die Fähigkeit des Belastungs-Systems bestimmt wird, rasch zu entladen. Der Begriff einer ‚dynamischen Steife‘ wird definiert. Für genügend kleine Verformungsgeschwindigkeiten und kurze Verzögerungszeiten des Servo-Systems kann der Bruch auch dann kontrolliert werden, wenn die Neigung der Post-Failure-Kurve sich sehr großen Werten (− ∞) nähert. Der Versuchsaufbau und die Versuchsdurchführung werden beschrieben und es werden einige Post-Failure-Kurven für Tennessee Kalkstein unter einachsiger und zweiachsiger Druckbeanspruchung wiedergegeben, wobei das neue Verfahren verwendet wurde.
    Abstract: Résumé Détermination du comportement après la rupture des roches fragiles au moyen d'une machine d'essai asservie. On présente un nouveau système pour contrôler la rupture des roches fragiles lorsque leur limite de rupture est dépassée. En général, il n'est pas possible d'étudier le comportement des roches dans ce domaine. L'emploi d'une machine d'essai traditionnelle libère inévitablement lorsque la limite de rupture est dépassée, un excès d'énergie qui provoque une violente désintégration de la roche. L'appareil, décrit dans cet article, contrôle la libération de l'énergie accumulée dans le système à l'aide d'un servosystème électronique à haute fréquence règlant un mécanisme hydraulique à temps de réponse très court. De cette facon, il est possible de limiter l'énergie transmise à la roche à la quantité nécessaire pour développer une rupture stable. L'analyse théorique du système révèle que la possibilité d'obtention d'une rupture stable, la limite de rupture ayant été dépassée, est déterminée par la rapidité avec laquelle le système hydraulique peut se décharger. Le concept de rigidité dynamique est défini. Si les vitesses de déformation sont petites et si les temps de réponse du servosystème sont courts, il est possible de contrôler la rupture, même lorsque la pente du diagramme effort-déformation tend à devenir infiniment raide, la limite de rupture étant dépassée. Le dispositif expérimental et l'exécution d'un essai sont décrits. Quelques diagrammes complets (y compris la partie descendante) d'un marbre du Tennessee pour les cas de compression simple et de compression double utilisant ce nouveau système sont présentés.
    Notes: Summary Determination of the Post-Failure Behavior of Brittle Rock Using a Servo-Controlled Testing Machine. The use of the servo-controlled testing machine to control fracture when a rock specimen is deformed beyond its peak strength is discussed. This region of deformation can not usually be examined because excess energy released by the loading system produces rapid disintegration of the specimen. In the test method described the energy release is controlled by a high frequency electronic servo-control system acting in combination with a hydraulic system of very short response time. The control causes the excess energy to be withdrawn before it can be released into the disintegrating specimen, by removing pressurized fluid from the hydraulic system. Theoretical considerations reveal that the condition for controlled fracture is determined by the ability of the hydraulic loading system to unload rapidly. This may be expressed in terms of a ‘dynamic stiffness’,K r , of the hydraulic system. For sufficiently small deformation rates and short servo-control response times the fracture process can be controlled, even though the unloading slope of the stress-strain curve of the rock specimen tends to become infinitely steep. The experimental technique is described in detail and some results obtained in studying the post-failure behavior of Tennessee Marble under uni-axial and bi-axial compression using the new system are presented.
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    Berichtigung (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 256-256 
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    Zum Aufsatz H. Malina (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 249-256 
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    Hydrofracture mechanisms in rock during pressure grouting (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 21-41 
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    ISSN: 1434-453X
    Keywords: soil mechanics ; rock mechanics ; hydrofracture ; permeation grouting ; seepage force ; fracture initiation ; fracture propagation ; energy balance
    Source: Springer Online Journal Archives 1860-2000
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    Description / Table of Contents: Zusammenfassung Brucherscheinungen im Fels bei Verpreβarbeiten. In der Arbeit wird der grundlegende Mechanismus untersucht, welcher bei Verpreßarbeiten in Fels und geschichtetem Boden zur Einleitung und Ausbreitung von Brüchen führt. Frühere Untersuchungen des Bruchbeginns stützten sich im wesentlichen auf vereinfachte Modelle, in denen der Untergrund als undurchlässiges Kontinuum angesehen wird, das entweder elastisch ist oder der Mohr-Coulombschen Bruchbedingung genügt. Die neue Methode berücksichtigt dagegen eine Porosität oder Klüftung des Untergrundes durch Ansatz der vom strömenden Medium auf das Gebirge ausgeübten Belastung. Diese Belastung wird aufgeteilt in einen Druckverlust an der Bohrlochwand (gleich ParameterN mal Verpreßdruck) und die entsprechende, über den gesamten durchströmten Bereich verteilte Belastung. Die Untersuchung der Bruchausbreitung geht von der Spannungsermittlung um ein Bohrloch in einem elastischen Kontinuum aus, wobei in der sich ausbreitenden Bruchzone um das Bohrloch herum nichtelastisches Material angenommen wird, das dem Mohr-Coulombschen Bruchkriterium genügt. Zur Ergänzung dient eine Energie-Betrachtung, bei der die von der Injektionspumpe abgegebene Energie gleichgesetzt wird der im Untergrund gespeicherten Energie und der aufgewendeten Brucharbeit.
    Abstract: Résumé Les mécanismes de la fracturation hydraulique dans les roches pendant les injections sous pression. Le mémoire examine les mécanismes fondamentaux qui gouvernent l'initiation des ruptures dans les roches et les sols stratifiés, au cours des injections et leur propagation dans les massifs. Les analyses antérieures de l'initiation de la rupture, se sont concentrées sur des modèles simplifiés où l'on considérait la roche comme un milieu élastique et imperméable, ou comme un milieu de Mohr-Coulomb. La présente méthode admet que le massif est poreux ou fissuré, en considérant l'action des forces de percolation engendrées par le gradient de pression interstitielle. Cette action est quantifiée par un paramètreN, tel que le rapport de la force du liquide employée à dilater le forage d'injection, à celle employée pour forcer le coulis à travers les vides soitN/(1—N). L'analyse de la propagation des ruptures se base sur l'analyse des contraintes autour d'un forage dans un milieu élastique, alors que la zone de la rupture qui se propage autour du forage est représentée par un milieu non-élastique admettant le critère de rupture de Mohr-Coulomb. Cette analyse est complétée par une approche énergétique, où l'énergie qui est fournie au massif par la pompe d'injection est égalée à l'énergie emmagasinée dans la roche et à l'énergie de rupture.
    Notes: Summary Hydrofracture Mechanisms in Rock During Pressure Grouting. The paper examines the basic meachnisms controlling the initiation of fractures in rocks and layered soils during pressure grouting, and their subsequent propagation into the ground mass. Previous analyses of fracture initiation have tended to concentrate on simplified models in which the ground is treated as an impervious elastic or Mohr-Coulomb continuum. The present method allows for the porous or fissured nature of the ground by considering the effect of seepage forces induced by the pore pressure gradient. The effect is quantified by use of a parameterN such that the ratio of fluid force used in expanding the injection hole, to that used in forcing fluid through void spaces, isN to (1—N). Analysis of hydrofracture propagation is based on stress analysis of a borehole in an elastic continuum, the propagating fracture zone around the borehole being represented as a non-elastic material governed by the Mohr-Coulomb failure criterion. This is supplemented by an energy approach which equates the energy supplied to the ground from the injection pump, with the energy stored in the ground and the energy necessary to fracture it.
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    International Centre for Mechanical Science (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 188-188 
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    On the origin of sheet jointing (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 163-187 
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    Description / Table of Contents: Zusammenfassung Über den Ursprung von Plattenklüften Obwohl die tiefliegenden, ungefähr zur Geländeoberfläche parallel verlaufenden, als Plattenklüfte bezeichneten Brüche verschiedentlich der Sonneneinstrahlung u. ä., weitgehend aber der Entlastung durch Erosion allein zugeschrieben werden, liegt eine Reihe von Argumenten vor, die Zweifel an dieser Hypothese aufkommen lassen. Es gibt für die Annahme einer Druckentlastung als Ursache für diese Entscheidung keinen mechanisch verständlichen Grund. Plattenklüfte sind deutlich in Gesteinen ausgebildet, die nie eine größere Überlagerung hatten. Domartige Inselberge oder Bornhardts, bei denen Plattenklüftung weit verbreitet und gut entwickelt ist, scheinen ihre Formresistenz dadurch zu sichern, daß ihre Klüftung unter Kompression stand. Dies widerspricht einer Erklärung als Effekt einer radialen Ausdehnung oder einer Dehnungsspannung. Einige Inselberge sind von Gesteinen unterlagert, die eine Plattenklüftung aufweisen, welche nicht parallel zum Bergprofil verläuft, sondern gegen die Hänge des Inselberges einfällt. Vieles deutet darauf hin, daß die Plattenklüftung nicht als Folge einer Druckentlastung, sondern als Folge einer Druckbelastung zu deuten ist. Plattenklüfte und druckbedingte Verwerfungen treten häufig zusammen auf. Messungen geben Zeugnis von hoher Druckbelastung in Bergwerken und Steinbrüchen. Druckbelastung scheint ein physikalischer Parameter für die Ausbildung von Plattenklüftung zu sein. Auch viele morphologische Merkmale, die mit Plattenklüftung verbunden sind, weisen auf Kompression hin. Eine solche macht insbesondere die Formresistenz der Inselberge verständlich.
    Abstract: Résumé Sur l'origine des joints en nappe L'origine des fractures profondes, dites joints en nappe, qui sont à peu près parallèles à la surface de la terre, a été attribuée à plusieurs causes, dont l'insolation, l'altération chimique, l'injection plutonique, l'expansion métasomatique et le soulèvement vertical. Ces idées peuvent fournir des explications partielles, ou bien elles peuvent éclaircir des cas particuliers, mais en tant qu'explications générales elles ne sont pas acceptables. La présence des joints en nappe est attribuée le plus souvent à l'allègement par l'érosion uniquement, au point que certains géologues les désignent sous le nom de joints d'allègement. Toutefois de nombreux témoignages et discussions mettent cette hypothèse en doute. Aucune raison mécanique valable ne mène normalement au développement des fractures par suite de la décompression. Les joints en nappe se montrent aussi bien dans des couches qui n'ont jamais été profondément enfouies. Les inselbergs à dôme ou bornhardts, sur lesquels les joints en nappe se manifestent amplement, paraissent subsister en raison de la compression de leurs joints; il s'ensuit que le développement de ces joints en nappe ne peut pas être attribuable à l'expansion radiale ou au travail à la tension. Quelques-uns des inselbergs ont pour base des roches qui ont été soumises à l'influence des joints en nappe qui ne sont pas parallèles au profil de la colline mais qui, au contraire, s'inclinent jusque dans les pentes des résiduels. D'autre part, divers témoignages et discussions font croire que les joints en nappe ont pu évoluer par la suite du travail à la compression. Certaines failles sont causées par la compression, et d'ordinaire les failles et les joints en nappe se produisent dans des conditions uniformes; il existe des observations de mesures de compression très considérable dans beaucoup de mines et carrières; le travail à la compression paraît matériellement capable de produire ces joints; de nombreuses caractéristiques morphologiques associées aux joints en nappe se rapportent à la compression. Ce qui s'explique surtout, c'est la conservation des inselbergs à dôme. Cette hypothèse propose donc que les joints en nappe déterminent les configurations de la surface terrestre, et non vice versa.
    Notes: Summary On the Origin of Sheet Jointing Although the deep-seated fractures which run approximately parallel to the land surface and are known as sheeting joints are widely attributed to erosional offloading alone, there is much evidence and argument which casts doubt on this hypothesis. There is no sound mechanical reason why fractures should normally develop as a result of decompression. Sheet jointing is well developed in strata which have never been deeply buried. The domed inselbergs on which sheet jointing is commonly displayed appear to survive by virtue of their joints being compressed, which is inconsistent with the sheet jointing developing through radial expansion or tensional stress. A few inselbergs are underlain by rocks affected by sheeting joints which are not parallel to the hill profile but on the contrary dip into the slopes of the residuals. These and other types of evidence and lines of argument point to sheeting joints having developed under compressive stress. The joints determine the shape of the land surface and not vice versa.
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    „Tunneltagung 1973– in Spindbruv Mlyn, ČSSR (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 249-249 
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    Notes (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 65-70 
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    Berichtigung (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 74-74 
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    Notes (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 118-119 
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    On the rheology of rock creep (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 138-145 
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    Keywords: creep ; rheology ; stress-strain relation
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    Description / Table of Contents: Zusammenfassung Über die Rheologie der Kriecherscheinungen im Gestein Es wird gezeigt, daß die üblichen linearen rheologischen Modelle nicht genügen, um das Kriechverhalten von Gestein zu beschreiben; zu diesem Zwecke muß eine neue rheologische Gleichung postuliert werden. Eine derartige Gleichung wird mittels eines Korrespondenzprinzips zu einem Kelvin-Körper abgeleitet. Sie ist nichtlinear und hat die folgende Form: $$\sigma ' = 2\eta \ddot \varepsilon + \beta \dot \varepsilon ^2 $$ wobeiε die Schiebung,σ die Schubspannung, ein Punkt Ableitung nach der Zeit undβ, η Konstanten bedeuten. Einige Folgerungen aus dieser Gleichung sind dargestellt.
    Abstract: Résumé Sur la rhéologie du fluage des roches Il est démontré que les modelès rhéologiques ordinaires (linéaires) ne suffisent pas pour décrire le caractère du fluage des roches. Dans ce but il faut postuler une nouvelle équation analytique. Une telle équation est déduite en utilisant un principe de correspondance avec un matériau de Kelvin. Elle est non-linéaire et s'écrit comme suit: $$\sigma ' = 2\eta \ddot \varepsilon + \beta \dot \varepsilon ^2 $$ où 2ε est l'angle de glissement,σ la contrainte de cisaillement,η etβ sont des constantes et un point signifie la différentiation par rapport au temps. Quelques conséquences de la nouvelle équation sont démontrées.
    Notes: Summary On the Rheology of Rock Creep The standard (linear) rheological models and the experimental evidence on rock creep are reviewed and it is shown that a new rheological equation (“stress-strain relation”) must be found to describe the most common behavior of rocks. Such a rheological equation is deduced by a correspondence principle with a Kelvin material and is presented. It is nonlinear and of the form: $$\sigma ' = 2\eta \ddot \varepsilon + \beta \dot \varepsilon ^2 $$ whereε is shear strain,σ shear stress, dot denotes time derivation, andη andβ are constants. Some consequences of this equation are discussed.
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    Der Bau von Druckstollen durch die Schwäbische Alb für die 2. Fernleitung der Bodensee-Wasserversorgung (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 146-166 
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    Description / Table of Contents: Summary Driving of Pressure Tunnels in the Suabian Alb for the Second Pipe Line of the Lake of Constance Scheme Within the last 2 1/2 years about 27.5 km of pressure tunnels have been driven for the second potable water pipeline from the Lake of Constance into the dry areas in the middle of Baden-Württemberg, South-West Germany. Not less than 18 km of these were driven by mechanical moles. Three different types of full-face boring machines with varying diameters were used in all kinds of rock in the White Jura and also in the upper part of the Brown Jura. The hard rock formations of the Upper White Jura were driven by a Demag-Mini-Mole of very compact design in the so-called Southern Pressure Tunnels. The total length of these 5 tunnels amounted to 3.4 km, the bored diameter was 2.15 m, the average rate of driving being 10 m per day, the maximum 32 m per day and 304 m per month. The crushing-strength of the rock was found to be 1800–2100 kp/cm2. About 60% of the 24 km long Alb Pressure Tunnel was driven by two moles in middle-hard and soft rock-formations. From the bottom of the 120 m deep Burladingen-Shaft, a Robbinsmole was set in operation in a southerly direction. This machine was not a new one, but it operated very successfully on a 4.7 km long tunnel section, the drilling diameter being 2.7–2.9 m. The following rates of progress were recorded: Rate in the soft marl of White Juraα (compressive strength about 600–800 kp/cm2), average 31.2 m per day, maximum 55 m per day, 860 m per month; in the upper part of White Juraα with some hard rock layers of varying thickness, average 23.3 m per day, maximum 42.0 m per day and in the middle-hard formations of the White Juraβ (horizontal stratified limestone, compressive strength 1600 kp/cm2), average 17.2 m per day, maximum 27.0 m per day. About 9 km in soft ground of the Upper Brown Jura (Ornatenton, compressive strength 400–600 kp/m) were driven by a mole built by Krupp. Despite the fact that the tunnel suffered from falls due to the geological weakness of the strata, and had therefore to be supported by bolting and sprayed concrete immediately after driving, the average rate of driving was 22.5 m per day and 500 m per month. Maximum values of 64 m per day and 847 m per month were recorded. A lot of experience was gained on mechanical driving, especially as there was occasion for direct comparison between these new driving methods and traditional blasting. With mechanical driving, the overbreak factor was limited to 0–3 percent against the about 20–30 percent overbreak observed in the rock formations described above, the amount of support required being only about 1/3 in the mechanical-driven tunnel-sections. The tunnels are to be completed in summer 1970.
    Notes: Zusammenfassung Der Bau von Druckstollen durch die Schwäbische Alb für die zweite Fernleitung der Bodensee-Wasserversorgung Für die zweite Trinkwasserfernleitung vom Bodensee in die Wassermangelräume Baden-Württembergs sind in den letzten Jahren 27,5 km Stollen aufgefahren worden. Hievon wurden nicht weniger als 18 km unter Einsatz dreier Stollenbohrmaschinen verschiedenen Fabrikates und Durchmessers in stark unterschiedlichen Gebirgsarten bezwungen. Nach einer Skizzierung der allgemeinen Projektzusammenhänge wird zunächst über den ersten Einsatz einer von der Demag gebauten Hartgesteinsmaschine in den sogenannten Südstollen berichtet. Diese Bohrmaschine hat etwa 3,4 km im oberen Weißjura durchfahren bei einer mittleren Leistung von 10 m/d, einer maximalen Auffahrung von 32 m/d und einer höchsten Monatsleistung von 304 m. Nahezu 60% des 24 km langen Albstollens, vornehmlich die mittelharten und milden Strecken im Nordtrum, sind mit 2 Vortriebsmaschinen durchörtert worden. Von einem 120 m tiefen Schacht aus kam ein von Robbins gebautes, aus den USA gebraucht bezogenes Gerät zum Einsatz, der sehr erfolgreich verlief. In den nahezu durchwegs standfesten 4,7 km langen Strecken wurden folgende Auffahrergebnisse erreicht: Im weichen Mergel des Weißjuraα i. M. 31,2 m/d, max. 55 m/d und 860 m/Monat; im oberen Weißjuraα, der mit harten Kalksteinbänken wechselnder Mächtigkeit durchzogen war, i. M. 23,3 m/d und max. 42,0 m/d; im Weißjuraβ, die mittelharten „Wohlgeschichteten Kalke“, i. M. 17,2 m/d, max. 27 m/d. Nahezu 9 km im weichen, aber größtenteils nicht standfesten Ornatenton, wurden mit einer durch Krupp gebauten Stollenfräse in 1 1/2 Jahren vorgetrieben. Die Auffahrleistung war durch die immer sofort notwendige Torkretabsicherung und -absiegelung stark beschränkt. Dennoch war die mittlere Leistung von 22,5 m/d und knapp 500 m/Monat beachtlich, noch mehr die Maximalwerte mit 64 m/d bzw. 847 m/Monat. An Hand der beim Albstollen und anderen Maschineneinsätzen gewonnenen Erfahrungen wird auf Konstruktion der Maschinen generell eingegangen und der mechanische Vortrieb als solcher besprochen. Vor- und Nachteile werden z. T. an Hand von Erfahrungswerten herausgearbeitet.
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    Gedanken eines Baugeologen zur Beanspruchung des Gesteins durch moderne Stollenbau- und Abbaumethoden (1970)
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    Rock mechanics and rock engineering 2 (1970), S. 242-244 
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Summary Some Reflections on Rock Stresses Due to Modern Tunnelling and Mining Methods. The safety of work crews at the tunnel face can be increased by blasting shorter rounds, since in this case the unprotected working room is shorter. Record performances in tunneldriving demand the highest degree of tunnel protection, otherwise the owner has to pay more for protection and preservation. Thus, the tunnelling schedule should be designed to allow as much time as realistically possible for completion of the project. In this way the work can be carried out with reasonable, but not excessive haste. Removal of material leads to discharge and ground control problems. This becomes clearly apparent with modern rapid tunelling methods. If the ground is plastic, it swells up in front of the face and leads to undesirable open joints which cause rock falls and, in extreme cases, collapse.
    Notes: Zusammenfassung Gedanken eines Baugeologen zur Beanspruchung des Gesteins durch moderne Stollenbau- und Abbaumethoden. Kürzere Schüsse erhöhen die Sicherheit der Mannschaft vor Ort, weil der ungesicherte Arbeitsraum kürzer ist. Rekordleistungen im Stollenvortrieb verlangen höchste Leistungsfähigkeit der Stollensicherung, sonst zahlt der Bauherr größere Sicherungs- und Erhaltungskosten. Aus diesem Grunde sollte der Stollenbau, wenn er nicht den Terminplan beherrscht, möglichst große Baufristen erhalten, damit rasch, aber nicht extrem rasch gearbeitet wird. Große Materialentnahmen führen zu Entlastungen des Untergrundes, die sich bei der Schnelligkeit des modernen Abbaues deutlich bemerkbar machen. Ist der Untergrund plastisch, dann quillt er vor der Abbauwand hoch und verursacht in ihr technisch unangenehme offene Klüfte, Steinfall und im Extrem auch Zusammenbrüche.
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    Stress distribution and rock fracture zones in the roof of longwall face in a coal mine (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 1-19 
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    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Spannungsverteilung und Bruchzonen in Firste und Ulmen von Strebbauen. Eine zweidimensionale Spannungsanalyse mittels der Finite-Element-Methode wurde benützt, um die Spannungsverteilung und die Entwicklung von Bruchbildungsvorgängen im Firstgestein am Streb einer Kohlengrube zu studieren. Bei der Ermittlung von Untergrundverschiebungen und der Anwendung einer „Inverse Approximation“-Technik wurden anstelle von Laborversuchsmessungen effektive Materialeigenschaften verwendet. Die Ausgangsspannungen im Fels um die Öffnung herum wurde ausfindig gemacht und drei Ansätze der Mohr-Coulombschen Bruchtheorie wurden zur Errechnung der entsprechenden Sicherheitsfaktoren benützt. Entsprechend den Druck- und Zugfestigkeiten wurden vier Zonen von Progressiven Brüchen festgestellt. Die wirksamen Elastizitätsmoduli für diese Zonen wurden mittels eines Verfahrens zur Bestimmung der Restelastizität errechnet. Schließlich wurden Kriterien für die Festigkeit von gebrochenem Gestein eingeführt und die Standsicherheitsfaktoren für den unmittelbaren Firstbereich errechnet. Aufgrund der Hauptspannungsrichtungen in den Zonen größter Schubspannungen wurden die Richtungen der Bruchlinien ermittelt.
    Abstract: Résumé Distribution des contraintes et zones de fracture en roche autour de la cavité d'une longue taille. Une analyse des contraintes par la méthode des éléments finis a été faite pour étudier la distribution des contraintes et le développement du processus de fracturation du toit rocheux d'une longue taille dans une mine de charbon. Les propriétés effectives du matériau furent utilisées au lieu de celles qu'on mesure par des essais de laboratoire. Elles furent obtenues à partir des enregistrements des déplacements souterrains et par une technique d'approximation inverse. Les contraintes initiales autour des cavités ont été trouvées et trois variantes de la théorie de la rupture de Mohr-Coulomb furent utilisées pour calculer les coefficients de sécurité correspondants. Quatre zones de rupture progressives furent définies d'après le rapport résistance à la compression/résistance à la traction. Le module élastique effectif de ces zones fut calculé au moyen d'une approche par résidu élastique. Finalement le critère de stabilité des roches rompues fut introduit et les facteurs de stabilité furent calculés pour la zone immédiate du toit. Les directions des lignes de fracture du toit furent prévues à partir des directions des contraintes principales dans la zone de cisaillement maximal.
    Notes: Summary Stress Distribution and Rock Fracture Zones in the Roof of Longwell Face in a Coal Mine. A two-dimensional finite element method of stress analysis was used to study the stress distribution and development of the fracturing process within the roof rock of a longwall face in a coal mine. Effective material properties were used instead of those measured in laboratory tests by employing underground displacement data and an inverse approximation technique. Initial stresses in the rock around the opening were found and three variations of the Mohr-Coulomb failure theory were used to calculate the corresponding safety factors. Four zones of progressive failure were established according to compressive-tensile stress proportions. The effective elastic moduli for these zones were calculated by means of a residual elasticity approach. Finally, the fractured rock stability criteria were introduced and the stability factors were calculated for the immediate roof area. Directions of fracture lines in the roof were found using the principal stress directions in the maximum shear stress zone.
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    International Symposium on Underground Openings, Lucerne (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 121-124 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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    Book reviews-Buchbesprechungen-Critiques de livres (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 125-128 
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    The application of size distribution equations to rock breakage by explosives (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 151-162 
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    ISSN: 1434-453X
    Keywords: blasts ; craters ; explosions ; fragmented materials ; graphical analysis ; mining engineering ; model tests ; rock excavation ; sieve analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Die Anwendung von Gröβenverteilungsgleichungen bei Gesteinslösung durch Sprengung Zur Beschreibung der Abmessungen der Gesteinsstücke, die beim Lösen durch Sprengung entstehen, kann eine Größenverteilungsgleichung benutzt werden. Die Veröffentlichung beschreibt die Ergebnisse kleiner Versuchssprengungen und die Herleitung von Gleichungen für die Trümmerkorngrößenverteilung als Funktion der Parameter der Sprengarbeit. Der Grad der Gesteinszerkleinerung wirkt sich erheblich auf die Kosten von Bergbau-und Steinbruchbetrieben aus. Eine Vorhersage der Kornverteilung des Schutter-gutes für die angewendete Sprengarbeit aufgrund mathematischer Ansätze würde eine Optimierung gestatten. Die Ergebnisse von Sprengversuchen kleinen Maßstabes haben gezeigt, daß es möglich ist, Beziehungen zwischen der Gesteinszerkleinerung und dem Ladungs-Vorgabe-Verhältnis (= tatsächliche Vorgabe: optimaler) für einen gegebenen Sprengstoff und eine bestimmte Gesteinsart aufzustellen. Großmaßstäbliche Versuche zur vollgültigen Auswertung dieser Beziehungen stehen noch aus, doch können die gefundenen Gleichungen schon jetzt zu einer quantitativen Schätzung der Wirkung von Lademengen aufgrund gemessener Kornverteilungen verwendet werden. Veröffentlichte Ergebnisse anderer Autoren zeigen aussichtsreiche Korrelationen mit Vorhersagen, welche aus den vorgeschlagenen Gleichungen gewonnen wurden.
    Abstract: Résumé Emploi des equations de la granulometrie pour l'etude de la fragmentation des roches par explosifs Les équations de la granulométrie peuvent être employées pour décrire le degré de fragmentation produit par la rupture des roches sous l'effet des explosifs. Cette note présente les résultats obtenus lors d'essais d'explosions à petite échelle et les équations qui en dérivent pour relier la granulométrie des fragments aux paramètres géométriques des explosions. L'application et la validité de ces techniques pour des explosions à grandes échelles sont également traitées.
    Notes: Summary The Application of Size Distribution Equations to Rock Breakage by Explosives Size distribution equations can be used to describe the degree of fragmentation produced by explosive rock breakage. This paper describes the results of small scale blasting experiments and the derivation of equations to relate size distributions to blasting design parameters. The application and relevance of these techniques to large scale blasting operations is also discussed.
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    Undrained shear testing of jointed rock (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 129-149 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Scherversuche an klüftigen Gesteinen ohne Dränung Wasserdruck in Klüften muß sich verändern, wenn ohne perfekte Dränage Scherkraft ausgeübt wird. In der vorliegenden Arbeit wird ein neuer, direkt wirkender Scherapparat beschrieben, in welchem ummantelte Prüfkörper mit gerichteten Klüften unter Konsolidationsbedingungen ohne Dränage untersucht werden können, wobei der Porendruck gemessen wird. Es wird außerdem die Technik von Triaxialversuchen beschrieben und typische Ergebnisse mit ungestörtem und geklüftetem Sandstein werden mit Ergebnissen aus direkten Scherversuchen verglichen. Während ungestörte Proben steigenden Porendruck, gefolgt von Dilatanz, aufweisen und der Porendruck vor der Höchstbelastung nachläßt, nimmt derselbe in geklüfteten Proben bis zur Höchstbelastung ständig zu.
    Abstract: Résumé Essais de cisaillement non drainé sur des échantillons de roche contenant une discontinuité Les pressions interstitielles à l'intérieur des discontinuités doivent changer lorsqu'elles sont soumises au cisaillement et que le drainage n'est pas parfait. Cet article décrit une nouvelle machine pour essais de cisaillement direct permettant de tester, dans des conditions de consolidation non drainée, des échantillons de roche gainés comportant une discontinuité d'orientation déterminée. La machine permet la mesure de la pression interstitielle. L'article décrit également les techniques de compression triaxiale correspondantes et des résultats typiques obtenus sur des échantillons de grès intact ou traversé par un joint sont comparés à ceux provenant des essais de cisaillement direct. Alors que les échantillons de roche intacte montrent un accroissement de la pression interstitielle suivi de dilatance et d'une réduction de pression avant que la contrainte de cisaillement maximum ne soit atteinte, la pression interstitielle dans les échantillons contenant une discontinuité croît jusqu'au droit de la contrainte de cisaillement maximum.
    Notes: Summary Undrained Shear Testing of Jointed Rock Water pressures must change inside joints undergoing shear without perfect drainage. This paper describes a new direct shear machine in which jacketed samples with oriented joints can be tested under consolidated undrained conditions with pore pressure measurement. Triaxial compression techniques for such tests are also described and typical results with intact and jointed sandstone samples are compared with results from the direct shear tests. Whereas intact specimens displayed increasing pore pressure followed by dilatancy and pore pressure decline before peak loading, the pore pressure in jointed specimens continued increasing right up to the peak load.
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    On the prediction of the reach and velocity of catastrophic landslides (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 231-236 
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    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Summary On the Prediction of the Reach and Velocity of Catastrophic Landslides An analysis of the data of rapid, catastrophic landslides shows that a correlation exists between the logarithm of the volume V of such landslides and the logarithm of the coefficient of frictionf which governs their course. This correlation is $${}_{10}\log f = - 0.15666 {}_{10}\log V + 0.62419$$ where the volume is in m3. The coefficient of correlation is 0.82. This correlation can be used to predict the reach and the velocity of an imminent landslide, if the volume can be estimated beforehand.
    Abstract: Résumé Sur la prédiction de la portée et du cours d'éboulements catastrophiques Les observations des éboulements rapides et catastrophiques qui sont rapportées dans la littérature sont analysées. Il est démontré qu'une corrélation existe entre le logarithme du volume V de ces éboulements et le logarithme du coefficient de la friction qui gouverne leur cours. Elle est $${}_{10}\log f = - 0,15666 {}_{10}\log V + 0,62419$$ où le volume est mesuré en m3. Le coefficient de la corrélation est 0,82. Cette corrélation peut être utilisée pour prédire l'extension et la vélocité d'un éboulement imminent si son volume est estimable en avance.
    Notes: Zusammenfassung Über die Vorhersage von Reichweite und Verlauf katastrophaler Bergstürze Eine Analyse der Beobachtungen von schnellen, katastrophalen Bergstürzen zeigt, daß eine Korrelation zwischen dem Logarithmus des Volumens V und dem Logarithmus des Reibungskoeffizientenf, der ihren Verlauf bestimmt, existiert. Diese Korrelation hat die Form $${}_{10}\log f = - 0,15666 {}_{10}\log V + 0,62419$$ wo das Volumen im m3 gemessen wurde. Der Korrelationskoeffizient beträgt 0,82. Diese Korrelation kann dazu verwendet werden, um die Reichweite und den Verlauf eines erwarteten Bergsturzes vorauszusagen, wenn dessen mutmaßliches Volumen abgeschätzt werden kann.
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    The influence of stress history on lateral strain (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 203-213 
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    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Der Einfluβ der Belastungsgeschichte auf die laterale Deformation Mit Hilfe einer steifen, von digitalen Kalkulatoren kontrollierten Prüfmaschine wurden bei der Untersuchung eines Sandsteines negative Poisson-Zahlen erhalten, die deutlich mit der vorangegangenen Belastungsgeschichte des Probestückes in Beziehung gebracht werden konnten und sogar als Zeugnis von großer Aussagekraft in bezug auf diese Vorgeschichte gewertet werden können, nicht nur für Belastungen im Labor, sondern möglicherweise auch für die Größe von Spannungen im Gebirge.
    Abstract: Résumé L'influence de l'histoire des contraintes à la dilatation latérale En étudiant un grès dans une machine rigide de chargement, contrôlée par un ordinateur digital, des coefficients de Poisson négatifs ont été rencontrés. Ils se trouvaient en corrélation évidente avec l'histoire antérieure des contraintes sur l'échantillon et, peut-être, peut-on y trouver une manifestation sensible de cette histoire, non seulement à l'égard de chargements de laboratoire mais aussi du niveau des contraintes in-situ.
    Notes: Summary The Influence of Stress History on Lateral Strain In the examination of a sandstone using a digital computer-controlled stiff loading frame, negative Poisson's ratios were encountered. They were strongly correlated with the previous stress history of the specimen, and may indeed prove to be an exceedingly sensitive manifestation of that prehistory not only as regards laboratory loading but probably also field stress levels.
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    A new digital method for three-dimensional stress analysis in elastic media (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 189-202 
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    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Neues digitales Verfahren zur dreidimensionalen Spannungsanalyse in elastischen Medien In der vorliegenden Arbeit werden die Grundlagen eines neuen Verfahrens der dreidimensionalen Spannungsanalyse beschrieben. Die Behandlung des allgemeinen Problems der Gebirgsmechanik, d. h. die Bestimmung der Spannungs- und Verschiebungsverteilungen in der Umgebung von untertägigen Hohlräumen, mit Hilfe konventioneller Verfahren — wie z. B. der Methode der Finiten Elemente — hat den Nachteil, daß der gesamte Gebirgskörper berücksichtigt werden muß. Dies hat zur Folge, daß sich realistische dreidimensionale Probleme auch mit modernsten Digitalrechnern nicht mehr innerhalb annehmbarer Rechenzeiten lösen lassen. Das hier vorgestellte Verfahren vermeidet diese Schwierigkeiten durch eine Formulierung, die ausschließlich die Randbedingungen an den Begrenzungsflächen des Mediums verwendet. Spannungen und Verschiebungen an diesen Flächen sowie im Inneren des Gebirgskörpers werden als Überlagerungseffekt einer Reihe von Grund-Lösungen mit geeigneten Eigenschaften ausgedrückt. Aus Gründen der Einfachheit wird in dieser Arbeit nureine solche Grund-Lösung verwendet. Diese beschreibt die Wirkungen einer Einzelkraft, die an einem Punkt eines unendlichen Mediums angreift. Mit Hilfe dieser Lösung kann die Wirkung eines Aggregates derartiger Kräfte in Matrizenform ausgedrückt werden. Läßt man eine Einzelkraft an jedem infinitesimalen Element einer kontinuierlichen Fläche angreifen, dann können die Spannungs- und Verschiebungsverteilungen im Körper mit Hilfe der an dieser Fläche herrschenden Randbedingungen beschrieben werden. Begrenzt die Fläche einen geschlossenen Hohlraum, so trennt sie das Medium in einen inneren und einen äußeren Teil. Auf diese Art entstehen zwei Problemklassen: Während der innere Bereich die Spannungsanalyse von Ingenieurbauten beinhaltet, entspricht der äußere Bereich dem Hohlraumproblem der Gebirgsmechanik. Die beschriebene Formulierung mittels Matrizen ist für beide Bereiche gültig. Es wird jedoch gezeigt, daß die entsprechenden Matrizen charakteristisch unterschiedliche Eigenschaften haben. Diese Beobachtung ist von grundlegender Bedeutung für die Entwicklung numerischer Lösungsverfahren. Die Konvergenz-Charakteristiken zweier Iterativ-Schemata werden in Betracht gezogen. Zusammenfassend wird noch einmal die generelle Gültigkeit des Verfahrens betont. Weitere Grund-Lösungen und ihre Anwendung auf spezielle Probleme werden erwähnt.
    Abstract: Résumé Une nouvelle méthode pour la solution de problèmes à trois dimensions dans la théorie de l'élasticité Les auteurs élaborent une nouvelle méthode pour la solution de problèmes à trois dimensions dans la théorie de l'élasticité. En Mécanique des Roches, lorsque les excavations sont situées dans une masse infinie de roches, les méthodes courantes, telle que les éléments finis, ont le désavantage d'avoir à opérer sur une quasi-infinité d'éléments. Il en résulte que l'analyse de configurations réelles à trois dimensions devient impossible même avec les plus grands ordinateurs modernes. La nouvelle méthode évite ces difficultés en reformulant le problème entièrement en fonction des conditions régnant aux limites de la configuration. Les tensions et les déplacements aux limites, ainsi qu'à l'intérieur de la masse, sont produits par les actions superposées d'un ensemble convenablement choisi de fonctions — solutions élémentaires. Pour alléger l'exposé on n'a employé qu'une seule fonction — solution dans cette publication. Elle décrit l'action d'une force concentrée en un point d'un milieu infini. Les actions d'une distribution de pareilles forces concentrées peuvent s'exprimer sous forme matricielle. En appliquant une force concentrée à chaque élément infinitésimal d'une surface continue située dans le milieu on arrive à exprimer les tensions et les déplacements en un point quelconque en fonction des conditions régnant sur cette surface. Si cette surface est fermée elle divise le milieu en une région intérieure et une région extérieure, ce qui donne lieu a deux classes de problèmes. Le problème intérieur se présente surtout en Résistance des Matériaux, tandis que le problème extérieur se recontre en Mécanique des Roches. Le formalisme matriciel mentionné ci-dessus est applicable dans les deux régions. Cependant il apparaît que les matrices associées ont des propriétés foncièrement différentes. Cette constatation est de première importance lors de l'élaboration de méthodes de solutions numériques ayant recours à l'ordinateur. Deux procédés de calculs appropriés sont analysés dans cette publication. Dans leurs conclusions les auteurs mettent de nouveau en relief la généralité de la méthode. Quelques exemples de fonctions — solutions élémentaires, différentes de la fonction — solution (force concentrée) employée dans cette publication, sont cités.
    Notes: Summary A New Digital Method for Three-Dimensional Stress Analysis in Elastic Media A new method for three-dimensional stress analysis in elastic media is outlined. According to this approach the problem is formulated purely in terms of conditions prevailing at the bounding surfaces of an elastic body. Stress and displacements on these surfaces, as well as inside the body, are expressed in terms of the superimposed effect of a set of basic solutions having suitable properties. The method is developed in matrix form. Some general properties of the governing matrices are established with a view to developing suitable numerical procedures. The convergence characteristics of two iterative schemes are considered. The paper concludes with observations concerning the generality of the approach.
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    The effect of particle strength on the compression of crushed aggregate (1973)
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    Rock mechanics and rock engineering 5 (1973), S. 237-248 
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    ISSN: 1434-453X
    Keywords: Aggregate ; Compressibility ; Compressive strength ; Particle size ; Rockfill ; Rock Mechanics ; Void Ratio ; Strain ; Stress ; Average particle size ; Compressive strength ; Void ratio ; Initial void ratio ; Final void ratio ; Angularity number ; Uniformity coefficient ; Deformation ; Force ; Modulus of elasticity ; Poisson's ratio ; Aggregat ; Kompressibilität ; Druckfestigkeit ; Körnung ; Steinpackung ; Felsmechanik ; Relativer Porenraum ; Verformung ; Spannung ; Korndurchmesser ; Druckfestigkeit ; relativer Porenraum ; anfänglicher relativer Porenraum ; endrelativer Porenraum ; Eckigkeit ; Ungleichförmigkeitsgrad ; Verformung ; Kraft ; Elastizitätsmodul ; Poisson-Zahl ; Agrégat ; Compressibilité ; résistance à la compression ; taille des particules ; enrochement ; mécanique des roches ; indice des vides ; déformation ; contrainte ; diamètre des grains ; résistance à la compression ; indice des vides ; indice des vides initial ; indice des vides final ; angulairité ; coefficient d'uniformité ; déformation ; force ; module d'élasticité ; coefficient de Poisson
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Einige Faktoren, die die Kompressibilität von Aggregaten bestimmen Diese Arbeit untersucht die Variablen, die die Kompressibilität von Gesteinsaggregaten bestimmen, und liefert experimentelle Angaben über das Verhalten von Kalkstein-, Dolerit- und Sandsteinproben bis zu 19,0 mm Korngröße. Die Ergebnisse weisen darauf hin, daß, während der anfängliche relative Porenraum des Aggregats den Grad der potentiell vorhandenen Kompressionsspannung bestimmt, der durchschnittliche Aggregatsdurchmesser (d m) und die eigentliche Druckfestigkeit (S c) die Kompressibilitäts-Spannungs-Verformungscharakteristik laut der Formel $$\varepsilon \alpha \ln \frac{{\sigma d_m {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}}}{{S_c }}$$ bestimmen.
    Abstract: Résumé Influence de la résistance des particules sur la compression d'un agrégat broyé Les auteurs examinent les paramètres qui affectent la compressibilité des agrégats de roches et présentent des résultats expérimentaux obtenus avec des échantillons de calcaire, de dolérite et de grès, sur l'influence du diamètre des grains en-dessous de 19 mm. Les résultats suggèrent que l'indice des vides initial impose le taux de la déformation à la compression dont on dispose, cependant que le diamètre des grains (d m) et la résistance à la compression (S c) définissen les caractéristiques de la courbe de compressibilité.
    Notes: Summary The Effect of Particle Strength on the Compression of Crushed Aggregate The paper examines the variables controlling the compression of rock aggregates, and presents experimental data on the behaviour of limestone, dolerite and sandstone samples in size ranges up to 19.0 mm. The results suggest that while the initial void ratio of the aggregate determines the degree of compressive strain potentially available, the average aggregate dimension (d m) and intrinsic compressive strength (S c) determine the compressive stressstrain characteristics in the form, $$\varepsilon \alpha \ln \frac{{\sigma d_m {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}}}{{S_c }}$$
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    Relation entre la résistance du béton et la résistance des agrégats (1970)
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    Materials and structures 3 (1970), S. 37-43 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary On the basis of an examination of the fracture of concrete test pieces the authors propose a criterion for determining the limit strength of the mortar and the granulate in terms of the expected strength of the concrete. They define the compressive loads by which the feeble, low-strength and disaggregated grains of a granulate can be determined and show the influence of the use of granulates of inadequate strength on the mechanical strength of the concretes. The tests carried out by the authors confirm the hypotheses advanced.
    Notes: Résumé Les auteurs proposent, sur la base de l'examen de la cassure d'éprouvettes de béton, un critère de détermination de la résistance limite du mortier et du granulat en fonction de la résistance donnée du béton. Ils définissent les charges de compression permettant de déterminer les grains faibles, peu résistants et désagrégés d'un granulat et mettent en évidence l'influence de l'emploi de granulats de résistance inadéquate sur la résistance mécanique des bétons. Les essais effectués par les auteurs confirment les hypothèses avancées.
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    The correlation between creep deformation and stress relaxation in concrete (1970)
    Springer
    Materials and structures 3 (1970), S. 75-80 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary The functional relation between creep deformation and stress relaxation can be represented by the Volterra integral equation. By substituting the creep function and the relaxation function into this equation and comparing coefficients it is possible to obtain an expression which relates the ultimate creep to the relaxed stress at time t=∞. The rate at which the stress decreases at the begenning of the experiment is proportional to the creep velocity, and the constant of proportionality is the modulus of elasticity. It is shown the half-life time of the relaxation process is always smaller than the corresponding half-life time of the creep process. The derived equations are compared with experimental results described in the literature.
    Notes: Résumé On peut traduire la relation entre fluage et relaxation par l'équation intégrale de Volterra. La substitution des fonctions «fluage» et «relaxation» dans cette équation et la comparaison des coefficients permet d'obtenir une expression qui relie le fluage final et la contrainte relâchée au tempst=∞. Le taux de décroissance au début de l'expérience est proportionnel à la vitesse de fluage; la constante de proportionnalité est le module d'élasticité. On montre que la mi-temps du processus de relaxation est toujours plus petite que la mi-temps correspondance du processus de fluage. On compare les équations dérivées avec les résultats expérimentaux décrits dans la littérature.
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    Estimation of the modulus of elasticity of concrete-like composite materials (1970)
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    Materials and structures 3 (1970), S. 253-260 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Résumé La déformabilité d'un solide composite peut être considérée comme une moyenne judicieusement choisie des déformations de ses composants. Les moyennes arithmétique et harmonique des déformations des composants fournissent les deux meilleurs et les deux plus simples modèles stratifés connus (fig. 1 et 1b). On montre que les moyennes de ces deux modèles (fig. 1c et 1d) permettent une plus juste approximation entre les valeurs calculées et expérimentales. Les analogies mécaniques de ces modèles stratifiés sont représentées par des ressorts connectés (fig. 2), et les analogies électriques par des résistances ohmiques connectées (fig. 3). Le modèle composite traduit par la moyenne géométrique des déformations des composants ne possède pas une simple analogie mécanique ou électrique. Les proportions des composants (g) peuvent être aussi déterminées si l'on connaît tant le module d'élasticité du matériau composite que celui de chacun des composants. Pour deux composants, on se référera aux équations de (6) à (10). Pour trois composants, le calcul se complique, mais peut être simplifié par l'emploi de diagrammes triangulaires. Une fois établi, un système linéaire des valeurs E constantes (voir fig. 5 pour Ea et les figures qui suivent pour les autres modules moyens), le module d'élasticité composite pour quelles constructions que ce soient des 3 phases peut être lu directement sur le diagramme ou, inversement, la totalité des combinaisons possibles de composants pour une valeur donnée de E composite, même avec des limites de tolérance et des conditions subsidiaires. La combinaison d'un calculateur couplé à un traceur de courbe avec la méthode du diagramme triangulaire se révèle comme particulièrement avantageuse.
    Notes: Summary The deformability of a composite solid can be estimated as a properly selected average of the deformabilities of the phases. The arithmetic and harmonic averages of the phase deformations provide the two best known and simplest laminated models. Analogues of these laminated models are shown as connected springs or as connected ohmic resistances. The needed “g” blending proportions can also be calculated when the required modulus of elasticity of the composite as well as the moduli of the phases are given. The mathematics of three-phase composite models is more complicated. This can be simplified by the use of triangular diagrams. The combination of a computer of graphical terminals with the triangular diagram method is shown as particularly advantageous.
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    Élévation de température lors de la polymérisation d'un béton de résine (1973)
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    Materials and structures 6 (1973), S. 49-51 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
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    URL: http://dx.doi.org/10.1007/BF02474842
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    Armatures de béton armé, et de béton précontraint (1973)
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    Materials and structures 6 (1973), S. 79-118 
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    Source: Springer Online Journal Archives 1860-2000
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    URL: http://dx.doi.org/10.1007/BF02475142
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    Deformation behaviour of mild steel beams under alternating loads (1973)
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    Materials and structures 6 (1973), S. 3-13 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Résumé On décrit une méthode susceptible de prédire le comportement de structures simples soumises à la flexion alternée dans les limites strictes de charges symétriques constantes. A cette fin, deux études expérimentales ont été faites. Une première série d'essais avec moment de flexion contrôlé a porté sur des éprouvettes en acier doux dans les conditions de flexion simple alternée; mais la variation, pour un cycle quelconque, n'était pas symétrique par rapport à l'axe central de la poutre. On a entrepris une seconde série d'essais sur des poutres-consoles en acier doux soumises à des charges alternées; l'intervalle de fléchissement variait d'un cycle à l'autre mais, pour un cycle quelconque, les amplitudes de la flèche étaient inégales. D'après les résultats de la première série d'essais, on a établi une relation moment-courbure. On a eu recours ensuite au calcul électronique et un programme a été réalisé afin de prédire le comportement de structures simples sous flexion alternée dans les conditions de charge contrôlée. On s'est servi de la méthode pour prédire le comportment d'une poutre-console dans des conditions de charge similaires et on a établi une comparaison avec la seconde série d'essais. La corrélation entre les caractéristiques moment-courbure et le nombre de cycles est satisfaisante entre500 et10 000 cycles. On croit que les discordances, relatives à l'intervalle de fléchissement ou à l'amplitude maximale de flèche, entre les résultats analytiques et expérimentaux pour un petit nombre de cycles et une charge élevée sont dues à un phénomène de déformation plastique discontinue qui se manifeste au-dessous d'un certain seuil. On suppose qu'il se produit un fluage cyclique dans une direction spécifique qui dépend de la nature des contraintes résiduelles engendrées durant la première moitié d'un cycle de chargement alterné.
    Notes: Abstract A method has been developed to predict the cyclic behaviour of simple structures subjected to reversed bending under load control conditions. Cyclic moment-curvature relations are developed from pure bending tests under moment control and are applied to predict deflection range and maximum deflection amplitude for a cantilever beam. Disagreement between analytical and experimental results at low life and high load is attributed to a discontinuous yield phenomenon which manifests itself below a certain threshold load range. Cyclic creep is believed to occur depending upon the nature of residual stresses initiated during the first half cycle of reversed loading.
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    Condensation in slabs of cellular plastics (1973)
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    Materials and structures 6 (1973), S. 53-56 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
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    URL: http://dx.doi.org/10.1007/BF02474843
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    The strain compensated modular ratio method and its application (1973)
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    Materials and structures 6 (1973), S. 123-128 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Résumé On décrit une méthode par laquelle les charges admissibles engendrées dans les conditions de service, ainsi que leur distribution dans un élément de poutre en béton armé délimité par deux fissures adjacentes, peuvent être calculées au moyen d'une simple inconnue, la valeur du coefficient d'équivalence “n”. On tient compte du fluage et des déplacements relatifs entre les matériaux. On a vérifié la méthode pour les charges dues au retrait, la valeur correspondante de n étant d'abord déterminée à partir de certains résultats de mesure puis substituées dans les formules à la contrainte limite supérieure de l'armature et au fléchissement maximal. On a comparé les résultats avec les observations faites au cours d'essais sur 5 poutres à pourcentages d'armature différents.
    Notes: Abstract A method is presented for calculation of the design state of stress in the working range in an arbitrary cross section of a cracked reinforced concrete beam, using the value of the modular ration as the only unknown coefficient. The method is applied to shrinkage in reinforced concrete.
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    Some effects of errors in angular dispositions of strain gauges (1973)
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    Materials and structures 6 (1973), S. 149-150 
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    URL: http://dx.doi.org/10.1007/BF02475148
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    Product development of prestressed standard beam types in Finland (1973)
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    Materials and structures 6 (1973), S. 155-156 
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    URL: http://dx.doi.org/10.1007/BF02475151
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    Stochastic analysis for time-dependent load transfer in reinforced concrete columns (1973)
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    Materials and structures 6 (1973), S. 269-276 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Résumé On présente un modèle de traitement stochastique de transfert de charge en fonction du temps du béton à l'acier dans des poteaux de béton armé soumis à une charge axiale constante et permanente. Ce phénomène est principalement dû au fluage et au retrait du béton. On définit d'abord un modèle déterministe qui consiste en une représentation idéalisée et simplifiée susceptible de fournir une bonne approximation du phénomène réel. Une fois le modèle mathématique mis au point, le choix du modèle de traitement stochastique dépend des mécanismes physiques réels du fluage et du retrait dans les poteaux de béton armé, ainsi que de la nature du modèle mathématique. Le modèle de traitement stochastique est un modèle probabiliste qui donne une fonction moyenne, reproduisant en fait le modèle mathématique et, en outre, les fonctions de variance et de covariance. La fonction de variance autorise la formulation d'énoncés relatifs aux limites inférieures et supérieures de transfert de charge en fonction du temps, ainsi que pour le même phénomène, des énoncés relatifs aux écarts possibles de la fonction moyenne. Les résultats fournis par le modèle de traitement stochastique sont comparés à ceux obtenus récemment en ce domaine par l'étude expérimentale; on constate que la concordance est très bonne.
    Notes: Abstract A stochastic process model is proposed for the phenomenon of time-dependent stress transfer from concrete to steel in reinforced concrete columns, subjected to axial loading. The phenomenon is caused by the mechanisms of creep and shrinkage. The importance of the stochastic model is brought out, in that it is now possible to have more meaningful information concerning the phenomenon under study. Furthermore, the importance of the stochastic model in practical problems involving the estimation of possible long-time stresses in structures, is mentioned. The results of the stochastic model are compared with practical tests results, and good agreements are obtained.
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    A thin-wall cement paste cylinder for creep tests at variable humidity or temperature (1973)
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    Materials and structures 6 (1973), S. 277-281 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Résumé Cet article décrit la confection de nouvelles éprouvettes cylindriques creuses de pâte de ciment pour les essais de fluage à humidité variable et, éventuellement, à température variable. L'épaisseur des parois n'est que de 0.75 mm, de sorte que l'équilibre des humidités à l'intérieur de l'éprouvette soit atteint suffisamment vite (en moins d'un jour) après une modification des conditions d'ambiance. Dans des conditions programmées d'humidité et de température ambiante lentement variable, l'éprouvette reste ainsi dans un état presque uniforme et de quasi équilibre, et l'on peut alors observer directement les propriétés du matériau à température et humidité variable. Le moule de confection des éprouvettes (dont le rapport eau/ciment est d'environ 0,45) est en téflon, ce qui assure une faible adhérence. Etant donné que le moulage s'accompagne de pressions élevées, le téflon est renforcé par de l'aluminium. La pâte de ciment est malaxée sous vide. Le démoulage (24 heures après) s'accomplit en eau glacée, par retrait thermique différentiel; le moule a été conçu de sorte que le refroidissement provoque une extension du diamètre externe du moule, tandis que le diamètre du mandrin intérieur se rétracte. Afin d'éviter la carbonatation, l'éprouvette est conservée dans de l'eau de chaux et les essais réalisés en atmosphère exempte de CO2. On présente quelques résultats d'essais préliminaires.
    Notes: Abstract Production of cement paste cylindrical specimens developed for creep tests at variable humidities and/or temperatures is described. The wall thickness is only 0.75 mm, which is required so that an equilibrium humidity distribution can be achieved in a short time with the result that the material parameters may be obtained directly by experiment.
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    A new indirect tension test for concrete and other brittle materials (1973)
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    Materials and structures 6 (1973), S. 307-308 
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    URL: http://dx.doi.org/10.1007/BF02473896
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    Séminaire RILEM sur le Béton Frais: Principales Propriétés et Leurs Mesures (1973)
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    Materials and structures 6 (1973), S. 311-311 
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    URL: http://dx.doi.org/10.1007/BF02473898
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    Méthodes d'essais des bétons (1973)
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    Materials and structures 6 (1973), S. 377-393 
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    URL: http://dx.doi.org/10.1007/BF02473624
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    Comparaison des essais d'adhérence par flexion (beam test) et par traction (pull-out test) (1973)
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    Materials and structures 6 (1973), S. 395-401 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary In three different institutes 33 series of bonding tests (beam test and pull-out test) have been carried out independently in accordance with the Recommendations published in Materials and Structures No. 15 of May–June, 1970, regarding high bonding-strength bars having diameters varying from 8 to 30 mm. The results obtained by the two types of tests have been interpreted in accordance with the Recommendations for the control and the agreement of high bonding strength (Section 1 of the Annexes to the CEB-FIP 1970 Practical Recommendations). The relative surface of the ribs ranged from 0.011 to 0.125, with a mean value of 0.47 and thus covered the whole practical range. The concrete's compression strength was within the normal scatter limits for all the series of tests. The bonding stresses τm and τR, determined by the flexural bond test, fall within the whole range of the practical values. For a few bars having very low fR values, the τm values do not come up to the imposed values. For others, showing high fR values, the τm values can be as high as twice the imposed values.
    Notes: Résumé Dans trois laboratoires, autrichien, belge et français ont été exécutés des essais d'adhérence selon les deux types d'éprouvettes retenus par la RILEM: beam-test et pull-out-test. Les résultats regroupés de tous les essais ont montré que les deux méthodes conduisaient à des valeurs moyennes des glissements, du même ordre mais avec des dispersions importantes à l'intérieur des séries. Aucune relation certaine n'a pu être trouvée entre les rapports POT/BT et la surface relative des nervures ou le diamètre des barres.
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    Commission RILEM des Béton Légers Terminologie et Définitions (1970)
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    Materials and structures 3 (1970), S. 60-69 
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    URL: http://dx.doi.org/10.1007/BF02475110
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    Un nouveau matériau de construction obtenu par la réaction argilo-calcaire (1970)
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    Materials and structures 3 (1970), S. 53-59 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary This material is different from usual ca cium silicate materials, because we use clay instead of sand. The reaction is more complete because of the fineness of clay. With the usual heat treatment (autoclave 200 °C, 16 atm.), we obtain an ultimate compressive stress of 900 kg/cm2. Then we add a second heat treatment (dry oven, 350 °C) and the ultimate compressive stress jumps to 2,000 kg/cm2. This material has a beautiful aspect; it looks like natural stone, almost like marble; it may be used as artificial stone for building construction; but its main application should be prestressed long-span or heavily loaded beams, or even bridges.
    Notes: Résumé Ce matériau diffère des matériaux silico-calcaires usuels, car nous employons l'argile au lieu du sable. La réaction est plus complète à cause de la finesse de l'argile. Avec le traitement thermique usuel (autoclave 200°C, 16 atm.), nous obtenons une résistance à la compression de 900 bars. Puis nous ajoutons un second traitement thermique (étuve sèche, 350°C) et la résistance bondit jusqu'à 2 000 bars. Ce matériau a un très bel aspect; il ressemble à la pierre naturelle, il est presque comme du marbre; on peut l'utiliser comme pierre artificielle pour la construction. Mais sa principale application serait les poutres précontraintes à très longue portée ou lourdement chargées, ou même les ponts.
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    Effect of stress concentrations on the static and fatigue strength of concrete in compression (1970)
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    Materials and structures 3 (1970), S. 85-89 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary The effect of stress concentrations produced by a circular hole, on the static and fatigue strengths of plain concrete in uniaxial compression, is investigated by experiments. Tests conducted on prismatic specimens showed that the ultimate static compressive strength and the fatigue strength is not significantly altered by the introduction of stress concentrating hole. The air cavities and microcracks inherently present in the concrete affect the ultimate strength and deformation characteristics of the material to such an extent that the effect of the artificially introduced stress concentrations is negligibly small.
    Notes: Résumé Cet article rend compte d'une étude expérimentale des effets de concentrations de contraintes sur les résistances statique et dynamique du béton non armé, en compression pure. Les essais statiques et dynamiques sur prismes de béton non armé, avec et sans entaille, indiquent que la résistance à court terme et sous charge répétée n'est pas diminuéer par la présence d'une entaille circulaire. Les inclusions d'air et les micro-fissures inhérentes au béton affectent les caractéristiques de résistance et de déformation du matériau de telle sorte que l'effet du facteur de concentration des contraintes artificielles introduit est négligeable.
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    Étude de la précision de différentes méthodes de mesure des déformations du béton (1970)
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    Materials and structures 3 (1970), S. 237-251 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary The various methods of measurement applied to a quasi-uniform field of strains in the compressed elements in concrete are examined. The aim of the study is to compare first four types of captors intended for measurements within the concrete and then to compare the measurements of the longitudinal strains of the surface carried out by means of resistance wire strain gauges and mechanical extensometers on different bases. The analysis of the results is based on the homogeneity of the measurements, assessed by different statistical criteria. The conclusions tend to indicate the construction of a captor better adapted to measurements inside concrete elements and likewise to determine the minimum basis of the extensometric measurements of the strains of the concrete. The method used to compare the homogeneity of the measurements of the strains of the concrete may be useful likewise in the other cases of measurements.
    Notes: Résumé On examine les méthodes diverses de mesure appliquées à un champ quasi-uniforme de déformations unitaires dans les éléments comprimés en béton. Le but de l'étude est de comparer d'abord quatre types de capteurs destinés aux mesures à l'intérieur du béton et ensuite de comparer les mesures des déformations longitudinales de la surface effectuées au moyen de jauges à fil résistant et d'extensomètres mécaniques sur des bases différentes. L'analyse des résultats repose sur l'homogénéité des mesures, appréciée par des critères statistiques différents. Les conclusions tendent à indiquer la construction d'un capteur mieux adapté aux mesures à l'intérieur des pièces en béton et également à déterminer la base minimale des mesures extensométriques des déformations du béton. La méthode employée pour comparer l'homogénéité des mesures des déformations du béton peut être utile également dans les autres cas de mesures.
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    Sand for gypsum-sand plaster (1970)
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    Materials and structures 3 (1970), S. 261-268 
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    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Résumé Cet article résume une série d'essais sur les mélanges gypse-sable avec différents sables et diverses compositions effectués dans le dessein de recueillir des informations relatives aux mortiers qui peuvent servir à un enduit au plâtre et au sable, en l'absence d'une pratique reconnue et d'instructions précises (la spécification en usage indique la composition du mélange sans tenir compte du type et de la qualité du sable, alors que les fabricants de plâtre recommandent un dosage fondé sur un rapport prédéterminé eau-semihydrate, (retardé) mais sans tenir compte non plus de la qualité du sable). Il a été constamment maintenu une consistance uniforme fixée d'après la moyenne en usage dans la pratique locale. Les critères d'évaluation pour le mortier endurci sont les suivants: la résistance, la dureté et la variation linéaire. Les épreuves effectuées se résument comme suit: 1. Pour une consistance uniforme du mortier et un plâtre donné, la quantité d'eau varie selon le type de sable et, pour le même sable et la composition du mélange, selon le type de gypse. 2. Letemps de prise varie selon le type de sable: pour du sable de carrière, il est beaucoup plus court que pour le sable naturel. 3. Pour ce qui concerne larésistance, on constate que, pour le même rapport eau-semihydrate, elle varie selon le type de sable. Il en résulte que le rapport seul ne constitute pas un critère de dosage satisfaisant, ce qu'il peut être malgré tout pour un sable spécifique. Il en est de même avec la composition du mélange. 4. Pour ladureté, on a constaté qu'elle varie avec le type de sable pour un même rapport eausemihydrate, d'où la possibilité qu'elle serve de critère de qualité du mortier pour un sable spécifique. 5. Quant à lavariation linéaire, on a constaté qu'elle varie avec le type de sable pour un même rapport eau-semihydrate et pour la même composition du mélange. Elle augmente avec l'un et l'autre (quoi-qu'on n'ait pas observé d'influence directe de la granulométrie du sable); mais dans tous les cas, elle restait plus faible, par comparaison avec les mortiers sable-chaux correspondants.
    Notes: Summary The paper summarises a series of tests carried out on gypsum-sand mixes—using different sands and mix proportions—and undertaken with a view to reliable information on base mortars for gypsum-sand plaster, in the absence of a local consensus and clear-cut instructions. (The current standard specification prescribes the mix proportion irrespective of the type and quality of the sand, while gypsum manufacturers recommend mix design based on a predetermined water-R.H.H. ratio, again irrespective of the sand quality). A uniform consistency was used throughout, based on the average accepted in local practice. Evaluation criteria for the hardened mortars were: flexural and compressive strength, hardness, and linear change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02474014
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    Apport de la microscopie électronique à balayage pour l'étude des plâtres durcis. Étude de l'influence de quelques modificateurs de prise (1973)
    Springer
    Materials and structures 6 (1973), S. 129-135 
    Details
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary Scanning electron microscopy is more and more used for studying the texture of materials. The first data dealing with such studies in the case of plasters have been published just some years ago in Great Britain and in France. The authors present new results obtained in the case of the hydration of an hemihydrate plaster in pure medium or in presence of some retarders (citric acid, boric acid, sodium phosphates, potassium phosphates, and proteins). The observation of photographs gives a good idea of the cristalline morphology and of the texture of hydrated plaster and their changes versus the nature of the substances added to the water before setting. But for the understanding of hydration mechanism, the results have to be connected with other experimental data.
    Notes: Résumé On utilise de plus en plus la microscopie électronique à balayage pour l'étude de la texture des matériaux. Pour les plâtres, les premières données, publiées en Grande-Bretagne et en France, ne datent que de quelques années. On présente ici de nouveaux résultats relatifs à l'hydration d'un semi-hydrate en milieu pur ou en présence de modificateurs de prise (acide citrique, acide borique, phosphates alcalins et protéines). L'observation des clichés donne une juste idée de la morphologie cristalline et de la texture du plâtre hydraté, ainsi que de leurs modifications en fonction de la nature des produits ajoutés à l'eau avant la prise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02475145
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    Causes, mechanisms and control of surface voids in concrete (1973)
    Springer
    Materials and structures 6 (1973), S. 153-154 
    Details
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02475150
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    Compression densitification of beech wood plasticized with anhydrous ammonia (1973)
    Springer
    Materials and structures 6 (1973), S. 137-139 
    Details
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Résumé Le bois est plastifié par adsorption d'ammoniac. Après désorption de l'ammoniac, la substance du bois retrouve ses propriétés de résistance. Par l'utilisation de cette méthode de plastification temporaire découverte aux Etats-Unis, on a pu montrer que le bois est susceptible de prendre de fortes courbures permanentes. L'étude décrite ici a été entreprise afin de déterminer si le bois de bouleau danois à l'état plastifé peut être densifié par compression perpendiculaire au grain de sorte qu'il constitute un matériau de construction à résistance mécanique accure. On est parti de la présomption que si la paroi de la cellule était réellement plastifiée, le bois densifié devrait montrer des propriétés mécaniques proportionnelles à sa densité après désorption de l'ammoniac. Les résultats expérimentaux ont montré que la densification par compression du bois de bouleau plastifié à l'ammoniac possède des propriétés mécaniques comparables aux meilleurs bois tropicaux. Il s'impose de poursuivre les recherches quant à la stabilisation effective de ces nouveaux produits avant de commercialiser la méthode de production indiquée.
    Notes: Abstract Compression densitification of ammonia plasticized beech wood is shown to yeild mechanical properties comparable to the best tropical woods. Continued research leading to effective moisture stabilization of the new products is required in order to utilize the outlined production method commercially.
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    URL: http://dx.doi.org/10.1007/BF02475146
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    Recommendations for the treatment of the variations of concrete strength in codes of practice (1973)
    Springer
    Materials and structures 6 (1973), S. 259-267 
    Details
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Summary Issu d'une Commission CEB/CIB/FIP/RILEM, un Groupe de Travail a été chargé d'étudier la variation de la résistance des bétons produits en usine et sur le chantier. 5 pays européens, ainsi que le Canada, Israël et les USA étaient représentés dans ce groupe qui a tenu des réunions annuelles de 1968 à 1971, au cours desquelles ont été présentées 21 communications et une bibliographie préparée par le BRS (France). On a discuté longuement de la question de savoir quel est le paramètre le mieux approprié pour mesurer la variabilité de la résistance du béton: l'écart-type ou le coefficient de variation. Cette question devient d'autant plus importante que le domaine des résistances du béton couvert par les codes de bonne pratique s'étend. Plusieurs enquêtes à grande échelle, particulièrement en Allemagne de l'Ouest, en Angleterre et aux Etats-Unis, ont permis au groupe de conclure que l'écart-type est le paramètre approprié et que, pour les résistances caractéristiques supérieures à 20 N/mm2, il devient indépendant de la résistance du béton produite par une même unité de production. On a tenté de distribuer la variation totale de la résistance du béton entre 3 groupes de facteurs: 1. Matériaux (variabilité de la qualité du ciment, de la granulométrie, etc ...). 2. Confection (type d'installation, main-d'œuvre et contrôle). 3. Essai (échantillonnage, réalisation, conservation et éprouvettes). Pour le moment, on manque de données de chantier pour tirer des conclusions définitives et il paraît plus important d'établir des méthodes d'essai normalisées. Le Groupe de Travail est d'avis qu'il n'est pas possible de prévoir l'écart-type à partir de facteurs tels que le type de construction ou le type d'unité de production. Cependant, il est possible d'estimer l'écarttype futur d'après les données précédemment fournies par une même unité de production, compte tenu que la fiabilité d'une telle estimation dépend du nombre de données disponibles. Si l'on ne dispose pratiquement pas de ces données, il convient alors d'adopter un écart-type, raisonnablement élevé, de 6 à 10 N/mm2, jusqu'à ce que l'on obtienne des résultats d'essai effectifs.
    Notes: Abstract Some time ago (Materials and Structures no 24, November–December 1971), Mr. Petersons published a paper referring to the work of Working Group III of the Joint CEB/CIB/FIP/RILEM Committee on the Statistical Control of Concrete. In the following, Mr. Teychenné gives a personal view of the ideas actually being discussed by Working Group I. The Joint Committee will at its next session discuss these proposals and hopes to finalize its work in the near future by publishing draft Recommendations on the Statistical Quality Control of Concrete.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02473890
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    The development of frost heave testing equipment (1973)
    Springer
    Materials and structures 6 (1973), S. 299-306 
    Details
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract The paper presents details of the development of a deep freeze cabinet and of a cold room for carrying out the Road Research Laboratory frost heave test and the results obtained in the two testing facilities are compared. The majority of the tests reported were undertaken on burnt and on unburnt colliery shale, both in their natural state and when stabilised with cement, and an indication is given of the scatter in the results of tests on nominally similar specimens. The paper includes mention of a commercial deep freeze unit developed as a result of the work reported in the paper.
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    URL: http://dx.doi.org/10.1007/BF02473895
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    The effect of public expenditure in providing adequate housing for low income families: A comparative socio-economic analysis of programs in five countries (1970)
    Springer
    The annals of regional science 4 (1970), S. 123-136 
    Details
    ISSN: 1432-0592
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01287737
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    Regional versus inter-regional efficiency in resource allocations (1970)
    Springer
    The annals of regional science 4 (1970), S. 1-14 
    Details
    ISSN: 1432-0592
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294884
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    Regional policy planning: Some possible implications for research (1970)
    Springer
    The annals of regional science 4 (1970), S. 53-67 
    Details
    ISSN: 1432-0592
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294889
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    Air travel, spatial structure, and gravity models (1970)
    Springer
    The annals of regional science 4 (1970), S. 97-107 
    Details
    ISSN: 1432-0592
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294893
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