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  • 1
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    Numerical Simulation of Hysteretic Live Load Effect in a Soil-Steel Bridge (2014)
    De Gruyter
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    Publication Date: 2014-03-01
    Description: The paper presents numerical simulation of hysteretic live load effect in a soil-steel bridge. The effect was originally identified experimentally by Machelski [1], [2]. The truck was crossing the bridge one way and the other in the full-scale test performed. At the same time, displacements and stress in the shell were measured. The major conclusion from the research was that the measured quantities formed hysteretic loops. A numerical simulation of that effect is addressed in the present work. The analysis was performed using Flac finite difference code. The methodology of solving the mechanical problems implemented in Flac enables us to solve the problem concerning a sequence of load and non-linear mechanical behaviour of the structure. The numerical model incorporates linear elastic constitutive relations for the soil backfill, for the steel shell and the sheet piles, being a flexible substructure for the shell. Contact zone between the shell and the soil backfill is assumed to reflect elastic-plastic constitutive model. Maximum shear stress in contact zone is limited by the Coulomb condition. The plastic flow rule is described by dilation angle ψ = 0. The obtained results of numerical analysis are in fair agreement with the experimental evidence. The primary finding from the performed simulation is that the slip in the interface can be considered an explanation of the hysteresis occurrence in the charts of displacement and stress in the shell.
    Print ISSN: 0137-6365
    Electronic ISSN: 2083-831X
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 2
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    Influence of bedding and backfill soil type on deformation of buried sewage pipeline (2018)
    De Gruyter
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    Publication Date: 2018-12-21
    Description: In the paper, the influence of different types of bedding and backfill soil surrounding underground sewage duct on its deformation was analysed. Impact of increased soil lateral pressure was examined by considering the construction of an embankment nearby the underground pipeline. Numerical computations of three different variants of bedding and backfill soil surrounding the pipe were carried out. Displacements and deformation of the pipe were calculated using the finite element method with adoption of elastic-perfectly plastic constitutive model of soil. Subsequent stages of the construction were taken into account. Shear strength reduction method was applied to evaluate the factor of safety of the entire system. Finally, the results and conclusions were depicted.
    Print ISSN: 0137-6365
    Electronic ISSN: 2083-831X
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 3
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    Shape optimization of road tunnel cross-section by simulated annealing (2016)
    De Gruyter
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    Publication Date: 2016-06-01
    Description: The paper concerns shape optimization of a tunnel excavation cross-section. The study incorporates optimization procedure of the simulated annealing (SA). The form of a cost function derives from the energetic optimality condition, formulated in the authors’ previous papers. The utilized algorithm takes advantage of the optimization procedure already published by the authors. Unlike other approaches presented in literature, the one introduced in this paper takes into consideration a practical requirement of preserving fixed clearance gauge. Itasca Flac software is utilized in numerical examples. The optimal excavation shapes are determined for five different in situ stress ratios. This factor significantly affects the optimal topology of excavation. The resulting shapes are elongated in the direction of a principal stress greater value. Moreover, the obtained optimal shapes have smooth contours circumscribing the gauge.
    Print ISSN: 0137-6365
    Electronic ISSN: 2083-831X
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 4
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    State of Strength in Massive Concrete Structure Subjected to Non-Mechanical Loads (2015)
    De Gruyter
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    Publication Date: 2015-02-28
    Description: The paper deals with an impact of non–mechanical loads on the state of strength in massive concrete hydraulic structures. An example of hydroelectric plant subjected to the effect of water temperature annual fluctuation is considered. Numerical analysis of transient thermal–elasticity problem was performed. After determining the temperature distributions within the domain, the Duhamel-Neumann set of constitutive equations was employed to evaluate fields of mechanical quantities: displacement, strain and stress. The failure criterion proposed by Pietruszczak was adopted in assessing whether the load induces exceeding of strength of concrete within the structure volume. The primary finding is that the temperature effect can lead to damage of concrete in draft tubes and spirals, especially in winter months.
    Print ISSN: 0137-6365
    Electronic ISSN: 2083-831X
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 5
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    Assessment of Internal Structure of Spun Concrete Using Image Analysis and Physicochemical Methods (2020)
    Molecular Diversity Preservation International
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    Publication Date: 2020-09-09
    Description: Taking into account the possibilities offered by two imaging methods, X-ray microcomputed tomography (µCT) and two-dimensional optical scanning, this article discusses the possibility of using these methods to assess the internal structure of spun concrete, particularly its composition after hardening. To demonstrate the performance of the approach based on imaging, laboratory techniques based on physical and chemical methods were used as verification. Comparison of obtained results of applied research methods was carried out on samples of spun concrete, characterized by a layered structure of the annular cross-section. Samples were taken from the power pole E10.5/6c (Strunobet-Migacz, Lewin Brzeski, Poland) made by one of the Polish manufacturers of prestressed concrete E-poles precast in steel molds. The validation shows that optical scanning followed by appropriate image analysis is an effective method for evaluation of the spun concrete internal structure. In addition, such analysis can significantly complement the results of laboratory methods used so far. In a fairly simple way, through the porosity image, it can reveal improperly selected parameters of concrete spinning such as speed and time, and, through the distribution of cement content in the cross-section of the element, it can indicate compliance with the requirement for corrosion durability of spun concrete. The research methodology presented in the paper can be used to improve the production process of poles made of spun concrete; it can be an effective tool for verifying concrete structure.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Molecular Diversity Preservation International
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  • 6
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    On the interpretation of seismic cone penetration test (SCPT) results (2013)
    De Gruyter
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    Publication Date: 2013-12-01
    Description: The paper deals with the methodology of performing and interpretation of seismic cone penetration test (SCPT). This type of test is used to determine velocity of the seismic wave in the soil medium. This study is focused on shear wave. The wave is triggered on the ground surface by hitting an anvil with a sledgehammer. Then, vibrations induced at different depths are measured. Based on recorded measurements wave velocity (Vs) and thus also small strain shear modulus Gmax may be calculated. An interpretation of exemplary seismic test results is presented. Crossover and cross-correlation methods are discussed and another, more adequate one is featured and then applied in the interpretation example. Conditions for correct test performance and interpretation are discussed.
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 7
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    SHAPE OPTIMIZATION OF UNDERGROUND EXCAVATION BY SIMULATED ANNEALING (2013)
    De Gruyter
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    Publication Date: 2013-03-01
    Description: The paper deals with the problem of shape optimization of underground tunnel excavation. In the pioneering work of Sałustowicz, the elliptic shape was assumed a priori to be an optimal one and then a determination of suitable semi-axes ratio was only the question. Two cases were distinguished there: self-supporting excavation and excavation with the structural support. An evolutionary structural optimization (ESO) procedure, employed in 2005 to optimize shape of underground excavation, confirms the assumptions concerning the case of self-supporting excavations. The case of supported excavation is considered in the present work. Optimization procedure of the simulated annealing (SA) is incorporated in the study. An energetic optimality condition, formulated in the authors’ previous papers is also adopted. Itasca FLAC software is utilized in numerical examples. Four different in situ stress ratios are investigated. The numerical results obtained confirm that the optimal shape tends to be an ellipse. The semi-axes ratio demonstrates compliance with the assumptions already existing in literature.
    Print ISSN: 0137-6365
    Electronic ISSN: 2083-831X
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 8
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    ON THE INTERPRETATION OF THE NEEDLE PROBE TEST RESULTS: THERMAL CONDUCTIVITY MEASUREMENT OF CLAYEY SOILS (2013)
    De Gruyter
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    Publication Date: 2013-03-01
    Description: Recently, there is an increasing need for accurate and rapid thermal measurement of soils. Within a variety of available methods a needle probe test is most widely used. The needle probe method was standardized for the measurement of thermal conductivity of soils and soft rocks. In the paper, two different interpretation methods of the needle probe test were used for determination of thermal conductivity of selected soils. The first method (ASTM D5334-05 Standard approach) takes into account only the data which are recorded during heating while the second approach is based on fitting the known analytical solution to the data obtained within both heating and cooling phases. The soil samples used were classified as clayey ones. Laboratory tests were performed using the KD2Pro thermal conductivity meter (Decagon Devices) with a TR-1 sensor. The main goal of the paper is to show that the selection of interpretation method is very important and may lead to significant differences in resulting thermal conductivities.
    Print ISSN: 0137-6365
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    Topics: Architecture, Civil Engineering, Surveying , Geosciences
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  • 9
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    Application of Nanoindentation and 2D and 3D Imaging to Characterise Selected Features of the Internal Microstructure of Spun Concrete (2019)
    Molecular Diversity Preservation International
    Details
    Publication Date: 2019-03-27
    Description: The spinning of concrete is a process in which concrete mixture is moulded and compacted under the action of the centrifugal force arising during the fast rotational motion of the mould around its longitudinal axis. As a result of the spinning of the liquid concrete mixture, an element annular in cross section, characterised by an inhomogeneous layered wall structure, is produced. The heavier constituents tend towards the cross-section wall’s outer side, while the lighter components tend towards its inner side. The way in which the particular constituents are distributed in the element’s cross section is of key importance for the macro properties of the manufactured product. This paper presents procedures for investigating spun concrete and interpreting the results of such investigations, which make it possible to characterise the microstructure of the concrete. Three investigative methods were used to assess the distribution of the constituents in the cross section of the element: micro-computed tomography (µCT), 2D imaging (using an optical scanner) and nanoindentation. A procedure for interpreting and analysing the results is proposed. The procedure enables one to quantitatively characterise the following features of the microstructure of spun concrete: the mechanical parameters of the mortar, the aggregate content, the pore content, the cement paste content, the aggregate grading and the size (dimensions) of the pores. Special attention is devoted to the determination of the variation of the analysed quantities in the cross section of the element. The result of the application of the investigative procedures is presented for an exemplary spun concrete element. The proposed procedures constitute a valuable tool for evaluating the process of manufacturing spun concrete elements.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Molecular Diversity Preservation International
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  • 10
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    Assessment of the Condition of Wharf Timber Sheet Wall Material by Means of Selected Non-Destructive Methods (2019)
    Molecular Diversity Preservation International
    Details
    Publication Date: 2019-05-10
    Description: This paper presents an assessment of the condition of wood coming from a wharf timber sheet wall after 70 years of service in a (sea) water environment. Samples taken from the structure’s different zones, i.e., the zone impacted by waves and characterised by variable water-air conditions, the zone immersed in water and the zone embedded in the ground, were subjected to non-destructive or semi-destructive tests. Also, the basic parameters of the material, such as its density and moisture content, were determined. Moreover, the ultrasonic, stress wave and drilling resistance methods were used. Then, an X-ray microtomographic analysis was carried out. The results provided information about the structure of the material on the micro and macroscale, and the condition of the material was assessed on their basis. Also, correlations between the particular parameters were determined. Moreover, the methods themselves were evaluated with regard to their usefulness for the in situ testing of timber and to estimate, on this basis, the mechanical parameters needed for the static load analysis of the whole structure.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Molecular Diversity Preservation International
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