ALBERT

Notes: Conclusions 1. Inspections of the Zhitomir dam showed that during its 15-yr operation the negligible cracks that appeared have not affected the strength of the structure, which confirmed the main theoretical and constructional decisions made during design and construction. 2. To improve monitoring of the condition of the hydraulic structures, it is recommended to equip them with measuring instruments (height markers, piezometers).

Notes: Conclusions 1. The measuring and monitoring equipment installed at the Kanev hydrostation permit systematic monitoring of the state and behavior of the main structures; the organization of on-site observations was rather successful and is recommended for use at other objects. 2. The data of the on-site observations confirmed the completely reliable state of the structures during construction and operation. 3. Safety and reliability of structures are provided by reliable designs and high-quality performance of the construction and assembly works, as well as by good organization of engineering supervision, which includes measures on conducting constant observations of the structures with observance of the technical operating regulations.

Notes: Conclusions 1. The monitoring and measuring instruments installed according to the design of the research department of Ukrgidroproekt, about 90% of which are still operating, on the navigation structures of the Kanev hydroelectric station enables the lock operating service to systematically check the state and behavior of the concrete and earth structures. 2. The data of on-site observations showed the reliable state of the structures in the construction period and in the period of temporary operation. Settlements of the sections occurred mainly uniformly and reached 40–65 mm. The relative movements of adjacent sections in the plane of the joints are insignificant and for the majority of joints did not exceed 1 mm, their slightly greater values were noted in the abutments to the lock heads and for certain sections of the jetties. The seasonal amplitudes of the width of opening of the joints was on average 5–8 mm. 3. The upper parts of lock chamber walls moved toward the lock axis in the winter and toward the backfill in the summer. The total movement of both walls into the chamber (from summer to winter) is equal to 15–17 mm, the movements caused by filling and emptying of the chamber are equal to 4–5 mm. 4. The groundwater levels behind the lock chamber walls changed in conformity with the seepage flow from the upper to the power pools.

Notes: Conclusions 1. The watertight and drainage elements of the concrete structures according to the results of on-site observations are operating rather effectively. A large part of the seepage head is reduced on the blanket and sheet piling parts of the underground contour. The residual heads behind the sheet piling under the powerhouse are close to the design. 2. The hydrostatic levels vary almost linearly with variations of the lower pool level. The hydrostatic levels in the backfill of the left-bank abutment due to the difference of geological conditions are 0.6–1.5 m higher than on the right-bank abutment.

Notes: Conclusions 1. The distribution of contact stresses under the buttress wall of the section of the cellular abutment of the Kiev and Kanev hydrostations in general differ from the linear distribution obtained by formulas of eccentric compression, in which the foundation of the frame is assumed absolutely rigid, which are widely used in calculation practice. For a more complete correspondence to the actual behavior of the structure, it is obviously necessary to take into account the finite rigidity of the foundation in calculations. The relation between the average stresses under the frame and on the base of the cells (the coefficient of nonuniformity of stresses) depends not only on the relationship of the moduli of deformation of the fill soil and soil of the foundation and other factors taken into account in calculations but also to a considerable degree on the characteristics of the technology of constructing the abutment, such as the rate of construction, degree of lagging of filling during construction, degree of deviation of the schemes of work on filling and compacting the soils from the design schemes. 2. The character of the stresses in the horizontal reinforcement of the buttress wall shows that their redistribution and concentration in the corners of the precast slabs are largely due to general misalignment of the section in a transverse direction due to differential settlement. Despite the fact that high stresses developed in the extreme (with respect to height) reinforcing bars of certain slabs, the overwhelming majority of bars in practically every slab and as a whole for the wall are underloaded and have a considerable factor of safety. With consideration of the continuing insignificant increase of opening of the joints and tensile stresses at individual points and the effect of corrosion, the stresses at several points can exceed the yield strength of the reinforcement, but in this case a redistribution of the stresses will occur and the load will be absorbed by adjacent underloaded bar, both of the given slab and of adjacent ones, i.e., the overall strength of the wall is ensured. 3. The earlier used method of calculating the overall strength of a cellular construction as an eccentrically compressed monolithic beam based on the hypothesis of plane sections [2] is far from the actual behavior of the structure and therefore is inapplicable. The method of calculating the overall strength of a frame on the basis of the theory of composite beams with representation of the precast slabs as infinitely rigid transverse members and members in shear [5] reflects the actual stress state of the structure, but the calculated stresses are substantially less than the actual ones at points of concentration and the given method does not explain the continuing increase of stresses. Evidently, in calculations of cellular constructions on weak soils it is necessary to take into account the flexibility of the foundation and yielding of the foundation soil.

Notes: Conclusions 1. According to results of inspections and full-scale monitoring by workers from the scientific research division of the Ukrainian Institute for Designing of Hydrotechnical Construction, and also analysis of all of the data from full-scale observations during the period of the lock's operation, it is noted that safe and reliable operation of the structures is provided by the design and high-quality performance of construction and erection work, and also by the organization of inspection, which includes measures to conduct constant observations of the structure, with observance of the rules of technical operation. 2. Settlements of concrete structures occurred mostly evenly and did not exceed 7.6 mm during the observed period. Relative movements of adjacent sections in the plane of joints did not exceed 3.2 mm; a somewhat larger value of them was noted in sections adjacent to the ends of the lock. The seasonal amplitude of the width of opening of joints was 0.3–6.8 mm. The amplitude of seasonal displacements of the top of the walls with a full chamber is almost two times less than with an empty one. 3. To improve monitoring of the structures' condition, for example, in sections adjacent to the downstream and upstream ends of the lock with mooring, it is recommended that the operating personnel be equipped with elevation and gap-measuring marks, and it is also suggested that they follow the instructions for observations at hydrotechnical structures.