In the given article the design of service life for hydraulic structure reinforced concrete elements has been performed analytically with the use of the basic techniques and by constructing reinforced structure protective layer carbonization models, mathematic modelling methods for physical processes. The main goal of the work is to determine the service life for reinforced concrete structures of spillways and its elements under impact of the environment during their operation.

The article reveals the fundamentals of engineering and designing mobile weir with rectangular opening for farmlands, applicable for measuring discharge in interfarm and temporary canals. It includes the fundamentals of choosing most efficient structural solutions for the weir, choosing material for fabrication of its main elements, performing the static design for weir horizontal beams according to marginal states of providing reliability and stability of weir main elements. Results of calculations of diameter of steel bar for rectangular weir with B=25cm showed that the diameter needed is 6mm. The diameter is small enough for the weir to be called a thin plate weir. Thus, using 6mm bar is reasonable enough from the point of view of stability and the by the requirements for a thin plate weir.

Great attention around the world is paid to the design and construction of riverbank protection and channel control structures on submountain section of rivers. High slopes (i=0,001÷0,004 and higher), flow kinetics and ability to transport large amount of sediments are the features of submountain section of rivers. Most of the research in this sphere has been conducted on the study of patterns of flow constrained by transverse structures in valley parts of rivers. The main goal of this work is to establish the physical picture of flow around a combined dam in submountian river, the through-flow part of which is made of tetrahedrons, as well as to develop a design method for flow velocity field. Formations of two regimes have been established experimentally, i.e. “calm” at ia<icr and “critical” at ia≥icr. These regimes are mainly affected by flow contraction degree na, and Froude number Fr. The presence of the following zones was established: core, intensive turbulent mixing and backflow zones, as well as the affinity of velocity fields in the zone of mixing by Shlihting-Abramovich. Prandtl has realized the task for “calm” regime with the use of integral relationship expressing law of conservation of momentum in the flow, equation for conservation of discharge and differential equation for nonuniform motion of transit flow with the account of tangential turbulent stresses on lateral surfaces. As opposed to the existing solutions, we accounted for the presence of two regions of spreading with different slopes of water surface, horizontal component of fluid weight, nonuniform distribution of velocities in head section, high roughness and the case when sections of target and vertical contraction do not match. Satisfactory results were obtained by comparing theoretical solution and experimental data.

The given method uses the safety coefficient by service life period and similar principles as for stochastic method. Moreover, the problem of forecasting the safety is examined in a deterministic form. The given option for the solution is compact in terms of design on an applied level in the format of the boundary conditions method, keeping the efficient control of safety within the service life period. This method has the advantage to design reinforced concrete structures for specified service life period. The proposed method is also applicable for the design of reinforced concrete elements of hydraulic structures in cases when the application of the other stochastic methods would be very complicated. The advantage of the given method is allowing including the stochastic nature of loading parameters and material strength.

Construction and operation of channel control structures in valley rivers require carrying out a comparative study of their operation during design operational periods. The goal of this work is to set target dimensions for flow deformed by the transverse blind dam in field conditions, on the dam № 30 in Amudarya river: the length of upstream and downstream vortex zones, boundaries between the core and intensive turbulent mixing zones, vortex zone boundaries, and their comparison with experimental data. Locations of the sections are set based on the possibility to accomplish the goal, in the headrace, where flow natural condition is maintained, in contraction zone, and within the borders of downstream vortex zone. Sections were fixed with landmarks and leveling instrument Vegal 24 was installed there. Zone boundaries and vortex lengths were set with the use of floats directly from the riverside of the use of boats. Design relationships obtained from the results of laboratory experiments were used to determine the length of upstream vortex zone, contraction area, downstream vortex zone, boundaries of hydraulically homogeneous zones, which were then compared with the field data. It was also set, that coefficients characterized flow spreading beyond the contracted section were equal to C 2 =0.186 and C 3 =0.545 as compared to 0.11 and 0.16 in the theory of turbulent jets. The length of vortex zones is shorter by 11.9% to 26.8%, which shows how much the distance between dams must be decreased in the system.