# RESEARCH OF STRENGTH AND DEFORMATIVITY OF PRESTRESSED MULTI-SPAN BEAM OF LENGTH 18 m UNDER DIFFERENT LOADING MODES

The paper presents only some problems of design and constraction of the bridge. The aim of the experimental study is to establish the behavior peculiarities of multi-span structure under the external static loading. The development of structure calculation methods for multispan reinforced concrete while taking into count the stages of its work is necessary to increase the effectiveness and widespread use of it. Improvement of structure calculation methods is an important problem. One of the main advantages of multi-span reinforced concrete structures is ability to simply create beam structures of static-indefinite systems with prestressed multispan and suppressed reinforcement. With its use, it is possible to adjust the stress both while structures. The program of static testing, the design schemes of testing loading and the devices for displacement and relative deformations measuring are proposed. Experimental-theoretical studies of prefabricated monolithic reinforced concrete pre-stressed beams of 18 m length were performed to study the load-carrying capacity, stiffness and cracking strength of the prefabricated elements at different stages of work at the installation stage of locking and comparing the data obtained with the calculations. The active provides the results of the research out composite muilti-span prestressed reinforced concrete beam for time building bridges. Comparison of experimental and theoretical sizes. Values of crack resisting, deformation property and strength index are received, work stages and studied slabe collapse odes are also described. The characteristic stage of the tensely deformed state are selected. State and practic making of multi-span iron concrete constractions by high productive modern technology. The analysis of the got results of experimental research is executed. The investigation of the large-scale bridge structure with bringing them to failure, thus avoiding the scale factor effect, is very important. Improving methods for calculation will provide the lower expence of materials when designing rainforced concred strutuctes and allow more efficient using all elements that make the constraction.

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