Analysis On Shear Behavior Of Prestressed Steel Reinforced Ultra-High-Strength Concrete Beams

In recent years, with the rapid development of China’s economic construction, and large-scale investment in transportation infrastructure, a variety of new structures are emerging. The large span, overload, good durability and the high-energy and low-cost thinking of structural materials gradually becomes the developing direction. And prestressed steel reinforced ultra-high-strength concrete structure is such a demand new structure, which has advantages of ordinary prestressed concrete structures, steel reinforced concrete structure and the ultra-high-strength concrete structure. Prestressed steel reinforced ultra-high-strength concrete beams can combine the compressive performance of ultra-high-strength concrete and the tensile properties of post-tensioned tendons, and its ductility is also improved by the application of shaped steel. So it is a structure with excellent performance and broad application prospects. But currently, at home and abroad there are very few research literatures on the force performance and design methods for prestressed steel reinforced ultra-high-strength concrete structure, and there are no related design specifications, which makes prestressed steel reinforced ultra-high-strength concrete structure lack strong theoretical support in design and construction. So the research in mechanical properties of prestressed steel reinforced ultra-high-strength concrete beams is very necessary.According to the National Natural Science Foundation project, namely study on the mechanical behavior of prestressed steel reinforced ultra-high-strength concrete bridge and calculation methods, and based on a shear experiment analysis of8prestressed steel ultra-high-strength concrete simply supported beams, the normal section crack load, the inclined section crack load, yield load, ultimate shear bearing capacity, characteristics of load-deflection curves, cracks and failure patterns of the beams under concentrated loads are analyzed in this paper. The effects of prestress degree, stirrup ratio and steel ratio of steel web on the shear bearing capacity and ductility are also thoroughly researched through the experiment. The calculation equation of the shear bearing capacity of such beams under concentrated loads is thus obtained by regression and the calculation results are very close to the experimental results. On the basis of the experimental results, the finite element program ANSYS is used to simulate comprehensive shear properties of prestressed steel reinforced ultra-high-strength concrete beams and the numerical simulation results agree well with the experimental results, which verifies the applicability of ANSYS program for prestressed steel reinforced ultra-high-strength concrete beams.