Study On Shear Behavior Of Prestressed Steel Reinforced Ultra-high-strength Concrete Beams

Prestressed steel reinforced concrete beam(PSRCB) is a new structural system, which has advantages of both prestressed concrete and reinforced concrete. Most studies on PSRCB, made by domestic and foreign scholars concentrate on concrete below C60, which is difficult to resist the complex and harsh environment. Therefore it is obviously inadequate in terms of durability. Due to the excellent durability of ultra-high-strength concrete, C100is used of PSRCB in the article. Prestressed steel reinforced ultra-high-strength concrete beams(PSRUHCB), can combine both the tensile property of post-tensioned tendons and the compressive performance of ultra-high-strength concrete. The ductility can also be improved by the application of steel, which reflects the trend of modern structural material to high-energy and low-cost.On the basis of the existing study, combined with the National Natural Science Foundation project-study on the mechanical behavior and calculation methods of prestressed steel reinforced ultra-high-strength concrete bridge. Monotonic static loading on7prestressed steel reinforced ultra-high-strength concrete beams and non-linear numerical simulation are operated. The following aspects are carried out:(1) The recent main achievements of ultra high strength concrete, prestressed steel reinforced concrete and shear behavior of high strength reinforced concrete beams are briefly reviewed and summarized in this paper.(2) The article briefly describes the preparation process and optimization of mixture ratio, as well as pouring of specimens.(3) Static experimental study is implemented on the specimens for the research of effects of the following factors:failure process, failure characteristics, characteristic value of loads, the bearing capacity of the beams, damage morphology, the load-displacement curve, prestressing ratio, steel ratio, stirrup ratio, web thickness, deflection and cracks are also analyzed based on test results.(4) Based on the test results, in order to obtain comprehensive shear performance of PSRUHCB, the finite element program ANSYS is established to simulate PSRUHCB subjected to shearing under static load, and the calculated and experimental results are compared. The test results, cracking load, ultimate load, crack development process, stress analysis and load-displacement curve calculated from the analysis model are very close to the experimental results, which verifies the correctness of the finite element model.(5) By comparing the load-displacement curve with the same parameters on different levels, research and analysis are operated on the influence of the designed parameters over the bearing capacity of the ultimate state and normal use limit state of prestressed steel reinforced ultra-high-strength concrete beams.