Theoretical Analysis And Experimental Study Of Flexural Bearing Capacity For Pretensioned Prestressed T-shaped Concrete Beam With Bent-tendons

Application of prestress technology is one of the effective solutions for the problem of the cracking of regular concrete.It can make the prestress distribution more flexible that bending the pre-stressed steel bars into fold lines,meeting to the requirements of large span structure.Pretensioned prestressed beam bridges with bent tendons have the advantages of good duribility and fsat construction,which have a broad prospect of application.However,the experimental research and theoretical analysis of the mechanical behavior of the pre-tensioned prestressed beams with bent tendons are still insufficient.This thesis focus on the analysis of ultimate bearing capacity of the pre-tensioned prestressed beams in approaches of theoretical analysis,experimental research and finite element simulation.It will also analysis the influence of the layer of post-placed concrete on the ultimate bearing capacity of the beams.In this thesis,the mechanical behavior of the prefabricated T-Shaped beam with the layer of post-placed concrete is analyzed,and the calculation method of the ultimate bearing capacity of the superposed structure is proposed,basing on a high-way project which has applied 35-meter prefabricated pre-tensioned prestressed T-beam with double bent tendons.Two full-scale model beams are designed to make static destruction test,one of which is prefabricated pre-tensioned prestressed T-beam,and the other of which is prefabricated T-Shaped beam with the layer of post-placed concrete.The thesis analyses the mechanical characteristics and failure process of the beams according to some measurable indicators,such as deflection,strains of concrete and steel,crack development and ultimate bearing loads.Meanwhile,the test model beams are simulated by using the three-dimensional finite element software ABAQUS.The concrete plastic damage model and the ideal elastic-plastic reinforced bar model are used to carry out the non-linear finite element calculation.The calculated results are in good agreement with the experimental results.The author caculates the ultimate bearing capacity with the 35-meter prefabricated pre-tensioned prestressed T-Shaped beam with double bent tendons with the layer of post-placed concrete,hoping that it can provide a reference for the design of similar structures.