Flexural Capacity Analysis of Prestressed Bent Cap with Precast Shell Formwork and Core-filled Concrete

JIA Junfeng; ZHANG Zhipeng; WU Zhiyong; ZHANG Fengchun; ZHAO Liansheng; DUAN Zhaohui

doi:10.15926/j.cnki.issn1672-6871.2024.06.007

Abstract：To solve the technical issues such as the heavy lifting weight of the integral prefabricated bent caps and the difficulty in achieving prefabricated assembly,an ABAQUS finite element model was established and its validity was verified based on the completed 1∶2 large-scale bending static load test of the partially prefabricated prestressed composite bent cap with post-cast concrete inside the prefabricated ultra-high performance concrete(UHPC)shell.On this basis,the influence of concrete strength,longitudinal reinforcement ratio,prestressing steel reinforcement ratio and bonding strength of the interface on the bearing capacity and failure mode of the prestressed composite bent cap were analyzed.Based on the experimental and finite element calculation results,a calculation method for the bending-bearing capacity of the prefabricated shell bent cap was established.The research results show that the composite bent cap have excellent mechanical and deformation performance.The interface shear keys can effectively strengthen the interface bonding strength,and the peak bearing capacity is 57.5％higher than that of the smooth interface.Using a bonded contact at the interface will overestimate the peak bearing capacity of the bent cap.When the shell material is UHPC,the peak bearing capacity increases by 28.4％compared to C50 concrete.The longitudinal reinforcement ratio and prestressing steel reinforcement ratio exhibit a linear increase trend in peak bearing capacity.The bending-bearing capacity calculation results using the method proposed in this paper is in good agreement with the experimental and finite element results.