界面滑移和剪切变形对钢-UHPC组合梁长期挠度影响研究

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中图分类号：TU378.2 文献标志码：A

Abstract： With the remarkable distinction of the shrinkage and creep behavior of ultra-high performance concrete （UHPC） and normal concrete（NC），the long-term deflection of steel-UHPC and steel-NC composite beams is significantly diffrent.In order to accurately calculate the deflection of steel-UHPC composite beams under long-term loads，the efects of interface slip and shear deformation are comprehensively studied in this paper.The interface slip of steel-UHPC composite beams is calculated iteratively by introducing Timoshenko beam theory to consider the structural shear deformation. The method for calculating the long-term deflection of steel-UHPC composite beams is derived by using the age-adjusted effective modulus method to consider the creep behavior of UHPC.By comparing the test data with the calculated resultsof steel-NC composite beams in existing literature，the reliability of the calculation formulas is verified.In addition，a steel-UHPC composite beam and a steel-NC composite beam with the same size are analyzed.The results show that ifonly shrinkage and creep are considered，the long-term deflection of steelNC composite beams is 2.64 times of the initial loading stage deflection and it increases by 31.86% and 4.4% ，respectively，for steel-UHPC composite beams cured at room temperature and high temperature. With the slip included，the deflection of stee-NC composite beams and that of steel-UHPC composite beams both increase by about 13.35% . However，on the 500th day，the former deflection increases by 23.66% ，and the latter cured at room temperature and high temperature rises by 24.37% and 17.78% ， respectively.The deflection increment after considering shear deformation also increases with time by several times of the initial loading stage，but it isfarlessthan the total deflection.Therefore，the shear deformation has litle effect，while slip，shrinkage and creep have a great effect on the deflection of steel-UHPC composite beams.

Key words ：steel-UHPC composite beam; shrinkage and creep； interface slip； shear deformation; long-term deflection

钢-UHPC组合梁是将超高性能混凝土（ultra-highperformanceconcrete，UHPC）作为桥面板与钢主梁结合而形成的一种新型组合梁结构[1]。（剩余13182字）