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传统预应力混凝土叠合梁大多采用矩形截面,存在自重大、运输及吊装困难等问题,提出了U形与倒T形两种预应力预制叠合梁。进行了3根U形预应力预制叠合梁、3根倒T形预应力预制叠合梁与1根整浇梁的对比试验,研究其破坏机理、受弯承载力、短期刚度、变形特征及裂缝分布等,并将试验结果与规范计算结果进行了对比。研究结果表明:从开始加载到破坏,叠合梁与整浇梁表现出相同的受力特点和变形特征;叠合梁的开裂弯矩、极限弯矩计算结果与实测值吻合较好,按整浇梁计算时比真实结果偏于安全;叠合梁的短期刚度及平均裂缝间距实测值与计算结果吻合较好。采用有限元程序ANSYS10.0进行模拟计算,计算结果与试验结果吻合良好。有限元结果表明:配筋适当的叠合梁与整浇梁的整体破坏特征基本相同;对于采用自然粗糙面的叠合梁,可不考虑叠合面相对滑移而按整浇梁进行计算分析。
Traditional prestressed concrete composite beams mostly adopt rectangular cross section, which has the problems of heavy weight, difficulty of transportation and hoisting. Prestressed prestressed composite beams with U shape and inverted T shape are proposed. Three U-shaped prestressed prestressed composite beams, three inverted T-shaped prestressed composite beams and a cast-in-situ concrete beam were compared to study the failure mechanism, flexural capacity, short-term stiffness and deformation characteristics and Crack distribution, etc., and compare the test results with the standard calculation results. The results show that: from the beginning of loading to failure, the composite beams and cast-in-situ beams show the same stress characteristics and deformation characteristics; the calculated results of cracking moment and ultimate bending moment of the composite beams are in good agreement with the measured values. The calculation of pouring beam is safer than the real one. The measured data of short-term stiffness and average crack spacing of composite beam agree well with the calculated results. The finite element program ANSYS10.0 was used to carry out the simulation calculation. The calculated results agree well with the experimental results. Finite element results show that the integral failure characteristics of the appropriate composite girder and the cast-in-situ concrete girder are basically the same. For the composite girder with natural rough surface, the integral girder can be calculated without considering the relative slip of the composite surface.