冀伟 孙斌 白倩 罗奎

摘要：為科学合理计算钢-混组合梁在长期荷载作用下的挠度，综合考虑钢梁与混凝土桥面板层间滑移效应、钢-混组合梁全截面剪切变形及混凝土桥面板收缩徐变的影响，运用能量变分法推导出钢-混组合梁挠度计算的控制微分方程.引入均布荷载作用下简支和两跨连续钢-混组合梁的自然边界条件，求解出了钢-混组合梁在这两种边界条件下的挠度计算公式.计算公式的可靠性得到了实测值和有限元值的验证.研究结果表明：考虑剪切变形与层间滑移后，两跨连续钢-混组合梁跨中最大挠度计算值相对于初等梁理论增大37.4%，而同时考虑混凝土收缩徐变后其挠度计算值增大58%；简支钢-混组合梁考虑混凝土的收缩徐变后挠度计算值相对于初等梁理论增大1.55倍，可见混凝土的收缩徐变效应对钢-混组合梁的挠度影响较大.研究成果可为实际工程中钢-混组合梁在长期荷载作用下的挠度计算提供理论依据.

关键词：钢-混组合梁；收缩徐变；长期性能；层间滑移；挠度分析

中图分类号：U448.216文献标志码：A

基金项目：国家自然科学基金资助项目（51708269，51868039），National Natural Science Foundation of China（51708269，51868039）；中国博士后科学基金资助项目（2018M643766），China Postdoctoral Science Foundation（2018M643766）；兰州交通大学“百名青年优秀人才培养计划”基金资助项目

Calculation and Analysis of Deflection for Steel-concrete Composite Girder under Long-term Loads

JI Wei1，SUN Bin2，BAI Qian1，LUO Kui1

（1. College of Civil Engineering，Lanzhou Jiaotong University，Lanzhou 730070，China；2. Chongqing Railway Group Co Ltd，Chongqing 401120，China）

Abstract：In order to accurately calculate the deflection of steel-concrete composite girders under long-term loads，considering the shear deformation of composite girder，slip effect at the steel-concrete interface and shrinkage and creep of the concrete slab，the equilibrium differential equations for calculating the deflections of steel-concrete composite girder are derived by using the energy variational method. By introducing the boundary conditions on the simply supported and continuous composite girders under uniformly distributed load，the deflection calculation formu-las can be obtained. The reliability of the calculation formulas is verified by comparing the experimental results and the results of finite element analyses. The results show that maximum deflection of two-span continuous composite girder considering shear deformation and interlayer slip increases by 37.4% when compared with the results from pri-mary beam theory，and the deflection increases by 58% after considering the shrinkage and creep of concrete. The calculated maximum deflection of simply supported composite girder after considering the shrinkage and creep of con-crete is 1.55 times larger than that of the primary beam theory. It can be seen that shrinkage and creep can have a sig-nificant influence on the girder’s deflection. The research results can provide a theoretical basis for the deflection cal-culation of steel-concrete composite girders under the long-term loads.

Key words：steel-concrete composite girder；shrinkage and creep；long-term behavior；interfacial slip；deflec-tion analysis

钢-混凝土组合结构可以充分发挥混凝土与钢材各自的优点，即混凝土主要抗压，钢材主要抗拉，结构受力较为合理.钢-混凝土组合结构特别适用于装配式中等跨径桥梁及快速施……