长期效应下不同边界钢-混凝土组合梁挠度分析

Deflection analysis of steel-concrete composite girders with different boundaries under long-term effects

为了研究长期荷载效应对钢-混凝土组合梁挠度的影响,本文对不同边界钢-混凝土组合梁进行分析。考虑组合梁的剪切变形、层间滑移及剪力滞效应,引入长期荷载下的混凝土收缩徐变作用,运用能量法和变分原理推导出均布荷载作用下不同边界条件的组合梁长期挠度解析解,并通过有限元和试验结果验证了解析解的正确性。通过简支组合梁、固结组合梁和连续组合梁3个算例的挠度分析结果表明:长期荷载作用对组合梁总挠度影响较大,对两跨连续梁尤其显著;除长期荷载影响外,简支组合梁挠度主要受层间滑移作用的影响,两端固结梁挠度主要受剪切变形和层间滑移作用的影响,两跨连续组合梁挠度主要受层间滑移作用的影响;3种不同边界条件的钢-混凝土组合梁挠度受剪力滞效应的影响最小。

In order to study the effect of long-term loading on the deflection of steel-concrete composite griders,steel-concrete composite griders with different bounderies were analyzed.By considering the shear deformation,in-terlayer slipping and shear lag effect of composite girders and introducing the concrete shrinkage and creep effect under long-term loads,the analytical solution of the long-term deflection of composite girders under different bound-ary conditions and uniform load is derived by the energy method and variational principle.Then,the correctness of the analytical solution is verified by the finite element and test results.The deflection analysis results of a simply supported composite girder,consolidated composite girder,and continuous composite girder show the following:A long-term load has a great influence on the total deflection of composite beams,especially for two-span continuous beams.In addition to the influence of the long-term load,the deflection of a simply supported composite girder is mainly affected by the interlayer slip,the deflection of consolidated composite girders at both ends is mainly affect-ed by a shear deformation and an interlayer slip,and the deflection of the two-span continuous composite girder is mainly affected by the interlayer slip.Moreover,the deflection of steel-concrete composite girders under three dif-ferent boundary conditions is least affected by the shear lag effect.