基于弯矩曲率法的U型外包钢混凝土组合梁延性及受弯性能分析

Ductility and flexural behavior analysis of steel-encased concrete composite beams based on moment-curvature method

为研究U型外包钢混凝土组合梁在静载作用下的延性及受弯性能,对5根缩尺简支组合梁进行两点对称集中加载试验研究。通过对试件在加载作用下的荷载-挠度曲线、荷载-应变曲线、截面应变沿高度分布规律的研究,提出弯矩曲率法在组合梁加载过程中受力模拟的程序算法。基于简化塑性理论公式对组合梁的截面弯矩进行理论计算,两者对比试验结果比较吻合,从而有效验证了弯矩曲率法的合理性,并依据构件计算所得的截面曲率与位移延性系数对U型外包钢混凝土组合梁的延性开展深入分析。

In order to study the ductility and flexural performance of U section steel encased concrete composite beam under static load, the experiments of five scale simply suppo（ted composited bridge under symmetrical two concentrically loads are carried out. By studying the load-deflection curves, load-strain curves and cross-strain change along height for samples under loading, a program algorithm for moment-curvature method used to simulate the composited bridge under loading is raised. Meanwhile, using the simplified plastic theory to calculate the cross section for the comparison with experimental results, the two results are identical, and it indicates the rationality of moment-curvature method effectively. Besides, deep analysis about the ductility of U section steel encased concrete composite beam is conducted according to sectional curvature and displacement ductility index once calculated.