外包钢板-混凝土组合连梁试验研究(Ⅱ):应力与内力分析

Experimental research on concrete filled steel plate composite coupling beams(Ⅱ) : stress and internal force analyses

根据6根外包钢板-混凝土组合连梁试件的应变量测数据,计算得到了不同荷载水平下的钢板应力,并通过应力积分和截面内力平衡方程,得到了外包钢板和内填混凝土承担的各内力分量。结果表明:连梁钢腹板的屈服均先于或几乎与钢翼缘同时屈服。试件钢板开始屈服时的连梁剪力与峰值剪力的比值在0.61~0.76之间。达到峰值剪力时,除试件CFSCB-5外的其他试件的钢板都发生了明显的强化;钢腹板75%以上的区域的轴向正应力为拉应力,且靠近受压翼缘处的剪应力大于靠近受拉翼缘处的剪应力。连梁的外包钢板承担的剪力和弯矩比例在加载过程中会发生变化。在接近峰值剪力时,各试件的外包钢板承担的剪力比例在31%~60%之间,承担的弯矩比例在57%~87%之间;混凝土的剪力-轴压比与相应的连梁对角线与梁轴线的夹角的正切值接近。

Based on the measured strain data of six concrete filled steel plate composite coupling beam specimens,the steel plate stresses at different loading levels were calculated. The internal forces sustained by the steel plates and concrete infill were also attained through integration of the stresses and equilibrium equations of the section. The main results of the stress and internal force analyses are as follows: the steel webs yield before or nearly at the same time as the steel flanges. The shear forces when the steel plates begin to yield are between 61% and 76% of the peak shear forces. At the peak states,evident cyclic hardening happens to the steel plates of all the specimens except CFSCB-5; the axial stresses of more than 75% of the steel webs are tensile stresses,and the shear stress near the compressive flange is larger than that of near the tensile flange. The proportions of shear forces and bending moments sustained by the steel plates varies with the loading process. When approaching to the peak states,the proportions of shear forces and bending moments sustained by the steel plates are between 31% and 60%,and between 57% and 87%, respectively; the ratios of shear forces to axial compressions of the concrete infill are close to the tangents of the angles between the diagonals and axes of the coupling beams.