中文摘要：

对工字型钢-混凝土连续组合梁负弯矩区腹板在复合应力作用下的力学性能进行了研究,提出了工字型组合梁腹板在复合应力作用下的局部稳定性计算模型,建立了相应的临界屈曲应力计算公式;基于组合梁腹板的稳定性特点和偏心受压与剪切作用下的相关方程,计算了工字型组合梁腹板在复合应力状态下的弹性屈曲因数,采用势能驻值原理分析得出了连续组合梁负弯矩区腹板稳定的临界应力,提出了弹性受力阶段腹板不设横向加劲肋的高厚比限值。计算结果表明：该计算方法有广泛的适用性,且大部分情况下可以放宽对高厚比的限制,为工字型组合梁负弯矩区腹板的合理优化设计提供了参考。

英文摘要：

The mechanical behaviors of continuous composite beam web in negative moment area under the load of complicated stress were studied, and the calculation model of local stability under the load of complicated stress was proposed, meanwhile, the corresponding calculation formulas of limited buckling stress were built. Based on the stability characteristics of composite beam web, according to the relevant equations under the action of eccentric compression and shear, the elastic buckling factors of I-section composite beam web under the complicated stress state were calculated. Furthermore, using potential energy principle, the limited stresses of continuous composite beam web in negative moment area were analyzed, and the limiting height to thickness ratio was also determined for webs without stiffing ribs in the elastic stage. The calculated results show that the method has broad applicability, and in most cases, the restrictions of height to thickness ratio can be relaxed, and it can provide reference for the reasonable optimization design of I-section composite beams web in negative moment area