带加劲肋腹板开洞组合梁极限承载力理论研究

THEORETICAL STUDY ON ULTIMATE BEARING CAPACITY OF COMPOSITE BEAMS WITH REINFORCED WEB OPENING

基于空腹桁架破坏机理,根据腹板开洞组合梁在极限状态下的洞口区域塑性应力分布建立洞口4个次弯矩函数。提出了一种带加劲肋腹板开洞组合梁极限承载力的计算方法,该方法考虑了洞口上方混凝土板对组合梁的竖向抗剪承载力的贡献。计算结果表明:洞口设置加劲板能有效的提高腹板开洞组合梁的抗弯和竖向抗剪承载力,而且竖向抗剪承载力随着加劲板面积的增大而增大,混凝土板对组合梁的抗剪承载力有较大的贡献。并与试验和有限元结果进行了比较,结果吻合较好,算例验证了该计算方法的准确性和可靠性。

Based on the failure mechanism of vierendeel truss, four secondary moment functions are developed according to plastic stress distribution at the perforated section of composite beam in ultimate limit state. A method for ultimate strength analysis of steel and concrete composite beams with reinforced rectangular web openings is presented, which can account for the contribution of the concrete slab to the shear strength of the composite beam. The calculated results show that the bending and vertical shear capacity of composite beam with web opening can be effectively enhanced by reinforced opening. The vertical shear capacity increases notably with the increase of stiffener plate area, and concrete slab has significant contribution to the shear strength. Comparison shows that the theoretical results agree well with the experimental and finite element method （FEM） results, with some examples illustrating the accuracy and reliability of the present method.