为研究新型部分充填式钢箱-混凝土组合梁裂缝开展、局部屈曲过程和竖向抗剪强度,对3根不同配筋率的试验梁进行了两点对称式反向加载试验,得到了试验梁的荷载-跨中挠度曲线、跨中应变分布曲线和剪应变分布曲线,分析了混凝土翼板配筋率和充填区混凝土对组合梁负弯矩区抗剪承载力的影响.通过塑性理论分析推导出抗剪承载力计算公式,计算值与试验值吻合良好.结果表明:在负弯矩作用下,充填区混凝土承担了截面的部分剪力,翼板区纵向钢筋抑制了混凝土翼板开裂,横向钢筋对剪力连接件起到约束作用;以上各项因素共同提高了组合梁的局部稳定性及抗剪承载力.
For the purpose of researching crack developing, local buckling process and shear strength of the new concrete-partial-filled steel box composite beam, the two points symmetric reverse loading experiments on three test beams with different reinforcement ratios were carried out. The load-mid-span deflection curve, the mid-span strain distribution curve and the shear strain distribution curve of the test beams were obtained. The influence of the reinforcement ratio of concrete flange and the shear capacity of concrete in the filling area under the hogging moment zone of composite beam were analyzed. The calculation formula of shear carrying capacity was deducted through plastic theory analysis and the calculated value is in good agreement with the experimental value. The results show that under the impact of hogging moment, concrete in the filling area carries part of the shear of the section, longitudinal reinforcement in the flange restrains the crack developing of concrete flange, and transverse reinforcement plays a role in restricting shear connectors; the above factors jointly improve the local stability and shear strength of the composite beam.