部分充填混凝土窄幅钢箱组合梁抗裂性能研究

Study on crack resistance of concrete-partial-filled narrow-width steel box composite beams

为了研究充填混凝土窄幅钢箱连续组合梁负弯矩区的弯曲性能,以及栓钉间距、配筋率对连续组合梁负弯矩区混凝土翼板抗裂性能、裂缝开展和宽度的影响,完成3根反向加载的简支组合梁的静力加载试验;考虑翼板混凝土收缩应力的影响,推导出连续组合梁负弯矩区翼板开裂弯矩理论计算公式。试验结果表明,在较低荷载下连续组合梁翼板负弯矩区就会开裂,而发生明显的内力重分布;箍筋间距对裂缝间距有一定的影响,且剪力连接程度和配筋率对连续组合梁负弯矩区裂缝发展以及宽度的影响较明显,适当增加配筋率可以减小组合梁负弯矩区翼板最大裂缝宽度。通过求解组合梁负弯矩区的开裂弯矩,考虑收缩应力的影响能够更准确的控制混凝土的开裂,并对计算值与试验值进行比较,证明这种理论计算式是可行的。

In order to study the bending capacity of concrete-partial-filled narrow-width steel box composite beams in negative moment regions, and the stud spacing well as the different reinforce-ment amount used to the composite beam negative moment region concrete slab the crack resistance, crack development and the width influence, three beams flexure behaviors under negative moments have been tested. A formula for calculating crack-moment relationship was established in considera-tion of the influence of concrete shrinkage stress, comparing the calculation and test results are simi-lar. Result showed, the internal force redistributes in the continuous composite beams negative mo-ment regions due to concrete cracking when the load is very small,and the crack space is influenced by the stirrup space;The factors such as connection-degree and reinforcement amount would affect the continuous composite beams crack develop and width. Appropriate increase reinforcement amount can decrease the negative moment region of the composite beams of maximum crack width. Solving the cracking moment in negative moment area of the composite beam, the influence of concrete shrinkage stress was considered to control cracks of the concrete more accurately, verifying the feasi-bility of the approach which was put forward in the paper by comparing calculation results and exper-imental results.