装配式双拼槽钢-混凝土组合梁抗弯刚度试验研究

Experimental study on flexural stiffness of prefabricated double C-shaped steel channel-concrete composite beams

提出一种新型装配式双拼槽钢-混凝土组合梁。为研究该组合梁的抗弯刚度,对7根组合梁的受弯性能进行试验,试验参数为混凝土翼缘板宽度、槽钢型号和抗剪连接件间距。首先,研究双拼槽钢-混凝土组合梁的协同工作性能和各参数对双拼槽钢-混凝土组合梁抗弯刚度的影响。然后,根据能量变分法和界面滑移模型,建立装配式双拼槽钢-混凝土组合梁的控制微分方程,并基于最小势能原理推导该组合梁考虑滑移效应的挠度计算公式。研究结果表明:组合梁整体工作性能良好,两侧预制模块能协同工作,高强螺栓能有效约束2个预制模块的分离;钢板连接件能有效传递界面剪力,槽钢与混凝土板之间有较强的组合作用;增加混凝土翼缘板宽度对装配式双拼槽钢-混凝土组合梁的抗弯刚度提高幅度较小;增大槽钢高度,装配式双拼槽钢-混凝土组合梁刚度显著提高;当槽钢型号由[32b转换为[40b时,抗弯刚度提高117.8%;抗剪连接件间距由250 mm增大到750 mm,组合梁抗弯刚度降低6.9%;组合梁考虑滑移效应的挠度计算公式理论值与实验值吻合良好,可为装配式双拼槽钢-混凝土组合梁在实际工程中的设计与应用提供参考。

A new type of prefabricated double C-shaped steel channel-concrete composite beam(DCCB)was proposed.In order to study the flexural stiffness of the composite beam,bending tests on seven DCCB specimens were firstly carried out.The investigated parameters were the concrete flange width,the size of channel and the spacing of the shear connectors.The synergistic performance of DCCB was studied,and the influence of various parameters on the flexural stiffness was explored.According to the energy variation method and the interface slip model,the governing differential equation of DCCB was established,and the deflection calculation formula considering the slip effect was deduced by using the minimum potential energy principle.The results show that the overall performance of the composite beam is good,the prefabricated modules on both sides can work together,and the high-strength bolts can effectively restrain the separation of the two prefabricated modules.The steel plate connector can effectively transmit the interface shear force,and there is a strong combined effect between the C-shaped steel channel and the concrete slab.Widening the concrete flange width has little effect on the improvement of the flexural stiffness of DCCB.Increasing the channel size has a significant effect on improving the stiffness of DCCB.When the channel size is changed from[32b to[40b,the bending stiffness is increased by 117.8%.The increase of the shear connector spacing from 250 mm to 750 mm results in a 6.9%reduction in the stiffness of the composite beam.The calculation result obtained by using the minimum potential energy principle is in good agreement with the experimental result,which can provide reference in practical engineering.