考虑施工阶段界面滑移钢-混组合梁刚度折减研究

Study of Rigidity Degradation in Steel-Concrete Composite Girder Construction Considering Interface Slippage

为了解施工阶段界面滑移作用对钢-混组合梁刚度的影响特征,以平阴黄河大桥主桥——钢-混组合梁斜拉桥为背景,设计3组不同长度剪力钉推出试验,研究剪力钉长度对剪力连接件承载力及剪切刚度的影响规律,并基于能量准则,推导剪力钉连接件剪切刚度计算公式;建立考虑界面滑移效应的钢-混组合梁施工阶段计算模型,研究施工阶段界面滑移对组合梁刚度折减的影响。结果表明:随剪力钉长度增加,试件的极限承载力略有下降,荷载~滑移曲线的塑性段趋于平缓;推导的剪切刚度计算公式不依赖荷载滑移~曲线,其计算结果与欧洲规范以及我国现行规范计算值较接近;界面滑移量与主梁挠度差值均随施工过程中组合梁的悬臂长度增大而增大,界面滑移会增大主梁挠度,对组合梁刚度造成不利影响。

To investigate the effect of interface slippage on rigidity of steel-concrete composite girder in the construction stage,the Pingyin Huanghe River Bridge,which is a steel-concrete composite girder cable-stayed bridge,is taken as the background project.Three groups of shear studs with different lengths were prepared for push-out test.The influential law of shear stud length on load bearing capacity of shear connector and shearing rigidity was studied.Based on the energy principle,the formulas to calculate shearing rigidity of shear stud connectors were derived.The calculation model for the steel-concrete composite girder in construction stage taking into account the interface slippage effect was built,to study the influence of interface slippage on the composite girder rigidity degradation.The results show that as the increase of shear stud length,the ultimate load bearing capacity of the specimen slightly fell,with smooth plastic section on the load-slippage curve.The shear rigidity calculation formulas derived do not rely on the load-slippage curve,and the results obtained approximate the values given in the Eurocode and the current valid steel structure specifications in China.The interface slippage and main girder deflection difference increase along with the increase of cantilever length of composite girder during the construction process,interface slippage can induce the enlargement of main girder deflection and exert adverse effect on rigidity of the composite girder.