再生混凝土框架节点受剪承载力计算新方法

New model for shear strength prediction of recycled aggregate concrete frame joints

鉴于再生混凝土框架梁柱节点抗震受剪承载力计算模型的缺乏,以改进的软化拉-压杆模型为基础,推导了一个简便而实用的再生混凝土框架节点的受剪承载力计算式,并显式考虑了再生骨料取代率的影响。收集了21组中、边及角节点试验数据对计算式进行了验证,得到试验值与理论结果的平均比值为1.06,离散系数为0.127,且优于现行规范修正计算式,表明本计算式预测结果精确、连续且偏于安全,可为再生混凝土框架节点的抗剪设计提供参考。

Due to the scarcity of rational models for predicting the shear capacity of recycled aggregate concrete frame joints under seismic loading,a simple and convenient formula is proposed based on modified softened strut-and-tie model.In the derivation,the effect of the recycled aggregate rate on the shear capacity is explicitly taken into account.A database consisted of 21 interior,exterior and corner beam-column joints is established and adopted to validate the proposed model.The comparison shows that the model predictions are accurate,consistent and conservative with an overall average test result to prediction of 1.06 and a coefficient of variation of 0.127,and also illustrate its superior accuracy over the modified concrete code design method.It indicates that the proposed model can be employed for shear design of frame joints made with recycled aggregate concrete.