纵筋配筋对柱托换节点影响的试验研究

Experimental study on the influence of longitudinal reinforcement ratio of the underpinning beam on the column-underpinning joints

托换是建筑物整体移位技术的关键环节,直接影响到移位过程中建筑物的稳定性和安全性。通过框架柱包裹式托换节点的正交实验,研究了托换节点外挑部分与包柱部分的承载力与托换梁纵筋配筋情况的关系,确定了托换梁纵筋配筋特征值对框架柱托换结构受力机理、破坏形式的影响。试验表明:试件的破坏形态分为托换梁的受弯破坏和弯剪破坏,行走梁受弯破坏主要发生在跨高比较大且纵筋配筋较少的构件;托换梁纵筋配筋特征值对托换节点的开裂荷载影响不大,与屈服荷载和破坏荷载之间均呈线性关系;提出了框架柱托换节点承载力计算公式。

The underpinning is a key link in the building moving technology,and it has direct impacts on the stability and security of the building in the shift process.Through the orthogonal experiment of the wrap-underpinning joints under the frame columns,the relationship is studied between the bearing capacity of the overhanging part and wrapped-column part of the underpinning joints and the longitudinal reinforcement ratio of the underpinning beam,and also the influence is determined of the longitudinal reinforcement eigenvalue of underpinning beam on the force mechanism and failure forms.The results show： there are two types of failure modes flexure failure and flexure-shear failure of the underpinning beam,and the flexure failure mainly appears in the specimens with larger span-depth ratio and less reinforcement;the influence of the longitudinal reinforcement eigenvalue of the underpinning beam on the crack load is not significant,but the linear relationship remains between the eigenvalue and the failure load or the yield load;the formula is put forward for calculating the shear-carrying capacity of the column underpinning joints.