滚轴布置形式对托换节点托件破坏形态的影响研究

Experimental study on underpinning joints under frame columns under the influence of the different roller arrangement of underpinning beam

为了解决移位改造过程中托换节点滚轴布置形式对建筑物的稳定性和安全性的影响,通过框架柱包裹式托换节点的缩尺模型试验,分析了托换梁滚轴布置形式与托换节点破坏形态的关系,研究了托换梁滚轴布置形式对框架柱托换结构受力机理、破坏形式的影响。试验表明:滚轴内移和滚轴满布两种布置形式对构件的开裂荷载基本上没影响,而破坏荷载分别提高30%和1倍左右;在滚轴内移和滚轴满布两种布置形式下,构件的破坏形态分别为托换梁受弯破坏和结合面冲切破坏;滚轴内移或者滚轴满布后,均使梁柱新旧混凝土结合面变得更加薄弱。研究结果可以为新旧混凝土咬合强度的研究提供依据。

To dissolve the impact of roller arrangement of underpinning joint on the stability and the security during shift transformation,an experiment of the wrap-underpinning joints under frame columns has been conducted.The relationship between the fracture morphology of the underpinning joints and the different roller arrangement of underpinning beam is studied,also the influence is determined of the different roller arrangement of underpinning beam on the force mechanism and failure forms.The results show:the crack load was influenced hardly by the roller arrangement,neither inside arrangement nor full arrangement,but the ultimate bearing capacity was increased approximately by 30%and 1 time separately.When the roller inside arrangement,the failure form of underpinning joint is flexural failure of the underpinning beam,and full arrangement,failure mode of bonding interface between underpinning-beam and column was relative slippage.After the rollers were inside or full arranged,the junction surface between connecting beam and column had become weaker than normal roller arrangement,and it can provide a basis for the study of the occlusal strength of new and old concrete.