桥梁拆除过程预应力残余作用效应研究

为研究桥梁拆除过程被切断的预应力束残余作用效应,建立三类不同预应力作用效应计算模型,分别为切断后预应力束剩余部分作用、切断后的预应力束传递长度范围外作用、切断后预应力束不作用,以此三类计算模型在各工况下的梁体变形情况与拆桥过程梁体实测变形进行对比,结果显示:拆桥过程考虑梁体切断后的预应力束残余预应力影响比较接近梁体实际受力状态,残余预应力值可近似按照先张法预应力筋的传递长度计算,即切断后的预应力束传递长度范围外作用。

Study on the Residual Effect of Prestressed Tendon During Bridge Demolishing

In order to study the residual effect of prestressed tendons during bridge demolishing,three kinds of calculation models for the effects of prestressed tendons are established.They are the residual action model,the external action model within the transfer length range of the cut prestressed tendon and the non-action model of the cut prestressed tendon.By comparing the deformation of the beam body under various working conditions with the measured deformation of the beam body during bridge demolishing,the results show that the residual effect of the prestressed tendons is close to the actual stress state of the girder in the process of bridge demolishing.The value of the residual prestress can be approximately calculated according to the transfer length of the prestressing tendons with pretensioned method,that is,the external action within the transfer length range of the cut prestressed tendon.