Analysis on Safety of Removing the Closure Segment in a Prestressed Concrete Cable-stayed Bridge

摘要

Aiming at failure of closure segment in a prestressed concrete cable-stayed bridge, a strengthening technology, namely replacing the closure segment, was firstly put forward. But removing the old closure segment was a process of release of internal force and had great risk. So the structural safety possibly induced by removing must be analyzed and confirmed. Based on FEM and summary of engineering experience, the construction stages for removing the old closure segment were simulated, and then some analysis relevant to safety, including thermal effect, dynamic characteristics and global stability of the whole bridge structure, were systematically presented. According to these analysis results, corresponding prevention and control measures were provided to ensure construction safety. Studies showed that, variation range of its structural state between before and after removing is not obvious, and its dynamic characteristics changed little after removing. In addition, structural instability could not be induced by removing, but for the sake of improving construction safety reliability, necessary safety prevention and control measures were indispensable. Analysis on safety of removing the old closure segment constituted the important part of the strengthening technology of replacing the closure segment, and became the theoretical basis of removing partial structural members for existing bridges.