跨线刚架拱桥快速拆除施工方案研究

Research on Rapid Demolition Construction Scheme of Cross-line Rigid Frame Arch Bridge

上跨某高速公路的刚架拱桥全长52 m,因高速公路改扩建要求拟对其进行拆除施工.为保障桥下高速公路正常通行,提出了先切割拆除后整体顶升移运的刚架拱桥快速拆除施工方案.利用杆系有限元模型,分析刚架拱桥的拆除方案,并通过对关键横断面内力变化分析,评估了刚架拱桥切割方案的实际效果.利用实体有限元模型分析刚架拱桥切割后整体顶升移运过程中的变形状态,并研究了刚架拱桥采用SMPT顶升快速移运过程的安全性.结果表明,切割后刚架拱桥的内力情况仍能满足其抗力要求,但切除弦杆后近拱腿顶部存在受力较大的横断面.考虑SMPT顶升过程中支点脱空的不利工况下,剩余刚架拱桥在顶升移运过程中变形仍能满足安全要求.

The rigid frame arch bridge is a bridge over crossing a certain highway with a total length of 52 m.This bridge is to be demolished due to the requirements of highway reconstruction and extension.In order to ensure the normal traffic of the highway below the bridge,a rapid demolition construction scheme of the rigid-frame arch bridge is proposed.The rapid demolition scheme is to cut the arch leg first and then lift and move the whole bridge with SMPT.The frame model of rigid-frame arch bridge is established ann the demolition scheme is analyzed with the finite element model.The internal force change of the key cross section of the rigid frame arch bridge is analysed,and the actual effect of the cutting scheme is evaluated.The stress state of the whole lifting and transportation process of the rigid frame arch bridge after cutting is analyzed by using the solid finite element model.The safety of the rapid lifting and transportation process of the rigid frame arch bridge by using SMPT is investigated.The results show that the internal force of the rigid frame arch bridge after cutting can still meet its resistance requirements.However,the force of the cross section near the top of the arch leg after cutting is relvantly large.When considering the adverse working conditions of pivot void during SMPT lifting,the remaining rigid frame arch bridge can still meet the safety requirements during lifting and transportation.