在役预应力混凝土斜拉桥合龙段置换加固技术研究  

Study on the technology of replacement of closure segment for strengthening existing prestressed concrete cable stayed bridges

作　　者：李宏江[1] 张劲泉[1] 李万恒[1] 蒋含莞[1] 

机构地区：[1]交通运输部公路科学研究院,北京100088

出　　处：《土木工程学报》2011年第7期83-89,共7页China Civil Engineering Journal

摘　　要：以天津永和大桥维修工程为背景,提出了合龙段置换加固技术。它是在役预应力混凝土斜拉桥维修加固的一种新方法,其实现的技术途径主要包括原合龙段拆除、合龙段重建并加强。原合龙段的拆除是实现置换的先决条件。在对合龙段置换前的结构现状计算模拟的基础上,预测分析了合龙段拆除可能会引起的结构变化,同时,还建立了空间有限元计算模型,分析了合龙段拆除前后全桥整体稳定性和动力特性变化,最终实现了原合龙段的安全拆除。新老混凝土的黏结和合龙段预应力的恢复是合龙段重建的关键技术环节。采用扩大截面法和设置无黏结体外预应力对新合龙段局部进行加强是保证其受力状态的有效措施。合龙段置换是国内外桥梁维修加固领域前所未有的尝试和探索,开辟了在役预应力混凝土斜拉桥维修加固的新的技术途径。With the maintenance of Yonghe Bridge in Tianjin as a background,a bridge strengthening technology,replacement of closure segment,is introduced.This technology is a new method for strengthening existing prestressed concrete（PC） cable stayed bridges,and its basic technical approach includes removing the old closure segment,reconstructing and strengthening the new closure segment.Removal of the old closure segment is the precondition of this method.Based upon simulation of structural state before replacing the closure segment,possible structural changes caused by removal of the old closure segment are predicted and analyzed.Moreover,3-D finite element models are established,and the differences in global stability of this bridge and in dynamic characteristics prior to and after the removal of the old closure segment are analyzed.Removal of the old closure segment is completed successfully.Cohesion of the new-old concrete and rehabilitation of pre-stress system are the key technologies for reconstruction of closure segment.Besides,the combined use of enlarging cross-section and non-glued external pre-stress methods is effective to ensuring appropriate structural state of the new closure segment.Replacement of closure segment is a new trial or exploration,and has provided to be a new way for maintaining and strengthening PC cable stayed bridges.

关 键 词：预应力混凝土 斜拉桥 加固 合龙段 置换 

分 类 号：U445.72[建筑科学—桥梁与隧道工程] U448.27[交通运输工程—道路与铁道工程]