不同边跨合龙方式对连续刚构桥结构的影响分析

针对某3跨连续刚构梁桥边跨合龙位置桥墩较高、现浇段较长而搭设托架不安全的施工条件,该大桥东岸边跨拟采用导梁法进行施工合龙。为验证该方案是否合理,根据力学方法和有限元原理,采用Midas/Civil软件建立了该桥的有限元模型,仿真模拟了实际施工过程并进行数值分析,并对两岸边中跨的内力与位移进行了对比分析,以验证采用导梁方案合龙施工的合理性。研究表明:1)边跨合龙方式的不同对桥梁结构受力影响较大,特别是边跨部分;2)使用导梁法施工的一岸,施工过程和成桥后桥面平顺性均不如使用托架法施工的一岸,产生的附加应力相对托架合龙稍大,但影响程度可接受,满足设计规范要求,并且节约了施工经费和缩短了施工周期。

Analysis of the Influence of Different Side Span Closure Modes on the Structure of Continuous Rigid Frame Bridge

In order to solve the unsafe construction conditions of erecting bracket due to the high pier and long cast-in-place section at the side span closure position of a 3-span continuous rigid frame beam bridge,the guide beam method is proposed to be used for the construction closure of the east side span of the bridge.In order to verify whether the scheme is reasonable,according to the mechanical method and finite element principle,the finite element model of the bridge is established by Midas/Civil finite element software,the actual construction process is simulated and the numerical analysis is carried out.By comparing the internal force and displacement of the middle span on both sides of the bank,the rationality of the closure construction with the guide beam scheme is verified.The research shows that:1)different closure modes of side span have great influence on the stress of bridge structure,especially the part of side span;2)for one bank constructed with guide beam method,the smoothness of the construction process and the bridge deck after completion is not as good as that of one bank constructed with bracket method.The additional stress generated is slightly larger than that of the closure of bracket,but the influence degree is acceptable,which meets the requirements of design specifications,saves construction funds and shortens construction period.