钢槽梁顶推施工法导梁桁架加固分析研究

Analysis on Reinforcement of Steel Channel Beam Top Pushing Construction Method for Guide Beam Truss

以某大跨度钢槽梁桥顶推施工为实例,按照实际顶推施工过程,采用Midas/civil建立有限元模型,并通过对比分析现场监测值与模拟值验证有限元模型的可靠性。根据施工中出现的特殊情况,提出一种加装临时桁架背撑结构的桥梁顶推加固方案,并基于验证后的模型对加固后的顶推结构进行有限元分析。结果表明,顶推结构的最不利位置多处于导梁与主梁的连接部位,在实际施工中应着重对该位置进行应力监测,避免局部出现破坏情况;通过加装临时桁架背撑结构的加固方案可以有效降低顶推过程中的应力及挠度来增强稳定性,最高可使结构的应力及挠度分别降低44%和39%,且在顶推结构的悬臂长度处于40 m之前,这种加固方案对结构的优化效果更为显著,该研究可为类似顶推施工提供了参考。

Taking the incremental launching construction of a long-span steel trough girder bridge as an example,the finite element model was established by Midas/civil according to the actual incremental launching construction process,and the reliability of the finite element model was verified by comparing and analyzing the field monitoring values and simulation values.According to the special situation in the construction,a bridge jacking reinforcement scheme with temporary truss back support structure is proposed,and the finite element analysis of the reinforced jacking structure is carried out based on the verified model.The results show that the most unfavorable position of the incremental launching structure is mostly in the connection part between the guide beam and the main beam.In the actual construction,the stress monitoring should be carried out at this position to avoid local damage.The reinforcement scheme of adding temporary truss support structure can effectively reduce the stress and deflection in the process of jacking to enhance the stability.The maximum stress and deflection of the structure can be reduced by 44%and 39%respectively.Before the cantilever length of the jacking structure is 40m,the optimization effect of the reinforcement scheme on the structure is more significant.This study can provide a reference for similar jacking construction.