Research On The Influence Of Foundation Settlement On The Joint Of Simply-Supported Beam Bridge After Widening

In order to respond to the slogan of “building China into a traffic power”,it is an important and urgent task to solve the contradiction between the increasing traffic volume and the insufficient traffic capacity of the existing highway,to solve the problem of traffic demand and traffic construction,and to increase the capacity of existing highway bridges.The uneven settlement of the new and old bridges will have a greater impact on the overall structure of the bridge,especially the splicing site.The influence of the splicing position can be effectively controlled,which determines that the widening of the bridge is successful.Therefore,it is of great theoretical significance and application value for the bridge widening project to study the settlement regularity and the stress state of the bridge superstructure.This article relies on the Shanghai-Nanjing Expressway bridge widening project as a research background.First of all,several widened T-bridges have been observed to obtain the uneven settlement data.It has been analyzed that the horizontal distribution model of the new bridge main beam settlement is a high-order curve model,not a linear model assumed.Then the full bridge model of the T beam bridge is established by MIDAS FEA software,and the deformation of the superstructure of the bridge is studied under the settlement of the new bridge foundation.The result shows that the transverse distribution pattern of the settlement is closer to the second order settlement curve,which is in agreement with the actual observation data.Then by comparing with the beam grillage method finite element model,it is proved that the settlement of the main beam of the new bridge is more reasonable according to the quadratic curve.After analyzing the widening structure of ordinary voided slab beam,it is concluded that the main beam of the new bridge settles by the quadratic curve.Finally,based on the obtained quadratic settlement curve,the vertical deformation of the bridge superstructure has been simulated to simulate the stress state of the joints and the allowable differential settlements after construction.It has been found that the allowable differential settlement is 5mm ultimately.At the end of the article,related suggestions for reducing the uneven settlements between foundations of new and old bridges have been proposed.