Impact Analysis And Countermeasures Study Of Ground Fissures On Concrete-steel Composite Continuous Bridge

Currently,when engineers build structure stepping across ground crack,they usually choose to avoid it.While the area of land available in cities decreases,so it is unavoidably built across ground crack.For the bridge stepping across ground crack,we usually choose simple beam.Because simple beam is determinate structure.The settlement of pile foundation makes little difference to bridge structure and is more safe than indeterminate structure.While the crossing ability of simple beam is small and engineer must chooses the continuous bridge whose span is larger when the space under bridge,pipeline and traffic lights are limited.How to build continuous bridge to reduce the impact of ground crack on bridge structure is the problem that many engineers want to solve.This article relies on the research project of Shanxi Provincial Department of Transportation “Study on monitoring construction and operational stage of Steelconcrete composite beam bridge stepping across ground crack”.The crossing angle of ground crack and the span of the continuous bridge are analyzed for the ground crack under YanTa overpass.It will provide theory for the choosing the crossing angle and the span of continuous bridge for building bridge crossing the ground crack.With the way of inspecting literature and numerical simulation,the analysis has been studied in-depth.The main work as follows:(1)The influence of the crossing angle of ground crack and the span of the continuous bridge on the mechanical properties is studied by creating a simulation model of the substructure and selecting two pile foundations closer to the ground crack as the target.The influence of ground crack on the mechanical properties of pile foundations is studied by grading loading.The results show the adverse effect of ground fissures on the pile foundation is minimal with the smaller crossing angle and the smaller span.(2)Three different span top structures model are established.The change of the mechanical properties for the top structure with the settlement being larger is studied by analyzing the force and the deformation.The study found the adverse effect of ground fissures on the bridge superstructure is minimal with the smaller crossing angle and the smaller span.(3)The analysis of limit condition including bend resistance,shear resistance,crack resistance and deformation are studied with the settlement prediction of ground crack bearing limit state and serviceability.The mechanical bridge properties of limit state and serviceability is got basing on the largest ground fissure settlement and it is helpful to assess security and to provide theoretical basis to develop countermeasures.According to the early warning analysis of the settlement,it can be seen that within the maximum settlement of the soil the bending moment and deformation caused by the ground fissure disaster is considered.(4)The monitor of settlement of bridge pier and the stress of bridge is illustrated thoroughly and the program of supporter and the way of ground reinforcement is formulated.