Study On The Static And Dynamic Characteristic Of Longju Large-span Continuous Rigid Frame Bridge Of Wanzhou-Lichuan Expressway

The growing development of bridge construction technology and it provides a favorable technical support for expressway in our country.With the superior crossing ability,lower cost,higher driving comfort and other advantages,large span continuous rigid frame bridge is widely used in the construction of road-bridges in China.The future developing directions of large span continuous rigid frame bridge are higher piers,thinner webs and longer spans,which will lead to various new problems during construction and operation maintenance.Therefore,studies on static and dynamic characteristics of large span continuous rigid frame bridge have important engineering value and theoretical significance for prophase construction design and latter maintenance of bridge.Based on Longju large-span continuous rigid frame bridge(main span 220 m)of Wanzhou-Lichuan expressway and using finite element software Midas Civil,a mechanical analysis model is performed to study static and dynamic characteristics of continuous rigid frame bridge.The main contents including:(1)Combined with finite element calculation model of Longju large-span bridge,the mechanical properties and the deformation characteristics are analyzed in the bridge maximum cantilever stage,side span closure segment,midspan closure segment and secondary dead loads segment,the feasibility of the construction method and the safety of the structure are validated.(2)In the process of static analysis,the typical load condition of large-span continuous rigid frame bridge during construction is simulated,and the internal variation laws of strength and stiffness is obtained.The effect of vehicle load,temperature load and foundation settlement on the mechanical behavior of bridge structure was studied,and the operational status of bridge structure under bridge complete stage.At the same time,the PSC section of the main girder is checked in three major areas: the normal stress of normal section in construction stage,the normal stress of normal section in usage stage,and the diagonal section stress in usage stage.Finally,some useful conclusions are drawn.(3)In the process of dynamic analysis,using superposition response spectrum method,the seismic responses of bridge are computed and analyzed to test the seismic performances of bridge structure whether meets the specification requirements.Through the research of this paper it shows that using symmetrical cast-in-place cantilever construction method is safe and reliable for long-span continuous rigid frame bridge construction.