Research On Shear-lag Effect For Curved Box Girder Jointless Bridges

Jointless bridges are becoming more popular and were used widely due to many advantages. With the development of country economy and trafficvolume are increasing,the curved bridges has became one indispensability part of traffic construct.Box beam is characterized by light in structure, strong in anti-bending and anti-twisting,it is adapted to bridge structure of continuous beam and curved bridges.It receives wide application and spreading in designing .With the action of symmetrical bending load, the box beam bridge may present the phenomenon of shear tag. Overlooking this problem in designing would have serious influence on the safety of bridge.But the account of the shear-lag is blank and the account of shear-lag about jointless bridges is not mentioned in specifications.due to the characteristics of jointless bridges ,the pristine theory of shear-lag have been found to be unrealistic for jointless bridges.So, some researches are present in this paper: 1) In this paper, a finite element model of curved box girder jointless bridges supported on piles is brought forward, considering the interaction between structure and soil. Research the distributive law of shear-lag of curved box girder jointless bridges by variation of load distribution,and compare with those in joints bridges.provide the basis about the account of account of shear-lag of jointless bridges. 2) A PMMA model test is performed to validate the ANSYS finite element model and the conclusions made in first step. 3) Analyse the distributive law of shear-lag effect and influence of each structural parameter: pile length , bending stiffness of pile, bending stiffness of abutment, abutment length, different type of soil behind abutment, curve radius, width to span ratio,width of beam, etc. And the main influencing parameters were picked up. 4) A chart about shear-lag coefficient for curved box girder jointless bridges is presented in this paper, which is developed by taking into account the main parameters based on engineering practice and the research for the future.