The Rigidity Analysis In Concrete Pouring Phase And Research On Rigidity In Design For CFST Truss Arch Bridge

With the rapid development of bridge construction in our country, concrete-filled steel tube(CFST)structures are widely applied.However,there is no standard for concrete filled steel tube arch bridge in our country.And the structural behavior of CFST arch bridge has not been researched detailedly.In the designing of CFST arch bridge,the rigidities are always calculated referring to the standards of CFST component.But there are many differences in the define of the rigidities for concrete filled steel tube(CFST)component between different countries,also in our country different departments have there own standards.And different rigidities will infuence the calculation results of internal forces,deformations and stability etc.So the methods to calculate the rigidities of CFST arch bridge have to be researched much further.In this paper,the differences in the define of the rigidities for concrete filled steel tube component between different standards have been discussed;Based on the Jingyanghe bridge in Enshi Hubei province,the finite element model of the bridge has been established using the finite element software MIDAS/Civil.By comparing the calculating results with the testing results,the value of rigidities for the concrete at early age has been researched.This article holds that the rigidities of the concrete at early age cannot be ignored in concrete pouring phase.The rigidities can be calculated according to logarithm formulation refers to the article wrote by ZHU Bo fang.And the effect of flexural rigidity and compressive rigidity on static characteristics of CFST truss arch bridge was discussed;the research indicates that compressive rigidity has much more influence than flexural rigidity.At last, according to the standards of different countries,the rigidities in design for CFST truss arch bridge were studied.Based on the field testing results,a method of using different rigidity reduction in different section of the arch ribs was put forward,the results of the above method have a better applicability to the whole arch ribs.