Analysis Of Shear-lag Effect On Concrete Box-girder Of The Double-Tower Cable-stayed Bridge With Single Cable Plane

Cable-stayed bridge is the unitized structure system composed by the tower, and cable.It is a bridge with girder system which beam is under pressure (micronesia cable system) or under bending (thin cable system), support system main composed by the tension cable-stayed and bridge tower under pressure.The main characteristics of cable-stayed bridge is the use of cable-stayed leaded from bridge towers as a flexible central support of beam, in order to reduce section moment of cross-bridge to reduce beam weight, improve the leaping capacity of the main beam .Cable-stayed bridge, concrete cable-stayed bridge especially has excellent performance, and is widely used in the large-span bridges . At present, cable-stayed is built with not only the increased span, also the increased horizontal width of main beam both at home and abroad.With the wide-span ratio and aspect ratio increasing, the shear-lag effect has become even more serious,it is bound to cause structural failure if ignoring its impact.Shear-lag effect makes roof and floor stress chich should be uniformly distributed in accordance with the analysis of elementary beam theory have a non-uniform distribution, it will make local stress too large causing damage . At present, the study of shear-lag effect has been carried broadly,but the study for the tower pier beam consolidated, non-symmetrical twin towers cable-stayed bridge is very little,pending further research and analysis, to deepen the understanding of this types of questions and promote the development of this bridge-type.This paper first makes a review of long-span prestressed concrete cable-plane single-tower cable-stayed bridge system and the studies of shear-lag effect, and elaborate on the effects factors and research prospects of shear-lag effect,then analysis the shear-lag effect under dead load for the special structural form of Fuling Wujiang Second Bridge . And to consider the imposition of pre-stressed on the shear-lag effect. Through analysis, reach conclusion of the critical cross-section stress distribution of Wujiang Second Bridge under dead load . At the same time, by comparison, obtaineing influence of stress distribution in each section of prestress . And obtaine the shear-lag coefficient of the key section before and after prestressed.The analysis results of this can provide the basis of such bridge design and technical guidance.