Analysis of Shear Lag Effect of Composite Girder CableStayed Bridge at Cantilever Construction Stage

To study the distribution law of the shear lag effect of composite girder cable-stayed bridge at cantilever construction stage,the south main bridge of the Xiazhang Sea-Crossing Bridge was cited as an example. 4 measured sections were selected on the bridge,the software ANSYS was used to set up the finite element analysis model for the main girder of the bridge and the shear lag effect of the composite main girder at the cantilever construction stage was measured in field and numerically analyzed. The results of the analysis indicate that under the joint action of the bending moment produced by axial load and vertical load of the stay cables,the main girder of the cable-stayed bridge presents obvious negative shear lag effect. In the whole cantilever construction stage,the effective width coefficients of the different sections range from 0. 85 to 0. 95. With reference to the analysis,it is proposed that the stress checking calculation of the construction stage should be made and the stress of the concrete deck slabs should be considered 15% higher than the results calculated according to the preliminary beam theory. In the design,the influence of the stringers on the shear lag effect of the deck structure can be neglected and the calculation will tend to be safe.