Design and Study of Main Girder of South Main Bridge of Xiazhang Sea-Crossing Bridge

The south main bridge of the Xiazhang Sea-Crossing Bridge is a double-pylon cablestayed bridge with span arrangement 135 m + 300 m + 135 m. The main girder of the bridge is the steel and concrete composite girder,of which the steel girder part is a steel frame formed by the double I-shape main girders,cross beams and stringers,is connected with the concrete deck slabs via shear studs and on the upper flanges of the I-shape girders,the anchor tensile plates are welded. The global and local analysis for the main girder of the bridge was respectively carried out and the two critical issues of the normal stress and storage time of the deck slabs were studied. The results of the analysis and study show that the force conditions of the steel girders and concrete deck slabs can all accord with the relevant requirements in the codes and the girders and slabs have certain safety margin. In the analysis of the normal stress of the deck slabs of the composite girder cable-stayed bridge,the influences of the shear lag effect under the comprehensive action of bending moment and axial forces should be considered. The storage time of the deck slabs has influence on the force conditions of the steel girders and it is proposed that the storage time of the deck slabs should not be shorter than half a year.