Technical Characteristics and Innovation of a Continuous Composite Box Girder Bridge with Main Spans 105 m

Shanghai Changjiang River Bridge is a combined highway and rail transit bridge.In the part of the Bridge with high-rise piers,the continuous composite box girders were applied on a large scale and the construction of the girders was carried out in a way of full-span girder prefabrication,lifting and erection.In this paper,the technical characteristics of the continuous composite box girders of the Bridge are presented from aspect of the bridge type alternative,structural formation and construction methods.The key technical points considered in the design and the technical innovation of the composite girders are described in details in the light of the design features,such as the allowance of cracks in deck slabs in the negative moment area,utilization of double layers of composite structures and connection parts between steel girders and deck slabs,and also in the light of the technical measures taken for pre-bending of the steel girders,late compositing of the deck slabs at intermediate supports and utilization of the method of raising and lowering of supporting points.