Overall Design and Study of South and North Bridges of Xiazhang Sea-Crossing Bridge

The Xiazhang Sea-Crossing Bridge,totally 9. 333 km long,is composed of four major parts of the north bridge,Haimen Island interchange and toll service area,south bridge and Haiping interchange. To accommodate the complicated natural and construction conditions of the bridge,the bridge site schemes were compared and the bridge type schemes for the critical control projects ( the north and south main bridges) were studied. According to the study,it was finally determined that the 5-span continuous steel box girder cable-stayed bridge with a main span 780 m would be adopted for the north main bridge and the composite girder cable-stayed bridge with a main span 300 m would be adopted for the south main bridge. In consideration of the complicated geologic conditions,high intensity earthquake and harsh wind environment,the well adaptive pile foundations were respectively utilized. For the pile foundations at the locations with poor geology,the foundations would be grouted. The structures of the bridge were designed in compliance with the seismic resistance requirements. At the connections between the pylons and girders of the main bridges,the longitudinal dampers were arranged and on the piers of the approach bridges,the earthquake isolation bearings were arranged. For the north main bridge,a kind of the wing type balustrade was utilized while for the south main bridge,the wind resistant measure of the guide vanes was taken.