Construction Techniques for Integral Blocks of Main Girder of an All-Welded Steel Truss Girder Cable-Stayed Bridge

The main bridge of the Second Minpu Bridge in Shanghai is a continuous composite steel plate and truss girder cable-stayed bridge with a single pylon and double cable planes and with span arrangement 251.4 m(main span)+(147+38.25) m(anchor spans).The main girder of the bridge is an all-welded structure that was constructed by the method of manufacturing each integral truss block in shop and installing the block in field.At the time each block was manufactured in shop,the plane trusses were firstly assembled and then the space trusses were generally assembled,for which the N+1 matching technique was used.In field,the sections of the truss girder used as the lifting and installation supports were installed by the 1 200-t capacity floating crane,the standard sections of the girder were installed by the 260-t capacity walking type deck crane and all truss blocks were connected by butt welding.