Key techniques for construction of open caissons of main ship channel bridge of Hutong Changjiang River Bridge

The main ship channel bridge of the Hutong Changjiang River Bridge is a rail-cum-road steel truss girder cable-stayed bridge with span arrangement (140+462+1092+462+140) m. The foundations for the 6 piers of the main ship channel bridge are all the open caissons, the upper parts of which are the reinforced concrete structures while the lower parts are the steel structures. Of the caissons, the plan dimensions of the caissons of the pylon piers are 86.9 m×58.7 m and in the plan, 24 nos. of the well holes in dimensions of 12.8 m×12.8 m are arranged for each caisson. The plan dimensions of the caissons of the side and auxiliary piers are 39.2 m×26.8 m. To resolve the problems of the floating, positioning and landing of the steel caissons onto the riverbed under the tremendous current forces and to ensure the construction quality, the steel caissons of the pylon piers were integrally manufactured in the workshop, integrally floated out from the shipyard by the floating aid measure of temporarily closing the 12 well holes in a caisson and the caissons were rapidly positioned in multiple directions, using the technique of the large diameter steel pipe pile anchorage system and hydraulic jacks. The caissons of the side and auxiliary piers were also integrally manufactured in the workshop, were integrally transported, lifted and installed in each two lifts of a caisson and were positioned, using the technique of the large diameter steel pipe piles inside the caissons. At the main pier No. 29, the technique of the riverbed pre-protection was applied. With all these key techniques as mentioned, the open caissons of the 6 piers of the main ship channel bridge have all reached their stable depth and the construction effect is sound. © 2015, Journal Press, China Railway Bridge Science. All right reserved.