The Sutong Cable stayed bridge in China is the longest spanning cable stayed bridge in the world. The bridge has a main span of 1088m and crosses the Yangtze river approximetaly 100km inland from Shanghai. The steel orthotropic deck for the bridge was fabricated offsite and then delivered by barge to the bridge site in 16m long segments weighing up to 450 tonnes each. The delivery barges were moored in the river below the bridge and the deck segments were then lifted to final height and aligned with the previously erected deck segment by eight purpose made deck erection gantries . DLT were sub-contractors for the design, supply and site supervision of these deck erection gantries, to main contractor 2nd Navigation Engineering Bureau. The first deck segement was erected on 9th November 2006, an operation which included a 125% overload test and a 110% dynamic test. The last segment was erected on 9th June 2007.
The contract for design and supply of these deck erection gantries was let by international tender, under the control of an independent government tendering agency and subject to the recommendations of a panel of Chinese experts. The hydraulic and electrical components for the gantries were manufactured in Europe and shipped to China, where they were be assembled onto fabricated steel frames made in China.
The gantries work in pairs to lift and align the deck units. Each gantry has one 290 tonne capacity DL-S290 strand jack to lift the deck unit and a system of secondary hydraulic rams to carefully adjust its final plan position and slope so that it can be accurately fitted to the previous deck segment for welding, to within a tolerance of +/- 1mm. The hydraulic systems on each pair of gantries are monitored and controlled by a single operator using our DL-P40 computer control system which ensures accurate synchronisation of the strand jacks and simple and failsafe operation. DLT project page
Cable stayed spans
The deck of the two 300m cable stayed spans was erected in 12m long 250 tonne segments by specially designed self launching deck erection gantries as shown below. Each gantry used 2 No DL-S185 strand jacks for lifting powered from a single DL-L30/2/E power pack for a lift speed of 17 m/hr. Each deck unit was delivered by barge into position for lifting and was then lifted to just above final level using the DL-S185 strand jacks. Deck units were lifted with a nominal 500mm gap to the previously erected deck unit. The strand jacks and deck unit were then skidded together by hydraulic rams to close and align the deck joint. Finally, the hydraulic bleed system incorporated in the DL-S185 strand jacks was used to very slowly lower the deck unit to final alignment to within +/- 1mm tolerance. The deck unit was then held on the strand jacks whilst the joint was bolted and welded.
DLT has previously been responsible for lowering of a 3050 tonne steel cofferdam on this project, using 16 No DL-S418 strand jacks monitored and controlled by the same DL-P40 computer control system that will be fitted to the deck erection gantries. More>
More details of the Sutong bridge project can be found at http://www.stbridge.com.cn