Post-Tensioning System incorporated into a large bridge construction project
The new Incheon bridge, a 12.3 km long toll bridge, is the second link from the »airport island« of Yongjing, the location of the international airport, to the mainland and the city of Seoul. The bridge runs in a southeastern direction, thus reducing the traveling time to the international business district of New Songdo City in southern Seoul by 40 minutes. Analyses have shown that this second bridge to link the airport island to the mainland is expected to stimulate economic development so that the economic benefits derived from this project justify the construction cost of nearly USD 1.3 billion.
Construction work, which began in June 2005, placed exceptional technical demands on all parties involved in the project. Since the bridge runs over the busy main shipping route to the port of Incheon, a safe solution for the marine traffic was required as well. The decision was made to build an 8.4 km long viaduct that is supplemented by a 1,480 m long stay-cable bridge over the shipping channel. The staycable bridge has a vertical clearance of 74 m, a main span length of 800 m and two side spans of 260 m and 80 m each. Thus, the bridge will be the longest stay-cable bridge in Korea and the fifth longest in the world after its scheduled completion in 2009.
The 230.5 m high Y-shaped concrete pylons of the stay-cable bridge rest on drilled cast-inplace foundation columns. The 31.4 m wide bridge deck consists of two parallel prestressed concrete box girders. Each girder supports three lanes in each direction. Concrete box girders in lengths of the individual span widths of 50 m each were prefabricated for the viaduct and lifted onto the bridge piers by means of a heavy lift floating crane. The bridge spans of the two 889 m long approach viaducts were built using the full span precast launching method.
DSI Korea supplied DYWIDAG Threadbars of grade 835/1035 in diameters ranging from 26.5 to 75 mm. The DYWIDAG Post-Tensioning System including comprehensive accessories such as anchors, hex nuts, couplers and protection caps were delivered to the construction site just in time by DSI Korea. As regards the selection of accessories, DSI Korea flexibly met the requirements of the particular site location.
DSI takes pride in having been able to contribute to the success of this outstanding worldclass project by supplying its high-quality DYWIDAG Post-Tensioning System as a member of a highly qualified and competent planning and execution team.