Gebze–Orhangazi–Izmir Motorway, Izmit Bay Suspension Bridge

Abstract

ABSTRACT: The Izmit Bay Suspension Bridge consists of a three span continuous suspension bridge having the main span of 1550 m and two transition spans will becomes the world’s forth longest suspension bridge at the completion in 2016. The suspended deck is 2.907 m long and continuous between two side span piers. The side span is each 566 m. There are 120 m and 105 m transition spans on the north and the south. The navigation clearance of the bridge is 64.30 m × 1000 m. The bridge girder will be of steel box girder construction with a stiffened steel plate deck with asphalt surfacing. The transition spans between the side span piers and transition piers will be formed by single span steel box girders. The main suspension cables will be formed from pre-fabricated parallel wire strands (PPWS). The main cables are deviated at the side span piers toward the cable anchorages located below the deck of the transition spans. The top elevation of the tower is 252 m above the sea level, each tower has two steel leg and two steel cross-beams. The towers will be of stiffened steel plate construction. The anchorages will be of the gravity type and will be supported on spread foundations. The tower foundations consist of a pre-fabricated rein-forced concrete caissons placed on a gravel bed on improved soil at 40 m water depth. Soil improvement will be achieved by steel pile inclusions. The bridge is sited in one of the world’s most seismically active regions where in 1999 the 7.6 Izmit Earthquake occurred on the North Anatolian fault in 1999. This paper deals with the project overview and construction method.