Kanchanapisek Bridge Over the Chao Phraya River, Thailand

The Kanchanapisek Bridge is one part of the Southern Outer Bangkok Ring Road Project crossing the Chao Phraya River (Fig. 1) to accomplish the loop of Road no.9, located on Samuthprakarn Province south of Bangkok, Thailand and owned by the Expressway and Rapid Transit Authority of Thailand (ETA). The whole project is 22,49 km long and total investment is about 15,584 billion Thai baht ($ 84 mill). The project started on September 2004 and opened to traffic at the end of 2007. The bridge is the largest spanning over the river at present, consisting of main span 500-m long, two side spans, total length is 951 m, 36,70-m wide, A-shaped pylon 187,64-m high with 168 stay cables. Navigation clearance under the bridge deck is 52,273 m (Fig. 2). The deck is a composite steel–concrete section. The pylon pile caps were redesigned to be prestressed in order to solve right of way and working area issues. Corrugated high-density polyethylene (HDPE) duct and vacuum grouting were selected to ensure durability of the posttension in the pile caps. The individual parallel strands in stayed cable were stressed by Iso-tension 8 method. This paper briefly presents the key techniques and construction method of the bridge.