Sanchaji Bridge: Three-Span Self-Anchored Suspension Bridge, China

Sanchaji Bridge across the Xiangjiang River is located at the northern section of the Second Ring Road Project in Changsha, Hunan Province, China. Its main span is the longest in the world among all self-anchored suspension bridges constructed using double towers and double cables till now. For a self-anchored bridge, structural behaviour and construction methods are totally different from those of a traditional suspension bridge. A main cable containing 37 prefabricated strands and streamlined steel box cross section was used as stiffened girder with a height of 3,6 m. A fully welded anchoring chamber was adopted to connect the main cable with the stiffened girder for the first time. The main tower is of reinforced concrete with a variable hollow box section. As for the construction method, launching methods were selected for the erection of steel box girder and “non-stress” method for installation of hangers. The construction of the bridge was started on 10 September 2004 and completed on 1 September 2006. The completion of the bridge effectively relieved the traffic pressure in the northern region of Changsha and played a vital role in improving local economy. This paper introduces several features of the Sanchaji Bridge, including type selection, structural behaviour and construction methods.