A French subcontractor is using a patented precast technique to build one of the world's longest precast-concrete arch-tunnel sections at the site of a residential complex along South Korea's new Suwon-Kwangmyeong Expressway. Paris-based Freyssinet Group claims its TechSpan technique is resulting in significant cost and time saving but acknowledges careful backfilling is key to maintaining safety during construction.
The twin-bore precast tunnel, some 60 kilometers south of Seoul, forms a 2.6-km-long section of the roughly 26-km-long expressway, which a large consortium, led by Korea Development Corp., is constructing under a build-operate-transfer contract.