Journal of Structure Research and Practice ISSN:3022-4241(Print) 3022-7267(Online) 한국교량및구조공학회 논문집

Currently, the world's longest concrete cable-stayed bridge with a main span of 540 meters is under construction on the Han River. The reinforcing girder was planned as a curved 3-cell box section, and the aesthetic aspect was emphasized by placing transverse ribs that lengthen the length of the outer cantilever. As a material for the reinforcing girder, high-performance concrete with a compressive strength of 80 MPa was used to reduce the weight of the superstructure, and high-strength strand with a tensile strength of 2,400 MPa was applied to increase the efficiency of the reinforcing girder cross-section. For cable-stayed cables, an high-strength cable (tensile strength of 2,160 MPa) was applied, and a single pylon was planned to minimize the overlap between cables and pylons to improve aesthetics. The 60 MPa concrete applied to the upper part of the pylon was planned as flow concrete to ensure high fluidity considering cable anchors, prestressing strands, and rebars. For the construction of the reinforcing girder, a 1/4 scale mock-up of the real bridge was performed to confirm the smooth construction of the curved cross section, and the installation of the upper cover formwork and the air hole at the lower slab were reflected in the form traveller fabrication. The construction of the cable was carried out with precision in two stages of stressing, introducing 70 % of the design tension in the first stage and additionally introducing 30 % of the remaining design tension based on the introduced tension confirmed through the lift-off test.