The project is a road construction project with a total length of 1,345m connecting Kyeongho-dong (Daegyeong Island) to Sinwol-dong in Yeosu, Jeollanam-do.

BANDI participated in the Turn-key tender design with Hyundai Engineering & Construction. According to the tender design, the total bridge length of the project is 915 meters, and there are two bridges. In the tender design, an asymmetrical two-span network arch bridge with main spans of 160 meters and 80 meters was proposed for the first bridge (Sinwol Gyeongdo Bridge No.1) and a single-span suspension bridge with with main spans of 280 meters was for the second bridge (Sinwol Gyeongdo Bridge No.2).

 In the previous phase of the project, the Sinwo Gyeongdo Bridge No.1 was planned as a single-span Nielsen arch bridge with a main span length of 150m. However, in the tender design, a creative two-span network arch bridge with innovative structural stability, which represents the sea waves of the front sea of Yeosu and the gateway and symbolism of Gukdong Port, was proposed for the first time in Korea.

 

 Structurally, we adopted a rigid connection structure of the main tower and girders, and planned the piers of the main tower as a twin-pier structure to minimise temperature effects and deformation caused by creep.

 The stiffness of the arch structure is increased by applying a radial network hanger cable layout where multiple cables intersect, and the amount of arch rib and  tie girder is significantly reduced compared to a typical arch bridge, improving structural efficiency.

  The application of a network hanger cable arrangement which is rarely used in Korea due to its complicated structure, allowed for the design of a slim arch structure that minimized the cross-sectional height of the bridge girder and arch rib, thereby improving the structural efficiency. As a result, the bridge was able to secure  the viewing rights of adjacent residential areas and navigational clearance for vessels.

 The orthotropic steel deck plate was applied to the bridge girder, and a double tie rib was at the pier axis to connect two arch ribs with different rise-to-span ratios  continuously, minimizing the need for expansion joints and improving both the aesthetics and structural performance of the bridge.

 The pier foundation was planned as a cast-in-situ drilled shafts with a diameter of 2.5m, and to enable eco-friendly construction, PC houses and sacrificial steel casings were applied instead of temporary steel cofferdams.

Structural features of suspension bridge

 In this project, the main cable is anchored directly to the tower instead of passing through the tower through the saddle of the pylon as in the conventional method. The three-dimensional shape of the main cable used in this method is a PWS cable system applied to cable-stayed bridges, which dramatically reduces the construction cost and installation process of the main cable of the suspension bridge.

 In particular, the erection of the cable was greatly simplified because it was possible to lift the cable strand directly from the barge by a crane without the need for a pilot rope, hauling rope, and catwalk system required for multi-strand cable erection, and there was no need for a complex structural system for anchorage installation. On the other hand, it is also a breakthrough in terms of maintenance, as it introduces a system that can replace the entire cable even if the main cable is damaged. 

 The girder is streamlined orthotropic edge steel box girder, which was more economical than single steel box girder due to the small bridge width, but also ensure structural safety.

 The main tower is a concrete A-type tower and is visually differentiated according to the angle to maximize aesthetics, and the foundation footings and pile arrangement are triangular footings connected by transverse beams instead of the usual four-shaped footings for economic design.