Sepung bridge

Sepung Bridge
Sepung Bridge, South Korea
Carries	4 lanes of motor vehicles
Crosses	Gwangyang Western River
Locale	Gwangyang, South Korea
Characteristics
Design	Cable-stayed
Material	Concrete
Total length	approach 150 metres (490 ft) main 725 metres (2,379 ft)
Width	23.9 metres (78 ft)
History
Constructed by	Daelim Industrial
Construction start	2006
Construction end	2014
Construction cost	$23 million USD
Opened	2014
References

The Sepung Bridge is the first curved cable-stayed bridge in South Korea. The Bridge, which is a total of 875m long, consists of a 150m-long approach bridge and a multi-span cable-stayed bridge with two 220m-long main spans and 52.5m-long side spans. It crosses the Gwangyang western river, a railway and a roadway in South Korea. It was built by Iksan Regional Construction & Management Administration.

The Sepung Bridge was commenced in October 2006 and completed its construction in June 2014. The bridge has been built by contractor Daelim Industrial Co., LTD. Contract amount is 23.0 million USD. The side spans of the cable-stayed bridge and the approach bridges were built using full staging, while the main spans at each tower were built out using the free cantilever method. For the erection of the 6m-long, 210t segments a form traveler was used because of being easy to observe the operation and suitable for cast-in-place concrete. The construction of three pylons is carried out in auto climbing form because of safety caused by working over the sea. PY1, PY2 and PY3 are 86.7m, 101m and 88m respectively in height and are made of concrete grade 40MPa. PY1 and PY3 were constructed at the same time. After finishing the construction of two pylons, PY2 was built.

The Sepung bridge is a curved one with a radius of 2000m. In order to reduce the deformation of the pylons toward the center of the circle, two cables are established from the top to the bottom of the pylon. It is also effective for increasing the torsional rigidity. This bridge is designed to accommodate dual four-lane traffic; its design incorporates a curved stiffening girder and additional transverse cables to stabilize each tower. The striffening girder is designed as a PC box using reinforced concrete of grade 40MPa; It is 3.3m deep and almost 24m wide, and incorporates steel struts and FRP pipe struts filled with concrete in the internal and external box respectively, to resist the local tensile stress. These internal and external struts are placed at typical centers of 6m and 3m respectively and give the stiffening girder and increased torsional rigidity and make the decks 20% lighter than a traditional concrete box girder. In this bridge, a single plane multiple cable system with harp arrangement was chosen in order to reduce the longitudinal and transverse deformation of the towers. As the shear center deviates from the center of the stiffening girder due to the application of the asymmetric cable forces and self-weight, twisting and transverse deformation may occur.