Deep Foundation for Offshore Structure: The Kwang-An Grand Bridge

The Kwang-An Grand Bridge in Pusan is a suspension bridge with central span of 500m and side span of 200m for a total length of 900m. Because Pusan City was developed linearly from the south to north direction, traffic congestion has caused a serious problem. To solve this problem, an outlying loop highway is presently constructing on the sea, which includes the Kwang-An Grand Bridge. Although there are not so much experience and know-how for the construction of suspension bridges in Korea, a suspension bridge of which both pier and anchor block are located on the sea is a rare case in the world. This paper introduces a case history for deep foundation (anchor block) of suspension bridge as an offshore structure. The results of plate bearing test and in-situ direct shear test at the position of final excavation level of the anchor block indicates that the bearing capacity is not sufficient. So the bearing capacity and in-situ shear strength were estimated by analyzing the results of plate bearing tests and in-situ direct shear tests.Also, the micro pile method as a countermeasure to improve the deformation modulus of bearing ground was adopted through a test construction.