RECOVERY OF LOAD-BEARING PERFORMANCE FOR A CONTINUOUS STEEL PLATE GIRDER BRIDGE DAMAGED BY THE 2016 KUMAMOTO EARTHQUAKE AND CONSIDERATION FOR ITS DESIGN

Abstract

 A 5-span continuous steel girder bridge “Ookirihata Ohashi Bridge” was severely damaged by the 2016 Kumamoto earthquake. Some of concrete columns and pile foundations were significantly cracked and almost of rubber bearing supports were ruptured, which caused movement of the superstructure in the transversal direction, buckling of the steel girders and significant cracks to RC slab. This paper presents the decision-making process of the repair method based on a policy of “Recovery of load-bearing performance of the bridge system”. Some of ideas were derived through the process, namely recovery of the superstructure performance by adding a new girder without removing the buckled girder, and the design concept of the bearing supports with consideration of the reliability of load-bearing capacity of substructures after repair. These ideas and consideration for the design are also introduced in this paper.