ABSTRACT
An intensive earthquake of 7.3 JMA magnitude occurred in the Kumamoto area of Japan in April 2016. Though the damage of most road bridges was insignificant, some road bridges with fatal damage have taken a long time to recover function. It is noted that ground displacement induced not only displacement of the substructure, but also a relatively large displacement between the superstructure and substructure to the bridges damaged by this earthquake. However, the construction period of restoration of the damaged bridges varies according to conditions such as structural type, location of the substructure, ground deformation and failure mode. In this paper, the Aso Choyo Ohashi bridge, with 4-span continuous PC rigid-framed structure, was studied. This bridge did not collapse even though the end of the superstructure lost vertical support due to slope failure, following subsidence of an abutment (about 2 m). This result suggests the importance of the bridge structural type selection and location of the substructure at the structural planning stage. Based on lessons learned from the damaged bridges and failure mode, a new Aso Ohashi bridge is under construction. This paper also introduces various technical considerations that are superior to redundancy and easy-to-recover considered in the new Aso Ohashi bridge construction.
