Investigation of Seismic Response on Girder Bridges: The Effect of Displacement Restriction and Wing Wall Types

Abstract

In the seismic design specified by Japanese Specifications of Highway Bridges (JSHB), a large gap size between two adjacent girders or the girder and abutment has recommended to be constructed in the concrete girder bridge with multi-spans in order to prevent the collision, when it is subjected to Level 2 ground motion. However, the adoption of large gap into PC bridge will increase the construction and seismic reinforcement costs since relatively large expansion joints have to be used. Also, it causes the girders falling in the presumption of strong earthquake. It has been suggested that allowing the girder collision at the abutment by restricting the girder bridges displacement, the size of expansion joints can be reduced. These conditions are able to reduce the seismic design and seismic reinforcement cost.Although many studies on the effect of the collision have been published, the effect of displacement restriction of girders is still remains to be elucidated. This present study aims to investigate the seismic response of concrete girder bridges taking into account the effect of displacement restriction of girders allowing the girder collision at the abutment and the wing wall. Two span concrete girder bridge was examined in theoretically by 3D FEM model of ABAQUS with four different approaches at the wing wall abutment model. The dead load and soil pressure were calculated based on JSHB loading conditions and gap between superstructure and parapet wall was chosen to be 10cm and 20cm. Level 2 earthquake ground accelerations were applied horizontally at the bottom of pier. The numerical results showed that the parameters such as shear stress, response stress, displacement, and cracking were affected by displacement restriction and different wing wall model. Installing of the wing wall in abutment generally increased the response stress in parapet wall and shear stress around vertical wall of abutment. In contrast, it significantly reduced the horizontal displacement of abutment.