Study on vibration characteristics of steel Gerber truss bridge and reinforcement methods to reduce vibration

The bridge under investigation is a cantilever truss bridge with 3 spans of 117.0 m, constructed in 1958. When heavy vehicles drive on this bridge, they cause very large vibration. This vibration threatens the drivers using this bridge in their everyday life. Furthermore, during an inspection in 2017, several cracks were found in the transverse girders of the assembled floor system of this bridge. Therefore, microtremor measurements were conducted during the repair work of the bridge’s transverse girders. The purpose of this study was to obtain the vibration characteristics and to propose several reinforcement methods to reduce the large vibration to some extent. As reinforcement methods, we proposed two approaches: reinforcement using truss members and reinforcement using PC cables. As a result, the truss reinforcement showed a slightly higher vibration reduction effect, with vibration amplitudes reduced by approximately 20–30%.