Fatigue Failure Analysis of Cracks near the Sole Plate of a Half-Through Steel-Arch Bridge

Abstract

A fractured bolt connecting the bearing and the stiffening girder of a half-through steel-arch bridge, with a main span length of 113 m, which was opened for public in September 1996, was found in October 2013 during periodic visual inspection. Cracks were also found in the bottom flange of the stiffening girder near the four corners of the sole plate in January of 2014, when the bolts were replaced. In order to assess the main causes of the cracks, fatigue failure analysis by dynamic testing and monitoring of strain conditions, temperature of the stiffening girder, and rotation of the bearing were carried out. Additionally, finite-element (FE) analysis was performed to provide further insight on the causes of the cracks. The results showed that bending moments due to axial forces in the stiffening girder, caused by longitudinal displacement of the girder under vehicle load, are the main cause of the cracks and bolt fracture.