Vibration of tayan bridge’s hanger in west Kalimantan, Indonesia

Abstract

In November 2015, vibration has been detected at hangers of Tayan steel arch bridge just before its opening for public. The vibrations occurred at certain wind speed in the first asymmetric torsional mode. Vibration on the hanger is a phenomenon that often occurs especially if the hanger is I-shaped. There are 3 possible reason of the vibration including Vortex Induced Vibration (VIV), Galloping and Flutter. To investigate the phenomena, a finite element analysis of the hanger was conducted by considering the effect of the axial force to the natural frequency of the hanger. The results of the analysis obtained in the form of the natural frequency of the structure in the first asymmetric torsional mode then compared with the frequency of vortex vibrations. It was found that the natural frequency of the structure corresponds to the vortex vibration frequency, and therefore, the hanger vibrated because of Vortex Induced Vibration (VIV). Several alternative solutions to increase Vortex Induced Vibration (VIV) wind speed were considered including improving the shape of the hanger and increasing the hanger’s stiffness by using cable struts.