Report of an Unexpected Vortex-Induced Vibration in an Actual Suspension Bridge

Abstract

An unexpected vibration was observed on the Yi Sun-sin Bridge on October 26th, 2014. Since the bridge was subjected to a single mode vibration in limited amplitude for one and half hours, it was regarded as a vortex-induced vibration (VIV). Since the bridge was aerodynamically well designed for the VIV as well as flutter instability, the cause of the vibration was investigated via a series of two-dimensional wind tunnel tests. The one-side lanes were closed to traffics and the epoxycoated wearing surface was being replaced at the time of the VIV. Since the primary source was estimated as the temporal screens applied on the bridge railings for maintaining curing temperature of the replaced wearing surface, wind tunnel tests were carried out for the section model of the deck section with and without the screens. This paper presents the screen effects on VIV of the investigated bridge and the illustration of the observed vibration based on in-depth investigation with a series of two-dimensional wind tunnel.

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