Journal of Natural Disaster Science

ALLOWABLE AMPLITUDE OF VORTEX-INDUCED OSCILLATION OF LONG-SPAN BRIDGES

Mitsuo KAWATANI
Associate Professor, Department of Civil Engineering, Osaka University, Osaka
and
Sadao KOMATSU
Professor, Department of Civil Engineering, Osaka Sangyo University, Osaka

(Received 18 June, 1988 and in revised form 13 August, 1988)

Abstract

A certain amount of restricted vibration is allowed for the wind-induced vibrations that affect long-span bridges if it does not cause fatigue damage to the structural members or the unserviceability of such bridges. The allowable amplitudes of vortex-induced oscillation were investigated here. First, the allowable amplitude was determined in terms of the allowable stress on structural members and the serviceability of a bridge, after which the fatigue damage done to structural members was examined.

The serviceability of a bridge is related to the sensitivity of pedestrians and drivers to its vibration. In our study of fatigue damage, the number of cycles of vortex-induced oscillation in the lifespan of a bridge was found by processing and analyzing stochastic data on natural wind recorded at the site of bridge's construction as well as the results of wind tunnel tests.

Key words

allowable amplitude, vortex-induced oscillation, fatigue damage, serviceability, probability of natural wind, wind tunnel test