Evaluation of Typhoon Induced Fatigue Damage using Health Monitoring Data

Abstract

This paper aims to evaluate the effect of a typhoon on IhtigllC damage in steel decks of long-span suspension bridges. The strain-time histories at critical locations of deck sections of long-span bridges during a typhoon passing the bridge area me investigated by using on-line strain data acquired fron1 the structural health monitoring system installed on the bridge. The fatigue damage models based on Miner's law and the continuum damage mechanics are applied to calculate the increment of fatigue damage due to the action of a typhoon. It is found that for the case of Tsing Ma Bridge the stress spectrum generated by a typhoon is mllch different than that by the nonnul traffic and its histogram shapes can be described approximately as a Rayleigh distribution. The influence of typhoon londing on accumulative fatigue damage is more significant than that due to normal traffic loading. The increment of fatigue damage generated by hourly stress specttrum tor the maximum typhoon loading may be much greater than those for normal traffic loading. It concludes that it is necessary to evaluate typhoon induced fatigue damage for the purpose of accurately evaluating accumulative fatigue damage for the long-span bridge located at the typhoon prone region.