Effects of high winds on a long-span sea-crossing bridge based on structural health monitoring

Abstract

This paper focuses on the effects of high winds on vibrational responses and modal parameter's variation for a unique sea-crossing cable-stayed bridge, i.e. Donghai Bridge, based on the long-term structural health monitoring (SHM) data. This bridge is located in a typhoon-prone area of the northwestern Pacific Ocean, and 80% of the vehicles traversing it are heavy-load container trucks. The relative influence of high winds and heavy-load traffic on the structural vibration responses is investigated by a comparison of typical operational cases. The high wind dominates in the girder's lateral vibration of Donghai Bridge, while the girder's vertical and torsional accelerations are more sensitive to heavy-load traffic rather than high winds. Also, the frequency band of the wind excitation is lower than that of traffic load. During high winds, the modal parameters of this bridge are relatively difficult to stably identify, thereby leading to a well-pronounced discreteness of the parameters' estimates. This paper could serve as a field evidence for the wind-resistant design and the performance evaluation of bridges in similar operational conditions.