Observed Along-Wind Vibration of a Long-Span Suspension Bridge Tower

As bridge spans get longer and towers get taller, they become more flexible and various types of vibration may appear under various types of actions such as winds, pedestrian and earthquakes. In this paper we describe an interesting wind-induced vibration of a long-span suspension bridge tower observed from a permanent monitoring system. The downstream leg of an H-shaped 132.5m tower experiences along-wind vibration, whose time-histories and frequency response characteristics resemble the in-line vortex-induced vibration in a moderate wind velocity range of 13m/s -24m/s.

The tower in‐plane vibrations also generate significant girder lateral vibration in the same range of wind velocity.