Field measurements of the wind-induced response of a 254 m high free-standing bridge pylon

The response to wind action of a 254 m high bridge pylon was measured in situ for a period of 7 weeks in the fall of 1995 in Denmark. Simultaneous and continuous measurements of accelerations, wind speed and direction were recorded at the top of the pylon in its free-standing configuration. In that period, the structure faced three major wind storms with 10-min mean wind speeds at the top of the pylon well above 25 m s −1. The response of the pylon was characterised by vortex-shedding-induced oscillations. This paper presents the main findings of the field measurement campaign including correlation between wind speeds and accelerations, estimates of Strouhal numbers for crosswind and alongwind response and estimates of damping and natural frequencies. Comparisons between full-scale observations and model-scale experiments are also presented.