FIELD-MEASUREMENTS OF THE WIND-INDUCED RESPONSE OF A 254 M HIGH FREESTANDING 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. Simult aneous and continuous measurements of accelerations, wind speed and di rection were recorded at the top of the pylon in its free-standing con figuration. In that period, the structure faced three major wind storm s 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 fi eld measurement campaign including correlation between wind speeds and accelerations, estimates of Strouhal numbers for crosswind and alongw ind response and estimates of damping and natural frequencies. Compari sons between full-scale observations and model-scale experiments are a lso presented. (C) 1998 Elsevier Science Ltd. All rights reserved.