Verification of closed-form solutions of fatigue life under along-wind loading

Records of wind-induced strains measured in 12 m high, tubular steel lighting columns have been collected over a range of mean wind speeds up to 17 m/s. Since this did not embrace the full transcritical range of Reynolds numbers, a novel approach was adopted to acquire a more complete data set. The diameter of one of the columns was increased from 0.14 to 0.58 m by means of plastic drums mounted so as not to influence the stiffness or strength of the column. The back-corrected data harmonised with the original data set. The full data set has been used to verify recently-proposed, simple, closed-form solutions of fatigue damage and fatigue life in structures subjected to along-wind loading. The closed-form model offers upper and lower-bound solutions corresponding to narrow-band resonant vibrations and wide-band background response, respectively. The solutions provide remarkably good predictions of the experimentally derived damage rates across the full range of Reynolds numbers tested, particularly when the shallower part of the bi-linear fatigue endurance curve for the shoulder-weld of concern is adopted in the model. Predictions of fatigue life are similarly promising in relation to the actual performance of similar lighting columns at sites with different wind exposures.