FAILURE OF A 140 M HIGH STEEL CHIMNEY CAUSED BY OSCILLATIONS DUE TO WIND ACTING PERPENDICULAR TO THE CHIMNEY

UNDER A CRITICAL WIND SPEED OF 13 TO 16 M/SEC, CONSIDERABLE OSCILLATIONS PERPENDICULAR TO THE WIND DIRECTION OCCURRED ON A 140 M-HIGH STEEL CHIMNEY AT THE DUISBURG - HAMBORN STEEL WORKS (FEDERAL REPUBLIC OF GERMANY). THESE OSCILLATIONS LED TO THE FAILURE OF THE STEEL SHELL, AND IT WAS NECESSARY TO REDUCE THE HEIGHT OF THE CHIMNEY TO 32 M OVER GROUND LEVEL. TESTS SHOWED THAT IT WAS POSSIBLE TO RECONSTRUCT THE CHIMNEY ON THE OLD BASE. IN ORDER TO AVOID VORTEX VIBRATIONS, THREE HELICOIDAL STRENGTHENERS WERE FIXED TO THE CHIMNEY. THESE STRENGTHENERS WERE OPTIMISED AS A RESULT OF WIND TUNNEL TESTS. VIBRATION TESTS MADE IT POSSIBLE TO DETERMINE THE NATURAL FREQUENCY AND DAMPING. FURTHERMORE, LONG TERM TESTS HAVE INDICATED THAT THE CHIMNEY IS ABLE TO SUSTAIN WIND EFFECTS. COMMENTS ARE MADE ON THE GERMAN STANDARD DIN 4133 "STEEL CHIMNEYS".