WIND INDUCED OSCILLATION OF BRIDGE MEMBERS

BRIDGE MEMBERS THAT ARE SUSCEPTIBLE TO WIND-INDUCED OSCILLATION MAY EXPERIENCE SEVERE DAMAGE TO THEIR CONNECTIONS. IN THIS REPORT TWO TYPICAL EXAMPLES OF WIND DAMAGE TO BRIDGES, THE ONE WITH INCLINED PIPE HANGERS AND THE OTHER WITH H-SHAPED VERTICAL HANGERS, ARE ILLUSTRATED. STATISTICS GATHERED FROM INVESTIGATION OF 141 ARCH BRIDGES WITH LONGITUDINAL STIFFENING WHICH WAS UNDERTAKEN ON A NATIONWIDE SCALE BY THE MINISTRY OF CONSTRUCTION ARE ALSO INTRODUCED. WIND TUNNEL TEST RESULTS ON THREE MODELS WITH H-CROSS SECTIONS ARE REPORTED (AEROSTATIC AND NONSTEADY AERODYNAMIC FORCES, STROUHAL NUMBER, AND AEROELASTIC STABILITY). IT IS POINTED OUT THAT A STRUCTURE OF H-SECTION SHOWS SELF-EXCITED OSCILLATION AS WELL AS FORCED OSCILLATION BY VORTEX EXCITATION. IT IS ALSO INDICATED THAT SUBHARMONIC OSCILLATION MAY OCCUR IN STRUCTURE OF H-SECTION. /AUTHOR/