Aerodynamic Response of Long H-Sections

Section models of several long H-section members of the Commodore Barry Bridge were tested in wind tunnels for aerodynamic coefficients and for vibration response when supported in a three degree-of-freedom mounting. Vibration testing was carried out in both smooth and turbulent flow. Comparisons were made with the response of an aeroelastic model tested at the Vertol Division of the Boeing Company. Tests results clearly show that for long H-section members, significant distress may occur due to static (mean) and fluctuating forces produced by wind effects. Vorttex excitation and self-excited motion are possible unless frequencies are relatively high and greater damping than the usual structural level is provided. Some remedies are considered; the actual solution adopted as worked out by others is noted.