Question

Wind engineering

6.3 Estimate the critical wind speed for torsional flutter for a long span bridge (length 7265 ft, width 105 ft). For the critical torsional mode (most vulnerable to flutter instability), assume mechanical damping ratio, frequency, modal integral, and generalized inertia to be as 0.7%, 0.2 Hz, 1.15, 9.7 x 109 lb ft s2, respectively. Use the figure on the next page for flutter derivatives. 1.0 0.8 0.6 0.4 0.2 0.0 -0.2 -0.4 2 3 6 U/nB 0 8 10

Answer 1

6.3 Estimate the critical wind speed for torsional flutter for a long span bridge (length 7265 ft, width 105 ft). For the critical torsional mode (most vulnerable to flutter instability), assume mechanical damping ratio, frequency, modal integral, and generalized inertia to be as 0.7%, 0.2 Hz, 1.15, 9.7 x 109 lb ft s2, respectively. Use the figure on the next page for flutter derivatives.