COUPLED MODE FLUTTER ANALYSIS USING FLUTTER DERIVATIVES

The "classical" coupled bending-torsion flutter of long-span bridges, possessing 3-dimensional vibration modes, is investigated both analytically and experimentally. In the analysis, self-excited forces are defined by using the so-called flutter derivatives. The vertical wind profile as well as the spanwise non-homogeneity of wind velocity are also incorporated. The analysis permits (i) straight forward prediction of the coupled flutter velocity by using the flutter derivatives and (ii) reasonable interpretation of 2-dimensional model tests to predict the coupled flutter behavior of bridges with 3-dimensional freedom of motion.