Aeroelastic forces and dynamic response of long‐span bridges

Abstract

SUMMARYIn this paper a time domain approach for predicting the non-linear dynamic response of long-span bridges is presented. In particular the method that leads to the formulation of aeroelastic and buffeting forces in the time domain is illustrated in detail, where a recursive algorithm for the memory term's integration is properly developed. Moreover in such an approach the forces' expressions, usually formulated according to quasi-static theory, have been substituted by expressions including the frequency-dependent characteristics. Such expressions of aeroelastic and buffeting forces are made explicit in the time domain by means of the convolution integral that involves the impulse functions and the structural motion or the fluctuating velocities. A finite element model (FEM) has been developed within the framework of geometrically non linear analysis, by using 3-d degenerated finite element. The proposed procedure can be used to analyze both the flutter instability phenomenon and buffeting response. Moreover, working in the geometrically non-linearity range, it verifies the possibility of strongly flexible structures of actively resisting the wind loading.

Modal Identification Study of Vincent Thomas Bridge Using Simulated Wind‐Induced Ambient Vibration Data

“…The experimental flutter derivatives in the above equations are usually obtained at a discrete set of reduced frequencies K (ω k ). Then, the rational function approximation method known as Roger's approximation is used to estimate the aerodynamic force coefficients defined in , also known as aerodynamic transfer functions, as continuous functions of the reduced frequency K (Roger, 1977; Chen et al, 2000a; Lazzari et al, 2004). For example, let where C Lh , i and d Lh , k ( d Lh , k ≥ 0; i = 1, … , n and k = 4, … , n )= frequency‐independent coefficients.…”

Time domain modelling of aeroelastic bridge decks: a comparative study and an application

“…Development of Equations (8)-(10) is summarized hereunder for lift only, since complete formulation for lift, drag and moment has been included in previous publications by the same authors (e.g. References [7,4,17]).…”

“…Other research works on bridge aerodynamics use a formulation based on the 'extension of aeroelastic derivatives to the time domain' with convolution integrals and complex rational approximation of the impulse (e.g. References [4][5][6][7]).…”

Cross-sectional distributions versus integrated coefficients of flutter derivatives and aerodynamic admittances identified with surface pressure measurement

“…Unsteady forces are modeled either in the time or frequency domain, taking into account their dependence upon the reduced velocity (frequency) and mean angle of attack (e.g. Chen and Kareem, 2008;Bartoli and Mannini, 2008;Lazzari et al, 2004;Caracoglia and Jones, 2003;Scanlan and Tomko, 1971).…”