Analysis of Multimode Coupled Buffeting Response of Long-Span Bridges to Nonstationary Winds with Force Parameters from Stationary Wind

Abstract

AbstractThis paper presents a general frequency domain framework for predicting multimode coupled buffeting response of long-span bridges to nonstationary winds. Within this framework, the wind speed field, aerodynamic forces, and bridge response are separated into deterministic time-varying mean and evolutionary random fluctuating components. Under the assumption of low variation rate of mean wind speed, the time-varying mean and self-excited and buffeting forces are modeled in static force coefficients, flutter derivatives, and admittance functions, determined in a wind tunnel under stationary wind, but with consideration of nonstationary wind characteristics in a quasi-steady manner. The time-varying mean bridge response is calculated through static analysis at each time instant. The random buffeting response is expressed in generalized modal displacements governed by the equations of a frequency-dependent linear time-variant (LTV) system. An equivalent frequency-independent LTV system is introduced, w...