Estimation of wind force time-history using limited floor acceleration responses by modal analysis

Abstract

Time-history analyses are usually performed to design and examine the performance of tall structures subjected to strong wind loading. An accurate estimate of the time history of wind forces is required to carry out time-history analysis. However, previous studies conducted to estimate the time-history of wind forces require a lot of priori information, such as complete structural parameters and wind-induced responses, which are generally not available in actual conditions. This work addresses the estimation of the time-history of wind forces acting on each story of a ten degree-of-freedom model under the assumption that only the mass and acceleration responses measured on three stories are known. First, cubic spline interpolation is used to determine the unknown acceleration responses and frequency domain integration is used to obtain the velocity and displacement responses. Then, unknown structural parameters (particularly stiffness and damping) are estimated by the Frequency Domain Decomposition method. Finally, the obtained responses and structural parameters are used to estimate the wind forces using the equation of motion. It is demonstrated that the proposed methodology can accurately estimate the input wind forces on the structure.