LATERAL-TORSIONAL MOTION OF TALL BUILDINGS TO ALONG-WIND FORCES

The study is concerned with the three-dimensional response of tall buildings (rectangular in plan) to along-wind dynamic forces. For the response analysis, a method based on a spectral approach with matrix formulation is presented. The power spectral density function (PSDF) matrix of the response is related to the PSDF matrix of the random dynamic forces through the complex frequency response function matrix [corresponding to dynamic degrees of freedom (DOFs)] of the building. The PSDF matrix of random forces is obtained by dividing the face of the building into a number of elemental areas forming a mesh and lumping the wind forces acting over the area at its centroid. The method is developed for a fixed base condition and wind incident normal to one of the faces of the building, and can be easily extended to include across wind and torsional wind forces.