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

The study is concerned with the three-dimensional response of tall bui ldings (rectangular in plan) to along-wind dynamic forces. For the res ponse analysis, a method based on a spectral approach with matrix form ulation is presented. The power spectral density function (PSDF) matri x of the response is related to the PSDF matrix of the random dynamic forces through the complex frequency response function matrix [corresp onding to dynamic degrees of freedom (DOFs)] of the building. The PSDF matrix of random forces is obtained by dividing the face of the build ing into a number of elemental areas forming a mesh and lumping the wi nd forces acting over the area at its centroid. The method is develope d for a fixed base condition and wind incident normal to one of the fa ces of the building, and can be easily extended to include across wind and torsional wind forces.