Fluctuating Wind Loads on Buildings

A method for evaluating the fluctuating wind forces and their distribution on buildings has been developed and applied to the understanding and quantification of crosswind loads on a square cross-section building. Wind loads are determined by integrating simultaneously monitored pressure fluctuations on a building model surface in a boundary layer wind tunnel. An example is presented to illustrate that a suitable combination of a limited number of pressure transducers can be used to monitor pressure fluctuations for the estimation of multi-level wind loads on building models. This methodology also provides information on the local spatio-temporal variation of pressure fluctuations which can provide useful input to the cladding design. Power spectral density and chordwise variation of co-spectra between locations at one level on the model surface are presented. The cross power spectral density matrices of the crosswind forcing function are developed for urban and suburban flow conditions. An increase in the incident turbulence has dampening effects on the crosswind forcing function, that is, a slight spectral peak. Methods of random vibration analysis can be used to compute the probabilistic response of a building modeled as a single or a multi-degree-of-freedom system.