Tall Building Response Parameters: Sensitivity Study Based on Orthogonal Factorial Experiment Design Technique

This work has two objectives. The first objective is to introduce structural engineers to the experiment design technique, whose future applications may include, for example, the total response of tall buildings, the strength reserve of statically indeterminate structures with nonlinear behavior, for which the duration of each run is large, and the aerodynamic response of a structure under a flow with a variety of simulated flow parameters. The second objective is to show, by using the experiment design technique, that wind load factors for tall buildings depend significantly upon uncertainties with respect to the natural frequencies of vibration and the damping ratios. Because this dependence is disregarded in the ASCE 7-05 Standard, wind load factors specified therein can lead to safety levels that are significantly lower for flexible buildings than for rigid buildings. An unexpected result of the study is that estimates of wind effects based on peak gust speeds entail nonnegligible errors. Consideration should therefore be given to replacing peak gust speeds by sustained wind speeds.