Effects of plan dimensions on gust wind loads for high-rise buildings

Abstract

Scale-model wind tunnel pressure measurements were carried out for rectangular-plan high-rise buildings with plan ratios ranging from 0.11 to 9. Mean, fluctuating, and peak wall pressure coefficient distributions and area-averages were investigated. In addition, comparisons with the ASCE 7–16 provisions for the Main Wind Force-Resisting System (MWFRS) were made. The results show that the plan ratio has significant effects on pressure coefficients on the leeward and side walls for plan ratios less than about 4. The largest mean base shear coefficient occurs for plan ratio of about 0.67, with large values in the range of 0.5–1, but decreasing for larger or smaller plan ratios. ASCE 7–16 mean load coefficients tend to underestimate the data, particularly because of the values on leeward walls. ASCE 7–16 also underestimates the peak load coefficients due to the value of the gust effect factor. For rigid buildings, ASCE 7–16 has a gust effect factor of 0.85, while measurements indicate that it is closer to 1 for plan ratios between 0.67 and 2. Thus, the overall mismatch between the ASCE 7–16 MWFRS loads and the measured data is due to both the mean pressure coefficients and the gust effect factor. For plan ratios below 0.67, the decrease in plan ratio tends to be favorable for the MWFRS load coefficients; while for plan ratios above 4, the effects of plan ratios on the MWFRS load coefficients are limited.