Methodology to Analyze Wind Pressure Data on Components and Cladding of Low-Rise Buildings
Dat Duthinh, Joseph A. Main
This note establishes a method to analyze wind pressure data on cladding and components of low-rise buildings using the National Institute of Standards and Technology-University of Western Ontario (NIST-UWO) database. The aerodynamic pressures induced on a structure by the wind field are random both in time and space. For design purposes, the pressure on any given area A is a function of A, and is defined as the aerodynamic force acting on area A divided by A. That aerodynamic force is obtained by summing up the product of pressure time series measured in wind tunnel tests at adjoining pressure taps by their respective tributary areas. The area A is the sum of those tributary areas. These operations are carried out for all sums of tributary areas that make up rectangles with aspect ratio not exceeding four. The peak of the resulting area-averaged time series is extrapolated to a realistic storm duration by the Sadek-Simiu method. The envelope of peaks over all wind directions is compared with current specifications from the American Society of Civil Engineers, ASCE 7-10. Results for two low-rise buildings for one terrain condition indicate serious underestimation by these specifications of the negative pressures (suction) on gable roofs, by factors ranging from 1.3 to 2.5, and of both positive and negative pressures on walls, by factors ranging from 1.5 to 2.0 and 1.2 to 2.4, respectively. More definitive conclusions will require analysis of more data from the NIST-UWO and other databases using the proposed or equivalent methodology. Future research includes the analysis of additional low-rise building configurations and the estimation of peak pressures by alternative methods.