Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Gregory A. Kopp

Abstract

Currently, the design of wall cladding and components are based on provisions provided in building codes, such as ASCE 7 for the United States. These codes provide pressure coefficients based on the tributary area, position on the building and the building category. For ASCE 7, low-rise and high-rise buildings are separated by an artificial boundary at 60 ft. (18.2 m). The reasoning for this artificial boundary is unclear. This work investigates the wall pressure coefficients for various buildings, based on aspect ratios, motivated by the large differences in design pressure coefficients for low-rise and high-rise buildings.

For this study, a systematic wind tunnel study was performed examining a square plan building with different aspect (i.e., height-to-width ratio) ratios. The wind profile and turbulence intensities were examined to determine the model-scale appropriate for the multiple building heights. Once the model-scale was selected, height configurations of low-rise (H/WH/W>1) buildings were tested. A statistical analysis was performed on these pressure coefficients and these values were converted to GCp (gust factored pressure coefficients) values, as a function of (full-scale) area. The pressure coefficients were compared to studies found in the literature to ensure the reliability of the data. Pressure patterns were observed and the impact of the wind directions was analyzed. Cladding element position and pressure coefficients were compared for the different buildings. The pressure coefficients were compared to ASCE 7.

This study concluded that the aspect ratio affected the length of the wall separation bubble, with smaller aspect ratios having more compressed separation bubbles. For positive pressure coefficients, low-rise buildings have different zones of pressure while high-rise buildings are more uniform. For negative pressure (i.e., suction) coefficients, the patterns continually vary with the different aspect ratios. The study showed that there were some aspects of ASCE 7 that were not in good agreement with the data.


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