Semester of Graduation

Spring 2021

Degree

Master of Science in Civil Engineering (MSCE)

Department

Department of Civil and Environmental Engineering

Document Type

Thesis

Abstract

The wind load performance of low-rise buildings during high wind events depends on the integrity of the building’s exterior components. Roofing components are exposed to winds of higher intensity and therefore account for a significant number of wind-related damages. The aerodynamic performance of a roof system depends considerably on its geometry, mitigation devices, and its aspect ratio. These parameters govern the flow pattern along the roof surface and, ultimately, the distribution of time-variant wind loads. The American Society of Civil Engineers (ASCE) offers guidance by publishing wind loading guidelines (ASCE 7-16) for building components and cladding (C&C) design. This study focuses on re-evaluating current design guidelines and suggesting ways to improve them. More specifically, the main objective of this study is to experimentally investigate how varying heights of solid perimeter parapets can alter the flow pattern of low-sloped gable roof with a large aspect ratio (width to height).

In order to evaluate the methods used by ASCE in the development of these guidelines, a brief examination into the benefits and challenges of existing methods is described. The majority of current wind data is generated from modeling in closed-loop wind tunnel testing over the last 50 years. This study utilized open-jet wind tunnel simulation as it has been seen to more accurately simulate real-world atmospheric boundary layer conditions. A model low-rise structure was fitted with solid parapets of varying heights and tested in an open-jet hurricane facility in a comparative study to understand their impact on roof pressures. Roof pressures are measured in the laboratory and compared with design values, gathered from previous wind tunnel testing in ASCE 7-16. The analytical approach by ASCE is compared to the experimental result of this study and improvements to wind zones and pressure coefficients are suggested based on the new testing protocol. It was found that the parapet at a height of 14% of the building height was the most efficient at reducing peak mean, peak, and area-averaged pressure coefficients when compared to other parapet heights. The ASCE 7-16 specification underpredicts external pressure coefficients for components and cladding of low-rise structures with small sloped gabled roofs.

Committee Chair

Mousaad Aly, Aly

Available for download on Sunday, March 12, 2028

Share

COinS