Engineering Commons^™

A Partial-Turbulence Approach To Estimate Peak Wind Loads On Low-Rise Building Roofs, Yitian Guo

Electronic Thesis and Dissertation Repository

Quasi-steady (QS) theory is a commonly-used tool in wind engineering for the assessment of wind loads on structures induced by large-scale gusts. However, the QS-based approach tends to underestimate peak loads significantly since it fails to capture the effects of small-scale and body-generated turbulence. The objective of this thesis is to develop a method to estimate peak wind loads on low-rise roofs based on a partial-turbulence approach, i.e., using the QS vector model for loads induced by large-scale fluctuations from the incident flow, and a separate statistical model to account for the effects due to body-generated turbulence.

Wind tunnel tests …

Effects Of Corner Radii On Wind Tunnel Testing Of Low-Rise Buildings, Kytin Kwan

Electronic Thesis and Dissertation Repository

Wind effects on buildings are commonly studied by testing 3D printed building models in a wind tunnel. A challenge with 3D printing is that the edges of these models may not be perfectly sharp, but rounded with a radius of curvature, R. It is well known that when edges are significantly rounded, the aerodynamics of the building can be altered (Robertson, 1991; Mahmood 2011), leading to inaccurate predictions of full-scale surface pressures and wind loads. However, there is presently no guidance on model edge radii prescribed in wind tunnel testing standards such as ASCE 49-12. The objective of the present …

Influence Of Turbulence On The Aerodynamics Of Low-Rise Buildings, Fakhruzzaman Arif

Electronic Thesis and Dissertation Repository

During extreme wind events, roofing failures may lead to damage of the whole structure. In order to alleviate the effect, surface pressure coefficients on the roofs have been extensively investigated. This research aims to determine the roof pressures acting on low-rise buildings with consideration of the effects of turbulence (terrain). Pressure measurements, as well as wind speed data, were taken at the Boundary Layer Wind Tunnel Laboratory (BLWTL) of the University of Western Ontario (UWO) to examine the influence of turbulence level (i.e., terrain condition) on the critical wind directions corresponding to the largest surface roof pressure coefficients for various …

Estimation Of Turbulence Effects On Wind-Induced Suctions On The Roof Of A Low-Rise Building, Chieh-Hsun Wu

Electronic Thesis and Dissertation Repository

The effects of turbulence in the atmospheric boundary layer (ABL) on surface pressures of a typical low-rise building roof are investigated in this thesis. A 1/50 geometrically-scaled model of the Texas Tech University Wind Engineering Field Research Lab (WERFL) building model is used for pressure measurements in wind tunnel experiments. ABL wind turbulence intensities ranging from about 10% to 30%, and length scales ranging from 6 to 12 times of the building height (H) are generated. The effects of ABL turbulence on the mean roof pressures within the separated flow are explained from the time-averaged Navier-Stokes equations. The pressure fields …

Wind-Induced Pressures In Air Permeable, Double-Layer Roof Systems In Regions Of Separated Flow, Jeong Hee Oh

Electronic Thesis and Dissertation Repository

This thesis is concerned with the wind-induced pressure distribution acting on air permeable, double-layer roof systems placed on low-rise buildings. Because of the pressure transmission into the cavity between layers, the pressure difference in the double-layer systems differs significantly from that in a single layer. The interior pressures (in the cavity between layers) are highly correlated with external pressures at the openings on the external surface of the outer layer and thereby, the net wind load for the design of the outer layer is considerably reduced by the pressure equalization between the external and internal surfaces of the outer layer. …

Response Of A Two-Story Residential House Under Realistic Fluctuating Wind Loads, Murray J. Morrison

Electronic Thesis and Dissertation Repository

Severe wind storms such as tropical cyclones, tornados, downbursts etc. can cause significant damage to infrastructure. Damage surveys following these events have shown that the roofs of residential, wood-frame construction are particularly vulnerable to failures. While damage surveys provide detail information of what components fail, they cannot provide the loads at which these failures occurred or how they initiated. Wind tunnel pressure models provide detailed information of the wind loads on buildings, however, they are not able to predict failures or how these loads are transferred through the structure. In order to better understand the response of wood framed houses …