Large-Scale Wind Testing on Roof Overhangs for a Low-Rise Building
Publication: Journal of Structural Engineering
Volume 148, Issue 11
Abstract
Roof overhangs are prone to wind damage because they are subject to wind load at both the upper and bottom surfaces. Wind standards assume that the pressure at the bottom covering of a roof overhang will be the same as the external pressure coefficient on the adjacent wall surface. A large-scale experimental campaign was carried out at the Wall of Wind (WOW) Research Experimental Facility to investigate the validity and possible limitations of such assumptions. The experimental setup considered two 1:10 scaled models [0.61 m (2 ft) and 1.83 m (6 ft) inclined overhangs with a soffit] of a low-rise hip roof building with roof slope 4:12, eave height of 7.5 m (24 ft), and horizontal dimensions of 12.2 m (40 ft) 15.24 m (50 ft). The two models were tested for open terrain for 40 wind directions (WDs). The study provided information on pressure variations at the top and bottom surfaces of overhangs, adjacent roof areas, and underneath walls. Pressure and correlation coefficients were generated between soffits and underneath walls to quantify the effect of overhang width. The research showed that the 0.61 m (2 ft) overhang experienced higher suction coefficients at the edges compared to the 1.83 m (6 ft) overhang. In addition, the results confirmed that, for both configurations, soffit positive pressure coefficients may be assumed to be equal to the adjacent wall external pressure, as stated by a common standard, while this might not be applicable for negative pressure coefficients. Correlation and regression analyses between soffit pressure taps and wall upper taps show that the 1.83 m (6 ft) soffit appeared to be less correlated with the wall upper taps, compared to the 0.61 m (2 ft) soffit. Finally, area-averaged pressure coefficients for overhangs and adjacent roof areas were compared to the provisions in one standard for each specified zone, and differences were found.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors are grateful to the support provided by Florida Building Commission Order B83FC1 for funding this research and to the staff at the WOW at FIU for their support in performing the experimental work.
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© 2022 American Society of Civil Engineers.
History
Received: Feb 5, 2022
Accepted: Jun 6, 2022
Published online: Aug 27, 2022
Published in print: Nov 1, 2022
Discussion open until: Jan 27, 2023
ASCE Technical Topics:
- Buildings
- Continuum mechanics
- Dynamic loads
- Dynamics (solid mechanics)
- Engineering fundamentals
- Engineering mechanics
- Load tests
- Low-rise buildings
- Roofs
- Solid mechanics
- Structural dynamics
- Structural engineering
- Structural members
- Structural systems
- Structures (by type)
- Tests (by type)
- Walls
- Wind engineering
- Wind loads
- Wind pressure
- Wind tunnel
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