Wind-Loading Effects on Roof-to-Wall Connections of Timber Residential Buildings
Publication: Journal of Engineering Mechanics
Volume 139, Issue 3
Abstract
Extensive damage to residential wood-frame buildings caused by failures of roof-to-wall connections during extreme wind events underscores the need to improve their performance. Most of these connections use mechanical connectors, e.g., metal clips and straps (sometimes referred to as hurricane clips and hurricane straps). The allowable capacity of these connectors is based on results of unidirectional component tests that do not simulate multiaxial aerodynamic loading effects induced by high wind events. The objective of this research was to facilitate a better understanding of these loading effects on roof-to-wall connections of a typical low-rise gable roof residential structure subjected to combined impacts of wind and a potential breach of the building envelope. Large-scale experiments on a heavily instrumented building model generated multiaxial aerodynamic loading data on roof-to-wall connections for various wind angles of attack and internal pressure conditions. The results showed the severity of increased loading on connections in certain configurations of wall openings that could occur from the breach of the building envelope in windstorms. It was also shown that lateral components of the wind load acting simultaneously with the uplift may be significant, depending on wind angles of attack and internal pressure conditions. Aerodynamic test data were used to perform component-level triaxial-load testing on hurricane clips to determine their load capacities and compare results to those obtained using the traditional approach of uniaxial-load testing. Component level test results showed that current uniaxial testing methods tend to overestimate the actual load capacities of metal connectors. Neglecting triaxial loading effects in testing of connectors and in the design of connections could potentially cause the type of failures frequently documented in hurricane damage reconnaissance reports.
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Acknowledgments
This research was supported by the National Science Foundation. Additional support was provided by the Gulf of Mexico Regional Sea Grant Program, Florida Center of Excellence in Hurricane Damage Mitigation and Product Development, and Soprema, Inc. of Wadsworth, Ohio. The Wall of Wind component of the project was additionally supported by the Florida Sea Grant College Program. The six-fan Wall of Wind was sponsored by RenaissanceRe Holdings Ltd. of Hamilton, Bermuda. The findings expressed in this paper are those of the authors alone, and do not necessarily represent the views of the sponsoring agency.
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Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 139 • Issue 3 • March 2013
Pages: 386 - 395
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Oct 12, 2011
Accepted: Jul 27, 2012
Published online: Aug 2, 2012
Published in print: Mar 1, 2013
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