Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads
Wood-frame residential roof failures are among the most common and expensive types of wind damage. Hip roofs are commonly understood to be more resilient during extreme wind in relation to gable roofs. However, inspection of damage survey data from recent tornadoes has revealed a previously unstudie...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2018-02-01
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| Series: | Frontiers in Built Environment |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/article/10.3389/fbuil.2018.00006/full |
| _version_ | 1818229651244318720 |
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| author | Sarah A. Stevenson Gregory A. Kopp Ayman M. El Ansary |
| author_facet | Sarah A. Stevenson Gregory A. Kopp Ayman M. El Ansary |
| author_sort | Sarah A. Stevenson |
| collection | DOAJ |
| description | Wood-frame residential roof failures are among the most common and expensive types of wind damage. Hip roofs are commonly understood to be more resilient during extreme wind in relation to gable roofs. However, inspection of damage survey data from recent tornadoes has revealed a previously unstudied failure mode in which hip roofs suffer partial failure of the framing structure. In the current study, evidence of partial framing failures and statistics of their occurrence are explored and discussed, while the common roof design and construction practice are reviewed. Two-dimensional finite element models are developed to estimate the element-level load effects on hip roof trusses and stick-frame components. The likelihood of failure in each member is defined based on relative demand-to-capacity ratios. Trussed and stick-frame structures are compared to assess the relative performance of the two types of construction. The present analyses verify the common understanding that toenailed roof-to-wall connections are likely to be the most vulnerable elements in the structure of a wood-frame hip roof. However, the results also indicate that certain framing members and connections display significant vulnerability under the same wind uplift, and the possibility of framing failure is not to be discounted. Furthermore, in the case where the roof-to-wall connection uses hurricane straps, certain framing members and joints become the likely points of failure initiation. The analysis results and damage survey observations are used to expand the understanding of wood-frame residential roof failures, as they relate to the Enhanced Fujita Scale and provide assessment of potential gaps in residential design codes. |
| first_indexed | 2024-12-12T10:21:59Z |
| format | Article |
| id | doaj.art-aec2ce638b5a41bebd4785be425e352e |
| institution | Directory Open Access Journal |
| issn | 2297-3362 |
| language | English |
| last_indexed | 2024-12-12T10:21:59Z |
| publishDate | 2018-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Built Environment |
| spelling | doaj.art-aec2ce638b5a41bebd4785be425e352e2022-12-22T00:27:33ZengFrontiers Media S.A.Frontiers in Built Environment2297-33622018-02-01410.3389/fbuil.2018.00006317033Framing Failures in Wood-Frame Hip Roofs under Extreme Wind LoadsSarah A. Stevenson0Gregory A. Kopp1Ayman M. El Ansary2Boundary Layer Wind Tunnel Laboratory, Faculty of Engineering, University of Western Ontario, London, ON, CanadaBoundary Layer Wind Tunnel Laboratory, Faculty of Engineering, University of Western Ontario, London, ON, CanadaDepartment of Civil and Environmental Engineering, University of Western Ontario, London, ON, CanadaWood-frame residential roof failures are among the most common and expensive types of wind damage. Hip roofs are commonly understood to be more resilient during extreme wind in relation to gable roofs. However, inspection of damage survey data from recent tornadoes has revealed a previously unstudied failure mode in which hip roofs suffer partial failure of the framing structure. In the current study, evidence of partial framing failures and statistics of their occurrence are explored and discussed, while the common roof design and construction practice are reviewed. Two-dimensional finite element models are developed to estimate the element-level load effects on hip roof trusses and stick-frame components. The likelihood of failure in each member is defined based on relative demand-to-capacity ratios. Trussed and stick-frame structures are compared to assess the relative performance of the two types of construction. The present analyses verify the common understanding that toenailed roof-to-wall connections are likely to be the most vulnerable elements in the structure of a wood-frame hip roof. However, the results also indicate that certain framing members and connections display significant vulnerability under the same wind uplift, and the possibility of framing failure is not to be discounted. Furthermore, in the case where the roof-to-wall connection uses hurricane straps, certain framing members and joints become the likely points of failure initiation. The analysis results and damage survey observations are used to expand the understanding of wood-frame residential roof failures, as they relate to the Enhanced Fujita Scale and provide assessment of potential gaps in residential design codes.http://journal.frontiersin.org/article/10.3389/fbuil.2018.00006/fullwood-frame structurestornado damageEnhanced Fujita Scalehip roofsfinite element modelingdegrees of damage |
| spellingShingle | Sarah A. Stevenson Gregory A. Kopp Ayman M. El Ansary Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads Frontiers in Built Environment wood-frame structures tornado damage Enhanced Fujita Scale hip roofs finite element modeling degrees of damage |
| title | Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads |
| title_full | Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads |
| title_fullStr | Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads |
| title_full_unstemmed | Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads |
| title_short | Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads |
| title_sort | framing failures in wood frame hip roofs under extreme wind loads |
| topic | wood-frame structures tornado damage Enhanced Fujita Scale hip roofs finite element modeling degrees of damage |
| url | http://journal.frontiersin.org/article/10.3389/fbuil.2018.00006/full |
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