Fragility assessment of wood sheathing panels and roof-to-wall connections subjected to wind loading

Abstract

The performance of the wood-frame buildings after tornadoes has shown that the majority of the wind damage resulted from building envelope failure most typically due to the loss of the roof. To assess the performance and the reliability of low-rise wood-frame residential buildings with a focus on the roofs, fragility analysis can be used to estimate the probability of failure of a roof when constructed with specified nails and sheathing sizes. Thus, this paper examines the fragility of specific types of nails, roof-to-wall (RW) connection details, and sheathing sizes based on the damaged roofs that were previously assessed in the Dunrobin area in Ottawa (Ontario) that was hit with an Enhanced Fujita (EF3) tornado on September 21, 2018. The presented fragility analysis considers four scenarios, including different sheathing and nail sizes. Dead loads, wind loads, and resistance on the sheathing panels were compiled and analyzed to determine the failure of the examined roofs. The eight fragility models suggest that the safest roof sheathing (RS) is the 1.22 m × 1.22 m sheathing panel with 8 d nails, and the safest RW connections is achieved by using H2.5 hurricane clips.

Graphical abstract

Keywords

tornadoes / wind loads / low-rise buildings / fragility analysis / risk assessment / structural failures

References

[1] BrooksH E, DoswellIII C A. Normalized damage from major tornadoes in the United States: 1890−1999. Weather and Forecasting, 2001, 16( 1): 168– 176

[2] KoppG A, GavanskiE. Effects of pressure equalization on the performance of residential wall systems under extreme wind loads. Journal of Structural Engineering, 2012, 138( 4): 526– 538

[3] GillA, GenikomsouA S. Reconnaissance of buildings impacted by the 2018 tornadoes in Ottawa, Canada. Journal of Performance of Constructed Facilities, 2020, 34( 4): 04020074–

[4] MehtaK C, MinorJ E, McDonaldJ R. Wind speed analysis of April 3−4 tornadoes. Journal of the Structural Division, 1976, 102( 9): 1709– 1724

[5] EllingwoodB R, RosowskyD V, LiY, Kim J H. Fragility assessment of light-frame wood construction subjected to wind and earthquake hazards. Journal of Structural Engineering, 2004, 130( 12): 1921– 1930

[6] AminiM O, van de LindtJ W. Quantitative insight into rational tornado design wind speeds for residential wood-frame structures using fragility approach. Journal of Structural Engineering, 2014, 140( 7): 04014033–

[7] GavanskiE, KoppG A. Fragility assessment of roof-to-wall connection failures for wood-frame houses in high winds, ASCE-ASME J. Risk Uncertainty Eng. Systems, Part A. Civil Engineering, 2017, 3( 4): 04017013–

[8] KoppG A, HongE, GavanskiE, StedmanD, SillsD M. Assessment of wind speeds based on damage observations from the Angus (Ontario) tornado of June 17 2014. Canadian Journal of Civil Engineering, 2017, 44( 1): 37– 47

[9] RosowskyD V, ChengN. Reliability of light-frame roofs in high-wind regions. I: wind loads. Journal of Structural Engineering, 1999, 125( 7): 725– 733

[10] NAHB. Reliability of Conventional Residential Construction: An Assessment of Roof Component Performance in Hurricane Andrew and Typical Wind Regions of the United States. Washington, D.C.: The Office of Policy Development and Research, 1999

[11] O. Reg. 332/12: Building Code, Ontario’s Building Code. Ontario: Government of Ontario, 2020

[12] LeeK H, RosowskyD V. Fragility assessment for roof sheathing failure in high wind regions. Engineering Structures, 2005, 27( 6): 857– 868

[13] Ellingwood B. Development of A Probability-Based Load Criterion for American National Standard A58: Building Code Requirements for Minimum Design Loads in Buildings and Other Structures. Washington, D.C.: US Department of Commerce, National Bureau of Standards, 1980

[14] Canadian Commission on Building and Fire Codes. National Building Code of Canada. Ottawa: National Research Council of Canada, 2015

[15] Environment and Climate Change Canada: Enhanced Fujita Scale. Toronto: Environment Canada, 2013

[16] BillahA H M, Shahria AlamM. Seismic fragility assessment of highway bridges: A state-of-the-art review. Structure and Infrastructure Engineering, 2015, 11( 6): 804– 832

[17] BalomenosG P, KameshwarS, PadgettJ E. Parameterized fragility models for multi-bridge classes subjected to hurricane loads. Engineering Structures, 2020, 208 : 110213–

[18] BalomenosG P, PadgettJ E. Fragility analysis of pile-supported wharves and piers exposed to storm surges and waves. Journal of Waterway, Port, Coastal, and Ocean Engineering, 2018, 144( 2): 04017046–

[19] BernierC, PadgettJ E. Fragility and risk assessment of aboveground storage tanks subjected to concurrent surge, wave, and wind loads. Reliability Engineering & System Safety, 2019, 191 : 106571–

[20] LiY, Ellingwood B R. Hurricane damage to residential construction in the US: Importance of uncertainty modeling in risk assessment. Engineering Structures, 2006, 28( 7): 1009– 1018

[21] BayatF, DaneshjooN, NisticoN, PejovicJ. Seismic evaluation of isolated skewed bridges using fragility function methodology. Computers and Concrete, 2017, 20( 4): 419– 427

[22] KwonS Y, YooM, Hong S. Earthquake risk assessment of underground railway station by fragility analysis based on numerical simulation. Geomechanics and Engineering, 2020, 21( 2): 143– 152

[23] BeilicD, CasottoC, NascimbeneR, CicolaD, RodriguesD. Seismic fragility curves of single storey RC precast structures by comparing different Italian codes. Earthquakes and Structure, 2017, 12( 3): 359– 374

[24] RamseyerC, HollidayL, FloydR. Enhanced residential building code for tornado safety. Journal of Performance of Constructed Facilities, 2016, 30( 4): 04015084–

Acknowledgements

The first and the second authors would like to thank the Natural Sciences and Engineering Council of Canada for the financial support provided through the grant: RGPIN-2017-04197 NSERC DG. Any findings, conclusions, or recommendations expressed in this manuscript are those of the authors and do not necessarily reflect the sponsor’s views.

RIGHTS & PERMISSIONS

2021 Higher Education Press 2021.