Wind and Structures

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Nonlinear modeling of roof-to-wall connections in a gable-roof structure under uplift wind loads

  • Enajar, Adnan F. (Department of Civil and Environmental Engineering, Faculty of Engineering, The University of Western Ontario) ;
  • Jacklin, Ryan B. (Tacoma Engineers) ;
  • El Damatty, Ashraf A. (Department of Civil and Environmental Engineering, Faculty of Engineering, The University of Western Ontario)
  • Received : 2018.02.06
  • Accepted : 2018.11.13
  • Published : 2019.03.25
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Abstract

Light-frame wood structures have the ability to carry gravity loads. However, their performance during severe wind storms has indicated weakness with respect to resisting uplift wind loads exerted on the roofs of residential houses. A common failure mode observed during almost all main hurricane events initiates at the roof-to-wall connections (RTWCs). The toe-nail connections typically used at these locations are weak with regard to resisting uplift loading. This issue has been investigated at the Insurance Research Lab for Better Homes, where full-scale testing was conducted of a house under appropriate simulated uplift wind loads. This paper describes the detailed and sophisticated numerical simulation performed for this full-scale test, following which the numerical predictions were compared with the experimental results. In the numerical model, the nonlinear behavior is concentrated at the RTWCs, which is simulated with the use of a multi-linear plastic element. The analysis was conducted on four sets of uplift loads applied during the physical testing: 30 m/sincreased by 5 m/sincrements to 45 m/s. At this level of uplift loading, the connections exhibited inelastic behavior. A comparison with the experimental results revealed the ability of the sophisticated numerical model to predict the nonlinear response of the roof under wind uplift loads that vary both in time and space. A further component of the study was an evaluation of the load sharing among the trusses under realistic, uniform, and code pressures. Both the numerical model and the tributary area method were used for the load-sharing calculations.

Keywords

References

  1. Chowdhury, A.G., Canino, I., Mirmiran, A., Suksawang, N. and Baheru, T. (2013), "Wind-loading effects on roof-to-wall connections of timber residential buildings", J. Eng. Mech., 139(3), 386-395. https://doi.org/10.1061/(ASCE)EM.1943-7889.0000512
  2. Datin, P.L., Mensah, A.F. and Prevatt, D.O. (2010), "Experimentally determined structural load paths in a 1/3-scale model of light-Framed wood, rectangular building", Proceedings of the 2010 ASCE Structures Congress, Orlando, Florida, United States, May.
  3. Datin, P.L. and Prevatt, D.O. (2013), "Using instrumented smallscale models to study structural load paths in wood-framed buildings", Eng. Struct., 54, 47-56. https://doi.org/10.1016/j.engstruct.2013.03.039
  4. Dessouki, A.A. (2010), "Analysis and retrofitting of low rise houses under wind loading", Master Thesis, University of Western Ontario, London, ON, Canada.
  5. Doudak, G., McClure, G. and Smith, I. (2012), "Experimental evaluation of load paths in light-frame wood structure", J. Struct. Eng., 138(2), 258-265. https://doi.org/10.1061/(ASCE)ST.1943-541X.0000439
  6. Edmonson, W.C., Schiff, S.D. and Nielson, B.G. (2012), "Behavior of light-framed wood roof-to-wall connectors using aged lumber and multiple connection mechanisms", J. Perform. Constr. Fac., 26(1), 26-37. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000201
  7. FEMA (1992), Building Performance: Hurricane Andrew in Florida, Observation, Recommendations, and Technical Guidance, Federal Emergency Management Agency, Federal Insurance Administration, United States.
  8. Foschi, R.O. (2000), "Modeling the hysteretic response of mechanical connections for wood structures", Proceedings of the 6th World Conf. on Timber Engineering, Whistler, Canada, July.
  9. Guha, T.K. and Kopp, G.A. (2014), "Storm duration effects on roof-to-wall-connection failures of a residential, wood-frame, gable roof", J. Wind Eng. Ind. Aerod., 133, 101-109. https://doi.org/10.1016/j.jweia.2014.08.005
  10. He, M., Lam, F. and Foschi, R.O. (2001), "Modeling threedimensional timber light-frame buildings", J. Struct. Eng., 127(8), 901-913. https://doi.org/10.1061/(ASCE)0733-9445(2001)127:8(901)
  11. Henderson, D.J., Morrison, M.J. and Kopp, G.A. (2013), "Response of toe-nailed, roof-to-wall connections to extreme wind loads in a full-scale, timber-framed, hip roof", Eng. Struct., 56, 1474-1483. https://doi.org/10.1016/j.engstruct.2013.07.001
  12. Jacklin, R.B. (2013), "Numerical and experimental analysis of retrofit system for light-framed wood structures under wind loading", Master Thesis, University of Western Ontario, London, ON, Canada.
  13. Jacklin, R.B., El Damatty, A.A. and Dessouki, A.A. (2014), "Finite-element modeling of a light-framed wood roof structure", Wind Struct., 19(6), 603-621. https://doi.org/10.12989/was.2014.19.6.603
  14. Kasal, B., Leichti, R.J., and Itani, R.Y. (1994), "Nonlinear finiteelement model of complete light-frame wood structures", J. Struct. Eng., 120(1), 100-119. https://doi.org/10.1061/(ASCE)0733-9445(1994)120:1(100)
  15. Kasal, B., Collins, M., Paevere, P. and Foliente, G. (2004), "Design models of light frame wood buildings under lateral loads", J. Struct. Eng., 130(8), 1263-1271. https://doi.org/10.1061/(ASCE)0733-9445(2004)130:8(1263)
  16. Khan, M.A.A. (2012), "Load-sharing of toe-nailed roof-to-wall connections under extreme wind loads in wood-frame houses", Master Thesis, University of Western Ontario, London, ON, Canada.
  17. Kumar, N., Dayal, V. and Sarkar, P.P. (2012), "Failure of woodframed low-rise buildings under tornado wind loads", Eng. Struct., 39, 79-88. https://doi.org/10.1016/j.engstruct.2012.02.011
  18. Luszczki, G.E., Clapp, J.D., Davids, W.G. and Lopez-Anido, R. (2013), "Withdrawal capacity of plain, annular shank, and helical shank nail fasteners in spruce-pine-fir lumber", Forest Products J., 63(5-6), 213-220. https://doi.org/10.13073/FPJ-D-13-00055
  19. Minghao, L., Foschi, R.O. and Lam F. (2012), "Modeling hysteretic behavior of wood shear Walls with a Protocol-Independent Nail Connection Algorithm", J. Struct. Eng., 138(1), 99-108. https://doi.org/10.1061/(ASCE)ST.1943-541X.0000438
  20. Morrison, M.J., Kopp, G.A., Gavanski, E., Miller, C. and Ashton, A. (2014), "Assessment of damage to residential construction from the tornadoes in Vaughan, Ontario, on 20 August 2009", Can. J. Civil Eng., 41,550-558. https://doi.org/10.1139/cjce-2013-0570
  21. Morrison, M.J., Henderson, D.J. and Kopp, G.A. (2012), "The response of a wood-frame, gable roof to fluctuating wind loads", Eng. Struct. 41, 498-509. https://doi.org/10.1016/j.engstruct.2012.04.002
  22. Morrison, M.J. and Kopp, G.A. (2011), "Performance of toe-nail connections under realistic wind loading", Eng. Struct., 33, 69-76. https://doi.org/10.1016/j.engstruct.2010.09.019
  23. NBCC (2010), User's Guide--NBC 2010: Structural Commentaries (Part 4 of Division B), Canadian Commission on Building and Fire Codes, National Research Council Canada, and Institute for Research in Construction (Canada), Ottawa, ON, Canada.
  24. NDS (2015), National Design Specification for Wood Construction, American Wood Council, Leesburg, Virginia, USA.
  25. Prevatt, D.O., van de Lindt, J.W., Back, E.W., Graettinger, A.J., Pei, S., Coulbourne, W., Gupta, R., James, D. and Agdas, D. (2012), "Making the case for improved structural design: tornado outbreaks of 2011", Leadership Manage. Eng., 12(4), 254-270. https://doi.org/10.1061/(ASCE)LM.1943-5630.0000192
  26. Reed, T.D., Rosowsky, D.V. and Schiff, S.D. (1997), "Uplift capacity of light-frame rafter to top plate connections", J. Architect. Eng., 3(4), 156-163. https://doi.org/10.1061/(ASCE)1076-0431(1997)3:4(156)
  27. Satheeskumar, N., Henderson, D.J., Ginger, J.D. and Wang, C. (2017), "Three-dimensional finite-element modeling and validation of a timber-framed house to wind loading", J. Struct. Eng., 143(9), 04017112. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001850
  28. Satheeskumar, N., Henderson, D.J., Ginger, J.D. and Wang, C.H. (2017), "Finite element modelling of the structural response of roof to wall framing connections in timber-framed houses", Eng. Struct., 134, 25-36. https://doi.org/10.1016/j.engstruct.2016.12.034
  29. Satheeskumar, N., Henderson, D.J., Ginger, J.D., Humphreys, M.T. and Wang, C.H. (2016), "Load sharing and structural response of roof-wall system in a timber-framed house", Eng. Struct., 122, 310-322. https://doi.org/10.1016/j.engstruct.2016.05.009
  30. Shivarudrappa, R. and Nielson, B.G. (2013), "Sensitivity of load distribution in light-framed wood roof systems due to typical modeling parameters", J. Perform. Constr. Fac., 27(3), 222-234. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000323
  31. Thampi, H., Dayal, V. and Sarkar, P.P. (2011), "Finite element analysis of interaction of tornados with a low-rise timber building", J. Wind Eng. Ind. Aerod., 99(4), 369-377. https://doi.org/10.1016/j.jweia.2011.01.004
  32. Van de Lindt, J.W., Graettinger, A., Gupta, R., Skaggs, T., Pryor, S. and Fridley, K.J. (2007), "Performance of wood-frame structures during hurricane katrina", J. Perform. Constr. Fac., 21(2), 108-116. https://doi.org/10.1061/(ASCE)0887-3828(2007)21:2(108)
  33. Zisis, I. and Stathopoulos, T. (2012), "Wind load transfer mechanisms on a low wood building using full-scale load data", J. Wind Eng. Ind. Aerod., 104-106, 65-75. https://doi.org/10.1016/j.jweia.2012.04.003

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