Testing and Modeling In-Plane Behavior of Retrofitted Timber Diaphragms
Publication: Journal of Structural Engineering
Volume 146, Issue 2
Abstract
An in-situ experimental campaign investigating the in-plane behavior of retrofitted timber floor diaphragms was undertaken on full-scale specimens located in a two-story clay brick unreinforced masonry building constructed circa 1913. The diaphragm retrofit strategies included renailing of board-to-joist connections, use of a fire-rated ceiling, use of steel chords, and the application of a plywood sheet overlay. When compared with as-built single straight-sheathed diaphragms, all tested solutions provided significant stiffening of the in-plane diaphragm response, with the sole exception being the configuration incorporating steel chords, where the chord influence was observed to be negligible. The fire-rated ceiling showed noticeable strength degradation due to cyclic loading while the plywood sheet overlay exhibited no strength loss between cycles to the same deformation levels, demonstrating the ability of the plywood-overlaid diaphragm to resist multicyclic loading. The subsequent phase of the study included comprehensive numerical modeling of the adopted retrofit strategies and their validation against the attained experimental results. A detailed parametric study on retrofitted timber floor diaphragms was also undertaken and is reported herein. These numerical investigations allowed evaluation of the most efficient overlay pattern, and also allowed the influence of aspects such as the plywood thickness and connection properties to be considered.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The 2019–2021 ReLUIS Project framework (funded by the Italian Emergency Management Agency) is gratefully acknowledged for the support given to the research.
References
Agbabian, M. S., S. B. Barnes, and J. C. Kariotis. 1981. “Diaphragm testing.” In Methodology for mitigation of seismic hazards in existing unreinforced masonry buildings. El Segundo, CA: N. S. Foundation.
ASCE. 2013. Seismic evaluation and retrofit of existing buildings. ASCE 41. Reston, VA: ASCE.
AS/NZS (Australian/New Zealand Standard). 2008. Structural plywood. AS/NZS 2269. Wellington, New Zealand: AS/NZS.
ATC (Applied Technology Council). 1981. Guidelines for the design of horizontal wood diaphragms. Berkeley, CA: ATC.
AWC (American Wood Council). 2012. National design specification for wood construction. Leesburg, VA: AWC.
Baldessari, C., M. Piazza, and R. Tomasi. 2008. “The refurbishment of timber floors: Characterization of the in-plane behavior.” In Proc., PROHITEC Int. Conf., 255–260. Rome: Taylor & Francis.
Beyer, K., and A. Dazio. 2012. “Quasi-static cyclic tests on masonry spandrels.” Earthquake Spectra 28 (3): 907–929. https://doi.org/10.1193/1.4000063.
Branco, J. M., M. Kekeliak, and P. B. Lourenço. 2014. “In-plane stiffness of traditional timber floors strengthened with CLT.” In Vol. 9 of Materials and joints in timber structures, 725–737. Dordrecht, Netherlands: Springer.
Brignola, A., S. Pampanin, and S. Podestà. 2012. “Experimental evaluation of the in-plane stiffness of timber diaphragms.” Earthquake Spectra 28 (4): 1687–1709. https://doi.org/10.1193/1.4000088.
CBI (Co-Ordinated Building Information). 2012. GIB fire rated systems. Auckland, New Zealand: CBI.
CEN (European Committee for Standardization). 2001. Timber structures—Test methods—Cyclic testing of joints made with mechanical fasteners. EN 12512. Brussels, Belgium: CEN.
CEN (European Committee for Standardization). 2009. Structural timber—Strength classes. EN 338. Brussels, Belgium: CEN.
CSI (Computers and Structures Inc.). 2014. CSI analysis reference manual. SAP2000 v17. Berkeley, CA: CSI.
Dizhur, D., et al. 2011. “Performance of masonry buildings and churches in the 22 February 2011 Christchurch earthquake.” Bull. N. Z. Soc. Earthquake Eng. 44 (4): 279–296. https://doi.org/10.5459/bnzsee.44.4.279-296.
Dizhur, D., J. M. Ingham, D. Biggs, and A. Schultz. 2016. “Performance of unreinforced masonry and infilled RC buildings during the 2015 Gorkha, Nepal earthquake sequence.” In Proc., 16th Int. Brick Block Masonry Conf., IBMAC, 2399–2408. London: Taylor & Francis.
Doglioni, F. 2000. Handbook (guidelines) for the design of adjustment interventions, seismic strengthening, and renewal of architectural treasures damaged during the Umbria-Marche earthquake in 1997. [In Italian]. Ancona, Italy: Official Bulletin of Marche Region.
FEMA. 2006. Techniques for the seismic rehabilitation of existing buildings. FEMA 547. Washington, DC: FEMA.
Gattesco, N., and L. Macorini. 2014. “In-plane stiffening techniques with nail plates or CFRP strips for timber floors in historical masonry buildings.” Constr. Build. Mater. 58 (May): 64–76. https://doi.org/10.1016/j.conbuildmat.2014.02.010.
Giongo, I., D. Dizhur, R. Tomasi, and J. M. Ingham. 2014. “Field testing of flexible timber diaphragms in an existing vintage URM building.” J. Struct. Eng. 141 (1): D4014009. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001045.
Giongo, I., E. Rizzi, J. M. Ingham, and D. Dizhur. 2018. “Numerical modelling of in-plane behavior of straight sheathed timber diaphragms.” J. Struct. Eng. 144 (10): 04018163. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002148.
Hsiao, J. K., and J. Tezcan. 2012. “Seismic retrofitting for chord reinforcement for unreinforced masonry historic buildings with flexible diaphragms.” Pract. Period. Struct. Des. Constr. 17 (3): 102–109. https://doi.org/10.1061/(ASCE)SC.1943-5576.0000117.
Manie, J., and W. P. Kikstra, eds. 2014. DIANA—Finite element analysis. User’s manual release 9.5. Delft, Netherlands: TNO DIANA BV.
McLain, T. E. 1975. “Curvilinear load-slip relations in laterally-loaded nailed joints.” Ph.D. thesis, Dept. of Forest and Wood Sciences, Colorado State Univ.
Moon, L., D. Dizhur, I. Senaldi, H. Derakhshan, M. Griffith, G. Magenes, and J. M. Ingham. 2014. “The demise of the URM building stock in Christchurch during the 2010/2011 Canterbury earthquake sequence.” Earthquake Spectra 30 (1): 253–276. https://doi.org/10.1193/022113EQS044M.
NZSEE (New Zealand Society for Earthquake Engineering). 2017. Assessment and improvement of the structural performance of buildings in earthquakes. Wellington, New Zealand: NZSEE.
NZS (Standards New Zealand). 1993. Timber structures standard. NZS 3603. Wellington, New Zealand: NZS.
Parisi, M. A., and M. Piazza. 2015. “Seismic strengthening and seismic improvement of timber structures.” Constr. Build. Mater. 97 (Oct): 55–66. https://doi.org/10.1016/j.conbuildmat.2015.05.093.
Pellicane, P. J., J. L. Stone, and M. D. Vanderbilt. 1991. “Generalized model for lateral load slip of nailed joints.” J. Mater. Civ. Eng. 3 (1): 60–77. https://doi.org/10.1061/(ASCE)0899-1561(1991)3:1(60).
Penna, A., P. Morandi, M. Rota, C. F. Manzini, F. da Porto, and G. Magenes. 2013. “Performance of masonry buildings during the Emilia 2012 earthquake.” Bull. Earthquake Eng. 12 (5): 2255–2273. https://doi.org/10.1007/s10518-013-9496-6.
Peralta, D. F., J. M. Bracci, and M. B. Hueste. 2003. “Seismic performance of rehabilitated wood diaphragms.” Ph.D. dissertation, Dept. of Civil Engineering, Texas A&M Univ.
Piazza, M. 2004. “Interventi di consolidamento con l’uso di elementi meccanici di collegamento: solai misti legno—Legno.” [In Italian] In Il manuale del legno strutturale, Vol. IV: Interventi sulle strutture, edited by Mancosu, 108–127. Roma: Mancosu Editore Srl.
Rinaldin, G., C. Amadio, and N. Gattesco. 2017. “Review of experimental cyclic tests on unreinforced and strengthened masonry spandrels and numerical modelling of their cyclic.” Eng. Struct. 132 (Feb): 609–623. https://doi.org/10.1016/j.engstruct.2016.11.063.
Rizzi, E., M. Capovilla, M. Piazza, and I. Giongo. 2019. “In-plane behavior of timber diaphragms retrofitted with CLT panels.” In Vol. 18 of Structural Analysis of Historical Constructions, edited by R. Aguilar, D. Torrealva, S. Moreira, M. A. Pando, and L. F. Ramos, 1613–1622. Dordrecht, Netherlands: Springer.
Schiro, G., I. Giongo, J. M. Ingham, and D. Dizhur. 2018. “Lateral performance of as-built and retrofitted timber diaphragm fastener connections.” J. Mater. Civ. Eng. 30 (1): 04017257. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002110.
Scotta, R., D. Trutalli, L. Marchi, and L. Pozza. 2018. “Seismic performance of URM buildings with in-plane non-stiffened and stiffened timber floors.” Eng. Struct. 167 (Jul): 683–694. https://doi.org/10.1016/j.engstruct.2018.02.060.
Valluzzi, M. R., E. Garbin, M. Dalla Benetta, and C. Modena. 2013. “Experimental characterization of timber floors strengthened by in-plane improvement techniques.” In Vol. 778 of Advanced Material Research, edited by M. Piazza and M. Riggio, 682–689. Zürich, Switzerland: Trans Tech Publications.
Wilkinson, T. L. 1971. “Theoretical lateral resistance of nailed joints.” J. Struct. Div. 97 (5): 1381–1398.
Wilson, A., P. J. H. Quenneville, and J. M. Ingham. 2013. “Natural period and seismic idealization of flexible timber diaphragms.” Earthquake Spectra 29 (3): 1003–1019. https://doi.org/10.1193/1.4000162.
Wilson, A., P. J. H. Quenneville, and J. M. Ingham. 2014. “In-plane orthotropic behavior of timber floor diaphragms in unreinforced masonry buildings.” J. Struct. Eng. 140 (1): 04013038. https://doi.org/10.1061/(ASCE)ST.1943-541X.0000819.
Wilson, A. W. 2012. “Seismic assessment of timber floor diaphragms in unreinforced masonry buildings.” Ph.D. dissertation, Dept. of Civil and Environmental Engineering, Univ. of Auckland.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 146 • Issue 2 • February 2020
Copyright
©2019 American Society of Civil Engineers.
History
Received: Oct 17, 2018
Accepted: May 11, 2019
Published online: Nov 26, 2019
Published in print: Feb 1, 2020
Discussion open until: Apr 26, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.