CYCLIC PERFORMANCE OF PERFORATED WOOD SHEAR WALLS WITH OVERSIZE OSB PANELS By Ming He,'Henrik Magnusson,2 Frank Lam,3 Member,ASCE,and Helmut G.L.Prion' n failure mode,especially for walls with oversi A n INTRODUCTION fiths 1996)it was observed that under monotonic loading con- The shear walls n tal985) ea tica culate eismic loading Its have show for the latter. s ( alls with open en tion provides acon wall without ope ith s is inereased.the gt)(Patton-Mallo ntegrit of od frame build y in mult create veak story Many models h ddes a sub the her linear finite-elemen models w re dev ut or with pen rack osek 1976,Fo shear wall system i and 1984:Gupta and Ku 1985) of the 1996 Line and Dougl nite-elem tprograms to per n time lls24× 12 of s with I pe liatrault 199).The aspect ratios rge pan els4.8×4.8 m)(Enjily Wood Sci..Univ.of British Columbia wa 118S-20P uct.Engrg,Lund Inst.of Technol.,Bo (OSB) Nood Sci..Univ.of Britis mbia.Vancou- sses with sheathir of Wood Sci.Univ.of British Colu nbia.Vancou shown that the racking strength of wall ver.BC hits for man 997.Th paper on A f the 15973-94 nd existing ruls has night een investiga case 10/JOURNAL OF STRUCTURAL ENGINEERING/JANUARY 199 d 05 Jan 2009 to 222.55.175.206.Rodistribution sub ct to ASCE liconse or copyright;soo http:pubs asco.orgfcopyright 10 / JOURNAL OF STRUCTURAL ENGINEERING / JANUARY 1999 CYCLIC PERFORMANCE OF PERFORATED WOOD SHEAR WALLS WITH OVERSIZE OSB PANELS By Ming He,1 Henrik Magnusson,2 Frank Lam,3 Member, ASCE, and Helmut G. L. Prion4 ABSTRACT: This paper reports the test results from a study investigating the influence of openings on the lateral resistance of wood-based shear walls built with both standard and oversize oriented strand board panels under monotonic and cyclic loading conditions. Test results showed that the application of nonstandard oversize panels significantly improved the performance of the perforated shear walls compared with standard 1.2 3 2.4 m panels. Door and window openings caused a significant decrease in the strength and stiffness of the walls and precipitated a change in failure mode, especially for walls with oversize panels. Although nail failure modes were commonly observed in walls without openings, a combination of nail and panel failures were observed in shear walls with openings. A newly proposed cyclic test protocol was used that consisted of fewer but more severe displacement excursions, compared with many other test protocols. This was believed to better reflect typical earthquake excitation and avoid low cycle nail fatigue failures, which were observed previously with long sequence cyclic test protocols. INTRODUCTION Wood frame construction using shear wall and diaphragm systems has been shown to be a very cost-effective means of building single- and multifamily residences. The shear walls provide buildings with a very efficient load resisting system to carry three major load components, namely (1) vertical loads, (2) transverse wind loads, and (3) in-plane lateral forces imposed by wind and seismic loading. For the latter, wood frame construction has a history of excellent performance, es￾pecially in residential applications with evenly distributed and relatively small openings and no excessive overhangs. For ex￾ample, in the 1995 Kobe earthquake in Japan, it was evident that residences built with North American wood-based shear wall techniques (2 3 4 platform construction) survived ex￾treme seismic forces with relatively little damage, even in ar￾eas where liquefaction of the supporting ground caused wide￾spread building collapses. As was shown in the 1994 Northridge Earthquake and Hurricane Andrew in Florida in 1993, however, the structural integrity of wood frame build￾ings under the action of natural hazards such as earthquakes and wind is not necessarily guaranteed, especially in multi￾story buildings where large openings often create weak story effects. Over the past few decades a substantial amount of experi￾mental work has been done on the structural behavior of wood-based shear wall systems without or with openings. Fol￾lowing studies on full-size shear walls or even full scale build￾ings under static lateral loads, perforated shear wall systems were studied under static and dynamic loading conditions (Pat￾ton-Mallory et al. 1985; Falk and Itani 1987; Sugiyama 1994; White and Dolan 1995, 1996; Line and Douglas 1996; Rose and Keith 1996). From tests on long shear walls (2.4 3 12 m) with openings (Johnson and Dolan 1996) and perforated shear walls with large panels (4.8 3 4.8 m) (Enjily and Grif- 1 Grad. Res. Asst., Dept. of Wood Sci., Univ. of British Columbia, Vancouver, BC Canada V6T 1Z4. 2 Visiting Student, Dept. of Struct. Engrg., Lund Inst. of Technol., Box 118, S-221 00 Lund, Sweden. 3 Asst. Prof., Dept. of Wood Sci., Univ. of British Columbia, Vancou￾ver, BC Canada V6T 1Z4. 4 Asst. Prof., Dept. of Wood Sci., Univ. of British Columbia, Vancou￾ver, BC Canada V6T 1Z4. Note. Associate Editor: William M. Bulleit. Discussion open until June 1, 1999. To extend the closing date one month, a written request must be filed with the ASCE Manager of Journals. The manuscript for this paper was submitted for review and possible publication on August 8, 1997. This paper is part of the Journal of Structural Engineering, Vol. 125, No. 1, January, 1999. qASCE, ISSN 0733-9445/99/0001-0010– 0018/$8.00 1 $.50 per page. Paper No. 16392. fiths 1996) it was observed that under monotonic loading con￾ditions the reduction in racking strength and stiffness of per￾forated shear wall was directly related to the proportional area of the openings. Based on their research work, empirical equa￾tions were introduced by Patton-Mallory et al. (1985) (based on the ratio of effective wall length) and by Sugiyama (1994) (using the sheathing area ratio) to calculate the strength loss due to openings. Experimental results have shown, however, that Patton-Mallory’s equation tends to overestimate the initial stiffness and ultimate load capacity of shear walls with open￾ings (Patton-Mallory et al. 1985), whereas Sugiyama’s equa￾tion provides a conservative estimate of the shear load ratio (the ratio of the ultimate lateral load of a shear wall with open￾ings to that of a wall without openings) at ultimate capacity (Johnson and Dolan 1996; Rose and Keith 1996). The results also indicated that as the area of the openings is increased, the governing design criterion may more likely be serviceability (stiffness) rather than ultimate load (strength) (Patton-Mallory et al. 1985; Enjily and Griffiths 1996). Under dynamic loading, shear walls with openings generally were found to exhibit lower damping ratios than similar walls without openings (Falk and Itani 1987). Many models have been proposed to analyze and predict the performance of wood-based shear walls subjected to lateral loads. Linear and nonlinear finite-element models were devel￾oped to simulate the load-deformation relations of shear walls under monotonic lateral racking loads (Polensek 1976; Foschi 1977, 1990; Tuomi and McCutcheon 1978; Easley et al. 1982; Itani and Cheung 1984; Gupta and Kuo 1985). The hysteretic behavior of the wall or its components under cyclic and dy￾namic loading was then studied and modeled in nonlinear fi- nite-element programs to perform time-history analysis and predict the dynamic response of shear walls (Dolan 1989; Fi￾liatrault 1989). The effects of openings and aspect ratios were also modeled (White and Dolan 1995). The development of these analytical models contributed greatly to a better under￾standing of the structural performance of wood-based shear wall systems. Oriented strand board (OSB) panels are often produced in large presses with sheathing sizes of up to 3.3 3 7.3 m, before they are cut into the standard 1.2 3 2.4 m panels. It has been shown that the racking strength of walls can be substantially increased (Lam et al. 1997) by using full-size panels instead of the standard panels, which could have significant economic benefits for prefabricated house construction or industrial building applications. The effect of openings in walls with large-size panels has not been investigated before, however, and existing rules might not apply to the continuous panel case. Downloaded 05 Jan 2009 to 222.66.175.206. Redistribution subject to ASCE license or copyright; see http://pubs.asce.org/copyright