Shear Wall Test Program

The results of a series of 109 shear walls (16 configurations) subjected to lateral in-plane loading were used in this study (Table 1). The testing consisted of three different size single-storey wall specimens: 610×2440 mm, 1220×2440 mm and 2440×2440 mm, which were composed of light gauge steel C-studs (92.1×41.3×12.7 mm) screw connected to steel tracks (92.1×31.8 mm) (Fig. 1). Both the studs and tracks were fabricated of ASTM A653 (2002) steel with a nominal grade and thickness of 230 MPa and 1.12 mm, respectively. Three types of wood sheathing (12.7 mm DFP (CSA O121, 1978), 12.7 mm CSP (CSA O151, 1978), 11 mm OSB (CSA O325,1992)) were connected to one side of each test wall with screws placed at a spacing of 76, 102 or 152 mm. Simpson Strong-Tie S/HD10 hold-downs were used to connect the chord studs to the test frame. A specially constructed shear wall test frame was utilized to allow for the application of a lateral in-plane load to the top of the wall, and to provide lateral support to limit out-of­plane movement (Boudreault, 2005; Branston, 2004; Branston et al., 2004; Chen, 2004).

Figure 1. Typical 1220×2440 mm shear wall test specimens.

Monotonic and reversed cyclic tests were carried out using the CUREE protocol for ordinary ground motions (Krawinkler et al., 2000; ASTM E2126, 2005). In most cases, 6 specimens (3 monotonic and 3 reversed cyclic) were tested per wall configuration. Subsequently, the results of each shear wall test were evaluated using a codified version of the equivalent energy elastic – plastic (EEEP) approach for calculating the design parameters of light framed shear walls (ASTM E2126, 2005). It was decided that the EEEP model best represented the behaviour of light gauge steel frame / wood panel shear walls subjected to both monotonic and reversed cyclic loading (Fig. 2) (Branston, 2004). The model results in an idealized load-deflection curve, of a simple bilinear shape, that can be easily defined and constructed, yet still provides a realistic depiction of the data obtained from laboratory testing. Moreover, the EEEP model recognizes the post-peak deformation capacity by taking into account the energy dissipated by the test specimen up to failure. In the case of each reversed cyclic test a backbone curve was first constructed for the resistance vs. deflection hysteresis. This backbone curve and the resistance vs. deflection curve for monotonic specimens were then used to create EEEP curves based on the equivalent energy approach.

Table 1. Matrix of shear wall tests.

Configuration

Wall Dimensions (mm)

Sheathing

Type

(mm)

Fastener

Schedule

(mm)

Researcher

1. 2, 3, 4

1220 x 2440

CSP 12.5

102 / 305

Boudreault (2005)

5,6

1220 x 2440

DFP 12.5

102 / 305

7, 8

1220 x 2440

CSP 12.5

152 / 305

Branston (2004)

9, 10

1220 x 2440

CSP 12.5

76 / 305

11, 12

1220 x2440

DFP 12.5

152 / 305

13, 14

1220 x 2440

DFP 12.5

76 / 305

15, 16

610×2440

CSP 12.5

152 / 305

Chen (2004)

17, 18

610×2440

CSP 12.5

102 / 305

19, 20

610 x 2440

OSB 11

152 / 305

21, 22

1220 x 2440

OSB 11

152 / 305

Branston (2004)

23, 24

1220 x 2440

OSB 11

102 / 305

25, 26

1220 x 2440

OSB 11

76 / 305

27, 28

610×2440

OSB 11

102 / 305

Chen (2004)

29, 30

2440 x 2440

CSP 12.5

152 / 305

31, 32

2440 x 2440

CSP 12.5

102 / 305

33, 34

2440 x 2440

CSP 12.5

76 / 305