SIP Shear Walls

Cyclic Performance of High-Aspect-Ratio 

Segments and Perforated Walls

Vladimir Kochkin

Douglas R. Rammer 

Kevin Kauffman

Thomas Williamson

Robert J. Ross

Research Paper

FPL–RP–682

United States Department of Agriculture

Forest 

Service

Forest Products

Laboratory

December

2015
Abstract

Increasing stringency of energy codes and the growing 

market demand for more energy efficient buildings gives 

structural insulated panel (SIP) construction an opportunity 

to increase its use in commercial and residential buildings. 

However, shear wall aspect ratio limitations and lack of 

knowledge on how to design SIPs with window and door 

openings are barriers to the wider adoption of SIP technology. An experimental study was conducted to evaluate the 

lateral resistance performance of high-aspect-ratio SIP shear 

wall segments and SIP shear walls with window and door 

openings. At most two replicates of fully anchored SIP shear 

walls were cyclically tested at the following aspects ratios: 

1:1, 2:1, 3:1, and 4:1. Five additional tests were conducted 

with multiple SIP wall panels that contained various sized 

door and window openings. Based on the experiments, the 

unit stiffness of the SIP shear wall varied by aspect ratio 

and the unit shear capacity decreased with increasing aspect 

ratio. Spline joints between wall segments also decreased 

capacity. Finally, test results indicate that multiple segment 

SIP shear walls with openings follow the overall trend predicted by the perforated shear wall method for both strength 

and stiffness.

Keywords: cyclic, shear wall, structural insulated panels, 

perforated shear walls

Contents

Introduction.....................................................................1

Objectives .......................................................................1

Background.....................................................................1

Shear Wall Design...........................................................2

Experimental Approach ..................................................3

Results.............................................................................7

Discussion.......................................................................7

Failure Modes................................................................7

Walls without Openings................................................7

Walls with Openings (Perforated Walls).......................10

Summary and Observations............................................13

References.......................................................................13

Appendix 1: Walls without Openings.............................15

Appendix 2: Walls with Openings..................................17

Appendix 3: Hysteretic Parameter Fits for 

Walls without Openings..................................................18

Appendix 4: Hysteretic Parameter Fits for 

Walls with Openings.......................................................19

December 2015

Kochkin, Vladimir; Rammer, Douglas R.; Kauffman, Kevin; Williamson, 

Thomas; Ross, Robert J. 2015. SIP shear walls: cyclic performance of highaspect-ratio segments and perforated walls. Research Paper FPL-RP-682. 

Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 19 p.

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SIP Shear Walls

Cyclic Performance of High-Aspect-Ratio Segments and 

Perforated Walls

Vladimir Kochkin, Director of Applied Engineering

Home Innovations, Upper Marlboro, Maryland 

Douglas R. Rammer, Research General Engineer

Forest Products Laboratory, Madison, Wisconsin 

Kevin Kauffman

Home Innovations, Upper Marlboro, Maryland 

Thomas Williamson

T. Williamson – Timber Engineering, LLC, Vancouver, Washington

Robert J. Ross, Supervisory Research General Engineer

Forest Products Laboratory, Madison, Wisconsin

Introduction

This study addresses the single structural insulated panel 

(SIP) panel length to height ratio (aspect ratio) limitations 

for a single SIP, as imposed by product evaluation agencies. 

NTA Inc. (Nappanee, IN) is a third party design review and 

inspection agency that provides product certification and 

testing services, and independently verifies both quality and 

standards compliance for many building products. The NTA 

listing report limits the aspect ratio to 2:1 for low seismic 

risk areas and 1:1 for high seismic risk areas. Many ICCES Evaluation Service (ICC-ES, Brea, California) evaluation reports currently limit the aspect ratio for SIP shear 

walls to 1:1. These limitations have significant implications 

for engineered shear walls in nonresidential and residential 

construction where narrow aspect ratio segments are common as a result of doors and windows closely spaced or 

placed near building corners. With the increasing stringency 

of energy codes and the growing market demand for more 

energy efficient buildings, the SIP construction is well postured to increase its market. However, in some markets the 

aspect ratio limitation is a barrier to the wider adoption of 

SIP technology.

Wood design provisions (AWC 2015a) include two methodologies for shear wall design: segmented shear wall and 

perforated shear wall methods. The results of the testing 

program summarized in this report provide information for 

both design approaches. Both approaches are investigated 

because high-aspect-ratio segments can be included in shear 

wall designed using either of the two methods.

Objectives

The overall goal of this study is to develop performance test 

data on the response of SIP shear walls with high-aspectratio segments. The results will provide the basis for developing design methodologies for future code, standard, or 

acceptance criteria proposals. The specific objectives of this 

study include the following:

1. Measure the performance of individual, fully anchored 

shear segments with the following aspect ratios: 1:1, 2:1, 

3:1, and 4:1.

2.Conduct a preliminary evaluation of the applicability 

of the perforated shear wall (PSW) method to SIP shear 

walls based on an initial limited set of perforated shear 

walls with high-aspect-ratio segments.

Background

SIP Lateral Wall Testing

Kermani and Hairstans (2006) researched the performance 

of 2.4 m by 2.4 m (8 ft by 8 ft) SIP wall systems with and 

without openings. Opening sizes ranged between 6% and 

65% of the wall specimen area. Segment aspect ratio varied from 1:1 to 8:1. The wall specimens were constructed 

with 2 panels, spliced with a 50 mm by 102 mm (2 in. by 

4 in.) lumber spline. Fastening of the panels to the perimeter 

boundary members was achieved with 35.1 mm (1.38 in.) 

long by 2.64 mm (0.104 in.) diameter screws at approximately 254 mm (10 in.) on center. Loading was applied 

monotonically, and each type of wall configuration was 

tested under two separate vertical loading conditions; the 

first condition was without any vertical load applied, and 

the second was with a 10.21 kN/m (700 lb/ft) gravity load 

along the top of the specimens. For walls without openings, 

the peak shear load ranged between 4.67 kN/m (320 lb/ft) 

for walls without vertical load to 11.38 kN/m (780 lb/ft) for 

walls with vertical load. For walls with openings, the research confirmed that capacity followed the general trend of 

the PSW method. 

Jamison (1997) tested 2.4-m by 2.4-m (8-ft by 8-ft) wall 

specimens with various boundary and anchorage detailing. 
Research Paper FPL–RP–682

2

The panels used an 11.1-mm (7/16-in.) OSB facing on one 

side and 12.7-mm (1/2-in.) drywall facing on the other. 

Nominal 50-mm by 102-mm (2-in. by 4-in.) lumber and 

12.7-mm (1/2-in.) OSB block spline connections were 

tested. The tested end-wall boundary conditions included 

25-mm by 102-mm (1-in. by 4-in.) lumber, 50-mm by 

102-mm (2-in. by 4-in.) lumber, and 12.7-mm (1/2-in.) 

OSB surface splines. One configuration also included a 

double 50-mm by 102-mm (2-in. by 4-in.) bottom plate 

member. Fastening of the panels to the perimeter boundary 

and splice members was with 41.3 mm (1-5/8-in.) drywall 

screws spaced at 152 mm (6 in.) on center and construction 

adhesive. Specimens were tested monotonically or cyclically without vertical loading. Only one of the five configurations included end-wall hold-down anchors. Peak 

shear loads for the monotonically tested specimens ranged 

between 4.82 kN/m (330 lb/ ft) and 12.84 kN/m (880 lb/ft), 

with the specimen with hold-down anchors achieving the 

greatest capacity. Cyclic testing of the same configurations 

resulted in peak shear loads ranging between 4.67 kN/m 

(320 lb/ft) and 12.70 kN/m (870 lb/ ft).

APA 2010

APA – The Engineered Wood Association (2010) summarizes testing of a single 2.4-m by 2.4-m (8-ft by 8-ft) SIP 

wall configuration subjected to various types of boundary 

restraint. The tested specimens were constructed with two 

panels, spliced together with an OSB box spline and attached to the boundary and spline members with 8d common nails spaced at 152 mm (6 in.) on center. The following 

configurations were tested monotonically: (1) only E72 type 

hold-downs with facers unrestrained from rotation, (2) E72 

type hold-downs and 50-mm by 152-mm (2-in. by 6-in.) 

top and bottom cap plates restraining facer panel edge 

rotation, or (3) Simpson Strong-Tie end-wall hold-downs, 

50-mm by 102-mm (2-in. by 6-in.) cap plates and additional 

46.70 kN/m (3,200 lb/ft) gravity load applied. The respective peak loads were 15.15 kN/m (1,038 lb/ft), 23.09 kN/m 

(1,582 lb/ft), and 30.94 kN/m (2,120 lb/ft) showing that 

facer bearing and gravity load contribute significantly to 

the wall’s capacity. Cyclic testing was conducted on walls 

with only Simpson Strong-Tie hold-downs and 50-mm by 

152-mm (2-in. by 6-in.) plate caps without gravity load with 

the walls reaching an average peak load of 17.19 kN/m 

(1,178 lb/ft), indicating a substantial reduction in capacity because of the cyclic protocol (however, out of the three 

tests, at least in two specimens the failure was at hold-down 

fasteners or post, not at the spline as with the monotonic 

tests). 

Manufacturer’s Evaluation Reports Data

Table 1 presents a summary of published allowable shear 

wall capacities obtained from ICC-ES Evaluation Reports 

(ESR) for several SIP manufacturers and NTA SIPA Listing Report. The summary includes allowable capacities as 

well as fastening schedules and boundary member lumber 

requirements.

Shear Wall Design 

Two methodologies for shear wall design assist in the National Design Specification for Wood Construction (AWC 

2015b) segmented shear wall and perforated shear wall 

methods. Segmented shear wall considers assume that only 

the full height sections or segments, which have hold-downs 

on each segment end, resist the lateral forces. Resist of each 

Table 1—Manufacturer’s shear wall capacities

ESR #/NTA #a Manufacturer

Allowable shear

capacity (kN/m) Fastening detail/lumber specific gravity (SG)

4.38 Nails at 152 mm (6 in.) oc/0.50 SG lumber

ICC-ES ESR 1882 Premier SIPS by 

INSULFOAM

8.76 Nails at perimeter at 102 mm (4 in.) oc and screws at splice 

at 102 mm (4 in.) oc/0.50 SG lumber

ICC-ES ESR 1138 Precision Panel 

Structures

2.48 Nails at 102 mm (4 in.) oc/0.50 SG lumber

ICC-ES ESR 1295 PFB America 

Corporation

5.34–9.33 Nails at 152 mm (6 in.) to 76 mm (3 in.) oc/0.42 SG lumber

ICC-ES ESR 1802 Korwall 2.63 Staples at 102 mm (4 in.) oc/0.55 SG lumber

ICC-ES ESR 2139 Stress Panel 

Manufacturing, Inc.

1.90 Nails or staples at 152 mm (6 in.)/0.50 SG lumber

ICC-ES ESR 2233 R-Control 4.89–13.43 Nails at 152 mm (6 in.) to 51 mm (2 in.) oc/0.42 SG lumber

NTA SIPA120908-10 Listed SIPA 

members

5.55–13.13 Nails at 152 mm (6 in.) to 76 mm (3 in.) oc/0.42 SG lumber

NTA PRS032808-3 Insulfoam, a 

Carlisle Company

5.25–13.43 Nails at 152 mm (6 in.) to 51 mm (2 in.) oc/0.50 SG lumber

NTA Assembly Report:

AFM031809-18

AFM Corporation 13.43 Nails at 51 mm (2 in.) oc/0.50 SG lumber

a

ICC-ES reports can be downloaded from www.icc-es.org. NTA reports can be downloaded from www.ntainc.com.
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

3

full height segment is summed together to determine resistance of the entire length of the shear wall. Resulting resistance is a conservative estimate. 

Perforated shear wall methods was first proposed by Sugiyama and Yasumura (1984) based on testing of one-third 

scale monotonic racking tests of wood stud, plywoodsheathed shear walls with openings. The researchers defined 

the sheathing ratio (Equation (1)), r, to classify walls based 

on the amount of openings and the empirical relationship to 

strength and stiffness.

r =

1 +

A0

H ΣLi

1

where A0 is total area of openings, H is height of the 

wall, and ΣLi is summation of length of a full height wall 

segments.

Subsequently, Sugiyama and Matsumoto (1996) determined 

an empirical equation to relate shear capacity and sheathing 

area ratio, based on scaled tests. They determined an empirical equation that related the ratio (Eq. (2)), F, of the shear 

load for a wall with openings to the shear load of a fully 

sheathed wall at shear deformation angle of 1–100 radians 

for ultimate capacity. 

F = r

3 – 2r

This method was referred to as the perforated shear wall 

(PSW) method. The method has since been adopted into 

the Special Design Provisions for Wind and Seismic (AWC 

2015a) for wood shear walls and referenced in U.S. model 

building codes.

Experimental Approach

Wall Specimens

Table 2 provides the test matrix to evaluate the performance 

of individual, fully anchored shear segments at various aspect ratios, while Table 3 provides the test matrix that evaluated the applicability of the perforated shear wall (PSW) for 

SIP shear walls. 

Tables 4 summarizes the materials and construction details 

and Table 5 summarizes the fastening schedule used in the 

construction of the test walls. All specimens were 2.4 m 

(8 ft) tall and ranged in length from 0.6 m (2 ft) to 6.1 m 

(20 ft). Each wall specimen was constructed on the laboratory floor adjacent to the test setup and lifted in place with a 

crane using the loading beam. Temporary bracing was used 

as needed to ensure specimen integrity during installation 

in the setup. In 6.1-m (20-ft) walls, splice joints in the top 

plate/spacer were offset a minimum 610 mm (24 in). Panel 

joints were constructed using block splines in accordance 

with Figure 1. All boundary members consisted of 50-mm 

by 152-mm (2-in. by 6-in.) nominal framing lumber inset 

into the foam core between the OSB facings of the SIP panel. Single framing members were used for top and bottom 

plates. Double-stud posts were used at walls’ ends to accommodate the attaching of the hold-downs. Single studs were 

used at cut-out openings and double studs were used with 

openings framed with individual header panels (one stud inserted into the full-height panel and one jack stud supporting 

the header panel). Double studs were nailed together using 

two 16d pneumatic nails every 406 mm (16 in.). Wall openings in Configurations 5, 7, and 8 were constructed in accordance to Figure 2. The wall openings in Configuration 6 

were constructed in accordance to Figure 3.

(1)

(2)

Figure 1—SIP spline detail.

Figure 3—Continuous SIP header detail for Configuration 6.

Figure 2—Segmented SIP header detail for 

Configurations 5, 7, and 8.
Research Paper FPL–RP–682

4

Table 3—Test matrix for walls with openings

Configuration

Specimen

width/

height

Segment

aspect

ratio

Overturning

restraint Loading Purpose

SIP

panel 

width

(m)

Bolt

locations

(mm from

left end)

5 6.1/2.4 All 2:1 Hold-downs 

at wall ends

Monotonic Evaluate wall 

with openings,

all segments 2:1

1.2, 1.2,

1.2, 1.2,

1.2

304, 1524, 

2743, 3962, 

5791

6 6.1/2.4 All 2:1 Hold-downs 

at wall ends

CUREE Same openings 

as (5) but with 

continuous panel 

joints at openings

0.6, 2.4,

2.4, 0.6

304, 1524, 

2743, 3962, 

5791

7 6.1/2.4 All 4:1 Hold-downs 

at wall ends

CUREE Evaluate wall 

with opening, 

all segments 4:1

0.6, 2.1,

0.6, 2.1,

0.6

203, 406, 

3048, 3962, 

5181, 5791

8 6.1/2.4 2:1 and 4:1 Hold-downs 

at wall ends

CUREE Evaluate wall 

with segment

with different

aspect ratios

0.6, 2.1,

0.6, 1.5,

1.2

203, 406, 

3048, 3962, 

4572, 5791

9 6.1/2.4 All 2:1 Hold-downs 

at wall ends

CUREE Evaluate the 

impact of multiple 

spline joints on the 

performance of the 

wall without 

openings

2.4, 2.4,

2.4, 2.4, 

2.4

304, 1524, 

2743, 3962, 

5791

Table 2—Test matrix for walls without openings

Configuration

Specimen 

width/

height

Aspect

ratio

Overturning

restraint

Sample 

size Loading Purpose

SIP

panel

width 

(m)

Bolt 

locations 

(mm from 

left end)

1 2.4/2.4 1:1 Hold-downs 

at wall ends

1 Monotonic Provide baseline 

performance under 

monotonic loading 

and to establish 

deformation for 

CUREE loading

2.4 304, 914, 

1524, 2560

1SPL 2.4/2.4 1:1 Hold-downs

at wall ends

1 CUREE Provide baseline 

performance under 

cyclic loading for 

spline wall

1.2 304, 914, 

1524, 2560

2 1.2/2.4 2:1 Hold-downs 

at wall ends

2 CUREE Evaluate 2:1 

aspect ratio

1.2 304, 914

3 0.8/2.4 3:1 Hold-downs 

at wall ends

2 CUREE Evaluate 3:1 

aspect ratio

0.8 203, 610

4 0.6./2.4 4:1 Hold-downs 

at wall ends

2 CUREE Evaluate 4:1 

aspect ratio

0.6 203, 406
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

5

Figure 4—2 by 6 bottom plate 

and 2 by 8 sill plate bolted to 

setup base.

Figure 5—OSB facing resting 

on sill plate.

Table 4—Construction materials and details

Material Details

Wall height 2.4 m (8 ft) 

Wall width Varies according to test matrix (Tables 2 and 3)

Openings Door height: 1.8 m (6 ft)

Door width: varies to achieve segment aspect ratios per test matrix

Windows height: 1.2 m (4 ft)

Window width: varies to achieve segment aspect ratios per test matrix

Wall panels 165 mm (6.5 in.) thick SIP panels; width varies to provide full segment aspect ratios per test matrix; 

OSB facing thickness: 11.1 mm (7/16 in.)

Block spline 140 mm (5.5 in.) thick by 76 mm (3 in.) wide SIP block used for connecting SIP panels 

Framing lumber Nominal 51 mm by 152 mm (2 × 6) Spruce–Pine–Fir (SPF) #2 grade 

Sill plate Nominal 51 mm by 203 mm (2 × 8) Southern Yellow Pine (SYP) lumber

Hold-down Simpson Strong-Tie HDU11 raised 25 mm (1 in.) above bottom plate fastened with 

(30) SDS25212-R25 screws

Anchor bolts 15.9 mm (5/8 in.) diameter bolts with Simpson Strong-Tie BP5/8 – 3 plate washers spaced a maximum 

of 1.2 m (4 ft) on center and located at 305 mm (12 in.) from corners. For 0.8 m (32 in.) wide walls, 

anchor bolts located at quarter points; i.e., 203 mm (8 in.) from corners. For 0.6 m (24 in.) wide walls, 

anchor bolts located at third points, i.e., 203 mm (8 in.) from corners.

Sheathing fasteners 8d pneumatic (60.3 mm by 2.87 mm) nails with full round head

Framing fasteners 16d pneumatic (82.6 mm by 3.33 mm) nails with full round head

Interior finish None (no gypsum installed)

Table 5—Fastener schedule

Connection Fastener Spacing

Panel sheathing to boundary framing 8d pneumatic 102 mm (4 in.) on center

Panel sheathing at spline 8d pneumatic 102 mm (4 in.) on center

Top/bottom plate to stud (end nailed) (2) 16d pneumatic Per connection

Hold-down bracket to end stud (30) Simpson Strong-Tie 

SDS25212-R25 Screws

Per hold-down

Double studs (face nailed) (2) 16d pneumatic 406 mm (16 in.) on center

Top plate to spacer (2) 16d pneumatic 152 mm (6 in.) on center
Research Paper FPL–RP–682

6

The bottom plate of the wall was placed on top of a preservative-treated 50 mm by 203 mm (2-in. by 8-in.) SYP sill 

plate and anchored down to the test setup using 15.9-mm- 

(5/8-in.-) diameter bolts with a 76-mm- by 76-mm- by 6.1-

mm- (3-in.- by 3-in.- by 0.24-in.-) thick Simpson Strong-Tie 

BP5/8 – 3 plate washers (Fig. 4). The anchor bolts were 

tightened prior to installing the wall in the test frame. All 

anchor bolts and hold-down bolts were tightened to a 1/8 

turn past a hand-tight fit. 

The wall specimen was placed on top of the bottom plate 

such that the OSB facings of the SIP panels rested on the sill 

plate (Fig. 5). The facings were nailed to the bottom plate in 

accordance with the sheathing nailing schedule (8d pneumatic nails at 102 mm (4 in.) on center). 

Testing Procedures

Testing was conducted in accordance with general provisions of ASTM E2126-11 Standard Test Methods for 

Cyclic (Reversed) Load Test for Shear Resistance of Walls 

for Buildings (ASTM International 2014). 

In total, 13 tests were conducted using a racking shear testing apparatus controlled via a computer-based system. 

Instrument readings including load and deformation measurements were recorded using a computer-based data acquisition system (see Fig. 6 for a schematic of the test setup 

and instrumentation plan and Fig. 7 for a photo of Configuration 1M specimen).

The load-deformation relationship from the monotonic test 

(Configuration 1M) was used to determine the reference 

deformation (Δ) for the cyclic CUREE protocol in accordance with ASTM 2126-11 Test Method C. The reference 

deformation of 40.6 mm (1.6 in.) was used in all cyclic tests. 

The cyclic tests were conducted by displacing the top of the 

specimen in accordance with the CUREE cyclic protocol 

(Fig. 8) (Method C, ASTM E 2126) at a constant frequency 

of motion of 0.2 Hz (5 s per cycle). The hydraulic actuator 

has a total stroke of 305 mm (12 in.) with the maximum excursion set at 146 mm (5.75 in.). The hydraulic cylinder was 

attached to the load beam using a 51 mm (2 in.) pin. A sampling rate of 20 Hz was used such that 100 data points were 

recorded for each cycle. 

The hydraulic actuator motion was applied using 102-mm 

by 102-mm by 6.4-mm (4-in. by 4-in. by 0.25-in.) walled 

steel distribution beam lag-bolted through a 50-mm by 

102-mm (2-in. by 6-in.) spacer and the 50-mm by 102-mm 

(2-in. by 6-in.) top plate with 15.9 mm (5/8 in.) diameter 

203 mm (8 in.) long bolts. The spacer was installed in such 

a manner that the wall panel skins were not allowed to bear 

on the spacer (the sheathing was able to rotate at the top 

plate without bearing restraint by framing members, spacer, 

or load distribution beam). The out-of-plane deformations 

were restrained by a set of rollers located on the side of the 

load beam.

Figure 7—Shear wall specimen (Configuration 1M).

Figure 6—Shear wall test setup.

Figure 8—CUREE protocol.

–150

–100

–50

0

50

100

150

100 150 200 250

Time (s)

0 50

Actuator displacement (mm)

δr = 40.6 mm

δr

 = –40.6 mm
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

7

The load was measured using an electronic load cell, with a 

capacity of 222 kN (50,000 lb), located between the cylinder 

and the steel distribution beam. The following deformations 

(Fig. 6) were measured using a string potentiometer and 

Linear Variable Differential Transformers (LVDT):

1. Displacement of the top plate relative to the setup base

2.Bottom plate slip relative to the setup base

3.Bottom plate slip next to a doorway relative to the 50-mm 

by 203-mm (2-in. by 2-in.) sill plate (if applicable)

4.Compression and uplift at the specimen corner stud relative to the setup base

5.Compression and uplift at the jack stud inside a doorway 

relative to the 50-mm by 203-mm (2-in. by 2-in.) sill plate 

(if applicable)

In addition to lateral wall tests, material property tests were 

conducted on the SIP ESP foam core, SIP OSB facing, and 

the wood framing.

Results

In accordance with ASTM E2126, performance parameters 

for all cyclic tests were derived as an arithmetic average 

of the positive and negative envelope curves. The reported 

performance parameters include peak load, unit shear, shear 

stiffness at 0.4 (40%) peak load, unit shear stiffness at 0.4 

peak load, and deflection at peak load. Results of the lateral 

wall testing are summarized in Table 6 for the walls tested 

for the evaluation of aspect ratios and Table 7 for the SIP 

walls tested to evaluate the effect of openings. Finally, Appendixes 1 and 2 provide load-deformation and backbone 

curves for all the walls without openings and with openings.

Material properties for framing lumber, SIP OSB panels, 

and SIP EPS core foam used in the manufacturing the shear 

wall test specimens were measured (Table 8). EPS foam 

core material and OSB facings meet the minimum requirements of the 2012 International Residential Code (IRC) for 

materials used in SIPs (2012 IRC Section R613.3) (International Code Council 2011) and ANSI/APA PRS 610.1-2013 

(APA – The Engineered Wood Association 2013). The OSB 

properties are higher than the minimum specification values 

required by the IRC. Because the objective of this study is 

to establish trends rather than establish minimum design values, using SIP panels that potentially have higher capacities 

will result in conservative conclusions and generalizations.

Discussion

Failure Modes

The primary failure modes included separation of the wall 

top plate from the SIP panel, degradation of the sheathing 

nail connections, and crushing of the sill plate by the OSB 

facings (Fig. 9). 

Rotation of the individual SIP panels relative to adjacent 

panels and/or the set-up was observed for all specimens 

leading to either opening of a gap between the adjacent 

segments or in some case a complete failure of the fasteners 

at the spline (Fig. 10). 

For walls with perforations, stress concentration at the 

openings’ corners lead to degradation of the connections 

between panels for walls framed with separate header panels 

(Configurations 5, 7, 8 – Fig. 11) or cracking of the OSB 

facings in walls framed with SIPs panels with cutout openings (Configuration 6 – Fig. 12). It should be noted that the 

separate header SIP panels were not directly attached to the 

framing of the adjacent SIP full-height panels. This configuration was tested to evaluate the lowest performance 

boundary. 

Configuration 4 specimens (single 4:1 aspect ratio panels) 

were the only walls to not experience a failure leading to 

a significant drop in resistance. Although the top plate did 

begin to separate from the SIP panel, the walls survived the 

full deformation profile without a catastrophic failure. 

Walls without Openings

Table 6 summarizes results for walls without openings. Both 

the unit shear capacity and unit shear stiffness show a strong 

Figure 10—Rotation of individual SIP panels.

Figure 9—Typical failure modes. (a) Separation of top plate 

from OSB facings. (b) Crushing of the sill plate by the OSB 

facings.

(a) (b)
Research Paper FPL–RP–682

8

Table 6—Summary of results for walls without openings

Configuration

Specimen

width/

height

Aspect

ratio

Peak

load

(kN)

Unit

shear 

(kN/m)

Stiffness at 

0.40Pload

(N/mm)

Unit stiffness

at 0.40Pload

(N/mm/m)

Deflection at

peak load

(mm)

1 2.4/2.4 1:1 63.596 26.081 2071.4 849.5 55

1SPL 2.4/2.4 1:1 65.793 26.982 1747.1 716.5 67

2 1.2/2.4 2:1

34.166 28.024 831.2 681.7 70

38.521 31.596 884.2 725.2 72

3 0.8/2.4 3:1

21.627 26.575 404.9 497.5 92

22.148 27.215 494.6 607.7 92

4 0.6./2.4 4:1

15.266 25.043 259.0 424.9 132

15.133 24.824 303.3 497.6 108

9 6.1/2.4 0.4:1 123.99 20.340 5634.4 924.3 57

Table 7—Summary of results for walls with openings

Configuration

Specimen 

width/

height

Aspect

ratio

Calculated characteristics:

perforated shear wall (PSW) method Measured characteristics

Sheathing

ratio,

r

PSW

ratio, 

F

Peak 

load

(kN)a

Peak

load 

(kN)b

Peak

load

(kN) PSW ratio, F

Deflection

at

peak

load

(mm)

Stiffness

(N/mm)

Stiffness

(N/mm)

Stiffness

@0.4Pload

(N/mm) Baseline 1 Baseline 2

5 6.1/2.4 2:1 0.71 0.44 73.10 55.11 68.33 0.42c 0.55 46

1941 2504 2404 0.55 0.43c

6 6.1/2.4 2:1 0.71 0.44 73.107 55.11 78.33 0.48 0.63 25

1941 2504 4457 1.02 0.79

7 6.1/2.4 4:1 0.41 0.19 30.60 23.07 41.64 0.25 0.34 49

812 1048 1438 0.33 0.26

8 6.1/2.4 2:1 0.51 0.26 42.11 31.74 57.87 0.35 0.47 44

1118 1442 2391 0.55 0.42

a

PSW prediction based on Configuration 1SPL–C as baseline (Baseline 1). b

PSW prediction based on Configuration 9 as baseline (Baseline 2).

c

Cases where the measured PSW ratio (F) is below the calculated ratio (F).
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

9

30

Unit shear (kN/m)

25

20

15

10

5

1:1

0

1:2

Aspect ratio

1:3 1:4

Config 2

Config 9

Config 3

Config 4 Config 1SPL

-C

dependency on the wall’s aspect ratio. However, different 

trends are observed for unit shear capacity and unit shear 

stiffness. The unit shear capacity follows a “bell” curve with 

the top of the “bell” associated with the 4-ft single-panel 

specimen as shown in Figure 13. The “bell” trend is a function of two competing response mechanisms driving the 

performance of the wall. The reduction in unit shear capacity for longer walls with multiple SIP panels (Configurations 

1SPL-C and 9)—the left side of the “bell”—is associated 

with the lower stiffness of spline connections between the 

SIP panels than a connection directly to framing members. 

For a 6.1-m (20-ft) long wall (Configuration 9) with a total 

of four spline joints, a reduction of 25% was observed relative to the 2.4-m- (8-ft-) long wall (Configuration 1SPL-C) 

with one spline joint and 32% relative to the 1.2-m- (4-ft-) 

long wall (Configuration 2) without spline joints.

The reduction in unit shear for high-aspect-ratio walls—the 

right side of the “bell”—is associated with the typical performance of narrow segments that is increasingly dominated 

by the uplift and bending components of the response. Using a 1.2-m- (4-ft-) long wall (Configuration 2) as a baseline, the 0.8-m- (2.67-ft) wall shows a 10% decrease and the 

0.6-m- (2-ft-) wall shows a 16% decrease in unit shear 

strength. If a 2.4-m (8-ft) wall is used as a baseline (Configuration 1SPL-C), which is a typical practice for light-frame 

walls, the 0.8-m (2.67-ft) wall shows no decrease and the 

2-ft wall shows an 8% decrease in unit shear strength. As a 

general observation for establishing design values and guidance, the unit shear reduction from the high-aspect-ratio 

effects is less than the reduction from the spline joint. 

Figure 11—Segment 

separated from header.

Figure 12—Configuration 6 cracking of OSB skins 

(black lines indicate location of cracks).

Figure 13—Unit shear.

Table 8—Material properties

SIP EPS foam core properties

Density (kg/m3) 17.62

Compression strength @ 10% strain (kPa) 108.9

Tensile strength (kPa) 211.7

Flexural strength (kpa) 200.6

OSB facing properties

Specific gravity 0.71

Parallel stiffness (E) (MPa/m) 2,120

Perpendicular stiffness (E) (MPa/m) 856.8

Parallel strength (N-m/m) 656 

Perpendicular strength (N-m/m) 440

Framing

Specific gravity 0.40

Moisture content 9%–12%
Research Paper FPL–RP–682

10

1000

Unit stiffness (N/mm/m) 750

500

250

1:1

0

1:2

Aspect ratio

1:3 1:4

Config 2

Config 9

Config 3

Config 4

Config 

1SPL-C

peak load and stiffness at 0.4 peak load. Because unit shear 

and unit shear stiffness for fully anchored SIP walls depend 

on the wall length, the PSW method was used with Configurations 1SPL-C and 9 as baseline for comparison purposes. 

Figures 16–17 and Figures 18–19 graphically show the predictive power of the PSW method for SIP shear walls using 

the two respective baselines. The test results indicate that 

the SIP shear walls closely follow the overall PSW method 

trend for both load and stiffness. With exception of Configuration 5, all wall specimens exceeded the PSW method 

predictions for both load and stiffness criteria. Configuration 

5 peak load was 6.5% below the predicted PSW value for 

the Configuration 1SPL-C baseline; Configuration 5 stiffness 

was 4% below the predicted PSW value for the Configuration 9 baseline. In Configuration 5, 7, and 8 specimens, 

the header panels were not directly attached to the adjacent 

full-height panels in order to simulate a low-bound condition (the OSB facings of the header panels were nailed to 

the top plate and bottom plate of the header was toe-nailed 

to the supporting jack studs). The header panels separated 

from the adjacent panel during the test as shown in Figures 

11 and 20.

Configuration 6 with cutout openings shows significantly 

higher stiffness than Configuration 5 that uses spline joints 

at the window panels (25.5 kips/in/lb vs. 13.7 kips/in/lb). 

Similarly, Configuration 6 unit shear stiffness is significantly higher than the PSW method prediction. This observation 

indicates that the construction method that uses openings 

cutout from a panel results in increased wall stiffness compared to the practice of constructing openings with individual panel headers. This increase in stiffness does not 

correspond to a comparable increase in strength (17.9 kips 

vs. 15.6 kips), likely because of a failure mode change for 

Configuration 6 that was associated with the facings cracking at window corners. 

Figure 15—Illustration of Stewart hysteretic model.

The unit shear stiffness followed a general trend of a 

reduction in stiffness with increasing aspect ratio as shown 

in Figure 14. Configuration 9 showed the highest stiffness 

with any potential impact of the spline joints on the stiffness 

of the panel to panel connection outweighed by the increase 

because of the wall length. Configurations 1SPL-C and 2 

exhibited comparable stiffness, again suggesting that any 

potential reduction from the higher aspect ratio for Configuration 2 was offset by the attachment of the SIP facings 

directly to framing members in lieu of the nailed OSB 

spline. Further increase in aspect ratio for Configurations 3 

and 4 resulted in a 20% and 33% reduction in stiffness, 

respectively. 

With the development of nonlinear time history analysis 

programs for the analysis of wood structures, such as SAWS 

and SAPWood, there is a need for hysteretic wall behavior data to model structural behavior under seismic events. 

Two hysteretic models have been for wood wall behavior, 

the Modified Stewart and the Evolution Damage Parameter 

models (Pang and others 2007). For the wall panels without 

openings, the modified Stewart model was fit to the experimental data. The modified Stewart model uses 10 parameters, highlighted in Figure 15, to describe the hysteretic 

behavior of the structural panel. A MATLAB program 

developed during the NEESWood program was used to 

optimize the 10 modeling parameters while minimizing the 

cumulative energy difference between the experimental and 

model behavior. Modeling parameters for Wall 1, 2, 3, 4 and 

9 are listed in Table 9. Appendix 3 provides load-deformation curves for experimental and modeled behavior for the 

walls without openings.

Walls with Openings 

(Perforated Walls)

Table 7 summarizes results for walls with openings. The 

perforated shear wall (PSW) method is used to evaluate 

Figure 14—Unit shear stiffness.

Displacement

Force

r3 Ko

r2 Ko

r

1 Ko

r4 Ko

Ko

(α,β)

δu

Fo

Fi

1

2
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

11

Figure 16—Shear strength ratio using Configuration 1SLP-C as baseline.

Figure 17—Shear stiffness ratio using Configuration 1SPL-C as baseline.

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Config 7

Config 6

Config 8

0.0

Shear strength ratio

Sheathing area ratio (r)

r

3 – 2 r

Config 5

1.2

1.0

0.8

0.6

0.4

0.2

0.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Config 7

Config 6

Config 8

0.0

Shear stiffness ratio

Sheathing area ratio (r)

r

3 – 2 r

Config 5

Table 9—Modified Stewart parameter for SIP tested without openings

Configuration

Ko r1 r2 r3 r4 Fo Fi δ α β

(N/mm) — — — — (N) (N) (mm) — —

1SPL 2286 0.069 –0.370 1.121 0.034 65260 3956 67.2 0.35 1.05

2 1047 0.065 –0.835 1.559 0.088 34503 3925 71.1 0.22 1.08

1118 0.068 –0.656 1.361 0.061 41262 3477 70.2 0.65 1.15

3 520.5 0.100 –0.125 1.500 0.032 23302 1271 75.9 0.65 1.07

663.2 0.064 –0.278 1.312 0.057 22812 1757 75.3 0.50 1.18

4 354.3 0.030 –0.054 1.152 0.032 15509 839.9 105.0 0.45 1.05

422.8 0.019 –0.162 1.214 0.037 16124 1092 104.1 0.45 1.05

9 6850 0.015 –0.200 1.400 0.038 130083 9629 68.4 0.25 1.10
Research Paper FPL–RP–682

12

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Config 7

Config 6

Config 8

0.0

Shear strength ratio

Sheathing area ratio (r)

r

3 – 2 r

Config 5

Figure 18—Shear strength ratio using Configuration 9 as baseline.

Figure 19—Shear stiffness ratio using Configuration 9 as baseline.

Figure 20—Configuration 5 failure 

mode at header panel.

1.2

1.0

0.8

0.6

0.4

0.2

0.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Config 7

Config 6

Config 8

0.0

Shear stiffness ratio

Sheathing area ratio (r)

r

3 – 2 r

Config 5
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

13

6.The test results indicate that perforated SIP shear walls 

follow the overall PSW method trend for both strength 

and stiffness.

References

AWC. 2015a. Special design provisions for wind and seismic. AWC SDPWS-2015. Leesburg, VA: American Wood 

Council. 

AWC. 2015b. National Design Specification for Wood Construction. ANSI/AWC NDS-2015. Leesburg, VA: American 

Wood Council.

APA – The Engineered Wood Association. 2010. Racking test of structural insulated panels (SIPs) with various 

bearing conditions. APA Report T2010P-17. Tacoma, WA: 

APA – The Engineered Wood Association. 

APA – The Engineered Wood Association. 2013. ANSI/APA 

PRS 610.1 Standard for performance-rated structural insulated panels in walls applications. Tacoma, WA: APA – The 

Engineered Wood Association. 18 p.

ASTM. 2014. Standard Test Methods for Cyclic (Reversed) 

Load Test for Shear Resistance of Vertical Elements of the 

Lateral Force Resisting Systems for Buildings. E2126-11. 

West Conshohocken, PA: ASTM. 15 p.

International Code Council. 2011. 2012 international residential code for one- and two-family dwellings. Country 

Club Hills, IL: International Code Council. 

Jamison, J.B. 1997. Monotonic and cyclic performance of 

structurally insulated panel shear walls. Thesis submitted to 

the Faculty of the Virginia Polytechnic Institute and State 

University in partial fulfillment of the requirements for the 

degree of Masters of Science in Civil Engineering. Blacksburg, VA. 97 p. 

Kermani, A.; Hairstans, R. 2006. Racking performance of 

structural insulated panels. Journal of Structural Engineering. 132(11): 1806–1812.

Pang, W.C.; Rosowsky, D.V.; Pei, S.; van de Lindt, J.W. 

2007. Evolutionary parameter hysteretic model for wood 

shear walls. ASCE Journal of Structural Engineering. 

133(8): 1118–1129. 

Again the 10 parameter modified Stewart hysteretic behavior model was fit to the SIP wall with opening data. Unlike 

the fits for the walls without openings, some parameters 

were adjusted outside of the MATLAB program to achieve 

better visual fits and reduce the cumulative energy difference between the experimental and model behavior. Modeling parameters for Wall 5, 6, 7, and 8 are listed in Table 10. 

Appendix 4 provides load-deformation curves for experimental and modeled behavior for the walls with openings.

Summary and Observations

The results of this testing program provide information 

on the cyclic performance of SIP shear walls with various aspect ratios tested as individual wall segments or as 

part of a perforated shear wall line. The applicability of the 

PSW method to perforated SIP shear walls is also explored. 

Specific observations based on the test results include the 

following:

1.The measured unit shear capacity for fully anchored 

SIP shear wall segments ranged from 20.43 kN/m 

(1,400 lb/ft) to over 30.65 kN/m (2,100 lb/ft) depending 

on the segment’s aspect ratio.

2.The measured unit shear stiffness for fully anchored SIP 

shear wall segments varied by a factor of two depending 

on the segment’s aspect ratio. 

3.The unit shear wall capacity and stiffness of SIP shear 

wall segments decreased with an increased number of 

panels jointed with a nailed spline connection. A 25% decrease in unit shear was observed for a 6.1-m (20-ft) wall 

with four spline joints compared to a 2.4-m (8-ft) wall 

with one spline joint.

4.The unit shear wall capacity of SIP shear wall segments 

decreases with an increased segment’s aspect ratio with a 

16% decrease for a 0.6-m (2-ft) segment as compared to a 

1.2-m (4-ft) segment. 

5.The unit shear wall stiffness of SIP shear wall segments 

decreases with an increased segment’s aspect ratio with 

a maximum 33% decrease for a 0.6-m (2-ft) segment 

as compared to either a 2.4-m (8-ft) or a 1.2-mm (4-ft) 

segment. 

Table 10—Modified Stewart parameter for SIP tested with openings

Configuration

Ko r1 r2 r3 r4 Fo Fi δ α β

(N/mm) — — — — (N) (N) (mm) — —

5 3692 0.241 –0.700 1.500 0.070 28182 4807 50.6 0.15 1.05

6 5962 0.095 –0.230 1.006 0.100 79034 13000 24.3 0.80 1.10

7 2276 0.272 –0.442 1.010 0.036 12449 1393 48.69 0.35 1.05

8 3200 0.181 –0.150 1.098 0.055 31723 3001 44.8 0.45 1.15
Research Paper FPL–RP–682

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Sugiyama, H.; Yasumura, M. 1984. Shear properties of 

plywood sheathed wall panels with openings. Transaction 

of the Architectural Institute of Japan. No. 338. April. 

pp. 88–98. 

Sugiyama, H.; Matsumoto, T. 1994. Empirical equations for 

the estimation of racking strength of a plywood sheathed 

shear wall with openings. Summary of Technical Papers, 

Annual Meetings, Trans. of A.I.J. Japan. pp. 89–90.
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

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Configuration 3-2

Appendix 1: Walls without Openings

Configuration 1M Configuration 1SPL-C

Configuration 2-1 Configuration 2-2

Configuration 3-1
Research Paper FPL–RP–682

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Configuration 4-1 Configuration 4-2

Configuration 9
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

17

Appendix 2: Walls with Openings

Configuration 5

Configuration 7

Configuration 6

Configuration 8
Research Paper FPL–RP–682

18

Configuration 3-2 Configuration 4-2

Appendix 3: Hysteretic Parameter Fits for Walls without Openings

Configuration 1SPL-C Configuration 2-1

Configuration 2-2 Configuration 3-1
SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

19

Appendix 4: Hysteretic Parameter Fits for Walls with Openings

Configuration 5 Configuration 6

Configuration 7 Configuration 8

Configuration 9