Using Modulus of Elasticity 

as the Sorting Criterion in the 

Manufacture of Lodgepole Pine 

Laminated Decking

A Pilot Study

Robert J. Ross

Robert J. Hoyle

United States Department of Agriculture

Forest

Service

Forest Products

Laboratory

Research Note

FPL–RN–0392

December

2020

Used with permission from Scott Breneman, WoodWorks, Washington, DC. 

Architect: Works Progress Architecture, Los Angeles, CA.
December 2020

Ross, Robert J.; Hoyle, Robert J. 2020. Using modulus of elasticity as 

the sorting criterion in the manufacture of lodgepole pine laminated 

decking—A pilot study. Research Note FPL-RN-0392. Madison, WI: 

U.S. Department of Agriculture, Forest Service, Forest Products 

Laboratory. 4 p.

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Abstract

The research presented in this research note was conducted 

to examine the potential to use lodgepole pine boards 

in laminated roof decking. A sample of visually graded 

lodgepole pine boards was obtained and evaluated. Modulus 

of elasticity (MOE), moisture content, specific gravity, and 

visual grade of each specimen were determined. Three-ply 

laminates were then prepared from the sample boards. Four 

types of laminates were prepared, based on either the visual 

grade or MOE of the boards used. Because bending MOE 

and strength are important mechanical properties for wood 

products in roof deck applications, each laminate was then 

tested in flatwise bending, and its MOE and strength were 

calculated. Results showed that the MOE and strength of 

laminates were dependent on visual grade of the boards. 

More importantly, using MOE as the sorting criterion and 

strategically placing boards in a laminate based on MOE 

of the boards produced laminates with greater modulus and 

strength. These results indicate that lodgepole pine can be 

used in decking applications.

Keywords: Laminate, laminated decking, lodgepole pine 

boards, modulus of elasticity, strength

Preface

The study summarized in this research note was conducted 

by Professor Robert J. Hoyle (deceased), P.E., when he was 

a faculty member at Washington State University. Professor 

Hoyle conducted the study to assist an industrial cooperator 

in determining the potential of using lodgepole pine boards 

for laminated roof decking. The information presented in 

his report is still pertinent today, as researchers and land 

managers continue to look for ways to use woody materials. 

The final report from that study serves as the basis for this 

research note.

Conversion table

English unit Conversion factor SI unit

foot (ft) 3.048 × 10–1 meter (m)

inch (in.) 2.54 × 101 millimeter (mm)

pound per square inch 

(lbf in–2)

6.894757 kilopascal (kPa)
Using Modulus of Elasticity as the Sorting 

Criterion in the Manufacture of Lodgepole 

Pine Laminated Decking

A Pilot Study

Robert J. Ross, Supervisory Research General Engineer

USDA Forest Service, Forest Products Laboratory, Madison, Wisconsin, USA

Robert J. Hoyle, Professor of Civil Engineering (deceased)

Washington State University, Pullman, Washington, USA

Introduction

Developing uses for woody materials is important to 

forest land managers throughout the world. Discovering 

economically viable products that would help use material 

from over-stocked, fire-prone lands is especially critical to 

allow land managers to enact forest management practices 

that will ultimately improve forest health, decrease fire risk, 

and provide an economic boost to rural economies.

Research on use of wood in engineering materials and 

products has been on-going at universities and government 

laboratories for many years. Many of the earliest efforts 

were targeted at demonstrating that by coupling fundamental 

engineering principles with a knowledge of wood science, 

engineered products that are economically and technically 

viable can be developed. An example is early research 

efforts to develop glued-laminated timber (Wilson 1939) 

and subsequent efforts to investigate using a range of 

wood species in making laminated timbers (Hernandez and 

Moody 1992; Hernandez and others 2005; Janowiak and 

others 1995; Manbeck and others 1993; Marx and Moody 

1981a, 1981b; Moody 1974; Moody and others 1993; 

Shedlauskus and others 1996).

Recently, there has been a renewed interest in research on 

laminated wood products. Specifically, the wood products 

research community has been investigating laminating 

boards or lumber pieces together to make panels for use in 

wall, flooring, and roofing applications (Williamson and 

Ross 2016).

The study summarized in this research note was conducted 

to examine the potential of using appearance grade 

lodgepole pine boards in a face-laminated, parallel-oriented 

product for roof decking (Hoyle 1970). Its specific objective 

was to investigate the modulus of elasticity (MOE) and 

bending strength of a sample of lodgepole pine boards and 

the laminated material made from them.

Materials and Methods

A random sample of lodgepole pine boards was obtained 

from an industrial cooperator. The sample consisted of 166 

nominal 1- by 6-in. 8-ft-long boards with the following 

nonstructural appearance grades: D-Select & No. 1 

Common, No. 2 Common, No. 3 Common, and No. 4 

Common. All boards were visually graded by the cooperator 

in accordance with the grading criteria used at the time. 

Upon receipt at Washington State University’s Wood 

Products Laboratory, each specimen’s dimensions, weight, 

and moisture content were determined. Static bending 

MOE was determined using a third-point loading test setup 

(Fig. 1). All MOE values were adjusted to a 12% moisture 

content level per ASTM D2555 (ASTM 2017).

The individual board specimens were then used to make 

nominal 3- by 6-in. three-ply, face-laminated, paralleloriented planks. Four types of laminated planks were 

prepared, based on visual grades and MOE values of the 

lumber specimens, as shown in Table 1.

The laminated specimens were then tested to failure in a 

flatwise bending mode, using the test setup illustrated in 

Figure 1. A span (L) of 72 in. was used, with loading at 

24-in. intervals (a). Actual specimen dimensions were 

2.25 in. thick, 5.5 in. wide, and 96 in. long. These 

dimensions provided for an approximate span-to-depth ratio 

of 32. From the load and deflection data collected, MOE 

Figure 1. Bending test setup used to measure the modulus 

of elasticity (MOE) and strength of the specimens in this 

study.

a

P/2

a

P/2

δ

L

Pa(3L2

 – 4a2)

48Iδ MOE =
Research Note FPL–RN–0392

2

was determined for each specimen in a group and bending 

strength was determined for two specimens per group. 

No correction for shear deflection was deemed necessary 

because the loading configuration provided for shear-free 

deflection in the middle third of the span and the spanto-depth ratio was relatively high. The specimens were 

orientated in the test setup such that face laminations were 

stressed in compression and back laminations were stressed 

in tension.

Results

Data obtained from testing of the boards and the laminated 

planks are presented in the Appendix. Average MOE values 

for the boards used in this study are summarized in Table 2. 

Observed MOE values were similar to those reported in 

the Wood Handbook (FPL 2010) for lodgepole pine clear 

wood (1.34 ×106 lb/in2). The MOE values varied with visual 

grade. The D Select and No. 1 common grade grouping had 

an average MOE of 1.76 ×106 lb/in2, and the No. 4 Common 

grouping had an MOE value of 1.36 ×106 lb/in2. This is 

in agreement with the known relationship between visual 

board grade and MOE.

Average specific gravity (SG) and MOE values of the 

laminated specimens are shown in Table 3. Maximum and 

minimum bending strength values are also summarized in 

Table 3. The SG values ranged from 0.394 to 0.404. The 

published value for SG of lodgepole pine clear wood is 

0.41. Average MOE values for the laminated specimens 

varied from 1.35 to 1.62 ×106 lb/in2.

Of particular significance are MOE and strength values for 

laminated specimens in the group (D) that used board MOE 

as the criterion for determining the layup pattern. This group 

had the lowest SG and highest MOE and strength values. 

The lowest strength specimen in this group was nearly 

as strong as or stronger than the specimens of maximum 

Table 1. Lamination selection criteria for the four groups

Laminate group Face grade Core grade Back grade

A No. 3 Common No. 4 Common No. 4 Common

B No. 2 Common No. 3 Common No. 4 Common

C D-Select or No. 1 Common No. 3 Common No. 4 Common

D Upper and middle MOE 

value boards

Lowest MOE boards Upper and middle MOE 

value boards

Table 2. Average modulus of elasticity (MOE) values for the 

boards used in this study

Visual grade MOE (×106 lb/in2) Number of specimens

D Select and No. 1 Common 1.76 9

No. 2 Common 1.60 54

No. 3 Common 1.48 61

No. 4 Common 1.36 42

strength in the groups that used visual grade of the boards 

for determination of layup patterns.

Concluding Comments

Results from this pilot study illustrated that lodgepole 

pine boards can be used to manufacture a laminated wood 

product that has mechanical properties greater than those 

for clear wood of the same species. The results also showed 

that by using the MOE of the boards as the criterion 

for determining layup pattern, laminated planks can be 

made with significantly improved mechanical properties 

compared with those of the individual boards. MOE is 

commonly used as a nondestructive test.

Literature Cited

ASTM. 2017. D2555 (current edition). Standard practice 

for establishing clear wood strength values. Section 04—

Construction; Volume 10—Wood. West Conshohocken, PA: 

American Society for Testing and Materials.

FPL. 2010. Wood handbook—wood as an engineering 

material. Gen. Tech. Rep. FPL-GTR-190. Madison, WI: 

U.S. Department of Agriculture, Forest Service, Forest 

Products Laboratory. 508 p.

Hernandez, R.; Moody, R.C. 1992. Improved performance 

of Southern Pine structural glued-laminated timber. Res. 

Pap. FPL-RP-514. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products Laboratory. 

22 p.

Hernandez, R.; Green, D.W.; Kretschmann, D.E.; Verrill, 

S.P. 2005. Improved utilization of small-diameter ponderosa 

pine in glulam timber. Res. Pap. FPL-RP-625. Madison, 

WI: U.S. Department of Agriculture, Forest Service, Forest 

Products Laboratory. 38 p.
Using Modulus of Elasticity as the Sorting Criterion in the Manufacture of Lodgepole Pine Laminated Decking—A Pilot Study

3

Table 3. Summary of results for the tests conducted on the laminated plank 

specimens

Group

Board MOEa

(×106 lb/in2)

Properties of laminate

MOEa

(×106 lb/in2)

Specific 

gravity

Number of 

specimems

MOR (lb/in2)

Maximum Minimum

A 1.45 (0.302) 1.35 (0.194) 0.394 10 3,920 3,690

B 1.47 (0.391) 1.39 (0.190) 0.396 10 5,650 3,650

C 1.55 (0.322) 1.52 (0.154) 0.404 10 5,570 4,280

D 1.53 (0.310) 1.62 (0.144) 0.391 20 7,500 5,300

a

Values in parentheses are standard deviations.

Hoyle, R.J. 1970. Wood products from lodgepole pine. 

Research Report No. 70/15-25. Pullman, WA: College 

of Engineering Research Division, Washington State 

University. 31 p.

Janowiak, J.J.; Manbeck, H.B.; Hernandez, R.; Moody, 

R.C.; Blankenhorn, P.R.; Labosky, P. 1995. Efficient 

utilization of red maple in glued-laminated timber beams. 

Res. Pap. FPL-RP-541. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products Laboratory. 

23 p.

Manbeck, H.B.; Janowiak, J.J.; Blankenhorn, P.R.; Labosky, 

P.; Moody, R.C.; Hernandez, R. 1993. Red maple glulam 

timber beam performance. Res. Pap. FPL-RP-519. Madison, 

WI: U.S. Department of Agriculture, Forest Service, Forest 

Products Laboratory. 32 p.

Marx, C.M.; Moody, R.C. 1981a. Bending strength of 

shallow glued-laminated beams of a uniform grade. Res. 

Pap. FPL-RP-380. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products Laboratory. 

19 p.

Marx, C.M.; Moody, R.C. 1981b. Strength and stiffness 

of small glued-laminated beams with different qualities 

of tension laminations. Res. Pap. FPL-RP-381. Madison, 

WI: U.S. Department of Agriculture, Forest Service, Forest 

Products Laboratory. 48 p.

Moody, R.C. 1974. Flexural strength of glued-laminated 

timber beams containing coarse-grain Southern Pine lumber. 

Res. Pap. FPL-RP-222. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products Laboratory. 

42 p.

Moody, R.C.; Hernandez, R.; Davalos, J.F.; Sonti, S.S. 

1993. Yellow poplar glulam timber beam performance. 

Res. Pap. FPL-RP-520. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products Laboratory. 

30 p.

Shedlauskas, J.P.; Manbeck, H.B.; Janowiak, J.J.; 

Hernandez, R.; Moody, R.C.; Labosky, P., Jr.; Blankenhorn, 

P.R. 1996. Efficient use of red oak for glued-laminated 

beams. Transactions of ASAE. 39(1): 203-209.

Williamson, T.; Ross, R.J. 2016. Proceedings, workshop 

on mass timber research. Gen. Tech. Rep. FPL-GTR-241. 

Madison, WI: U.S. Department of Agriculture, Forest 

Service, Forest Products Laboratory. 364 p.

Wilson, T.R.C. 1939. The glued laminated wooden 

arch. Technical Bulletin No. 691. Washington, DC: U.S. 

Department of Agriculture.
Research Note FPL–RN–0392

4

Appendix—Data from Test Results

Table A1. Load and deflection data from testing of lodgepole pine boards and 

laminated planks

Group Specimen

MOE of board (×106 lb/in2) MOE of plank 

(×106 lb/in2)

MOR of planka

(lb/in2 Face Center Back )

A 1 1.07 1.54 1.62 1.41

2 1.36 1.48 1.69 1.25

3 0.92 1.84 1.91 1.32

4 1.70 1.33 1.29 1.37

5 1.59 0.88 1.56 1.02 3,690

6 1.27 1.19 1.78 1.32

7 1.12 1.03 1.21 1.17

8 2.02 0.95 1.74 1.75 3,920

9 1.61 1.41 1.68 1.30

10 1.68 1.29 1.62 1.59

B 1 2.24 1.54 1.47 1.64 5,650

2 1.16 1.30 1.33 1.28

3 1.61 1.09 1.72 1.60

4 1.63 1.54 0.77 1.15

5 1.82 1.69 1.10 1.38

6 1.34 2.22 1.26 1.41

7 1.40 1.95 0.98 1.08 3,650

8 2.20 1.26 1.10 1.54

9 0.87 1.69 1.95 1.22

10 1.73 1.18 1.05 1.58

C 1 2.14 1.64 1.43 1.70

2 2.08 1.35 1.47 1.74 5,570

3 1.88 1.30 1.58 1.62

4 1.34 0.97 1.48 1.22 4,280

5 2.11 1.55 1.01 1.46

6 1.17 1.30 1.72 1.50

7 2.09 1.47 1.20 1.47

8 1.70 1.38 1.10 1.53

9 1.81 1.69 1.95 1.64

10 1.61 1.73 1.31 1.33

D 1 1.71 0.99 1.67 1.77

2 1.29 0.95 1.73 1.67

3 2.01 1.01 1.70 1.87

4 1.69 1.36 1.49 1.52

5 1.83 1.17 1.31 1.73

6 2.28 1.08 1.37 1.52

7 1.83 1.34 1.50 1.73

8 1.91 1.37 1.47 1.45

9 1.80 1.33 1.55 1.84

10 1.77 1.33 1.32 1.52

11 2.19 0.90 1.61 1.49

12 1.83 1.10 1.53 1.87 7,500

13 – – – 1.55

14 – – – 1.38

15 1.99 1.22 1.44 1.58

16 1.67 1.08 1.35 1.58

17 1.84 1.30 1.79 1.73

18 1.83 1.39 1.46 1.63

19 1.74 1.07 1.36 1.50

20 1.84 1.21 1.57 1.10 5,300 a

Only two specimens were tested to failure. Therefore, only two MOR values are reported per group.