WOOD - Materials for Civil and Construction Engineers - page 431

T ABLE 10.9 Characteristic Test Values for APA-EWS Performance Rated LVL (APA-

EWS, 2000)

Allowable

Allowable tensile Compressive Compressive

extreme stress stress Edgewise stress

APA-EWS Bending fiber parallel to parallel shear perpendicular

Stress Class modulus stress grain to grain stress to grain

10 6 psi

( ) (psi) (psi) (psi) (psi) (psi)

1.5E-2250F 1.5 4725 3150 3705 695 960

1.8E-2600F 1.8 5460 3570 4560 900 1170

1.9E-2600F 1.9 5460 3570 4845 900 1170

2.0F-2900F 2.0 5460 3990 5225 900 1255

2.1E-3100F 2.1 5460 4620 5700 900 1420

bonds the strands together. The strands are carefully oriented, coated with
adhesive, and run through a continuous press to achieve a high density, pro-
ducing billets that are typically 0.28 m by 0.48 m (11 in. by 19 in.). Length is
limited only by handling capability. The billets are sawn into the desired di-
mensions (USDA-FS, 1999).
Currently, parallel strand lumber is a proprietary material with a single
producer, marketed under the trade name Parallam (Trusjoist, 2003). The
mechanical design properties of this product, as reported by the manufac-
turer, are given in Table 10.10.

T ABLE 10.10 Mechanical Properties of Parallel Strand and Laminated
Strand Lumber (Trusjoist)

Parallel Laminated

Strand Strand

Property Lumber Lumber

Shear modulus of elasticity (psi) 125,000

10 6 10 6 Modulus of elasticity (psi)

Flexural stress (psi)

2.0 * 1.5 *

2900 2250

Tension stress (psi) 2025

Compression perpendicular to grain (psi) 750 475

Compression parallel to grain (psi) 2900 1950

Horizontal shear parallel to grain (psi) 290 400