| SOUTHERN PINE DESIGN
VALUES |
Based on 1994 SPIB Grading Rules
Values in pounds per square inch (psi) |
| Table 3
Mechanically Graded Lumber - 2" thick or less, 2" and wider |
| Based on Normal Use
Conditions (MC< 19%) - See Tables A-1 thru A-4 for Adjustment Factors |
Grade
Designation1 |
Extreme
Fiber Stress
in Bending
"Fb" |
Tension
Parallel
to Grain
"Ft" |
Horizontal
Shear
"Fv"3 |
Compression
Perpendicular
to Grain
"Fc*"3 |
Compression
Parallel
to Grain
"Fc" |
Modulus
of
Elasticity
"E" |
Single
Member Uses |
Repetitive
Member Uses2 |
|
|
| Machine
Stress Rated (MSR) Lumber |
1650f-1.5E |
1800f-1.6E |
1950f-1.7E |
2100f-1.8E |
2250f-1.9E |
2400f-2.0E |
2550f-2.1E |
2700f-2.2E |
|
1650 |
1900 |
1020 |
90 |
565 |
1700 |
1,500,000 |
1800 |
2070 |
1175 |
90 |
565 |
1750 |
1,600,000 |
1950 |
2240 |
1375 |
90 |
565 |
1800 |
1,700,000 |
2100 |
2420 |
1575 |
90 |
565 |
1875 |
1,800,000 |
2250 |
2590 |
1750 |
90 |
565 |
1925 |
1,900,000 |
2400 |
2760 |
1925 |
90 |
565 |
1975 |
2,000,000 |
2550 |
2930 |
2050 |
90 |
565 |
2025 |
2,100,000 |
2700 |
3110 |
2150 |
90 |
565 |
2100 |
2,200,000 |
|
| Machine
Evaluated Lumber (MEL) |
|
1100 |
1270 |
600 |
90 |
565 |
1300 |
1,000,000 |
1400 |
1610 |
800 |
90 |
565 |
1600 |
1,200,000 |
2000 |
2300 |
1300 |
90 |
565 |
1825 |
1,600,000 |
2400 |
2760 |
1900 |
90 |
565 |
1975 |
1,800,000 |
|
(1) The most commonly produced Mechanically Graded
Lumber grades are given here. See the SPIB Grading Rules for a complete listing of all MSR
and MEL grades.
(2) Repetitive member uses apply to joists, truss chords, rafters, studs, planks, decking
or similar members which are in contact or spaced not more than 24" on center, are
not less than three [3] in number, and are joined by floor, roof or other load
distributing elements adequate to support the design load. The Repetitive Member Factor,
Cr = 1.15, has been included in the listed Repetitive Member Use design values.
(3) Approval is pending for higher shear and compression-perpendicular-to-grain design
values for MSR and MEL grades with a 1.7E and higher. Contact SPIB for additional
information.
| Table
4 Scaffold Plank1 - 2" and 3" thick, 8" and
wider |
Size |
Grade |
Extreme
Fiber Stress
in Bending "Fb"
Single Member Uses |
Modulus
of Elasticity "E" |
2" thick,
8" and wider
MC*19%2 |
Dense Industrial 72 Scaffold
Plank Dense Industrial 65 Scaffold Plank |
2400
2200 |
1,800,000
1,800,000 |
3" thick,
8" and wider
MC*19%2 |
Dense Industrial 72 Scaffold
Plank Dense Industrial 65 Scaffold Plank |
1800
1650 |
1,600,000
1,600,000 |
(1) Scaffold plank design values are for flatwise use
only. They were calculated using ASTM D245 and D2555 standards and modified using
procedures shown in "Calculating Apparent Reliability of Wood Scaffold Planks,"
as published by the Journal on Structural Safety, 2(1984) 47-57.
(2) For exposed conditions of use (where moisture content may exceed 19%) the values shall
be multiplied by: 0.86 for "Fb" and 0.97 for "E". |
