| Bending | Compression | |||
| Species of Timber | Stress in extreme fibre Lbs. sq.in. | Horizontal shear stress Lbs. sq.in. | Parallel to grain "Short Columns" Lbs. sq.in. | Perpen- dicular to grain Lbs. sq.in. |
| *Fir, Douglas | ||||
| Dense grade | 1,600 | 100 | 1,200 | 350 |
| Sound grade | 1,300 | 85 | 900 | 300 |
| Hemlock, eastern | 1,000 | 70 | 700 | 300 |
| Hemlock, western | 1,300 | 75 | 900 | 300 |
| Oak | 1,400 | 125 | 900 | 400 |
| Pine, eastern white | 900 | 80 | 700 | 250 |
| Pine, Norway | 1,100 | 85 | 800 | 300 |
| *Pine, southern yellow | ||||
| Dense grade | 1,600 | 125 | 1,209 | 350 |
| Sound grade | 1,300 | 85 | 900 | 300 |
| Spruce | 900 | 70 | 600 | 200 |
| Tamarack | 1,200 | 95 | 900 | 350 |
* NOTE: The safe working stresses given in this table are for timbers with defects limited according to the sections on defects in the rules of the Southern Pine Association for Select Structural Material. "Dense" southern yellow pine and "dense" Douglas fir should also conform to the other requirements of this rule. "Sound" southern yellow pine and "sound" Douglas fir require no additional qualifications, whereas the other species should, in addition to being graded for defects, have all pieces of exceptionally low density for the species excluded.
This table gives working unit stresses for structural timbers used in dry locations, and is compiled in the main from material furnished by the Forest Products Laboratory, Madison, Wis.
TABLE OF BRICK WALL CONTENTS IN NUMBER OF BRICKS
Seven Bricks to Each Sq. Ft. of Wall Surface
| No. of sq ft. of wall | Thickness | |||||
| 4" | 8" | 12" | 16" | 20" | 24" | |
| 1 | 7 | 15 | 23 | 30 | 38 | 45 |
| 2 | 15 | 30 | 45 | 60 | 75 | 90 |
| 3 | 23 | 45 | 68 | 90 | 113 | 135 |
| 4 | 30 | 60 | 90 | 120 | 150 | 180 |
| 5 | 38 | 75 | 113 | 150 | 188 | 225 |
| 6 | 45 | 90 | 135 | 180 | 225 | 270 |
| 7 | 53 | 105 | 158 | 210 | 263 | 315 |
| 8 | 60 | 120 | 180 | 240 | 300 | 360 |
| 9 | 68 | 135 | 203 | 270 | 338 | 405 |
| 10 | 75 | 150 | 225 | 300 | 375 | 450 |
| 20 | 150 | 300 | 450 | 600 | 750 | 900 |
| 30 | 225 | 450 | 675 | 900 | 1,125 | 1,350 |
| 40 | 300 | 600 | 900 | 1,200 | 1,500 | 1,800 |
| 50 | 375 | 750 | 1,125 | 1,500 | 1,875 | 2,250 |
| 60 | 450 | 900 | 1,350 | 1,800 | 2,250 | 2,700 |
| 70 | 525 | 1,050 | 1,575 | 2,100 | 2,625 | 3,150 |
| 80 | 600 | 1,200 | 1,800 | 2,400 | 3,000 | 3,600 |
| 90 | 675 | 1,350 | 2,025 | 2,700 | 3,375 | 4,050 |
| 100 | 750 | 1,500 | 2,250 | 3,000 | 3,750 | 4,500 |
Example—Determine the number of bricks in a wall 12" × 18' × 60'.
Solution—The wall contains a surface area of 1,080 sq. ft. By
the table 100 sq. ft. contains 2,250 bricks, then 1,000 sq. ft. will
contain 22,500 bricks. 80 sq. ft. will contain, by the table, 1,800
bricks, making a total of 24,300 bricks.
APPENDIX IV
(Short Cuts to Roof Framing)
Griffith's Framing Tables For the Square and Octagonal Roof