THE MECHANICAL PROPERTIES OF WOOD INCLUDING A DISCUSSION OF THE FACTORS AFFECTING THE MECHANICAL PROPERTIES, AND METHODS OF TIMBER TESTING TEXT

| COMPRESSION AND SHEAR TESTS ON GREEN MATERIAL | |-----------------------------------------------------------------------------------------------------------------------------------------------| | | Compression | Compression | Shear | | | parallel to grain | perpendicular to grain | | | |------------------------------------------------------+-------------------------------------------+--------------------------| | | | | | Cr. | | Cr. | | | | | Cr. | | | | | Species | | | Per | str. | M. of | str. | | | | Per | str. | | Per | | | | Size of | No. | cent | at | E. | at max. | Stress | | No. | cent | at max. | No. | cent | Shear | | | specimen | of | of | E. L. | per | ld.,. | area | Height | of | of | ld., | of | of | strength | | | | tests | mois- | per | square | per | | | tests | mois- | per | tests | mois- | | | | | | ture | square | inch | square | | | | ture | square | | ture | | | | | | | inch | | inch | | | | | inch | | | | |-----------------+----------+-------+-------+--------+--------+---------+--------+--------+-------+ ------+---------+-------+-------+----------| | | | | | | 1,000 | | | | | | | | | | | | Inches | | | Lbs. | lbs. | Lbs. | Inches | Inches | | | Lbs. | | | Lbs. | | | | | | | | | | | | | | | | | | Longleaf pine | 4 by 4 | 46 | 26.3 | 3,480 | | 4,800 | 4 by 4 | 4 | 22 | 25.3 | 568 | 44 | 21.8 | 973 | | | 2 by 2 | 14 | 34.7 | | | 4,400 | | | | | | | | | | Douglas fir | 6 by 6 | 515 | 30.7 | 2,780 | 1,181 | 3,500 | 4 by 8 | 16 | 259 | 30.3 | 570 | 531 | 29.7 | 765 | | | 5 by 6 | 170 | 30.9 | 2,720 | 2,123 | 3,490 | | | | | | | | | | | 2 by 2 | 902 | 29.8 | 3,500 | 1,925 | 4,030 | | | | | | | | | | Douglas fir | | | | | | | | | | | | | | | | (fire-killed) | 6 by 6 | 108 | 34.8 | 2,620 | 1,801 | 3,290 | 6 by 8 | 16 | 24 | 33.7 | 368 | 77 | 35.8 | 631 | | | 2 by 2 | 204 | 37.9 | | | 3,430 | | | | | | | | | | Shortleaf pine | 6 by 6 | 95 | 41.2 | 2,514 | 1,565 | 3,436 | 5 by 8 | 16 | 12 | 37.7 | 361 | 179 | 47.0 | 704 | | | 5 by 8 | 23 | 43.5 | 2,241 | 1,529 | 3,423 | 5 by 8 | 14 | 12 | 42.8 | 366 | | | | | | 2 by 2 | 281 | 51.4 | | | 3,570 | 5 by 8 | 12 | 24 | 53.0 | 325 | | | | | | | | | | | | 5 by 5 | 8 | 24 | 47.0 | 344 | | | | | | | | | | | | 2 by 2 | 2 | 277 | 48.5 | 400 | | | | | Western larch | 6 by 6 | 107 | 49.1 | 2,675 | 1,575 | 3,510 | 6 by 8 | 16 | 22 | 43.6 | 417 | 179 | 40.7 | 700 | | | 2 by 2 | 491 | 50.6 | 3,026 | 1,545 | 3,696 | 6 by 8 | 12 | 20 | 40.2 | 416 | | | | | | | | | | | | 4 by 6 | 6 | 53 | 52.8 | 478 | | | | | | | | | | | | 4 by 4 | 4 | 30 | 50.4 | 472 | | | | | Loblolly pine | 8 by 8 | 14 | 63.4 | 1,560 | 365 | 2,140 | 8 by 4 | 8 | 16 | 67.2 | 392 | 121 | 83.2 | 630 | | | 4 by 8 | 18 | 60.0 | 2,430 | 691 | 3,560 | 4 by 4 | 8 | 38 | 44.6 | 546 | | | | | | 2 by 2 | 53 | 74.0 | | | 3,240 | | | | | | | | | | Tamarack | 6 by 7 | 4 | 49.9 | 2,332 | 1,432 | 3,032 | | | | | | 24 | 39.2 | 668 | | | 4 by 7 | 6 | 27.7 | 2,444 | 1,334 | 3,360 | | | | | | | | | | | 2 by 2 | 165 | 36.8 | | | 3,190 | | | | | | | | | | Western hemlock | 6 by 6 | 82 | 46.6 | 2,905 | 1,617 | 3,355 | 6 by 4 | 6 | 30 | 48.7 | 434 | 54 | 65.7 | 630 | | | 2 by 2 | 131 | 55.6 | 2,938 | 1,737 | 3,392 | | | | | | | | | | Redwood | 6 by 6 | 34 | 83.6 | 3,194 | 1,240 | 3,882 | 6 by 8 | 16 | 13 | 86.7 | 473 | 148 | 84.2 | 742 | | | 2 by 2 | 143 | 36.8 | 3,490 | 1,222 | 3,980 | 6 by 6 | 12 | 14 | 83.0 | 424 | | | | | | | | | | | | 6 by 7 | 9 | 13 | 74.7 | 477 | | | | | | | | | | | | 6 by 3 | 14 | 13 | 75.6 | 411 | | | | | | | | | | | | 6 by 2 | 12 | 12 | 66.5 | 430 | | | | | | | | | | | | 6 by 2 | 10 | 11 | 55.0 | 423 | | | | | | | | | | | | 6 by 2 | 8 | 12 | 56.7 | 396 | | | | | | | | | | | | 2 by 2 | 2 | 186 | 75.5 | 569 | | | | | Norway pine | 6 by 7 | 5 | 29.0 | 1,928 | 905 | 2,404 | | | | | | 20 | 26.7 | 589 | | | 4 by 7 | 8 | 28.4 | 2,154 | 1,063 | 2,652 | | | | | | | | | | | 2 by 2 | 178 | 26.8 | | | 2,504 | | | | | | | | | | Red spruce | 2 by 2 | 58 | 35.4 | | | 2,750 | 2 by 2 | 2 | 43 | 31.8 | 310 | 30 | 32.0 | 758 | | White spruce | 2 by 2 | 84 | 61.0 | | | 2,370 | 2 by 2 | 2 | 46 | 50.4 | 270 | 40 | 58.0 | 651 | |-----------------------------------------------------------------------------------------------------------------------------------------------| | _Note.--Following is an explanation of the abbreviations used in the foregoing tables:_ | | F.S. at E.L. = Fiber stress at elastic limit. | | M. of E. = Modulus of elasticity. | | M. of R. = Modulus of rupture. | | Cr. str. at E.L. = Crushing strength at elastic limit. | | Cr. str. at max. ld. = Crushing strength at maximum load. | |-----------------------------------------------------------------------------------------------------------------------------------------------| |-----------------------------------------------------------------------------------------------------------------------------------| | TABLE XX TABLE XX | |-----------------------------------------------------------------------------------------------------------------------------------| | BENDING TESTS ON AIR-SEASONED MATERIAL | |-----------------------------------------------------------------------------------------------------------------------------------| | | Sizes | | | | F.S. at E.L. | M. of R. | M. of E. | Calculated | | |-----------------| Num- | Per | Rings | | | | shear | | Species | | | ber | cent | per |-----------------+-----------------+-----------------+-----------------| | | Cross | Span | of | mois- | inch | Average | Ratio | Average | Ratio | Average | Ratio | Average | Ratio | | | Section | | tests | ture | | per sq. | to 2" | per sq. | to 2" | per sq. | to 2" | per sq. | to 2" | | | | | | | | inch | by 2" | inch | by 2" | inch | by 2" | inch | by 2" | |-----------------+----------+------+-------+-------+-------+---------+-------+---------+-------+---------+-------+---------+-------| | | | | | | | | | | | 1,000 | | | | | | Inches | Ins. | | | | Lbs. | | Lbs. | | lbs. | | Lbs. | | | | | | | | | | | | | | | | | | Longleaf pine | 8 by 16 | 180 | 5 | 22.2 | 16.0 | 3,390 | 0.50 | 4,274 | 0.37 | 1,747 | 1.00 | 288 | 0.75 | | | 6 by 16 | 132 | 1 | 23.4 | 17.1 | 3,470 | .51 | 6,610 | .57 | 1,501 | .86 | 388 | 1.01 | | | 6 by 10 | 177 | 2 | 19.0 | 8.8 | 4,560 | .68 | 7,880 | .68 | 1,722 | .99 | 214 | .56 | | | 4 by 11 | 180 | 1 | 18.4 | 23.9 | 3,078 | .46 | 8,000 | .69 | 1,660 | .95 | 251 | .66 | | | 6 by 8 | 177 | 6 | 20.0 | 13.7 | 4,227 | .63 | 8,196 | .71 | 1,634 | .94 | 177 | .46 | | | 2 by 2 | 30 | 17 | 15.9 | 13.9 | 6,750 | 1.00 | 11,520 | 1.00 | 1,740 | 1.00 | 383 | 1.00 | | Douglas fir | 8 by 16 | 180 | 91 | 20.8 | 13.1 | 4,563 | .68 | 6,372 | .61 | 1,549 | .91 | 269 | .64 | | | 5 by 8 | 180 | 30 | 14.9 | 12.2 | 5,065 | .76 | 6,777 | .65 | 1,853 | 1.09 | 218 | .52 | | | 2 by 2 | 24 | 211 | 19.0 | 16.4 | 6,686 | 1.00 | 10,378 | 1.00 | 1,695 | 1.00 | 419 | 1.00 | | Shortleaf pine | 8 by 16 | 180 | 3 | 17.0 | 12.3 | 4,220 | .54 | 6,030 | .50 | 1,517 | .85 | 398 | .98 | | | 8 by 14 | 180 | 3 | 16.0 | 12.3 | 4,253 | .55 | 5,347 | .44 | 1,757 | .98 | 307 | .76 | | | 8 by 12 | 180 | 7 | 16.0 | 12.4 | 5,051 | .65 | 7,331 | .60 | 1,803 | 1.01 | 361 | .89 | | | 5 by 8 | 180 | 6 | 12.2 | 22.5 | 7,123 | .92 | 9,373 | .77 | 1,985 | 1.11 | 301 | .74 | | | 2 by 2 | 30 | 67 | 14.2 | 13.7 | 7,780 | 1.00 | 12,120 | 1.00 | 1,792 | 1.00 | 404 | 1.00 | | Western larch | 8 by 16 | 180 | 23 | 18.3 | 21.9 | 3,343 | .57 | 5,440 | .53 | 1,409 | .90 | 349 | .96 | | | 8 by 12 | 180 | 29 | 17.8 | 23.4 | 3,631 | .62 | 6,186 | .60 | 1,549 | .99 | 295 | .81 | | | 5 by 8 | 180 | 10 | 13.6 | 27.6 | 4,730 | .80 | 7,258 | .71 | 1,620 | 1.04 | 221 | .61 | | | 2 by 2 | 30 | 240 | 16.1 | 26.8 | 5,880 | 1.00 | 10,254 | 1.00 | 1,564 | 1.00 | 364 | 1.00 | | Loblolly pine | 8 by 16 | 180 | 14 | 20.5 | 7.4 | 4,195 | .81 | 6,734 | .72 | 1,619 | 1.10 | 462 | 1.45 | | | 6 by 16 | 126 | 4 | 20.2 | 5.0 | 2,432 | .47 | 4,295 | .46 | 1,324 | .90 | 266 | .84 | | | 6 by 10 | 174 | 3 | 21.3 | 4.7 | 3,100 | .60 | 6,167 | .66 | 1,449 | .99 | 173 | .54 | | | 4 by 12 | 174 | 4 | 19.8 | 4.7 | 2,713 | .52 | 5,745 | .61 | 1,249 | .85 | 185 | .58 | | | 8 by 8 | 180 | 9 | 22.9 | 4.9 | 2,903 | .56 | 4,557 | .48 | 1,136 | .77 | 93 | .29 | | | 6 by 7 | 144 | 2 | 21.1 | 5.0 | 2,990 | .58 | 4,968 | .53 | 1,286 | .88 | 116 | .36 | | | 4 by 8 | 132 | 8 | 19.5 | 9.1 | 3,384 | .65 | 6,194 | .66 | 1,200 | .82 | 196 | .62 | | | 2 by 2 | 30 | 123 | 17.6 | 6.6 | 5,170 | 1.00 | 9,400 | 1.00 | 1,467 | 1.00 | 318 | 1.00 | | Tamarack | 6 by 12 | 162 | 5 | 23.0 | 15.1 | 3,434 | .45 | 5,640 | .43 | 1,330 | .82 | 318 | .75 | | | 4 by 10 | 162 | 4 | 14.4 | 9.7 | 4,100 | .54 | 5,320 | .41 | 1,386 | .84 | 252 | .59 | | | 2 by 2 | 30 | 47 | 11.3 | 16.2 | 7,630 | 1.00 | 13,080 | 1.00 | 1,620 | 1.00 | 425 | 1.00 | | Western hemlock | 8 by 16 | 180 | 44 | 17.7 | 17.8 | 4,398 | .69 | 6,420 | .62 | 1,737 | 1.04 | 406 | 1.06 | | | 2 by 2 | 28 | 311 | 17.9 | 19.4 | 6,333 | 1.00 | 10,369 | 1.00 | 1,666 | 1.00 | 382 | 1.00 | | Redwood | 8 by 16 | 180 | 6 | 26.3 | 22.4 | 3,797 | .79 | 4,428 | .57 | 1,107 | .96 | 294 | 1.05 | | | 6 by 12 | 180 | 6 | 16.1 | 17.7 | 3,175 | .66 | 3,353 | .43 | 728 | .64 | 167 | .60 | | | 7 by 9 | 180 | 6 | 15.9 | 15.2 | 3,280 | .69 | 4,002 | .51 | 1,104 | .96 | 147 | .53 | | | 3 by 14 | 180 | 6 | 13.1 | 24.4 | | | 5,033 | .64 | | | 291 | 1.04 | | | 2 by 12 | 180 | 5 | 13.8 | 14.4 | 3,928 | .82 | 5,336 | .68 | 1,249 | 1.09 | 260 | .93 | | | 2 by 10 | 180 | 5 | 13.8 | 24.8 | 3,757 | .79 | 4,606 | .59 | 1,198 | 1.05 | 186 | .67 | | | 2 by 8 | 180 | 6 | 13.7 | 20.7 | 4,314 | .90 | 5,050 | .65 | 1,313 | 1.15 | 166 | .60 | | | 2 by 2 | 28 | 122 | 15.2 | 18.8 | 4,777 | 1.00 | 7,798 | 1.00 | 1,146 | 1.00 | 279 | 1.00 | | Norway pine | 6 by 12 | 162 | 5 | 16.7 | 8.1 | 2,968 | .56 | 5,204 | .61 | 1,123 | .97 | 286 | 1.02 | | | 4 by 10 | 162 | 5 | 13.7 | 12.0 | 5,170 | .98 | 6,904 | .82 | 1,712 | 1.48 | 317 | 1.13 | | | 2 by 2 | 30 | 60 | 14.9 | 11.2 | 5,280 | 1.00 | 8,470 | 1.00 | 1,158 | 1.00 | 281 | 1.00 | |-----------------------------------------------------------------------------------------------------------------------------------| | _Note.--Following is an explanation of the abbreviations used in the foregoing tables:_ | | F.S. at E.L. = Fiber stress at elastic limit. | | M. of E. = Modulus of elasticity. | | M. of R. = Modulus of rupture. | | Cr. str. at E.L. = Crushing strength at elastic limit. | | Cr. str. at max. ld. = Crushing strength at maximum load. | |-----------------------------------------------------------------------------------------------------------------------------------| |-----------------------------------------------------------------------------------------------------------------------------------------------| | TABLE XXI TABLE XXI | |-----------------------------------------------------------------------------------------------------------------------------------------------| | COMPRESSION AND SHEAR TESTS ON AIR-SEASONED MATERIAL | |-----------------------------------------------------------------------------------------------------------------------------------------------| | | Compression | Compression | Shear | | | parallel to grain | perpendicular to grain | | | |------------------------------------------------------+-------------------------------------------+--------------------------| | | | | | Cr. | | Cr. | | | | | Cr. | | | | | Species | | | Per | str. | M. of | str. | | | | Per | str. | | Per | | | | Size of | No. | cent | at | E. | at max. | Stress | | No. | cent | at max. | No. | cent | Shear | | | specimen | of | of | E. L. | per | ld.,. | area | Height | of | of | ld., | of | of | strength | | | | tests | mois- | per | square | per | | | tests | mois- | per | tests | mois- | | | | | | ture | square | inch | square | | | | ture | square | | ture | | | | | | | inch | | inch | | | | | inch | | | |