Page 235 - Standard Handbook Of Petroleum & Natural Gas Engineering

208 General Engineering and Science

Table 2-17
Allowable Unit Stresses for Lumber [lo]
SPECIES, SIZES, ALLOWABLE STRESSES, AND MODULUS OF ELASTICITY
Normal Loading Conditions: Moirlhlre Content Not Over 19 Percent
AUowpble unit stresses, psi'
Species and Exbeme Teasion Modulus
grades fiber in of elasticity,
(virunl grading)' bending psi
5no
Idaho white pine 2x4 W 850 800 I 240 1.1 20,000
2 x 6 and wider 1,200 240 1.4on,wo
500
Ponderosa pine 2x4 W 8511 800 1 280 1 1 ,000 950,000
280
2 x 6 and wider 1,150 1,000 i,iw,oon
Lodgepole pine 2x4 w 1,400 850 250 1,1nn 1,030,ooo
4x4 1,350 800 240 1,050 I .onn,ooo
Southern pine 2x4 S 1,RIO i.19n 405 1,190 1,800,000
4x4 S 1,NIO 1,190 405 1.300 1,700,000
Douglas fir 2x4 W 1,700 1 ,ooo 385 1,510 1,800,oon
2 x 6 and wder W 1.900 1,250 385 1.8nn i,8in,ooo
Western hemlock 2x4 W 1.450 x5n 245 1.m i,2in,ooo
2 x 6 and wder 1,650 1,100 245 1,450 1,520,000
Western sprucc 2x4 W 1,150 650 220 950 920.000
2 x 6 and wider 1,050 7011 220 1 .no0 1,150.000
Western cedar 2x4 W 850 500 295 1,150 860,000
2 x 6 and wider 1,200 no0 295 1,150 1,070,000
Redwood 2" and 4" R 1,640 - 305 1,190 I ,240,ono
(unseaoned) "Comtmction"
~
Note: Allowable "nil stresses !n horizontal shear are in the range of 75 to 15
'There is no ingle grade designation that applies to all lumber. Values in the table apply approximately lo "No 1 ..although this designarion II often
modified by terms such as denre or dry. For grades better than No. I, such terms as ~Vuciural. heavy. select. dcnr, etc. arc used. hwcr gradcr arc No 2.
No. 3 factory, light industrial, ec , but iherc are seldom more than four grader of a single size in a given species. The allowable stress arc for "rcpetiuve
member" USCIS.
*Most lumber is graded by the following agcncicr, alrhough there are other grading organizarions.
W = Weirern Wood ProducU Arsociation
S =Southern Pine Inspection Bureau
R =Redwood lnrpcruon Sewice
"Inad applied tojoists or planks. For beam or ~iringer grades, SL~CJYI are for load applied IO the narrow face.
'For engineered uses rhc allowable IUCII~S dm slightly lower; for kilndried lumber slightly higher For ,horl-tem loads, such ai( wind, earthquake, or
impact. higher unit ~trrsies are allowed
REFERENCES
"Wwd Handbook,'C.S Departmcnt ofApculturc Handboak No 72. 1955
"Timber Con~truruon Manual,"Amencan Institute of Timber Conslructton, John Wilq &Sons. 1966.
"National Design Specification for SrrcwGradc Lumber," National Forest Producu Aswciarion. Washington D C , 1968
Table 2-18
Physical, Mechanical, and Thermal Properties of Common Stones [l]
i
i
.t,
4
-
Granite 3.56.5 0.63.8 I 0.024.58 2W35 3.6-4.6
Marble 165-179 1..%6.5 0.42.1 0.024.45 a36 3.0-8.5
Slate 1%-180 2.0-3.6 0.1-1.7 0.01-0.6 12-26 3.S5.6
Sandstone 0.3-3.0 1.9-27.3 2.0-12.0 4-40 3.9-6.7
Limestone 0.&3 6 1.1-31 n 10-10.0 20-32 2.8-4.5