[National Emergency Specifications for the Design, Fabrication and Erection of Stress Grade Lumber and Its Fastenings for Buildings] [From the U.S. Government Publishing Office, www.gpo.gov] CONSERVATION DIVISION WAR PRODUCTION BOARD WASHINGTON, D. C. * NATIONAL EMERGENCY SPECIFICATIONS FOR THE DESIGN, FABRICATION AND ERECTION OF STRESS GRADE LUMBER AND ITS FASTENINGS FOR BUILDINGS DIRECTIVE NO. 29 AUGUST 9, 1943 /V j c •X CONSERVATION DIVISION Lo WAR PRODUCTION BOARDS WASHINGTON, D. C. * NATIONAL EMERGENCY SPECIFICATIONS FOR THE DESIGN, FABRICATION AND ERECTION OF STRESS GRADE LUMBER AND ITS FASTENINGS FOR BUILDINGS DIRECTIVE NO. 29 AUGUST 9, 1943 '.¿WB * UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1943 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington, D. C. - Price 15 cents ■ -, ■ August 9, 1943 DIRECTIVE 29 WAR PRODUCTION BOARD PART 905—SPECIFICATIONS [Directive 29] National Emergency Specifications for the Design, Fabrication and Erection of Stress Grade Lumber and Its Fastenings for Buildings Pursuant to the authority vested in me by Executive Orders No. 9024 of January 16, 1942, No. 9040 of January 24, 1942, and No. 9125 of April 7, 1942, and pursuant to the policy stated in the Joint Directive of the War Production Board and the War and Navy Departments dated May 20, 1942, and the Army and Navy Munitions Board “List of Prohibited Items for Construction Work”, dated April 1, 1942, as revised and supplemented, the following policy is prescribed (1) for the War Production Board and for the Army, Navy, Maritime Commission, Reconstruction Finance Corporation, National Housing Agency, and (2) for all other departments and agencies in respect to war construction and the financing of war construction. § 905.3 National Emergency Specifications for the design, fabrication, and erection of stress grade lumber and its fastenings for buildings, (a) National Emergency Specifications for the Design, Fabrication, and Erection of Stress Grade Lumber and Its Fastenings for Buildings issued by the War Production Board on August 9, 1943, shall apply to and shall govern the design, fabrication and erection of all buildings in which stress grades of lumber are used, and which are constructed by, or the construction of which is financed by or must be approved by any of such departments or agencies. Such emergency specifications shall be used only in the design, fabrication, and erection of buildings) at other than 0° and 90° to the grain, the least spacings for allowable connector loads obtained as provided by paragraphs 500-M and 500-N shall be determined from the following formula and values for A and B given in Table No. 4 p_ AB ■J A? sin2 cos2 0 in which R=least spacing of connectors, measured in inches along connector-axis, required for the angle of load to grain (0) and angle of connector-axis to grain (0) used. A—value in column (3), Table No. 4, opposite the connector in column (1) and angle of load to grain in column (2) which are used. B=value in column (4), Table No. 4, opposite the connector in column (1) and angle of load to grain in column (2) which are used. 0=angle of connector-axis to grain. (3) The values under C, column (5), Table No. 4, are minimum allowable spacings for any angle of load to grain (0) other than 0° and 90°. They are also the minimum allowable spacings for any angle of connector-axis to grain (0) other than 0° and 90°. (4) For spacings intermediate between R and the minimum C from column (5), Table No. 4, the allowable load shall be determined by straight line interpolation between the load for R spacing and 75 percent of the load for R spacing, respectively. Table No. 4.—Values for use with paragraph 500—L—J/. 1 Type and size of connector 2 Angle of load to grain (0) 8* A 4 B 5 C (75 percent value) Degrees Inches Inches Inches 0 6% 3% 3% 2%-inch split ring or 2%-inch shear plate. 15 30 *45 6 5/s 4% 3% 3% 4% 3% 3% 3% *60-90 3% 4% 3% 0 9 5 5 15 8 5% 5 4-inch split ring or 4- 30 7 5% 5 inch shear plate. *45 6 5% 5 *60-90 5 6 5 0 4 2% 2% 15 3% 2% 2% 2-inch toothed ring 30 3% 2% 2% *45 2% 2% 2% *60-90 2% 3 2% 0 5% 3% 3% 15 4% 3% 3% 2%-inch toothed ring 30 4% 3% 3% - *45 3% 3% 3% *60-90 3% 3% 3% 0 6% 3% •3% 15 6 4% 3% 3%-inch toothed ring. 30 5% 4% 3% *45 4% 4% 3% *60-90 3% 5 3% 0 8 4% 4% 15 7% 4% 4% 4-inch toothed ring 30 6% 5% 4% *45 5% 5% 4% *60-90 4% 5% 4% 0 7 3% 3% 2%-inch claw plate 15 6 3% 3% 30 5 3% 3% *45 4 3% 3% *60-90 3% 4 3% 0 7% 3% 3% 3%-inch claw plate 15 6% 4 3% 30 5% 4% 3% *45 4% 4% 3% *60-90 3% 4% 3% 0- 9 4% 4% 4-inch claw plate 15 7% 4% 4% 30 6% 5% 4% *45 5% 5% 4% *60-90 4% 5% 4% * See par. 500-L—4 (b). (b) Load Limitations for Multiple Connectors in a Single Piece. When the connectors -29- 500-501 NATIONAL EMERGENCY SPECIFICATIONS on the same face are not offset (from each other) perpendicular to grain a distance (measured between lines parallel to grain and passing through centers of connectors) equal to one connector diameter and the connector loads or components thereof all act in the same direction and at angles (0) of 45° to 90° with the grain on the loaded faces of the piece, the maximum allowable loads for multiple connectors for this condition shall be taken as the summation of the allowable loads for each connector used, but the total allowable load for the group of connectors shall not exceed the load permitted for the single connector multiplied by the percentages in Table No. 5. For the conditions and allowable loads in this paragraph, the spacings shall not be less than those determined by paragraph 500-L-4(a). Table No. 5.—Values for use with paragraph 500-L-4 (b) [Maximum allowable loads for 4 connectors in percent based on allowable loads for 1 connector] Type and size of connectors Thickness of loaded member, inches 1% 2 2% 3 and thicker 2%-inch split ring or 2% shear Percent Percent Percent Percent plate _ _ _ 300 300 300 300 4-inch split ring oi 4-inch shear plate 230 248 269 300 2-inch toothed ring. 300 300 300 300 2%-inch toothed ring _ 300 300 300 300 3%-inch toothed ring 300 300 300 300 4-inch toothed iing_ 225 250 300 . 300 2%-inch claw plate X 300 300 300 3%-inch claw plate__ X 250 300 300 4-inch claw plate X 248 269 300 X—Not permitted in this thickness. For each additional connector over the 4 connectors, add 33 percent , of the allowable load for 1 connector. M. LOAD AT ANGLE TO GRAIN 1. The angle of load to grain is the angle between the direction of the resultant load acting on the member and the longitudinal axis of the member. 2. For angles of load to grain intermediate of parallel and perpendicular to grain, the allowable connector load shall be determined by application of the Hankinson formula (see par. 404 and Appendix C) between the allowable connector loads for parallel and perpendicular- to-grain loading given in Tables Nos. 8, 9, 10, and 11, except that: (a) For toothed rings, allowable loads shall be determined as follows: (1) The allowable connector loads for angles of load to grain of 45° to 90° shall be the same as th.e tabulated allowable connector load for an angle of load to grain of 90°. (2) For angles of load to grain intermediate of 0° and 45°, the allowable connector loads shall be determined by application of the Hankinson formula between the allowable loads at angles of load to grain of 0° and 45°. (b) For shear plates when the tabulated allowable loads are equal to the limits imposed in the notes in Table No. 11, allowable loads at angles of load to grain other than parallel and perpendicular to grain shall be determined by the application of the Hankinson formula between the following limits. The parallel-to-grain load for use in the formula shall be taken as 143 percent of the perpendicular-to-grain load for the second loaded-edge distance tabulated for the thickness used. The tabulated peipendicular-to-grain load for. the appropriate loaded-edge distance and thickness shall be used therewith in the formula. In no case, however, shall the allowable angle-to-grain load so determined be permitted to exceed the limits imposed by the notes in Table No. 11. N. INTER - RELATIONSHIP OF THICKNESS, DISTANCES AND SPACING 1. Loads reduced because of thickness (see tabulated loads) do not permit any reduction of edge distance, end distance or spacing and conversely loads reduced for edge distance, end distance or spacing do not permit reduction of thickness. 2. When allowable load is reduced due to reduced edge distance, end distance or spacing, the reduced allowable load for each shall be determined separately and the lowest allowable load so determined for any one connector shall apply. Such load reductions are not cumulative. Conversely if the allowable load is reduced because of a reduced distance or spacing, the other distances or spacings may be reduced to those resulting in the same reduced allowable load. 501 Use of Lag Screws Instead of Bolts with Timber Connectors A. TYPE OF SCREW 1. The lag screw shall have a out thread, not a rolled thread. -30- FOR STRESS GRADE LUMBER 501-502 B. DIAMETER OF LAG SCREW 1. The shank of the lag screw shall have the same diameter as the bolt specified for the connector. C. HOLE FOR SHANK AND THREADED PORTION 1. The hole for the shank shall be the same diameter as the shank. 2. The hole for the threaded portion of lag screw shall have a diameter equal to approximately 75 percent of that of the shank. (See par. 700-G.) D. ALLOWABLE LOADS 1. When lag screws instead of bolts are used with connectors, the allowable loads on connectors shall vary uniformly from full allowable load (allowable load for connector unit with common bolt) with an anchorage of threaded portion of lag screw equal to 9 times the diameter of the shank to 90 percent of full allowable load with an anchorage of 5 times the shank diameter. With anchorage of less than 5 times the shank diameter, 75 percent of full allowable connector load shall apply but the anchorage shall not be less than 3% times the shank diameter. 502 Net Section A. The net section shall be determined by subtracting from the full cross-sectional area of the timber the projected area of that portion of the connectors within the member and that portion of the bolts not within the connector projected area, located at the critical plane. (See Fig. 12.) Figure 12.—Shaded area shows net cross-section of timber. B. In tension members, the critical or net section of a timber in square inches shall not be less than that determined by multiplying the total load in pounds which is transferred through the critical section of the member, by the appropriate constant in Table No. 6. Table No. 6.—Constants for use in determining required net section in square inches Duration of loading Thickness of wood member in inches Constants for each connector load group Group A Group B Group C Group D Permanent. 4 inches or less. Over 4 inches _ 0. 00040 . 00050 0. 00047 . 00059 0. 00056 . 00070 0. 00068 . 00085 Snow. 4 inches or less. Over 4 inches _ . 00035 . 00044 . 00041 . 00051 . 00049 . 00061 . 00059 . 00074 Wind or earthquake. 4 inches or less_ Over 4 inches- . 00027 . 00033 . 00031 . 00039 . 00037 . 00047 . 00045 . 00057 Table No. 7.—Connector load grouping of species when structurally graded Connector load grouping Species Group A Ash, white. Beech. Birch. Douglas fir (dense). Elm, rock. Hickory. Pecan. Maple, hard. Oak, red and white. Pine, southern (dense). Group B ; Douglas fir (coast region). Elm, soft. Larch, western. Maple, soft. Pine, southern. Gum, black or red. Group C Cypress, southern and tidewater red. Hemlock, west coast. Pine, Norway. Redwood. Poplar, yellow. Spruce, eastern. Spruce, Sitka. Group D Cedar, western red. Fir, commercial white. Hemlock, eastern. Pine, ponderosa. Pine, sugar. Pine, eastern white. Pine, western white. Spruce, Engelmann. -31- Table No. 8.—Allowable loads for one SPLIT-RING and bolt in single shear Splitring diam. Bolt diam. Number of faces of a piece containing connectors on same bolt Thickness (net) of lumber Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) - Edge distance Allowable load per connector unit and bolt for— Edge distance Allowable load per connector unit and bolt for— Group woods Group B woods Group C woods Group D woods Unloaded-edge distance (edge opposite loaded edge) Loaded-edge distance (edge toward which connector load acts) Group A woods Group B woods Group C woods Group D woods Inches 2^ Inches % 1 Inches 1 min Inches min. or more.. 1% min. or more. - Pounds 2,875 3,450 Pounds 2,480 2,975 Pounds 2,080 2,500 Pounds 1,790 2,140 Inches IJi min. or more.. IJi min. or more. . Inches IJi min Pounds 1,720 2,045 2,070 2,455 Pounds 1,475 1,750 1,770 2,105 Pounds 1,230 1,460 1,475 1,750 Pounds 1,055 1, 255 1,265 1,500 A^ and thicker 2Ji or more. IJi min 2Ji or more 2 1% min IJi min. or more. _ IJi min. or more. _ 2,875 3,450 2,480 2,975 2,080 2,500 1,790 2,140 IJi min. or more.. min. or more._ IJi min 1,720 2,045 2,070 2,455 1,475 1,750 1,770 2,105 1,230 1,460 1,475 1,750 1,055 1,255 1,265 1,500 2 and thicker 2 Ji or more IJi min 2Ji or more.... . 4 . % 1 1 min and thicker 2Ji min. or more. _ 2J£ min. or more. _ 4,465 6,695 3,830 5,735 3,185 4,780 2,755 4,135 2 Ji min. or more. _ 2Ji min. or more. . 2Ji min 2,585 3,110 3,880 4,660 2,220 2,665 3,330 3,995 1,850 2,220 2,770 3,330 1,595 1,915 2,395 2,875 3 Ji or more 2ji min 3 Ji or more 2 l^g min __ 2% min. or more. -2^ min. or more. _ 2ji min. or more., 2% min. or more.. 4,700 5,400 6,575 6,695 4,025 4,630 5,635 5,735 3,355 3,860 4,700 4,780 2,900 3,330 4,055 4,135 2Ji min. or more.. 2Ji min. or more. _ 2 Ji min. or more. _ 2Ji min. or more.. 2Ji min 2,725 3,270 3,130 3,760 3,810 4,570 3,880 4,660 2,335 2,800 2,690 3,220 3,270 3,925 3,330 3,995 1,945 2,335 2,240 2,690 2,725 3,270 2,770 3,330 1,680 2,015 1,930 2,315 2,350 2,820 2,395 2,875 2 * 3 Ji or more. 2Ji min 2% 3Ji or more 2ji min 3 and thicker 3 Ji or more. 2Ji min 3Ji or more END DISTANCES AND SPACINGS FOR SPLIT-RINGS AND PERCENTAGES OF TABULATED LOADS TO USE End distance Spacing—center to center of connectors Splitring diam. (inches) Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Tension member (end toward which connector load acts) Compression member (unloaded end) Spacing parallel to grain Spacing perpendicular to grain Spacing parallel to grain Spacing perpendicular to grain Tension end distance (inches) Percentage of tabulated loads Compression end distance (inches) Percentage of tabulated loads End distance (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads For spacing in inches of— Use 100 percent of load given for loaded-edge-distance of— 2 Ji 2Ji min 5 Ji or more. 62.5 100 2Ji min..... 4 or more 62.5 100 2Ji min 5 Ji or more.. 62.5 100 3 Ji min 6Ji or more.. 75 100 3J^ min. or more. 100 3^ min. or more. See par. 500-L-4. 3Ji min 4J< or more. IJi min. 2Ji or more. 4 3Ji min 7 or more 62.5 100 3 Ji min 5Ji or more. 62.5 100 3Ji min 7 or more 62.5 100 4Ji min 9 or more.... 75 100 5 min. or more. 100 5 min. or more. See par. 500-L-4. 5 min 2Ji min. 3% or more. 6 or more DIMENSIONS IN INCHES '2H" 4" 2 Ji" 4" Split ring: Inside diameter at center when closed 2 Ji 4 Washers, standard: Round, cast iron or malleable iron, diameter 2 Ji 3 Thickness of metal at center __ _* _ .163 .193 Round^ wrought iron (minimum): Diameter Depth of metal (width of ring) .750 1.000 IJi 2 Groove: Inside diameter. Thickness . 2.56 4.08 Square plate: Width .18 .21 Length of side.... 2 3 Depth .375 .50 Thickness - • Jé Jía Bolt hole: Jie ijie Projected area: Portion of one ring within member, sq. in ... 1.10 2.25 -32- Table No. 9.—Allowable loads for one TOOTHED-RING and bolt in single shear Number of faces of a piece Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Tooth- Bolt diam. Thickness (net) of lumber Allowable load per connector unit and bolt for— Edge distance Allowable load per connector unit and bolt for— ed ring diam. taining connectors on same bolt Edge distance Group A woods Group B woods Group C woods Group D woods Unloaded - edge distance (edge opposite loaded . edge) Loaded-edge distance (edge toward which connector load acts) Group woods Group B woods Group C woods Group x D woods Inches 2 Inches X 1 Inches 1 min ._ . IX and thicker Inches IX min. or more.. IX min. or more.. Pounds 1,320 1,450 Pounds 1,200 1,320 Pounds 1,080 1,190 Pounds 940 1,030 Inches 1)4 min. or morels min. or more.. Inches IX min 2 or more 1)4 min 2 or more Pounds 880 1,000 965 . 1,105 Pounds 800 910 880 1,000 Pounds 720 820 790 900 Pounds 625 710 685 780' ♦ 2 IX min 1)4 min. or more.. 1,320 1,450 1,200 1,320 1,080 940 1)4 min. or more.. 1)4 min. or more.. 1)4 min 880 800 720 625 2 and thicker IX min. or more.. 1,190 1,030 2 or more IX min.. 2 or more 1,000 965 1,105 910 880 1,000 820 790 ■ 900 710 685 780 2% % 1 1 min 1)4 min. or morels min. or more.. 1,980 1,800 1,620 1,405 1,750 1)4 min. or more.. 1)4 min 1,320 1,200 1,370 1,500 1,705 1,080 1,230 1,350 1,540 940 IX and thicker 2,470 2,250 2,030 1)4 min. or more.. 2)4 or more.... IX min 2)4 or more 1,500 1,650 1,880 1,060 1,170 1,330 2 IX min 2 2X and thicker 1)4 min. or more.. IX min. or more.. IX min. or more.. 1,980 2,190 2,470 1,800 1,990 2,250 1,620 1,795 2,030 1,405 1,555 1,750 1)4 min. or more.. 1)4 min. or more.. 1)4 min. or more.. IX min 2)4 or more 1)4 min 2)4 or more 1)4 min 2)4 or more 1,320 1,500 1,465 1,660 1,650 1,880 1,200 1,370 1,325 1,510 1,500 1,705 1,080 1,230 1,195 1,360 1,350 1,535 940 1,060 1,040 1,180 1,170 1,330 Ws % 1 1 min IX and thicker—-— 2)4 min. or more.. 2)4 min. or more.. •2,575 3,475 2,340 .3,155 2,105 2,845 1,825 2,465 2)4 min. or more.. 2)4 min. or more.. 2)4 min 3)4 or more 2)4 min 3)4 or more 1, 715 2,040 2,315 2,755 -1, 560 1,855 2,105 2,500 1,405 1,670 1,895 2,250 1,220 1,445 1,645 1,950 ’ 2 IX min 2)4 min. or more.. 2,575 2,340 2,560 2,935 3,155 2,105 2,305 2,640 2,845 1,825 2,000 2,290 2,465 2)4 min. or more.. 2)4 min 1, 715 1,560 1,855 1,710 2,030 • 1,955 2,320 2,105 2,500 1,405 1,670 1, 535 1,825 1,760 2,090' 1,895 2,250 1,220 2 . 2X 3 and thicker 2)4 min. or more.. 2)4 min. or more.. 2)4 min. or more.. 2,820 3,230 3,475 2)4 min. or more.. 2)4 min. or more.. 2)4 min. or more.. 3)4 or more 2)4 min....... 3)4 or more 2)4 min 3)4 or more.... 2)4 min... 3)4 or more 2,040 1,880 2,230 2,155 2,555 2,315 2,755 1,445 1,330 1,585 1,525 1,810 1,645 1,950 4 % 1 1 min IX and thicker 2)4 min. or more.. 2)4 min. or more.. 3,100 4,030 2,820 3,665 2,540 3,300 2,200 2,860 2)4 min. or more.. 2)4 min. or more.. 2)4 min 3)4 or more.... 2)4 min 3)4 or more 2,070 2,485 2,690 3,230 1,880 2,255 2,440 2,935 1,690 2,030 2,200 2,640 1,465 1,760 1,910 2,285 2 IX min 2)4 min. or more__ 2)4 min. or more.. 2)4 min. or more.. 2)4 min. or more.. 3,100 3,355 3,780 4,030 2; 820 3,050 3,440 3,665 2,540 2,750 3,090 3,300 2,200 2,380 2,680 2,860 2)4 min. or more.. 2)4 min. or more.. 2)4 min. or more.. 2)4 min. or more.. 2)4 min 3)4 or more.... 2)4 min 3)4 or more 2)4 min 3)4 or more.... 2)4 min 3X or more 2,070 2,485 2,240 2,680 2,520 3,025 2,690 3,230 1,880 2,255 2,035 2,440 2,290 2,750 2,440 2,935 1,690 2,030 1,830 2,195 2,065 2,470 2,200 2,640 1,465 1,760 1,585 1,900 1,790 2,140 1,910 2,285 2 2X 3 and thicker L... END DISTANCES AND SPACINGS FOR TOOTHED-RINGS AND PERCENTAGES OF TABULATED LOADS TO USE Toothed ring diam. (inches) End distance Spacing—center to center of connectors Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Tension member (end toward which connector load acts) Compression mem-' ber (unloaded end) Spacing parallel to grain Spacing perpendicular to grain Spacing parallel to grain Spacing perpendicular to grain Tension end distance (inches) Percentage of tabulated loads Compression end distance (inches) Percentage of tabulated loads End distance (inches) Percentage of tabu-, la ted* loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads For spacing in inches of— Use 100 percent of load given for loaded-edge distance of— 2 2 min 3X or more.. 66.7 100 2 min. or more. 100 2 min 3X or more.. 66.7 100 2 min . 4 or more.— 75 100 2J^ min. or more. 100 2M min. or more See par. 500-L-4. 2X min 3 or more IX min. 2 or more. IX min. 2X or more. 2)6 2)6 min 4Xormore._ 66.7 100 2)6 min. or more. 100 2X min..... 4Xor more.. 66.7 1O0 2% min 5Xormore„ 75 100 3H min. or more. 100 3% min. or more. See par. 500-L-4. 3 min 3X or more.. 3X 3X min 5)6ormore— 66.7 100 3X min. or more. 100 3X min 5)6 or more.. 66.7 100 3X min 6X or more.. 75 100 3% min or. more. 100 3% min. or more. See par. 500-L-4. 4 min 5 or more.— 2X min. 3X or more. 4 4 min 7 or more... 66.7 100 4 min. or inore. 100 4 min......_ 7 or more 66.7 100 4 min 8 or more 75 100 4H min. or more. 100 4J^ min. or more. See par. 500-L-4. 4X min..... 5X or more.. •2X min. 3X or more. 1 ♦ ±_ — 4 XTX ’1® 1. d @ © S—t A® CP k J ♦ ♦ DIMENSIONS IN INCHES Toothed ring: Diameter Thickness of metal Depth Depth of filet (minimum) 2' 2)6" 3)6' 4" Washers, minimum: Round, cast or malleable iron (diameter) Square plate: Length of side Thickness.... ..... 2' 2)6' 3)6" 4" 2 .061 .94 .25 2)6 .061 .94 .25 3)6 .061 .94 .25« 4 .061 .94 .25 2 2 X« 2)6 2X X 3 3 X 3J6 3X % Bolt hole: Diameter (maximum) ± % rX6 Projected area: Portion of one ring within member (sq. in.) .94 1.23 1.59 1.89 -33- Table No. 10.—Allowable loads for one CLAW-PLATE unit and bolt in single shear [Loads tabulated below are for wood side plates *] 1 Tabulated values also apply for metal side plates, except that for 3)4-inch claw-plates the tabulated parallel to grain (not perpendicular) values for Groups A, B, and C, shall be increased 11,11, and 5 percent, respectively, and for 4-inch claw-plates, 18,11, and 5 percent, respectively. Num- Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Claw-plate diam. Bolt ber of faces of a piece con- Thickness (net) of Allowable load per connector unit and bolt for— Edge distance Allowable load per connector unit and bolt for— diam. taining connecters on same bolt lumber Edge distance Group woods Group B woods Group C woods Group D Woods Unloaded - edge -distance (edge opposite loaded edge) Loaded-edgedistance (edge toward which connector load acts Group A woods Group B woods Group O woods Group D woods Inches 294 Inches 94 1 Inches 194 min. and thicker.. Inches 194 min. or more.. Pounds 3,690 Pounds 3,650 Pounds 3,450 Pounds 3,150 Inches 194 min. or more.. Inches 194 min.., 294 or more. Pounds 2.740 3,260 Pounds 2,370 2,815 Pounds 2,005 2,375 Pounds 1,715 2,035 2 2 min 294 and thicker....... 194 min. or more 194 min. or more.. 2,460 3,690 2,430 3,650 2,300 3,450 2,100 3,150 194 min. or more.. 194 min. or more.. 194 min .... 294 or more 194 min 294 or more 1,830 2,170 2,740 3,260 1,580 1,880 2,370 2,815 1,330 1,585 2,005 2,375 1,140 1,355 1.715 $035 3)4 94 1 194 min. and thicker.. 294 min. or more.. 4,795 4.610 4,380 4,070 2)4 min. or more.. 2)4 min 3)4 or more.— 3,450 4,100 2,980 3,540 2,515 2,990 2,170 2,580 2 2 min.. 294 3 and thicker......... 294 min. or more.. 2)4 min. or more.. 294 min. or more.. 3,200 4,195 4,795 3,070 4,030 4,610 2,920 3,835 4,380 2,710 3,560 4,070 2)4 min. or more.. 2)4-min. or more.. 2)4 min. or more.. 2)4 min 3)4 or more.... 2)4 min 3)4 or more.... 2)4 min 3)4 or more 2,300 2,730 3,020 3,590 3,450 4,100 1,985 2,365 2,610 3,095 2,980 3,540 1,675 1,990 2,200 2,610 2,515 2,990 1,445 1,715 1.900 2,255 2,170 2,580 4 94 1 194 min 2 and thicker. ..... 294 min. or more.. 254 min. or more.. 5,995 6,745 5,780 6,500 5,280 5,940 4,840 5,450 294 min. or more.. 294 min.,or more.. 294 min 394 or more.... 294 min 394 or more 3,780 4,535 4.250 5,100 3,275 3,930 3,685 4,420 2,760 3,310 3,110 3,730 2,370 2,845 2,670 3,205 2 2 min 294 3 394 and thicker 294 min. or more. _ 294 min. or more.. 294 min. or more.. 294 min. or more.. 4,495 5,430 5,995 6,745 4,330 5,240 5,780 6,500 3,960 4,790 5,280 5,940 3,630 4,385 4,840 5,450 294 min. or more.. 294 min. or more.. 294 min. or more.. 294 min. or more.. 294 min 394 or more.... 294 min 394 or more. 294 min 394 or more.... 294 min 394 or more 2,830 3,400 3,425 4,110 3,780 4,535 4,250 5,100 2,455 2,945 2,970 3,565 3,275 3,930 3,685 4,420 2,070 2,485 2,500 3,005 2,760 3,310 3,110 3,730 1,780 2,135 2,150 2,580 2,370 2,845 2,670 3.205 END DISTANCES AND SPACINGS FOR CLAW-PLATES AND PERCENTAGES OF TABULATED LOADS TO USE Clawplate diam. (inches) End distance Spacing—center to center of connectors Loaded parallel to grain (0°) . Loaded perpendicular to grain (90°) Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Tension member (end toward which connector load acts Compression member (unloaded end) Spacing parallel to grain Spacing perpendicular to grain Spacing parallel to grain Spacing perpendicular to grain Tension end distance (inches) Percentage of tabulated loads Compression end distance (inches) Percentage of tabulated loads End distance (inches) Per? centage of tabulated loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads For spacing in inches of— Use 100 percent of load given for loaded-edgedistance of 2% 294 min 594 or more. 62.5 100 294 min..... 4)4 or more.. 62.5 100 294 min..... 594 or more.. 62.5 100 3 min 7 or more 75 100 3H min. or more. 100 min. or more. See par. 500-L-4. 3)4 min..... 4 or more 194 min. 294 or more. 3% 3 min 6)4 or more. 62.5 100 3 min 494 or more.. 62.5 100 3 min....... 6)4 or more.. 62.5 100 3)4 min 794 or more.. 75 100 3% min. or more. ■ 100 3% min. or more. See par. 500-L-4. 3)4 min 4)4 or more.. 2)4 min. 3)4 or more. 4 3)4 min 7 or more 62.5 100 3)4 min 5)4 or more.. A 62.5 too 3)4 min 7 or more 62.5 100 4)4 min..... 9 or more 4 75 100 4^ min. or more. 100 4^ min. or more. See par. 500-L-4. 494 min 594 or more.. 294 394 min. or more. _L 4 '4 -© © © f^© ©‘if 4-^ tjXJ ♦ 4 DIMENSIONS IN INCHES Claw plates: Type: 2%' Male 255' Female 355' Male 315' Female 4' Male 4' Female Bolt hole: 255' Male 255' Female 355' Male 355' Female 4' Male 4' Female Diameter 2)5 255 355 355 4 4 Diameter in straps or plates 2952 2 952 2952 2%2 154 ijepiu 01 piaie ana teem .75 .75 .75 .75 .75 .75 Diameter in timber:—when male plates or Depth of outside hub Diameter of outside hub Diameter of central hole .37 .87 .37 .87 — .37 1.22 a combination of male and female are used. —when female plates are used without male 94b — 94« —.... *54b — . 53 .90 .53 .90 .78 *1.25 plates 254e *54b - 1*546 Circular Dap Bolt diameter:—when male plates are used singly, or male and female "used in combi- . U - A A 2.64 2.64 3.16 3.16 4.07 4.07 nation —when female plates are used without male 55 95 55 ...... 94 — -±-> ♦ ♦ r b 1.12 1.12 1.14 1.14 1.55 1. 55 plates % 154 ; c... 94 6 *54« 94« % *94« 154 Washers (minimum): D-- .52 .52 .76 .76 1.01 1.01 Tim,ber-to-timber connections: —3 *• / 1—D—4e 1- E_... .25 .25 .25 .25 .25 .25 Round, cast or malleable iron diameter 255 555 255 355 3 494 F .38 .38 .38 .38 .38 .38 Square plates: G.... .22 .22 .22 .22 .28 .28 Length of side ..... 2 3 2 3 3 4 bolt holox^ r H .42 .42 .42 .42 .45 .45 Thickness Timber-to-steel conneciions, round, wrought iron: 54« 54 54b 54 55 54 Steel straps or shapes for use with claw plates: Diameter ... 2 2 2 2 4 4 Standard thickness. % 55 % 55 55 55 Thickness . 552 552 552 552 »554 *554 •Minimum thickness (washers must be used Projected area: to take up difference in hub depth of male Portion of one claw plate within member ciaw piate;__ 54 54. 54 54 54 54 (square inches) 1.97 1.97 2.34 2.34 3 3 ♦When used without male plate, and with IX" bolt, ream hole to IMo inches. -34- Table No. 11.—Allowable loads for one SHEAR-PLATE unit and bolt in single shear [Loads tabulated below are for wood side plates. Also see notes below] Shearplate diam. Bolt diam. Number of faces of a piece containing connectors on same bolt Thickness (net) of lumber Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Edge distance Allowable load per connector unit and bolt for— Edge distance Allowable load per connector unit and bolt for— Group A woods Group B woods Group C woods Group D woods Unloaded - edge -. distance (edge opposite loaded edge) Loaded-edgedistance (edge toward which connector load acts Group A woods Group B woods Group O woods Group D woods Inches 2Ji Inches Ji 1 Inches IJi min. and thicker... Inches IJi min. or more Pounds 3,175 Pounds 3,155 Pounds 2,629 Pounds 2,267 Inches IJi min. or more... Inches IJimin......... 2Ji or more Pounds 2,135 2,576 Pounds 1,830 2,208 Pounds 1,525 1,840 Pounds 1,315 1,586 2 IJi min... 2 2% and thicker IJi min. or more.. IJi min. ormore... 1 % min. or more... 2,863 3,175 3,175 2,454 2,980 3,155 2,045 2,483 2,629 1,764 2,142 2,267 IJimin. ormore... 1 Ji min. or more... IJimin. ormbre... 1 Ji min 2Ji or more IJi min... 2Jiormore IJi min_. 2Ji or more.... 1,661 2,003 2,016 2,434 2,135 2,576 1,423 1,717 1,728 2,086 1,830 2,208 1,186 1,430 1,440 1,738 1,525 1,840 1,022 1,234 1,242 1,499 1,315 1,586 4 Jé 1 IJi min and thicker.. 2% min. or more... 2Ji min. or more... 5,184 5,300 4,443 4,761 3,703 3,967 3,193 3,421 2Ji min. or more 2Ji min. or more... 2Ji min 3Ji or more 2 Ji min 3 Ji or more 3,006 3,629 3,221 3,888 2,577 3,111 2,761 3,333 2,147 2,592 2,301 2,777 1,852 2,235 1,984 2,395 2 IJi min........ ....... 2 2Ji—- - —- 3 —- 3% and thicker 2% min. or more... 2% min.ormore. 2% min. or more 2 Ji min. ormore 2 Ji min. or more... 3,703 4,130 4,842 5,269 5,300 3,174 3,540 4,150 4,516 4,761 2,645 2,950 3,459 3,764 3,967 2,281 2,544 2,983 3,246 3,421 2 Ji min. or more... 2Ji min. or more... 2 Ji min. or more... 2Ji min. or more... 2Ji min. or more... 2Ji min 3Ji or more 2Ji min. :.. 3 Ji or moré 2Ji min.^ 3 Ji or more 2 Ji min 3Ji or more 2 Ji min 3 Ji or more 2,147 2,592 2,395 2,891 2,808 3,390 3,056 3,689 3,221 3,888 1,840 2, 222 2,053 2,478 2,407 2,906 2,619 3,.162 2,761 3,333 1, 534 1,851 1,711 2,065 2,006 2,421 2,183 2,635 2,301 2,777 1,323 1,597 1,475 1,781 1,730 2,088 1,882 2,272 1,984 2,395 4 y». 1 IJi min IJi and thicker 2 Ji min. or more 2 Ji min. or more... 5,T84 5,554 4,443 4,761 3,703 3,967 3,193 3,421 2 Ji min. or more 2Ji min. or more... 2Ji min 3Ji or more 2 Ji min 3Ji or more 3,006 3,629 3,221 3,888 2,577 3,111 2,761 3,333 2,147 2,592 2,301 2,777 1,852 2, 235 1,984 2,395 2 1 Ji min . 2.... 2Ji 3 - 3 Ji and thicker....... 2% min. or more 2 Jí min. or more... 2Jimin.ormore___ 2Jimin. ormore... 2% min. or more 3,703 4,130 4,842 §,269 5,554 3,174 3,540 4,150 4,516 4,761 2,645 2,950 3,459 3,764 3,967 2,281 2,544 2,983 3,246 3,421 2 Ji min. or more... 2Ji min. or more... 2Ji min. or more... 2Ji min. or more... 2Ji min. or more... 2 Ji min 3 Ji or more 2Ji min... 3Ji or more.... 2Ji min 3 Ji or more 2Ji min... 3Ji or more 2Ji min 3Ji or more 2,147 2,592 2,395 2,891 2,808 3,390 3,056 3,689 3,221 3,888 1,840 2,222 2,053 2,478 2,407 2,906 2,619 3,162 2,761 3, 333 1, 534 1,851 1, 711 2,065 2,006 2,421 2,183 2,635 2,301 2,777 1,326 1,597 1,475 1,781 1,730 2,088 1,882 2,272 1,984 2,395 Notes 1. Tabulated loads shall apply for metal side plates except that for 4-inch shear plates, tabulated parallel-to-grain values (not perpendicular) for wood side plates for Groups A, B, and C woods shall be increased 18,11, and 5 percent, respectively, but shall not exceed limitations in notes 2 and 3. 2. For the 2%-inch shear plate with Ji-inch bolt, the allowable loads for loading other than wind shall not exceed 3,175 pounds for parallel-to-grain loading or 2,800 pounds for perpendicular-to-grain loading. The allowable wind loads shall not exceed 3,475 pounds for parallel-to-grain loading and 2,900 pounds for perpendicular-to-grain loading. END DISTANCE AND SPACINGS FOR SHEAR-PLATES 3. For 4-inch shear plate with bolt, the allowable loads for loading other than wind shall not exceed 5,300 pounds for parallel-to-grain or perpendicular-to-grain loading when used with a Ji-inch bolt, and 7,200 pounds for parallel-to-grain loading or 6,500 pounds for perpendicular-to-grain loading when a Ji-inch bolt is used. The allowable wind loads shall hot exceed 6,650 pounds for parallel-to-grain loading and 5,775 pounds for perpendicular-to-grain loading when used with a Ji-inch bolt or 7,775 pounds for parallel-to-grain loading and 6,700 pounds for perpendicular-to-grain loading when used with a Ji-inch bolt. AND PERCENTAGES OF TABULATED LOADS TO USE Shearplate diam. (inches) End distance Spacing—center to center of connectors Loaded parallel to grain (0°) Loaded perpendicular to grain (90°) Loaded parallel to grain (0°) • Loaded perpendicular to grain (90°) Tension member (end toward which connector load acts) Compression member (unloaded end) Spacing parallel to grain Spacing perpendicular to grain Spacing parallel to grain Spacing perpendicular to grain Tension end distance (inches) Percentage of tabulated loads Compression end distance (inches) - Percentage of tabulated loads End distance (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads Spacing (inches) Percentage of tabulated loads For spacing in inches of— Use 100 percent of load given for loaded-edge distance of— 2)4 2)4 min 5)4 or more— 62.5 100 2)4 min 4 or more. 62.5 100 2)4 min 5)4 or more.. 62.5 100 3)4 min 6)4 or more.. 75 100 3H min. or more. 100 3H min. or more. See par. 500-L-4. 3)4 min 4)4 or more.. 1)4 min. 2)4 or more. 2)4 min. 3)4 or more. 4 3)4 min 7 or more 62.5 100 3)4 min 5)4 or more.. 62.5 100 3)4 min 7 or more 62.5 100 4)4 min 9 or more 75 100 5 min. or more. 100 5 min. or more. See par. 500-L-4. 5 uin 6 oi more.... ■4 1 _L_ 1 1® JL o DIMENSIONS IN INCHES Shear-plates: Material Diameter of plate Diameter of bolt hole Thickness of plate Depth of flange 2)4" 4" 4" Steel strap or shapes for use with shear-plates (minimum thickness): Plates on one face of straps or shapes Plates opposite on both faces of straps or shapes Hole diameter in straps or shapes for bolts 2)4" 4" 4" Pressed steel. 2.62 .81 .172 .42 Malleable iron. 4.02 .81 .20 .62 Malleable iron. 4.02 .94 .20 .62 Vi 54 ^B % Circ ular Dap—Dimensions: -A — ■ - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Illi I Illi 111111*11 1 1 I I 1 1 1 1 1 1 1 Ij 1' 1' 1 1 1 1 ll'tlllllt 1 1 1 III 1 1 1 1 1 I • I I 1 • I 2.63 ^6 .19 .45 .25 2.25 4.03 1.55 0.97 .27 .64 .25 .50 3.49 4.03 1.55 .97 .27 .64 .22 .50 3.49 Bolt hole—Diameter in timber Washers, standard: Round, cast or malleable, iron, diameter Round, wrought iron, minimum: Diameter Thickness Square plate: Length of side ... - Thickness _ _ ' ----- A Projected area: Portion of one shear plate within member, square inches © £ CO xw OO i^CO M to CO O» 1)Í6 3 2 %2 3 2.48 3)4 2)4 1)41 3 M 2.48 • A ♦ ♦ ♦ / e X E >0 — D —it • / It hole/* u 1 -c 1^0 J g -35- 600 NATIONAL EMERGENCY SPECIFICATIONS PART VI. BOLTED JOINTS The provisions of Part VI and the tabulated allowable loads for bolted joints herein shall apply in stress grade lumber. 600 Basic Design Considerations and Limitations A. TYPE OF LOAD 1. Tabulated allowable bolt loads are the maximum for permanent loading, i. e., long time loading whether dead or live. Pertinent modifications of stresses and provisions of paragraphs 200, 201, 202 and 203 for lumber shall apply likewise to the tabulated bolt loads given in Part VI. B. NUMBER OF BOLTS 1. Tabulated loads are for one common bolt in double shear in a 3-member joint. 2. Loads for more than one bolt, each of the same or miscellaneous sizes, are the sum of the loads permitted for each bolt. Spacings, end distances and edge distances shall be sufficient to develop the full strength of each bolt. C. QUALITY OF BOLTS 1. Tabulated loads are for common bolts with a yield point of approximately 45,000 pounds per square inch. 2. Where high strength bolts are used, higher allowable loads are permissible in some cases as noted in reference No. 9, Appendix E. For high-strength bolts, allowable bolt loads given herein shall be modified proportionately, using basic provisions of the reference for guidance. D. SPECIES OF LUMBER 1. Tabulated loads apply to species as given in Table No. 12. 2. For proportionate loads for other species, see reference No. 9, Appendix E. E. GRADE OF LUMBER 1. Tabulated loads apply to species irrespective of grade of lumber used. F. CONDITION OF LUMBER 1. Tabulated loads are for lumber seasoned to a moisture content approximately equal that to which it will eventually come in service. 2. For green lumber which may season after installation, allowable bolt loads shall be one-third of the tabulated loads. -36 G. BOLT HOLES 1. Bolt holes of a diameter permitting bolts to be driven easily and careful centering of holes in main members and splice plates are assumed. 2. Tight fit requiring forcible driving of bolts is not recommended. H. NUTS 1. Loosening of nuts, resulting from any shrinkage, is assumed and allowed for in the tabulated bolt loads. 2. Tabulated bolt loads shall apply for .tight nuts also. I. SIDE MEMBERS—MATERIALS 1. Tabulated bolt loads are for side members of wood. Bearing thrust on side plates is assumed to be parallel to fibers. 2. When wood splice plates are used, the allowable load perpendicular-to-grain shall not exceed the load parallel-to-grain for any given size» and quality of timbers. 3. When steel plates are used for side members, the tabulated loads for parallel-to-grain loading shall be increased by 25 percent but no increase shall be made for perpendicular-to-grain loads. Steel plates shall be of ample strength. J. SIDE MEMBERS—DIMENSIONS 1. Tabulated loads apply when side members of wood are each one-half the thickness of main member. (Fig. 13.) 2. If side members are thicker than one-half the thickness of the main member, no increase in tabulated loads is permissible. (Fig. 14.) FOR STRESS GRADE LUMBER 600 3. When the side members are less than one-half the thickness of the main member, the tabulated loads indicated for a main member which is twice the thickness of thinnest side members used shall apply. For example, with 2-inch side members and a 10-inch center member, the tabulated loads for a 4-inch center member shall be used. (Fig. 15.) K. NUMBER OF MEMBERS IN JOINT 1. Tabulated loads are for a joint consisting of three members (double shear). Length of bolt (Z) is measured in the main member (i. e., thickness of the piece). (Fig. 16.) 2. When a joint consists of two members (single shear) of equal thickness, one-half the tabulated load for a piece twice the thickness of one of the members shall apply (Fig. 17.) Figure 17. 3. When members of a two-member joint are of unequal thickness, one-half the tabulated load for a piece twice the thickness of the thinner member shall apply. (Fig. 18.) Figure 18. load for a piece the thickness of one of the members shall apply. (Fig. 19.) Figure 19. L. EXPOSURE TO WEATHER 1. Tabulated loads shall apply for joints used indoors or in a location “always dry.” 2. When joints are to be exposed to weather, 75 percent, and where always wet, 67 percent of the tabulated loads shall apply. M. LOAD AT AN ANGLE WITH AXIS OF BOLT (Fig. 20.) 1. Tabulated loads are for loading acting per-pendicular-to-axis of bolt. 2. If the load in a two-member joint acts at an angle with the axis of a bolt, the allowable load component acting at 90° with the bolt axis shall be equal to one-half the tabulated load for a bolt twice the length of the bolt length in the thinner piece. Ample bearing area under washers or plates shall be provided to resist the load component acting parallel to the' axis of the bolt. N. LOADS NEITHER PARALLEL NOR 4. For multiple-member joints other than two or three members, of which the pieces are of equal thickness, the allowable load shall vary as the number of shear planes involved; the allowable load for each shear plane shall be equal to one-half the tabulated load for a piece the thickness of the member involved. Thus, when a joint consists of four members of equal thickness, one and one-half times the tabulated PERPENDICULAR TO GRAIN. (Fig. 21.) -37- 600-601 NATIONAL EMERGENCY SPECIFICATIONS 1. Allowable bolt loads acting in a direction inclined to grain shall be determined from the Hankinson formula which for total bolt loads, may be stated as follows: AT PQ ---——--------—-------- P sm2 cos2 0 in which N= allowable load per bolt in a direction at inclination 0 with the direction of the grain, P— allowable load per bolt in compression parallel to grain, Q= allowable load per bolt in compression perpendicular to grain, 0=angle between the direction of the load and the direction of the-grain. For tabulated values of sin2 0 and cos2 6, and graphical solution of Hankinson formula, see Appendix C. 601 Placement of Bolts in Joint. (Fig. 22.) A. l/d OF BOLT 1. l/d of bolt is the ratio of its length, I, in main member, to its diameter, d. B. CRITICAL SECTION 1. The critical section is that section of the member, taken at right angles to the direction of the load, which gives the maximum stress in the member based on the net area remaining after reducing it for bolt holes at that section. C. ROW OF BOLTS 1. “Row of Bolts” means a number of bolts placed in a line parallel to the direction of the load when parallel or perpendicular to grain. D. SPACING 1. All spacings and distances given are measured from center of bolt. E. SPACING OF BOLTS IN A ROW 1. For parallel-to-grain loading, the minimum spacing is 4 times bolt diameter d. 2. For perpendicular-to-grain loading: (a) If design load approaches bolt bearing capacity of side members, space same as parallel-to-grain. (b) If design load is less than bolt bearing capacity of side members, spacing may be reduced. F. SPACING BETWEEN ROWS OF BOLTS 1. For parallel-to-grain loading, net tension area remaining at critical section must equal at least 80 percent of total area in bearing under all bolts in the particular timber in question for softwoods, and 100 percent for hardwoods. 2. For perpendicular-to-grain loading, the spacing shall be at least 2% times bolt diameter for Ijd ratio of 2, and 5 times bolt diameter for ratios of 6 or more. For ratios between 2 and 5, the spacing shall be obtained by straight line interpolation. G. END DISTANCE 1. “End Distance” is the distance from the end of a bolted timber to the center of the bolt hole nearest the end. 2. For parallel-to-grain loading, the end distance shall be: (a) In tension, 7 times the bolt diameter for softwoods and 5 times for hardwoods. (b) In compression, 4 times the bolt diameter. 3. For perpendicular to grain loading, when members abut at a joint, the strength of the joint shall be-evaluated not only for the bolt load but also as a notched beam, considering the notch to extend from the lower side of the beam to the center of the bolt nearest the bottom. (For notched beams, see paragraph 400-D.) Loads parallel to Grain Loads perpendicular to Grain Figure 22. -38- FOR STRESS GRADE LUMBER 601 Table No. 12.—Allowable load in pounds on one bolt loaded at both ends (double shear) * for following species Cedar, northern Cypress, tidewater red; Cedar, western red; cedar, Alaska, Port Orford; Douglas fir, (Rocky Mountain); hemlock, west coast; pine, Norway and southern white; fir, bal- Ash, commercial white; beech; Ash, black, brown; aspen Douglas fir, sam, commercial birch; sweet and Maple, soft; elm, soft; gum, black, red, tupelo; and large toothed (coast and in- white; hemlock. yellow; elm, rock; aspen; basswood; 3^^ land); larch, western; pine, southern longleaf eastern; pine, northern white. hickory, tnie and pecan; maple, birch, paper; chestnut; cotton- Idaho white, hard; oak, coin- sycamore wood, eastern and shortleaf; ponderosa, sugar; mercial red and and western; redwood; tamarack spruce, red, Sitka,’ white yellow poplar white, Engelmann Length of bolt in main member Diameter of bolt Projected area of bolt Parallel to grain Perpendicular to grain Parallel to grain Perpendicular to grain Parallel to grain Perpendicular to grain Parallel to grain Perpendicular to grain Parallel to grain Perpendicular to grain Parallel to grain Perpendicular to grain 1 d l/d A=lXd P Q P Q P Q P Q P Q P Q Inches Inches Sg. in. 940 410 720 290 % 3.3 6.8125 1,000 460 780 320 620 240 1,140 660 % 2.6 1.0156 1,260 500 970 370 780 280 1,460 740 1,180 470 900 320 1^_ . %, 2.2 1.2188 1,520 560 1,180 410 940 310 1,750 830 1,400 1,630 520 1,080 360 Vs 1.9 1. 4219 1,780 620 1,370 460 1,090 340 2,050 910 560 1,260 400 1 1.6 1.625 2,030 680 1,560 490 1,250 370 2,340 1,000 1,870 620 1,440 430 - Vs 4.0 1.00 1,150 550 940 410 770 300 1,330 800 1,130 500 890 350 Vs 3.2 1.25 1,540 620 1,200 460 960 340 1,780 910 1,440 580 1,100 1,330 400 2 'A 2.7 1.50 1,860 700 1,440 490 1,150 380 2,150 1,020 1,730 640 440 Vs 2.3 1.75 2,180 770 1,680 560 1,340 420 2,520 1,120 2,020 700 1,560 490 1 2.0 2.00 2,500 840 1,920 610 1,540 460 2,880 1,220 2,300 770 1,780 530 5.3 1.3125 1,250 720 1,070 530 940 400 1,440 1,060 1,270 660 1,080 470 4.2 1.6406 1,850 830 1,510 600 1,250 440 2,140 1,200 1,820 740 1,440 530 2H - y. 3.5 1.9688 2,380 910 1,870 670 1,510 500 2,740 1,330 1,460 2,260 830 1,750' 590 Vs 3.0 2.2969 2,830 1,010 2,210 730 1,760 550 3,280 2,640 910 2,040 650 i 2.6 2.625 3; 260 1,100 2,520 800 2,020 600 3,770 1,600 3,020 1,000 2,330- 700 6.0 1.50 1,260 830 1,090 600 980 460 1,450 1,160 1,310 760 1,140 530 Vs 4.8 1.875 1,940 940 1,630 680 1,390 520 2,230 1,370 1,520 1,960 850 1,610 600 3 Ji 4.0 2.25 2,590 3,190 1,070 1,150 2,100 2,510 770 1,720 580 3,000 2,520 950 1,990 670 % 3.4 2.625 840 2,020 620 3,670 1,680 3,010 1,040 2,330 730 1 3.0 3.00 3,710 1,260 2,880 910 2,300 680 4,270 1,820 3,460 1,140 2,660 800 7.3 1.8125 1,260 960 1,090 720 980 550 1,450 1,220 1,610 1,310 860 1,140 640 Vs 5.8 2.2656 1,970 1,140 1,700 830 1,540 620 2,270 2,040 1,030 l,'78O 720 3% 'A 4.8 2.7188 2; 810 3,620 1,260 1,390 2; 360 940 2,020 700 3,240 1,840 2,830 1,150 2,330 800 Vs 4.1 3.1719 2,950 1,010 2,420 760 4,180 2,030 3,540 4,140 1,270 2,800 890 1 3.6 3.625 4,340 1,520 3,440 1,100 2,780 830 5,020 2,210 1,380 3,220 960 Ji 8.0 2.00 1,260 970 1,090 770 980 600 1,450 1,210 1,310 890 1,140 710 6/s 6.4 2.50 1, 970 1,250 L700 910 1,540 680 2,270 1,700 2,050 1,140 1,790 790 4 % 5.3 3.00 2,830 3,730 1,390 2,440 1,020 2,150 770 3,260 2,020 2,920 1,270 2,480 3,020 890 Vs 4.6 3.50 1,540 3,120 1,120 2,620 840 4,310 2,230 3,740 1,390 1,520 980 1 4.0 4.00 4; 620 1,680 3,740 1,220 3,060 910 5,330 2,440 4,490 3,530 1,070 Ji 9.0 2.25 1,260 960 1,090 780 980 650 1, 450 1,180 1,310 880 1,140 1,790 760 % 7.2 2.8125 1,970 1,360 1, 700 1,030 1,540 770 2,270 1,730 2,050 1,240 900 4^ y 6.0 3.375 2; 830 3,850 L570 1,730 2,460 3,290 1,140 2,220 850 3,260 2,210 2,940 1,430 1,570 2,570 1,000 1,100 Vs 5.1 3.9375 1,260 2,870 950 4,450 2,520 3,950 3,310 i 4.5 4.50 4,870 1,880 4; 060 1,370 3,380 1,030 5,630 2,750 4,860 1,720 3,910 1,200 4.0 5.0625 5,840 2,050 4; 730 1,490 3,860 1,120 6,740 2,990 5,680 1,870 4,480 1,310 Ji 10.0 2. 50 1,260 940 1,090 770 980 650 1, 450 1,120 1,310 850 1,140 760 Vs 8.0 3.125 1,970 1,380 1,700 1,090 1,540 850 2,270 1,700 2,050 2,940 1,260 1,790 1,000 5 % 6.7 3.75 2,830 3,850 1,730 1,920 2; 460 3,350 1,270 2,220 950 3,260 2,280 1,560 2,570 1,100 Vs 5.7 4.375 1,390 3,010 1,040 4,450 2,740 4,010 5,090 1,750 3,470 1,220 1 5.0 5.00 4,990 2,100 4,240 1,520 3,660 1,140 5,760 3,050 1,910 2,080 4,240 1,330 Ui 4.4 5.625 6,180 •2,280 5,110 1,660 4,250 1,250 7,130 3,320 6,130 4,920 1,450 Vs 8.8 3.4375 1,970 1,360 1,700 1,120 1,-540 900 2,270 1,670 2,050 1,240 1,790 1,060 % 7.3 6.3 4.125 4.8125 2,830 3,850 1,810 2,110 2,460 3,350 1,390 1,540 2,220 3,010 1,040 1, 150 3,260 4,450 2,340 2,890 2; 940 4,010 1,660 1,920 2,570 3,480 1,220 1,340 1 5.5 5.50 5i 020 2,300 4,340 1,680 3,860 1,260 5,780 3,320 5,210 2,100 4,460 1,460 1,600 Ui 4.9 6.1875 6,290 2,510 5,320 1,820 4,560 1, 370 7,250 3,650 6,370 2,280 5,280 Vs 9.6 3.75 1,970 1,330 1,700 1,100 1,540 910 2,270 1,620 2,050 1,210 1,680 1,790 1,070 %. 8.0 4.50 5.25 2,830 3,850 1,850 2,260 2,460 3,350 1,460 1,680 2,220 3,010 1,140 1,260 3,260 2,290 2,940 2,570 1,330 6 6.9 4,450 2,950 4,010 2,050 3,480 1,460 1 6.0 6.00 Si 030 2,520 4,370 1,820 3,950 1, 370 5,810 3,520 5,240 2,280 4,560 1,600 Ui 5.3 6.75 6,400 2,740 5,470 1,990 4,840 1,490 7,340 3,980 6,580 2,500 5,590 1,740 Vs 10.4 4.0625 1,970 1,300 1,700 1,070 1,540 900 2,270 1,540 2,050 1,180 1,790 1,040 Ji 8.7 7.4 4.875 5.6875 2^830 1,820 2,360 2,460 3,350 1,480 1,800 2,220 3,010 1,200 1,370 3,260 2,220 2,940 1,660 2,570 1,390 4,450 2,980 4,010 2,150 3,480 1,580 1 6.5 6.50 5j 030 2,700 4,370 1,980 3,950 1,490 5,810 3,650 5,240 2,460 4,560 1,730 US 5.8 7. 3125 6,400 2,960 5,500 2,160 4,940 1,620 7,340 4,210 6,600 2,700 5,710 1,880 Vs 11.2 4.375 1,970 1,270 1,700 1,060 1,540 890 2,270 1,510 2,200 2,050 1,150 1,790 1,030 'A 9.3 5.25 2,830 1,800 2,460 1,480 2,220 1,220 3,260 2,940 1,630 2,570 1,430 1,720 7 Vs 8.0 6.125 3; 850 5,030 2; 360 2,870 3,350 4,370 1,880 2,140 3,010 3,950 1,460 4,450 2,940 4,010 2,150 3,480 1 7.0 7.00 1,600 5,810 3,700 5,240 2,600 4,560 1,870 US 6.2 7.875 6,400 3,190 5,560 2,330 5,000 1,740 7,340 4,430 6,660 2,900 5,760 2,040 Ji 12.0 4.6875 1,970 1,220 1,700 1,040 1,540 880 2,270 1,460 2,050 1,120 1,790 780 % 10.0 5.625 2; 830 1, 760 2,460 1,440 2; 220 1,210 3,260 2,110 2,940 1,610 2,570 3,480 1,420 71^ Vs 8.6 6. 5625 3,850 5,030 2,340 2,920 3,350 4,370 1,910 3,010 1,540 1,720 4,450 2,900 4,010 2,120 1,790 1 7.5 7.50 2; 270 3,950 5,810 3,710 5,240 6,660 2,650 4,560 2,000 US 6.7 8.4375 6,400 3,-400 5,560 2,500 5,000 1,870 7,340 4,500 3,080 5,760 2,180 ji 12.8 5.00 1,970 1,180 1,700 1, 030 1, 540 860 2,270 1,390 2,050 1,070 1,790 1,010 s4 10.7 6.00 2,830 1,730 2,460 1,430 2,220 1,200 3,260 2,040 2,940 1,560 2,570 1,400 8 % 9.1 7.00 3,850 5,030 2,330 2,950 3,350 4,370 1,900 2,340 3,010 1,570 4,450 2,860 4,010 2,120 3,480 1,840 1 8.0 8.00 3,950 1,820 5, 810 3,650 5,240 2,690 4,560 2,140 us 7.1 9.00 6,400 3,530 5,560 . 2,650 5,000 1,990 7,340 4,540 6,660 3,220 5,760 2,330 Ui 6.4 10.00 7.860 3,920 6,840 2,860 6,170 2,140 9,070 5,330 8,200 3,580 7,130 2,500 % 12.7 7.125 2,830 1,570 2,460 1,370 2,220 1,150 3,260 1,880 2,940 1,430 2,570 1,340 Vs 10.9 9.5 8.3125 9.50 3; 850 5,030 2,200 2,860 3,550 4,370 1,810 2,350 3,010 1,520 4,450 2,590 4,010 1,990 3,480 1,790 9J^ 1 3,950 1,940 5,810 3,470 5,240 2,590 4,560 2,280 US 8.4 10.6875 6^ 400 3,640 5,560 2,930 5,000 2,330 7, 340 4,460 6,660 3,300 5,760 2,710 Ui 7.6 11.875 7,860 4,310 6,840 3,340 6,170 2,540 9,070 5,410 8,200 3,920 7,130 2,960 Vs 11.4 8.75 3,850 2,160 3,350 1,800 3,010 1,520 4,450 2,570 4,010 1, 970 3,480 1,780 2,270 1 10.0 10.00 5,030 2,810 4,370 2,330 3,950 1,940 5,810 3,360 5,240 2,540 4,560 in iji 8.9 11.25 6; 400 7,860 3,560 4,330 5,560 2,920 5,000 2,360 7,340 4,380 6,660 3,240 5,760 2,760 Ui 8.0 12.50 6,840 3,420 6,170 2,680 9,070 5,340 8,200 3,940 7,130 3,120 1 11.5 11.50 5,030 2,690 4,370 2,230 3,950 1,910 5,810 3,200 5,240 2,450 3,140 4,560 2,220 nu US Ui 10.2 12.9375 6i 400 7,860 3; 460 5,560 2,830 5,000 2,380 7,340 4,100 6,660 5,760 2,770 9.2 14. 375 4,220 6,840 3,460 6,170 2,840 9,070 5,170 8,200 3,840 7,130 3,320 1 12.0 12.00 5,030 2,620 4,370 2,220 3,950 1,880 5,810 3,110 5,240 2,880 4,560 2,200 12 US 10.7 13.50 6^400 7,860 3,380 4,150 Si 560 2,780 5,000 2,350 7,340 4,020 6,660 3,070 5,760 2,750 Ui 9.6 15.00 6,840 3,420 6,170 2,980 9,070 5.040 8,200 3,780 7,130 3,340 "Three (3) member joint. -39- NATIONAL EMERGENCY SPECIFICATIONS* 601 H. EDGE DISTANCE 1. “Edge Distance” is the distance from the edge of the timber to the center of the nearest bolt hole. 2. For parallel-to-grain loading in tension or compression, the edge distance shall be at least 1% times the bolt diameter, except that for l/d ratios more than 6, use one-half the distance between rows of bolts. 3. For perpendicular-to-grain loading, the edge distance nearest the edge toward which load is acting shall be at least 4 times the bolt diameter. I. STAGGERED BOLTS 1. For parallel-to-grain loading with staggered bolts, special precaution shall be taken to provide sufficient area at the critical section. Adjacent staggered bolts shall be considered as being placed at the critical section. 2. For perpendicular-to-grain loading, if dedesign load for mam member is less than bolt bearing capacity of side timbers, staggering may be employed. J. BOLTING FOR LOADS AT ANGLE TO GRAIN 1. It is virtually impossible to set up .general rules regarding the alignment, spacing, and distances of bolts to cover all possible directions of applied load. Uniform stress in main members and a uniform distribution of load to all bolts, however, require that the gravity axis of the members shall pass through the center of resistance of the bolt groups. -40- FOR STRESS GRADE LUMBER 700-701 PART VII. LAG SCREW JOINTS The provisions of Part VII herein shall apply for machine (cut) thread lag screw (lag bolt) joints in stress grade lumber: 700 Provisions Applicable to Both Withdrawal and Lateral Resistance A. TYPE OF LOAD 1. Allowable loads for lag screws given in Part VII are the maximum for permanent loading, i. e., long-time loading whether dead or live. Pertinent modifications of stresses and provisions of paragraphs 200, 201, 202 and 203 for lumber shall apply likewise to loads for lag screws given in Part VII. B. NUMBER OF LAG SCREWS 1. Loads given are for one lag screw either in withdrawal or in lateral resistance in single shear in a two member joint. 2. Loads for more than one lag screw, each of the same or miscellaneous sizes, are the sum of the loads permitted for each lag screw provided that spacings, end distances, and edge distances are sufficient to devlop the full strength of each lag screw. C. QUALITY OF LAG SCREW 1. The following allowable loads are based on lag screws of metal having a yield point of 45,000 pounds per square inch and a tensile strength of 77,000 pounds per square inch. 2. For other metal, the values herein shall be adjusted in proportion to the tensile strength of the metal for maximum allowable loads in withdrawal (paragraph 701-A) and in proportion to square roots of the yield point stresses of the metal for allowable loads in lateral resistance. D. SPECIES OF LUMBER 1. The method of determining allowable loads for lag screws in the various species is indicated by formulas and provisions and tabulated values herein. E. GRADE OF LUMBER 1. The allowable loads for lag screws in a given species apply to all grades of that species. F. CONDITION OF LUMBER 1. The allowable loads given in the following paragraphs are for lag screws in seasoned lumber. For wet condition two-thirds and for alternate wet and dry three-fourths of the allowable loads given shall apply. G. LEAD HOLES 1. Lead holes shall be prebored as follows: (a) The lead hole for the shank shall have the same diameter as the shank and the same depth as the length of unthreaded shank. (b) The lead hole for the threaded portion shall have a diameter equal to 65 percent to 85 percent of the shank diameter in oak, 60 • percent to 75 percent in Douglas fir and southern pine, and 40 percent to 70 percent in redwood and northern white pine and a length equal to at least the length of the threaded portion. The larger figure in each range shall apply to screws of the greater diameters. For other species the diameter shall be determined from the foregoing percentages by proportions based on the relative specific gravities of the species. (c) Lead holes slightly larger than those specified in paragraphs 700-G-l-(a) and (b) shall be used with lag screws of excessive length. H. INSERTION 1. The threaded portion of the screw shall be inserted in its lead hole by turning with a wrench, not by driving with a hammer. 2. Soap or other lubricant shall be used on the screws, particularly with the denser species, to facilitate insertion and prevent damage to screw. I. PENETRATION OF THREADED PORTION OF LAG SCREW 1. In determining the penetration of threaded portion of lag screw into a member, the reduced portion (threaded or gimlet point) shall not be considered as part of the threaded portion. For dimensions of standard lag screws, see Table No. 13. 701 Withdrawal Resistance A. TENSILE STRENGTH OF LAG SCREW 1. In determining withdrawal resistance, the allowable tensile strength of lag bolt at net (root) section shall not be exceeded. Penetration of threaded portion of about 7 times the -41- 701 NATIONAL EMERGENCY SPECIFICATIONS shank diameter in the denser species and 10 to 12 times the shank diameter in the softer species will develop approximately the ultimate tensile strength of the screw in axial withdrawal. (See par. 701-B.) B. ALLOWABLE WITHDRAWAL LOAD IN SIDE GRAIN 1. The allowable load for lag screws in withdrawal from side grain with axis of the lag screw perpendicular to the fibers shall be determined from the formula: p=1800D^ in which p—allowable load per inch of penetration of threaded portion of lag screw D—shank diameter of lag screw in inches (See Table No. 13.) G— specific gravity of oven dry wood (See Table No. 14.) C. ALLOWABLE WITHDRAWAL LOAD IN END GRAIN 1. If possible, the design shall be such that lag screws are not loaded in withdrawal from end grain of wood. When this condition cannot be avoided, the allowable load in withdrawal from end grain shall not be taken as more than three-fourths of that for withdrawal from side grain. Table No. 13.—Dimensions of standard lag bolts or lag screws for wood—Cut thread, gimlet and cone point T 1 Y ow [All dimensions m mcnesj -I. t — s — • T h —T-E—|E * D > - Ds- « Dr= =Nominal diameter. =_D=Diameter of shank. =Diameter at root of thread. H=Height of bolt head. L = Nominal length of bolt. £> = Length of shank. E—Length of tapered tip. N= Number of threads per inch. w =Width of bolt head across flats. T=Length of thread. Nominal Dimensions of lag bolt with nominal diameter (D) of length of bolt (L) in inches* Item M« 7 7s 7 7s 7 7s 7 M 7 1 17 1M All lengths Ds=D Db E H W N 0.190 .120 Mz %4 Hz 11 0.250 .173 M« ^4 M 10 0.3125 .227 74 1%4 7 9 0.375 .265 7. M 7s 7 0.4375 .328 Mz 1%4 7 7 0.500 .371 7s 2H4 M 6 0.5625 .435 7 M 7 6 0.625 .471 7 2M< !M« .5 0.750 .579 7s 7 IM 4M 0.875 .683 7 !Mz 1M« 4 1.000 .780 7s 2Mz IM 3M 1.125 .887 7 M DM« 3M 1.250 1.012 M 2Mz 17 3M 1 1 S T T-E M % 1%2 M M M« M 7 7 M M 7 M M iMz M M 7s — IM IH 3 Hz M 1H iM« M 17 M 34 17 7 3A 17 2Hz ■17 17s — 2 s T T-E M IH PMz M IM 17s 7 17 IM 7 17 1M 7 IM iMz 7 17 17s 7 17 17. ' 7 1M 1M 2M — S T T-E 1 IH PH« 1 1M 17s 7 17 17 M 17 17 M 1M D7z M IM 17s M 1M 17 M IM IM 3. S T T-E 1 2 l2Mz 1 2 PM« 1 2 17 1 2 1M 1 2 l2Mz 1 2 D7s 1 2 17 1 2 IM 1 2 1M« 1 2 1M 1 2 17s — 4 » J 1H 2H 21Hz IM 2M 27s 17 27 27 17 27 2M IM 2M 2Hz 17 27 27s 17 27 27 IM 2M 2M 1M 2M 27s 1M 2M 2 17 27 PM « IM 2M IM 17 27 1M 6 s T T-E 2 3 22Hz 2 3 2‘M« 2 3 27 2 3 2M 2 3 22Mz 2 3 21M« 2 3 27 2 3 2M 2 3 2M« 2 3 2M 2 3 27s 2 3 2M 2 3 2M 6 S T T-E 2H 3M 31 Hz 2M 3M 37 s 27 37 3M 27 37 3M 2M 3M 3Hz 2M 3M 37 s 27 37 37 2M 3M 3M 2M 3M 3M« 2M 3M 3 2M 3M 21M« 2M 3M 2M 2M 3M 2M 7.'. S T T-E 3 4 3% 3 4 31M« 3 4 374 3 4 3M 3 4 32Mz 3 4 31H« 3 4 3M 3 4 ■ 3M 3 4 3M« 3 4 3M 3 4 37s 3 4 3M 3 4 3M 8 : 3M 4M 41H« 3M 4M 4M« 37 4M 4M 37 4M 4M 3M 4M 4Mz 3M 4M 4M« 3M 4M 4M 3M 4M 4M 3M 4M 4M« 3M 4M 4 37 4M 31M« 3M 4M 37 3M 4M 3M 9 T T-E 4 5 42Hz 4 5 4% 4 5 4M 4 5 4M 4 5 42Mz 4 5 41M« 4 5 4M 4 5 4M 4 5 4M« 4 5 4M 4 5 4M« 4 5 4M 4 5 4M 10 S T T-E 4% 5M 5%z 4?4 5M 57 s 4M 5M 5 4M 5M 5 4M 5M 43Mz 4M 5M 41M« 4M 5M 4M 4M 5M 4M 4M 5M ^7s 4M 5M 4M 4M 5M 41M« 4M 5M 4% 4M 5M 4M 11 S T T-E 5M 5M 5iHz 57 57 5Mz 57 57 5M 5M 5M 5M 5M 5M 57% 5M 5M 5M« 57 57 57 5M 5M 5M 57 57 57s 5M 5M 5 ’ 5M 5M 41M« 5M 5M 4M 5M 5M 4M 12 1 6 6 52Hä 6 6 5% 6 6 5M 6 6 5M 6 6 527i 6 6 5!M« 6 6 5M 6 6 5M 6' 6 57 s 6 6 ' 5M 6 6 57 s 6 6 5M 6 6 5M •Length of thread (T) on intervening bolt lengths is the same as that of the next shorter bolt length listed. The length of thread (T) on standard bolt lengths (L) m excess of 12 inches is equal to M the bolt length (L/2). -42- FOR STRESS GRADE DUMBER 701-702 Table No. 14.—Specific gravity of commercially important species of wood based on oven dry weight and volume Specific Specific Species gravity- Species gravity Alder, red__________ 0. 43 Gum, red______________ . 53 Ash, black________ . 53 Gum, tupelo---------- . 52 Ash, white__________ . 64 Hackberry----------- . 56 Aspen_______________ . 40 Hemlock, eastern____ . 43 Basswood____________ . 40 Hemlock, western____ . 44 Birch, yellow_______ . 66 Hickory------------- . 72 Buckeye, yellow. ___ .38 Larch, western---------- .59 Butternut___________ . 40 Locust, black------- . 71 Cedar, northern Madrone------------- .69 white________. 32 Magnolia, evergreen__ . 53 Cedar, Port Orford__ . 44 Maple, hard--------- . 68 Cedar, western red__ . 34 Maple, soft________— . 51 Cherry, black_______ . 53 Oak__________________ .68 Chestnut____________ .45 Pine, northern white. _ .37 Cottonwood, eastern. . 43 Pine, ponderosa----- . 42 Cucumber, magnolia. . 52 Pine, southern yellow. . 58 Cypress, southern___ . 48 Poplar______________ . 43 Douglas fir_________ . 51 Redwood_____________ . 39 Elm, American_______ . 55 Spruce-------------- . 39 Elm, rock___________ . 66 Sycamore.----------- . 54 Fir, commercial Tamarack------------ . 56 white________________ . 42 Walnut, black-------- . 56 Gum, black__________ . 55 Willow, black.______ . 41 702 Lateral Resistance A. THICKNESS OF WOOD SIDE PIECE 1. The allowable loads for lateral resistance of lag screws given in paragraph 702-E shall be for wood side members having a thickness equal to 3.5 times the shank diameter. 2. For other ratios of thickness of side piece to shank diameter, the percentages given in Table No. 15 shall be applied to the allowable loads for lateral resistance obtained from the formulas in Table No. 17. Table No. 15.—Percentages of allowable loads for ratio of thickness of side member to shank diameter Ratio of thickness of side member to shank diameter of lag screw Percentage of the allowable load for a ratio of 3.5 Ratio of thickness of side member to shank diameter of lag screw Percentage of the allowable load for a ratio of 3.5 2. 0 62 4. 5 113 2. 5 77. 5 5. 0 118 3. 0 93 5. 5 121 3. 5 100 6. 0 122 4. 0 107 6. 5 122. 5 B. STEEL SIDE PIECE 1. Where steel plates rather than wood side pieces are used, the allowable loads given by the formulas for parallel to grain loading (paragraph 702-E) shall be increased by 25 percent but no increase shall be made in the allowable loads for perpendicular-to-grain loading. 2. The stresses induced in the steel plate and at bearing of lag bolt on plate shall not exceed the allowable stresses for the metal used. C. PENETRATION OF SHANK IN SIDE AND MAIN MEMBERS 1. The allowable loads given in paragraph 702-E are for the condition where the junction of the unthreaded shank and threaded portion of lag screw is at the plane of contact of the side and main member. 2. When the shank penetrates into the main member, the following percentage loads apply: Table No. 16.—Percentages or allowable loads for ratio of penetration of shank into main member to shank diameter Ratio of penetration of shank into main member to shank diameter Percentage of allowable load for zero penetration Ratio of penetration of shank into main member to shank diameter Percentage of allowable load for zero penetration 0.0 100 4. 5 135 0. 5 104 5. 0 136 1. 0 108 5. 5 137 1. 5 112. 5 6. 0 138 2. 0 117 6. 5 138. 5 2. 5 122 7. 0 139 3. 0 126. 5 7. 5 139 3. 5 130. 5 8. 0 139 4. 0 133 8. 5 139 3. When the junction of the shank and threaded portion of the lag screw is within the side member, the allowable load shall be determined from the actual penetration of. shank by interpolation between the allowable load given in paragraph 702-C-l for complete penetration of side member and 80 percent of that load for no penetration (thread extended to head of screw). D. DEPTH OF PENETRATION OF THREADED PORTION IN THE MAIN MEMBER 1. The formulas in paragraph 702-E for determining allowable loads for lateral resistance are based on a minimum penetration of the threaded portion of the lag screw into the main member of 11 times the shank diameter for Group 1 woods (the softer woods) to 7 times for Group 4 woods (the harder woods), when the ratio» of thickness of side member to shank diameter is 3.5 and the length of the shank is equal to the thickness of the side member. 2. Higher ratios of thickness of side member to shank diameter (up to about 7 to 1 and in excess of 3.5, paragraph 702-A-2) and greater ratios of penetration of shank into main member to shank diameter (up to a ratio of about 7 to 1, paragraph 702-C-2) require greater depths of penetration into main member to develop the -43- 702 NATIONAL EMERGENCY SPECIFICATIONS percentage loads given in Table No. 15 of paragraph 702-A-2 and Table No. 16 of paragraph 702-C-2. The required penetration of threaded portion into main member shall be obtained through multiplication of the standard penetration by a fraction having the square root of the product of the two percentage loads as the numerator and 100 percent as the denominator. If the product of the two percentages is less than 100 percent, due to the use of thin side members, or of side members thicker than the length of shank, or of both, the required depth of penetration of threaded portion into main member shall be obtained by direct proportion of the percentage product to 100 percent for standard penetration, but shall not be less than 5 times the shank diameter. If the above required penetration of threaded portion into main member cannot be obtained, the allowable loads given in paragraph 702-E shall be reduced in direct proportion of the actual penetration to the required penetration, but, if greater penetration than required is used, the allowable loads shall not be increased. E. ALLOWABLE LOADS FOR LATERAL RESISTANCE WHEN THE LOADS ACT PARALLEL TO GRAIN AND LAG SCREW IS INSERTED IN SIDE GRAIN 1. Allowable loads for lateral resistance when the loads act parallel to grain, lag screw is inserted perpendicular to the fiber (i. e., in side grain of main member), and a wood side piece is used, shall be determined from the formulas in Table No. 17 for the species under consideration. 2. For adjustment of loads for metal instead of wood side pieces, see paragraph 702-B. F. ALLOWABLE LOADS FOR LATERAL RESISTANCE WHEN THE LOADS ACT PERPENDICULAR TO GRAIN AND LAG SCREW IS INSERTED IN SIDE GRAIN 1. Allowable loads for lateral resistance when the loads act perpendicular to grain, lag screw is inserted perpendicular to the fibers (i. e., in side grain of main member), and wood side piece is used, shall be determined by multiplying the allowable loads for lateral resistance parallel to grain for wood side plates by the factors from Tables No. 18 and No. 19 for the species used. Table No. 17.—Equations for computing allowable lateral loads parallel to grain for lag screws screwed into side grain Group Species of wood Equation 1 Cedar, northern and southern white i Fir, balsam and commerical white Hemlock, eastern Pine, ponderosa, sugar, northern white and western white. Spruce, Engelmann, red, Sitka and white P*= 1800D2 2 Aspen and largetooth aspen Basswood Cedar, Alaska, Port Orford and western red Chestnut Cottonwood, black and eastern_ _ Cypress, southern Douglas fir (Rocky Mountain type) Hemlock, western Pine, Norwây Redwood Tamarack Yellow poplar ’ P-2040D2 3 Ash, black Birch, paper Douglas fir (coast type) Elm (soft), American and (gray) slippery - Gum, black, red and tupelo Larch, western Maple, (soft) red and silver Pine, southern yellow Sycamore P=2280D2 4 Ash, commercial white Beech _ _ Birch, sweet and yellow Elm, rock _ Hickory, true and pecan Maple (hard), black and sugar.__ Oak, commercial red and white_ _ P=2640D2 P—Allowable load per lag screw in pounds. D=Shank diameter of lag screw in inches. Table No. 18.—Factors for computing allowable lateral loads for perpendicular-to-grain loading of lag screw in side grain Lag screw diameter Factor Group 1 Group 2 Group 3 Group 4 Group 5 1. 00 1. 00 1. 00 1. 00 1. 00 Yi . 94 1. 00 1. 00 . 89 1. 00 . 82 . 87 . 89 . 77 . 91 % . 73 . 78 . 80 . 69 . 82 Ye- . 67 . 72 . 74 . 64 . 76 Y . 62 . 67 . 68 . 59 . 70 % . 57 . 61 . 62 . 54 . 64 % . 53 . 56 . 57 . 50 . 59 %-— . 50 . 53 . 54 . 47 . 56 1 . 48 . 51 . 52 45 . 53 2. The allowable loads for lateral resistance when the loads act perpendicular to grain shall be the same for both metal and wood side pieces. -44- FOR STRESS GRADE LUMBER 702-703 Table No. 19.—Grouping of species for use with table No. 18 Group Species of wood Ash, black Aspen and largetooth aspen Basswood Birch, paper Butternut Cedar, northern and southern Chestnut 1 Cottonwood, black and eastern Fir, balsam and commercial white Hemlock, eastern Pine, lodgepole, ponderosa, sugar, northern white and western white Poplar, yellow Spruce, Engelmann, red, Sitka and white Cedar, Alaska, incense, Port Orford and western red 2 Douglas fir (Rocky Mountain region) Hemlock, western Pine, Norway Cedar, eastern red Cypress, southern Douglas fir (coast region) 3 Larch, western Pine, southern yellow Redwood Tamarack 4 Alder, red Elm, American and slippery Gum, black, red and tupelo Hackberry Magnolia, cucumber and evergreen Maple, bigleaf, and red and silver (soft) Sugarberry Sycamore Ash, commercial white and Oregon Beech Birch, sweet and yellow Cherry, black Elm, rock Hickory, true and pecan Locust, black Locust, honey Maple (hard), black and sugar Oak, commercial red and white Walnut, black G. ALLOWABLE LOADS FOR LATERAL RESISTANCE WHEN THE LOADS ACT AT ANGLES OTHER THAN 0° AND 90° WITH THE GRAIN AND THE LAG SCREW IS INSERTED IN SIDE GRAIN 1. When the load acts at an angle other than 0° and 90° with the grain, the lag screw is inserted perpendicular to the fiber (i. e., in sidd grain of main member), and either wood or metal side piece is used, the allowable loads for lag screws under lateral loading shall be determined from the Hankinson formula. 2. For Hankinson formula, see paragraph 600-N and Appendix C. H. ALLOWABLE LOADS FOR LATERAL RESISTANCE WHEN THE LOADS ACT PERPENDICULAR TO THE GRAIN AND THE LAG SCREW IS INSERTED IN END GRAIN 1. Allowable loads for lateral resistance when the loads act perpendicular to grain and the lag screw is inserted parallel to the fibers (i. e., in the end grain of the main member) shall be two-thirds of those for lateral resistance when the loads act perpendicular to the grain, the lag screw is inserted perpendicular to the grain (i. e., in the side grain of the main member) and a wood side piece is used. 703 Placement of Lag Screws in Joint A. The spacings, end distances, edge distances and net section for lag screw joints shall be the same as for joints with bolts of a diameter equal to the shank diameter of the lag screw used, see paragraph 601. -45- 800 NATIONAL EMERGENCY SPECIFICATIONS PART VIII. NAIL, SPIKE, DRIFTPIN, AND WOOD SCREW JOINTS 800 Nailed Joints The allowable loads and other provisions of paragraph 800 for nail joints shall apply in stress . grade lumber: A. GENERAL PROVISIONS 1. The following provisions (except par. 800-A—2) shall apply to common wire nails. 2. For nails other than common wire nails, allowable loads herein for common wire nails shall be adjusted by proportion in accordance with the provisions of reference No. 2, Appendix E. 3. When more than one nail is used in a nailed joint, the total allowable load in withdrawal or lateral resistance shall be the sum of the allowable loads for the individual nails. B. TYPE OF LOAD 1. The allowable loads for nails given in paragraph 800 are the maximum for permanent loading, i. e., long-time loading whether dead or live. Pertinent modifications of stresses and provisions of paragraphs 200, 201, 202, and 203 for lumber shall apply likewise to the allowable nail loads in paragraph 800. C. WITHDRAWAL FROM SIDE GRAIN (See Table No. 20) 1. If possible, the structural design shall be such that nails are not loaded in withdrawal. When this condition cannot be avoided, the following provisions shall apply: (a) For common wire nails, the allowable withdrawal load per inch of penetration of a nail driven in side grain (perpendicular to fibers) of main member of seasoned wood or unseasoned wood which will remain wet shall be: (1) that given in Table No. 20 for species listed, (2) determined from the following formula for species not tabulated. p= 1,380 G^D, in which p—allowable load per inch of penetration, G=specific gravity of oven dry wood (see Table No. 14, Part VII), D=diameter of nail in inches. (b) When driven in unseasoned wood which will season subsequently under load, the allowable load from side grain shall be onefourth of that given in sub-paragraph (a) above. D. WITHDRAWAL FROM END GRAIN 1. The structural design shall be such that nails are not loaded in withdrawal from end grain of wood. Table No. 20.—Allowable loads for common wire NAILS IN WITHDRAWAL from side grain Nail data: Pennyweight Length (inches) Diameter (inches) 6 2 0. 113 8 2% 0. 131 10 3 0. 148 12 3% 0. 148 16 3^ 0. 162 20 4 0. 192 30 4/2 0. 207 40 5 0. 225 50. 5H 0. 244 60 6 0. 263 Allowable load in pounds per inch of penetration in main member Species: Birch, yellow and sweet 61 72 80 80 89 104 113 122 133 144 Douglas fir 29 34 38 38 42 49 53 58 62 67 Maple, sugar. 60 68 78 78 85 101 109 119 128 138 Oak, red and white 61 72 80 80 89 104 113 122 133 144 Pine, longleaf 41 47 54 54 56 60 66 71 77 83 Pine, northern white 16 18 20 20 23 26 29 31 34 36 Pine, ponderosa 18 20 23 23 25 30 32 36 38 42 Pine, shortleaf 34 38 43 43 46 49 53 58 62 68 Redwood, _ 18 20 23 23 25 30 32 36 38 42 Spruce, Sitka. _ 17 20 23 23 25 30 32 35 37 41 -46- FOR STRESS GRADE LUMBER 800-801 E. LATERAL RESISTANCE OF NAILS DRIVEN IN SIDE GRAIN OF WOOD 1. The allowable load per common wire ' nail in lateral resistance when driven in side grain (perpendicular to fibers) of seasoned wood with the load applied in any lateral direction shall be determined from the formulas in Table No. 21. These loads apply only for conditions where the side piece and main member have approximately the same density and where the nail penetrates in the main member a minimum distance equal to two-thirds of its length in softwoods and one-half in hardwoods. 2. For nails driven into side grain of unseasoned wood which will remain wet or will be loaded before seasoning, the allowable load per nail in lateral resistance shall be three-fourths of that given in paragraph 800-E-l. 3. Where metal side plates are used, the allowable load per nail given in paragraph 800-E-l shall be increased by 25 percent. F. LATERAL RESISTANCE OF NAILS DRIVEN IN END GRAIN OF WOOD 1. The allowable load per nail in lateral resistance for a common wire nail driven in the end grain (parallel to fibers) shall be two-thirds of that given for nails in paragraph-800-E. G. SPACING OF NAILS 1. The end distance, edge distances, and spacings of nails shall be such as to avoid unusual splitting of the wood. 801 Spiked Joints The allowable loads and other provisions of paragraph 801 for spike joints shall apply in stress grade lumber. A. GENERAL PROVISIONS 1. The following provisions (except par. 801-A-2) shall apply to common wire spikes with diamond or chisel points. 2. For boat spikes which are square in cross section allowable loads given in reference No. 2, Appendix E, shall be adjusted in proportion to values given herein for common wire spikes. 3. When more than one spike is used in a spiked joint, the total allowable load in withdrawal or lateral resistance shall be the sum of the allowable loads for the individual spikes. B. TYPE OF LOAD 1. The allowable loads for spikes given in paragraph 801 are the maximum for permanent Table No. 21.—Allowable loads for common wire NAILS IN LATERAL RESISTANCE when driven in side grain Equation for computing allowable lateral load for common wire nails driven perpendicular to the grain of wood in seasoned lumber expressed in pounds per nail. Species Equation Aspen and largetooth aspen Basswood P= 1,080 Butternut- _ _ . _ Cedar, northern and southern white Chestnut __ _ Cottonwood, black and eastern Fir, balsam and commercial white Hemlock, eastern Pine, lodgepole, ponderosa, sugar, northern white, and western white. Poplar, yellow Spruce, Engelmann, red, Sitka, and white Cedar, Alaska, incense, Port Orford, and western red Cedar, eastern red Cypress, southern Douglas fir (Rocky Mountain region) Hemlock, western Pine, Norway- P= 1,350 D»/2 Redwood Tamarack - Alder, red _ _ _ P= 1,500 Ash, black _ Birch, paper __ __ Elm, American and slippery. v_ Gum, black, red, and tupelo Hackberry Magnolia, cucumber Magnolia, evergreen Maple, bigleaf Maple (soft), red and silver Sugarberrv ' ____ Sycamore Douglas fir (coast region) Larch, western _ _ _ _ _ _ P= 1,650 Pine, southern yellow Ash, commercial white Ash, Oregon P= 2,040 DM Beech Birch, sweet and yellow Cherry, black _ _ Elm, rock _ _ - - - Hickory, true and pecan Locust, honey and black Maple (hard), black and sugar Oak, commercial red and white Walnut, black _ P— Allowable load per nail in pounds. D— Diameter of nail in inches. loading, i. e., long-time loading whether dead or live. Pertinent modifications of stresses and provisions of paragraphs 200, 201, 202, and 203 for lumber shall apply likewise to the allowable spike loads in paragraph 801. C. WITHDRAWAL FROM SIDE GRAIN 1. If possible, the structural design shall be such that spikes are not loaded in withdrawal. When this condition cannot be avoided, the following provisions shall apply: -47- NATIONAL EMERGENCY SPECIFICATIONS 801-802 (a) For common wire spikes, the allowable withdrawal load per inch of penetration of spike driven in side grain (perpendicular to fibers) of seasoned wood or unseasoned wood which will remain wet shall be: (1) That given in Table No. 22. (2) Determined from formula in paragraph 800-C-l (a) (2) for species not tabulated in Table No. 22. (b) When driven in unseasoned wood which will season subsequently under load, the allowable withdrawal load shall be one-fourth of that given in paragraph 801-C-l (a). D. WITHDRAWAL FROM END GRAIN 1. The structural design shall be such that spikes are not loaded in withdrawal from end grain of wood. E. LATERAL RESISTANCE OF SPIKES DRIVEN IN SIDE GRAIN 1. The allowable load per common wire spike in lateral resistance when driven in side grain (perpendicular to fibers) of seasoned wood with the load applied in any direction shall be determined from the formulas in Table No. 21. The loads apply only for conditions where the side piece and main member have approximately the same density and where the spike penetrates in the main member a minimum distance equal to two-thirds of its length in softwoods and one-half its length in hardwoods. 2. For spikes driven in side grain of unseasoned wood which will remain wet or will be loaded before seasoning, the allowable load per common wire spike in lateral resistance shall be three-fourths of that given in paragraph 801-E-l. F. LATERAL RESISTANCE OF SPIKES DRIVEN IN END GRAIN OF WOOD 1. The allowable load per spike in lateral resistance of a common wire spike driven in end grain (parallel to fibers) shall be two-thirds of that for spikes driven in side grain given in paragraph 801-E. G. SPACING OF SPIKES 1. The end distance, edge distances, and spacings of spikes shall be such as to avoid unusual splitting of wood. 802 Driftpin Joints A. WITHDRAWAL OF DRIFTPINS OR DRIFTBOLTS FROM SIDE GRAIN 1. The ultimate withdrawal load per linear inch of penetration of a round drift bolt or pin from side grain when driven into a prebored hole having a diameter one-eighth inch less than that of the bolt diameter shall be determined from the formula: p = 6,000 G2D in which p = ULTIMATE withdrawal load per linear INCH OF PENETRATION. G = specific gravity of oven-dry wood. (See Table No. 14.) D = diameter of driftbolt in inches. 2. The allowable load per linear inch of penetration shall be determined by dividing the ultimate withdrawal load given in paragraph 802-A-l by a factor of safety which is Table No. 22.—Allowable loads for common wire SPIKES IN WITHDRAWAL from side grain Spike data: Pennyweight Length (inches) Diameter 10 3 0. 192 12 3% 0. 192 16 3H 0. 207 20 4 0. 225 30 4/2 0. 244 40 5 0. 263 50 5% 0. 283 60 6 0. 283 7 8-12 % Allowable load in pounds per inch of penetration in main member Species: Birch, yellow and white. 104 104 112 123 133 144 155 155 171 205 Douglas fir 49 49 53 58 63 68 73 73 80 96 Maple, sugar 101 101 109 118 128 138 149 164 164 197 Oak, red and white 104 104 112 123 133 144 155 155 171 205 Pine, longleaf 60 60 65 71 77 83 89 89 99 116 Pine, northern white 26 26 29 31 33 36 39 39 43 52 Pine, ponderosa 30 30 32 35 38 41 44 44 49 59 Pine, shortleaf 49 49 53 58 63 68 73 73 81 97 Redwood 30 30 32 35 38 41 44 44 49 59 Spruce, Sitka 30 30 32 35 37 40 43 43 48 58 -48- FOR STRESS GRADE DUMBER 802-803 consistent with the character of the work. Although not mandatory, a factor of five is suggested for general use. B. LATERAL RESISTANCE OF DRIFT-BOLTS 1. The allowable load in lateral resistance for a driftbolt or pin driven in the side grain of wood shall not exceed, and ordinarily shall be taken as less than, that for a common bolt of the same diameter. When possible, additional penetration of pin into members shall be provided in lieu of the washers, head, and nut on a common bolt. 803. Wood Screw Joints In the design and construction of wood screw joints, the provisions of paragraph 803 for wood screw joints shall apply in stress grade lumber: A. TYPE OF LOAD 1. Allowable loads for wood screws given in paragraph 803 are the maximum for permanent loading, i. e., long-time loading whether dead or live. Pertinent modifications of stresses and provisions of paragraphs 200, 201, 202, and 203 for lumber shall apply likewise to loads for wood screws given in paragraph 803. B. NUMBER OF WOOD SCREWS 1. Loads given are for one wood screw either in withdrawal or in lateral resistance in a two member joint. 2. Loads for more than one wood screw each of the same or miscellaneous sizes are the sums of the loads permitted for each wood screw, provided that spacings, end distances, and edge distances are sufficient to develop the full strength of each wood screw. C. QUALITY OF WOOD SCREWS 1. The allowable loads herein are for any wood screw of sufficient strength to cause failure in the wood rather than the metal. D. SPECIES OF LUMBER 1. The method of determining allowable loads for wood screws in the various species is indicated by formulas and provisions and tabulated values herein. E. GRADE OF LUMBER 1. The allowable loads for wood screws in a given species apply to all grades of that species. F. CONDITION OF LUMBER 1. The allowable loads given in paragraph 803 are for wood screws in seasoned lumber. For wet condition use two-thirds, and for alternate wet and dry three-fourths allowable loads given. G. LEAD HOLES 1. Lead holes shall be prebored as follows: (a) For Withdrawal Resistance: (1) For hardwoods, the lead hole shall have a diameter of about 90 percent the root diameter of the wood screw. (2) For conifers, the lead hole shall have a diameter of about 70 percent of the root diameter of the wood screw. (b) For Lateral Resistance: (1) For hardwoods, such as oak, the part of the lead hole receiving the shank shall have about the same diameter as the shank, and that receiving the threaded portion shall have about the same diameter as the root of the thread. (2) For conifers such as southern pine and Douglas fir, the part of the hole receiving the shank shall be about seven-eights the diameter of the shank and that for the threaded portion shall be about seveneights the diameter of the screw at the root of the thread. H. INSERTION 1. The screw shall be inserted in its lead hole by turning with a screw driver or other tool, not by driving with a hammer. 2. Soap or other lubricant may be used on the screws to facilitate insertion and to prevent damage to screw. I. PENETRATION OF WOOD SCREWS IN MAIN MEMBER 1. For withdrawal Resistance. (a) The depth of penetration into member receiving the point shall not be less than two-thirds the length of the screw. 2. For Lateral Resistance. (a) The length of screw in main member shall be approximately seven times the shank diameter. (b) If the depth of penetration is less than seven times the diameter of the shank, the allowable load for lateral«resistance shall be reduced in proportion to the length of penetration, but a length of penetration of less than four times the shank diameter shall not be used. -49- 803 NATIONAL EMERGENCY SPECIFICATIONS J. WITHDRAWAL RESISTANCE OF WOOD SCREWS 1. If possible, the structural design shall be such that wood screws are not loaded in withdrawal. When this condition cannot be avoided, the following provisions shall apply: (a) Tensile strength of wood screw: (1) In determining the allowable withdrawal resistance from subparagraph (b) below, the allowable tensile strength of wood screw at net (root) section shall not be exceeded. (b) Withdrawal from side grain: (1) The allowable load in withdrawal from side grain with axis of the wood screw perpendicular to the fibers shall be determined from the formula: p=2,040 G2D in which p=the allowable load per inch of total length of screw (two-thirds of screw length shall be in member receiving point), G— specific gravity of oven dry wood (See Table No. 14), D=diameter of the screw in inches. (2) The preceding equation is applicable to the wood screw lengths and gages given in Table No. 23. Table No. 23.—Screw-lengths and gage limits. Screw length Gage limits Screw length Gage limits 1-6 2 7-16 % 2-11 2% 9-18 1 3-12 . 3 12-20 1% 5-14 (3) Allowable loads for other wood screw lengths and gages shall be adjusted proportionately to those herein in accordance with reference No. 2, Appendix E. (c) Withdrawal from end grain. (1) T,he structural design shall be such that wood screws are not loaded in withdrawal from end grain of wood. K. LATERAL RESISTANCE OF WOOD SCREWS 1. Thickness of wood side piece. (a) See paragraph 803-1-2. 2. Steel side piece. (a) Where steel side plates rather than wood side pieces are used, the allowable load for wood screws in lateral resistance of any angle of load to grain shall be increased by 25 percent. 3. Depth of penetration of threaded portion in main member. (a) See paragraph 803-1-2. 4. Penetration of shank in side and main members. (a) See paragraph 803-1- 2. 5. Allowable loads for lateral resistance with wood screws in side grain. (a) The allowable loads for lateral resistance to any angle of load to grain when the wood screw is inserted perpendicular to the fibers (i. e., in side grain of main member) and a wood side piece is used, shall be determined from the formula in Table No. 24 for the species under consideration. 6. Allowable loads for lateral resistance when loads act perpendicular to the grain and the wood screw is inserted in end grain. (a) The allowable loads for lateral resistance when the loads act perpendicular to grain and the wood screw is inserted parallel to the fibers (i. e., in the end grain of the main member) shall be two-thirds of those for lateral resistance given in paragraph 803-K-5. L. PLACEMENT OF WOOD SCREWS IN JOINTS. 1. Spacings,, end distances, and edge distances for wood screw joints shall be such as to prevent unusual splitting. -50- FOR STRESS GRADE LUMBER Table No. 24—Allowable loads in LATERAL RESISTANCE FOR WOOD SCREWS in side 803 grain Species Equation Species Equation Ash, commercial white __ Ash, Oregon Beech Birch, sweet and yellow Cherry, black . ; Elm, rock _ Hickory, true and pecan Honey, locust .__ Locust, black Maple (hard), black and sugar Oak, commercial red and white P = 4,800 D* Cedar, Alaska, incense, Port Orford and western red Cedar, eastern red Cypress, southern ; Douglas fir (Rocky Mountain region) _ Hemlock, western , __ Pine, Norway Redwood v Tamarack _ L _ _ P = 3,240 D» Aspen and largetooth aspen Basswood Butternut Douglas fir (coast region) Larch, western ! ; Pine, southern yellow . P = 3,960 D2 Cedar, northern and southern white __ Chestnut Cottonwood, black and eastern. _ Alder, red Ash, black _ _______ Fir, balsam and commercial white Hemlock, eastern P = 2,520 D* Birch, paper Elm, American and slippery _ Gum, black, red and tupelo Hackberry iLuv Magnolia, cucumber_ _ P = 3,480 D* Pine, lodgepole, ponderosa, sugar, northern white and western white. Poplar, yellow Spruce, Engelmann, red, Sitka and white _ Magnolia, evergreen Ù Maple, bigleaf . Maple (soft), red and silver Sugarberry Sycamore P = Allowable load per screw in pounds. D = Shank diameter of screw in inches. -51- 900-902 NATIONAL EMERGENCY SPECIFICATIONS PART IX. GLUED LAMINATED STRUCTURAL MEMBERS In the design and construction of glued laminated structural members of lumber, the provisions of Part IX shall apply. 900 General Provisions A. Except as otherwise provided in Part IX, pertinent provisions of Parts I, II, III, and IV shall apply to glued laminated members. B. The term “glued laminated structural members” as used herein refers only to those glued laminated structural members in which the grain of all laminations of a member is approximately parallel, and for members in bending, only to those members in which the laminations are parallel (not perpendicular) to the neutral axis of the beam. C. The glue line between laminations shall be assumed to be as strong as the wood itself provided that all the requirements of Part IX are fulfilled. D. Strength shall be calculated on the basis of net dimensions of wood in a member, i. e., voids between pieces of lumber used shall not be considered part of the section. E. Sections other than rectangular shall be designed in accordance with the procedures in references 2 * and 10, Appendix E, but the design shall be based on allowable unit stresses given herein. 901 Workmanship A. The construction of laminated members shall be in accordance with good practices and under the' supervision of properly qualified personnel. B. Gluing practices shall take into consideration the characteristics and limitations of the specific glue used and shall conform to good practices as to preparation of wood surfaces for gluing, control of temperature and moisture content of materials, mixing and spreading of glue, maintenance of adequate pressures, assembly time within life of glue, and compatibility of the glue with any other wood treatments employed. See references 10 and 11, Appendix E. 902 Allowable Unit Stresses for Laminated Members A. For a member built of laminations consisting of seasoned stress grades of Joist and Plank or *For sections in bending, see reference 2, page 153 for Form Factor and page 159 for Lateral Buckling. For sections in compression, see reference 2, page 165 for Wrinkling and Twisting and page 162 for Column Formula. For long columns, use Euler formula. seasoned boards graded on Joist and Plank grading rules, the allowable unit stresses in flexure shall be equal to the allowable unit stresses in extreme fiber in bending, given for the corresponding Joist and Plank grades in Table No. 1. The allowable unit stresses for compression parallel to grain shall be the value in Table No. 1 for the grade and species increased by 50 percent except that 90 percent of the allowable unit stresses for compression in Table No. 25, for clear, dry material 4 inches and less in thickness, shall not be exceeded. Allowable unit stresses for combined bending and compression shall be determined from the formula in paragraph 402-B. For glued laminated members, the highest allowable unit shearing stress given in Table No. 1 for stress grades of a given species and density shall apply to all grades of that species and density. Table No. 25.—Basic stresses in compression parallel to grain for clear, dry material 4 inches or less in thickness in laminated members [Not for use in design but for determining the maximum stress under the provisions of paragraph 902-A] Species: Pounds Ash, white________________________________________2, 200 Beech_____________________________________________2, 400 Birch_____________________________________________2, 400 Cypress, southern________1________________________2, 200 Cypress, tidewater________________________________2, 200 Douglas fir, all regions, dense___________________2, 575 Douglas fir, coast region, close grained__________2, 350 Douglas fir, coast region_________________________2, 200 Douglas fir, inland region, close grained_________2, 225 Douglas fir, inland region_______:________________2,075 Elm, rock_________________________________________2, 400 Elm, soft_________________________________________ 1, 600 Gum, black and red________________________________ 1, 600 Hemlock, eastern__________________________________ 1, 400 Hemlock, western___________1_________v____________ 1, 800 Hickory___________________________________________3, 000 Larch, dense__________________,___________________2, 575 Larch, close grained___________________________2, 350 Larch____________________________;________________2, 200 Maple, hard_______________________________________ 2, 400 Oak, red and white________________________________ 2, 000 Pecan_____________________________________________3, 000 Pine, Norway______________________________________ 1, 600 Pine, southern longleaf-______:___________________2, 575 Pine, southern shortleaf, dense___________________2, 575 Pine, southern shortleaf._________________________2, 200 Poplar, yellow____________________________________ 1, 600 Redwood, close grained____________________________2, 125 Redwood___________________________________________2, 000 Spruce, eastern___________________________________ 1, 600 Tupelo____________________________________________ 1, 600 Allowable unit stresses for laminated members composed of material 2 inches or less in thickness conforming to standard commercial grades or special grading may be determined by applying the principles used in reference 3, Appendix E, (assuming the values in columns 2, 3, 4, and 5 of Table No. 8 therein to be increased by 20 percent). The stresses so determined for combined bending and -52- FOR STRESS GRADE LUMBER 902-905 compression and for compression parallel to grain shall be used for bending and for longitudinal compression, respectively, the bending stress being modified for curvature in accordance with paragraph 905-A. The stress for combined bending and compression shall then be governed by paragraph 402-B. B. If all laminations within one-ten th of the depth of the member from the outer face of each outer lamination of a member in bending are selected so that the knots do not exceed one-half the size of the maximum knot permitted in the Joist and Plank grade used elsewhere in the laminated member, the allowable unit stress in extreme fiber in bending for the next higher grade in Table No. 1 shall apply. This provision is to be applied only within the group of grades designated by footnote 7 to Table No. 1 as including density requirements or within the group of grades not so designated. C. When the material in the middle three-fifths of the depth of cross-section in a laminated beam or arch stressed principally in bending is but one grade lower than that in the upper and lower fifths of the depth, the allowable unit stresses in bending for the higher grade in the outer fifths shall apply. This provision shall be applied to dense and non-dense grades as in the preceding paragraph. D. For laminated members designed and constructed in accordance with the provisions of -reference 10, Appendix E, the allowable stresses shall be those recommended in reference 10 (except that the numerical values in columns 2, 3, 4, and 5 of Table No. 24 therein shall be increased by 20 percent). Modification of the increased values shall be made in accordance with that in paragraph 902-A. E. When stress grade lumber is resawn, it shall be regraded and the allowable unit stresses for the resulting grades shall apply thereto. Only those pieces meeting the stress requirements of the member shall be used. F. For a member in bending, in that portion of a laminated member which is stressed up to or more than two-thirds of its allowable stress, the end joints in laminations shall be scarfed. 903 Lumber A. At time of gluing, the moisture content of all laminations in a member shall be uniform and as close as is practical to the moisture content at which the member will be in service. B. All surfaces to be glued shall be surfaced flat to as smooth a finish as possible (approaching a machine polished surface, but not sanded) after seasoning to the appropriate moisture content. C. Surfaces to be glued shall be flat, clean, and free from oil and dust. Material shall be free from warp which will prevent surfaces of adjacent laminations from being brought into intimate contact which will assure a proper thickness and uniform spread of glue. In curved portions of member material shall be free from warp, knots or knot holes which will prevent bending of laminations to uniform curvature. D. Before assembling, lumber shall be so sorted that the material in all laminations of an individual member shall be either flat grain (angle of annual ring with wide face of less than 45°) or edge grain (angle of annual ring with, wide face of 45° or more). 904 Glues and Gluing (See references 10 and 11, Appendix E) A. Glue shall be of a quality which will develop the full strength of the wood used. B. Only glue which will provide adequate strength under conditions of service and for the expected service life of the structure shall be used. C. Good glue bond shall be made over the entire surface to be glued. 905 Curved Laminated Members A. For the curved portion of laminated members, the allowable unit stress in bending shall be modified by multiplication by the following factor: l-2,000HH in which t=thickness of lamination in inches, R—radius of curvature in inches. Note.—No curvature factor shall be applied to stress in a straight portion of a member regardless of curvature elsewhere. B. No defects shall be permitted that interfere with bending to the required curvature without localized irregularities in the curvature or that interfere with bringing laminations into intimate contact. C. For portions of members in which the laminations are curved to a radius of less than 150 times the thickness of lamination, the slope of grain in the laminations within one-tenth, the depth of the member from the outer face of each outer lamination shall not exceed 1 in 15. D. There shall be no end joints in* laminations where the radius of curvature is 100 times the thickness of lamination or less. End joints in laminations where the radius of curvature is be -53- NATIONAL EMERGENCY SPECIFICATIONS 905-906 tween 100 and 150 times the thickness of lamination shall be scarfed. 906 Joints A. The slope of scarfed joints where laminations are highly stressed shall not be steeper than permitted for slope of grain in the grade of lumber used, except that a slope of scarf flatter than 1 to 12 shall not be required for straight members or curved members where the radius of curvature exceeds 150 times the thickness of lamination. B. If there are end joints in the two exterior laminations they shall be scarfed. C. Scarfed joints shall be glued, the glue set, and the laminations then dressed to a uniform thickness before they are finally assembled into the member. D. In adjacent laminations and in corresponding laminations located symmetrically with respect to the tension and compression faces of a member, the scarfed end joints of the laminations shall be staggered longitudinally by at least 24 times the thickness of a lamination and butt end joints by at least 40 times (measured center to center of joints). E. For wide members, a lamination may consist of two or more pieces of lumber placed side by side to form the full width of lamination provided that all longitudinal joints in adjacent laminations are staggered at least inches laterally and preferably more. In width, top and bottom face laminations of the member shall be of one piece or pieces glued together edgewise with excess glue removed from surfaces prior to final assembly into the member. F. For laminations consisting of two or more pieces in width the sum of the widths (parallel to width of lamination) of scarfed or butted end joints in any three adjacent laminations at any given cross-section shall not exceed the overall width of one lamination. G. When stepped-scarf end joints are used, the slope of scarf shall not be steeper than for other scarf joints and any reduction in the effective cross section of the lamination caused by the step shall be taken into consideration in the design. H. A laminated member with scarfed joints properly made and placed shall be designed as a solid member. I. When butt end joints are used, they shall not be assumed to transfer load from one side of the end joint to the other side of the end joint within the same lamination, i. e., the load shall be assumed to be transferred to and carried by the adjacent laminations rather than by the lamination in which the butt joint occurs. J. When laminations are glued over tapered pieces, the taper shall not exceed a slope of 1 in 12. K. The minimum practicable number of end joints of laminations shall occur at any given cross-section of a member. There shall not be more than one end joint in any three successive laminations at a given cross-section where highly stressed. -54- FOR STRESS GRADE LUMBER APPENDICES MANDATORY AND OPTIONAL PROVISIONS Parts 1 to 9 of this Specification are mandatory and are based on the assumption of competent engineering design, accurate fabrication,, and adequate supervision, with the preparation, installation, and joining of wood members and the connectors, mechanical devices, and adhesives for their fastenings conforming throughout to good engineering practice. In the engineering design, care should be taken that the connections, both at joints and splices, are such that each individual piece carries its proportional stress and consideration is given to stresses resulting from moment in joints. If knots occur at the critical section, the cross-sectional area of the knots outside the area deducted for connectors and bolts shall also be deducted in determining the net section. Posting of commercial and industrial structures indicating the design live loads is recommended as additional assurance against overloading. The provisions and data given in the following appendices are recommended as desirable practice for good design and construction but are not mandatory. APPENDIX A LATERAL DISTRIBUTION OF A CONCENTRATED LOAD A. Lateral Distribution of a Concentrated Load for Moment The lateral distribution of a concentrated load for bending moment may be determined by the following method (see reference 19, Appendix E): When a concentrated load at the center of span is distributed to adjacent parallel beams by a wood (plank or laminated strip) or concrete floor slab, the loa d on the beam nearest the load shall be determined as follows: Load on critical Kind of floor: beam** 2-in ch wood__________________________________________________ £/4. 0 4-inch wood.'_________________________________________________ 8/4. 5 6-in ch wood_________________________________________________ *8/5. 0 Concrete____________________________________________________ *8/5. 0 £=average spacing of beams in feet. *In case S exceeds the numerical factor (5.0 or 6.0) the load on the two adjacent beams shall be the reactions of the load, with the assumption that the floor slab between the beam acts as a simple beam. **For more than one traffic lane, see additional data in reference 19, Appen* dix E. B. Lateral Distribution of a Concentrated Load for Shear When the distribution for moment at the center of a beam is known or assumed, the distribution to adjacent parallel beams when loaded at or near the quarter point, i. e., the point of maximum shear (see par. 400-D-2 (c) (3) ), shall be assumed as follows: Table No. A—1—Distribution in terms of proportion of total load Load applied at center of span Load applied at J4 point of span Center beam Distribution to side beams Center beam Distribution to side beams 1. 00 0 1. 00 0 . 90 . 10 . 94 . 06 .80 . 20 . 87 . 13 . 70 . 30 . 79 . 21 . 60 . 40 . 69 . 31 . 50 . 50 . 58 . 42 . 40 . 60 . 44 . 56 . 33 . 67 . 33 . 67 -55- NATIONAL EMERGENCY SPECIFICATIONS APPENDIX B FORMULAS FOR WOOD COLUMNS WITH SIDE LOADS AND ECCENTRICITY A. General The following information is provided for use when more accurate calculation of the maximum direct compression load that can be put upon an eccentrically loaded column or one with a side load is desired. The most accurate of all the column formulas for the critical load on a long, originally straight, centrally loaded column of uniform cross section is the Euler formula, and for long columns with an eccentric application of load is the secant formula. The inaccuracies of these formulas are too small to be detected by the ordinary methods of testing such columns and are much smaller than the inaccuracy of calculating the stiffness of wooden beams neglecting the distortions due to shear. The formulas here presented can be made to have an accuracy fairly comparable to that for the Euler column, but in their simplified form they do not pretend to such accuracy; however, they do have an accuracy well within an acceptable range for most engineering purposes (reference 18, Appendix E). B. Assumptions The following assumptions have been made in arriving at the following simplified equations, but normally they change the results but little. 1. The stresses which cause a given deflection as a sinusoidal curve are the same as those for a beam with a uniform side load. 2. For a single concentrated side load the stress under the load can be used, regardless of the position of the load with reference to the length of the column. 3. The stress to use with a system of side loads is the maximum stress due to the system. (With large side loads near each end some slight error on the side of overload will occur.) 4. The equations can be used for solving for PI A with rectangular wood columns with an lid ratio of 20 or more, provided that for the column between Z/d=20 and lld=K\ that is, when the Euler formula begins to apply, the c is the stress for a centrally loaded column of intermediate length, using the Forest Products Laboratory fourth power parabolic formula. 5. For columns with an II d ratio of 11 or less, the stress due to deflection of the column may be neglected. 6. Between lid ratios of 11 and 20 the stress may be assumed to vary as a straight fine. C. Notation PIA—direct compressive stress in pounds per square inch induced by axial load. M/S= flexural stress in pounds per square inch induced by side loads. c=the allowable unit stress in compression parallel to the grain in pounds per square inch that would be permitted for the column if axial compressive stress only existed; that is, the allowable unit stress for the lid of the column under consideration. /=the allowable unit stress in flexure in pounds per square inch that would be permitted if flexural stress only existed. g=eccentricity in inches. I—length of column in inches. d=side in inches of a rectangular column, measured in the direction of the side loads. 2=ratio of flexural stress induced by side loads to compressive stress induced by axial end load, i e ’• e-’ P/A D. Formulas The following formulas, which are for pin end columns of rectangular cross section, give the maximum allowable combined unit stress. (For design data on columns loaded axially only, see par. 401.) 1. Columns having an l/d ratio of 11 or less: P j A—C (a) End and Side Loads: J -56- FOR STRESS GRADE LUMBER (b) Eccentric Load: /OA (c) Side Load Proportional to End Load : . PIA 1 MIS=z{PIA) (d) Combined End Load, Side Loads, and Eccentricity: 2. Columns having an l/d ratio between lld=ll and Z/d=20. Assume that the stress induced by loads varies as a straight line between that for a column having an l)d ratio of 11 and for one having an l/d ratio of 20. 3. Columns having an lid ratio of 20 or more: (a) End and Side Loads: MIS , PIA , PIA^^-^Ki^} —cfJ—M/S) J=PiA+~c---1 V\ 2 / M;s.JJ-PIW°-PIA) ' c (b) Eccentric Load: (c) Side Load Proportional to End Load: Hg P/A^i+^-^^±^Sj MIS=z{PIA) (d) Combined End Load, Side Loads, and Eccentricity: MIS+(PIA)(^+z(PIA) i p/A i^PiA +~=1 -57- NATIONAL EMERGENCY SPECIFICATIONS E. Columns with Side Brackets An exact solution of the stresses in a column with end and bracket loads is difficult. The following simple rule for determing loads to be used in the combined loading formulas is safe, and for brackets in the upper quarter of the height of a column is sufficiently accurate. Instead of using the bracket load P in its actual position, add to the end load on the column an axial end load P equal to the load on the bracket and calculate the bending stress from an assumed side load P', concentrated at the center of the length of the column and determined as follows (See Fig. B-l): in which P—actual load in pounds on bracket, P'=assumed horizontal side load in pounds assumed to be placed at center of height of column, a=horizontal distance in inches from load on bracket to center of column. I— total length of column in inches, Z'=distance in inches measured vertically from point of application of load on bracket to farther end of column. Use P' to determine the induced unit flexural stress MIS, as if the column were a beam with a concentrated load P' at midlength. Then combine these stresses with those from other loads and apply the appropriate combined stress formulas previously given under paragraph D of this Appendix. APPENDIX C SOLUTION OF HANKINSON FORMULA The allowable unit stresses in compression for lumber and allowable loads for connectors, bolts, and lag screws at an angle of load to grain between 0° and 90° are obtained from the Hankinson formula given in figure C-l. The Hankinson formula is for the condition where the loaded surface is perpendicular to the direction of the load. See Fig. 5, paragraph 404. Where the resultant force is at an angle other.than 90° with the surface under consideration, the angle 0 is the angle between the direction of grain and the direction of the force component which is perpendicular to the surface. The bearing surface for a connector, bolt, or lag screw is assumed perpendicular to the force. See Fig. 21, paragraph 600-N. For specific applications of the formula, see paragraphs 210-A, 211, 404, 500-M, 600-N, and 700-G. The following table lists sin2 0 and cos2 6 for various angles of 0. Sin* 9 9 Cos* 9 Sin* 9 9 Cos * 9 0. 00000 0 1. 00000 . 58682 50 . 41318 . 00760 5 . 99240 . 67101 55 . 32899 . 03015 10 . 96985 . 75000 60 . 25000 . 06698 15 . 93302 . 82140 65 . 17860 . 11698 20 . 88302 . 88302 70 . 11698 . 17860 25 . 82140 . 93302 75 . 06698 . 25000 30 . 75000 . 96985 80 . 03015 . 32899 35 . 67101 . 99240 85 . 00760 . 41318 40 . 58682 1. 00000 90 00000 . 50000 45 . 50000 -58- FOR STRESS GRADE LUMBER The Hankinson formula may be solved graphically through use of the following charts: Fig. C-l. — BEARING STRENGTH OF WOOD AT ANGLES TO THE GRAIN (HANKINSON FORMULA) The compressive strength of wood depends on the direction of the grain with respect to the direction of the applied load. It is highest parallel to the grain and lowest perpendicular to the grain, with variation in these values for different grades within a species and with different species. — The PQ N= P sin20+ Q cos 30« 35* ^Direction of grain. Direction of load. variation in strength at angles between parallel and perpendicular is determined by the Hankinson formula. The Scholten nomographs shown here are a graphical solution of this formula which is — 20« - 12'x12 30 mn with radial line of 0=35° gives a value of 3870« Direction of load, (force, Example C. — Timber joints in general. The direction of load is the direction of the force acting which is the bolt value at N. bearing. Values for connectors and lag screws at various angles are determined the same as for bolts. See Parts V and VII, for values of P and Q. Direction of load. against and normal to the face under consideration. The stress value on two contact faces is governed by the face cut at the lesser angle to the grain. If a joint angle is bisected, as angle A, the stress values of adjacent faces are equal. P=Unit stress in compression parallel to the grain. Q=Unit stress in compression perpendicular to the grain. G = Angle between the direction of grain and direction of load normal to the face considered, N=Unit compressive stress at inclination 0 with the direction of grain. ’ The difference between the two charts is a difference in scale, the one on the right being adapted to the large values of big bolts and the one on the left for timber joints and lag screw values. Example A. — Timber joint. Given: Allowable unit stresses of P= 1550 #/□" Q= 455X^0« 0= 40° Required: The value of N; Connect pointx on line AC at value of 455« 0=40' with pointy on line AB at 65 value of 1550^ The radial line of VALUES IN 1000 LBS. PER SQ. IN.FOR P, Q,and N. § g J d intersects this isopleth line . at a value of 777**/n" which is the value of N. Example B. — Bolted joint. Direction of grain. The value of the bolt is found by plotting the isopleth line mn. as instructed in example A, using values of P=5030:B andQs2620*i. Bolt values for P and Q are obtained from Table 12. The intersection of line Direction of grain. Angle of face to grain.- -59« NATIONAL EMERGENCY SPECIFICATIONS APPENDIX D RECOMMENDED CONSTRUCTION PRACTICES A. Care of Material 1. Lumber shall be so handled and covered as to prevent marring, and moisture absorption from snow or rain. B. Foundations 1. Foundations shall be adequate to support the building or structure and any required loads, without excessive or unequal settlement or uplift. 2. For permanent structures it is desirable: (a) That foundations or piers be of concrete, masonry, wood with an approved preservative treatment, or the heartwood of a durable species; (b) That the space under the floors of buildings without basements or cellars be ventilated through foundation walls by openings having a net area of not less than 2 square feet for each 25 linear feet of exterior wall; (c) That a ventilating space of at least one-half inch, preferably more, be provided on sides, tops, and ends of wood members such as girders, beams, or other structural members where surrounded by masonry, or concrete; (d) That basement and exterior posts of materials other than provided in paragraph B-2 (a) be placed on concrete, masonry or cast-iron base blocks or piers extending at least 2 inches above floor levels or 6 inches above the finished ground level. (e) That, wherever there is need to take precautions against entry of termites from the ground into the structure, all debris, whether above or below the ground, shall be removed from around foundations and under the structure, and one or more of the following construction practices shall be followed: (1) Extend foundations at least 12 inches and preferably 18 inches above ground under the building and provide a solid reinforced cement mortar cap 2 inches thick over foun-. dations of unit or hollow block construction. If foundations can be readily inspected for termite shelter tubes, the exterior grade line may be a minimum of 6 inches from the sills or siding. (2) Place metal termite shields of an approved design at the upper edges of all unit or block foundation walls and piers, and, if not on top, in the sides of all monolithic foundation walls and piers, and around all pipes entering buildings, except that the overhanging portion of the shield may be omitted on exterior surfaces and basement or cellar interiors, which are open to easy occasional inspection. Foundations not easily inspected shall have termite shields set at least 12 inches and preferably 18 inches above the ground. (3) Where structural lumber is in contact with the soil, or is less than 12 inches from the ground and not protected by termite shields, except for the exterior 6-inch minimum clearance as noted in recommendation in paragraph B-2 (e) (1), it shall be impregnated with an approved preservative or be the heartwood of a termite resistant species. (4) Insulate outside steps from the soil by masonry foundations; also insulate steps from buildings or porches by metal shields. C. Structural Design 1. Consideration shall be given in the design to the possible effect of cross grain dimensional changes which may occur in lumber fabricated or erected in a green condition, i. e., provisions shall be made in the design so that if dimensional changes caused by seasoning to moisture equilibrium occur, the structure will move as a whole, and the differential movement of similar parts and members meeting at joints will be a minimum. 2. When lumber is fabricated green and used in a dry location, application of end sealers to exposed end grain of material while wet is recommended. (See reference 42, Appendix E.) D. Drainage 1. In exterior structures the design shall be such as to minimize pockets in which moisture can accumulate, or adequate caps, drainage, and drips shall be provided. E. Camber 1. Adequate camber in trusses to give proper appearance and to counteract any deflection from - 60- FOR STRESS GRADE LUMBER loading should be provided and for connector construction may be estimated from the formula: △ Ty I -^2 yy in which A=recommended camber in inches at center of truss Z=span of truss in feet H=height of truss in feet at center K\—0.000032 for any type of truss X2= 0.0028 for flat and pitched trusses, or 0.00063 for bowstring trusses, i. e., trusses without splices in upper chord. F. Erection 1. Provision shall be made to prevent the over-stressing of members or joints during erection. 2. Bolted connections shall be snugged-up but not to the extent of crushing wood under washers. G. Inspection 1. Provision shall be made for competent inspection of materials and workmanship. H. Maintenance 1. There shall be competent inspection and tightening of bolts (see par. F-2) in joints of trusses and structural frames after the material has seasoned, but within the first year after erection. - 61 - NATIONAL EMERGENCY SPECIFICATIONS APPENDIX E REFERENCES 1. American Lumber Standards for Softwood Lumber— Simplified Practice Recommendation R1&-39, by Bureau of Standards, U. S. Department of Commerce* (1939). 2. Wood Handbook—Basic Information on Wood as a Material of Construction with Data for Its Use in Design and Specifications, by Forest Products Laboratory, U. S. Department of Agriculture* (1940). 3. Miscellaneous Publication No. 185, Guide to the Grading of Structural Timbers and Determination of Working Stresses, by T. R. C. Wilson, Forest Products Laboratory, U. S. Department of Agriculture* (1934). 4. Technical Bulletin No. 479, Strength and Related Properties of Woods Grown in the United States, by L. J. Mark-wardt and T. R. C. Wilson, Forest Products Laboratory, U. S. Department of Agriculture* (1935). 5. Grading Rules for Lumber. See column 2 of Table No. 1 in Part II. 6. Anchorage for Factory Roofs—Principles and Design Data, by Associated Factory Mutual Fire Insurance Companies, Boston, Mass; (1940). 7. Factory Roofs Need Anchorage—Various Studies of Wind Forces and Their Effects Upon Buildings, by Associated Factory Mutual Fire Insurance Companies, Boston, Mass. (1940). 8. Technical Bulletin No. 597, Lag Screw Joints; Their Behavior and Design, by J. A. Newlin and J. M. Gahagan, Forest Products Laboratory, U. S. Department of Agriculture* (1938).' 9. Technical Bulletin No. 332, The Bearing of Wood Under Bolts, by G. W. Trayer, Forest Products Laboratory, U.. S. Department of Agriculture* (1932). 10. Technical Bulletin No. 691, The Glued Laminated Wooden Arch, by T. R. C. Wilson, Forest Products Laboratory, U. S. Department of Agriculture* (1939). 11. Department Bulletin No. 1500, The Gluing of Wood, by T. R. Truax, Forest Products Laboratory, U. S. Department of Agriculture* (1929). 12. Wood Structural Design Data, Volume I and 7 Supplements, by National Lumber Manufacturers Association, Washington, D. C. (1941). 13. Douglas Fir Use Book and 4 Supplements, by West Coast Lumbermen’s Association, Seattle, Wash. (1940). 14. Southern Pine Manual of Standard Wood Construction, by Southern Pine Association, New Orleans, La. (1942). 15. Timber—Concrete Composite Decks—for Bridges, Piers, Docks, Ramps, Buildings, and other Structures Requiring Heavy Duty Floors, by Service Bureau, American Wood Preservers’ Association, Chicago, Ill. (1941). 16. Highway Technical Bulletin No. 1, Loading Tests on a New Composite Type Short Span Highway Bridge Combining Concrete and Timber in Flexure, by R. H. Baldock and C. B. McCullough, Oregon State Highway Commission (about 1933). »Available from Superintendent of Documents, Government Printing Office, Washington, D. C. 17. Designing for Strength of Flat Panels with Stressed Coverings, by J. A. Newlin, Forest Products Laboratory7, Madison, Wis. Mimeograph R-1220 (1940) . 18. Formulas for Wood Columns with Side Loads and Eccentricity, by J. A. Newlin, Building Standards Monthly, December 1940. 19. Standard Specifications for Highway Bridges, by American Association of State Highway Officials, Washington, D. C. (1941). 20. Trouble-Shooter for Joint-Gluing, by Casein Company of America, New York, N. Y. (1942). 21. Exposing the Termite, by National Lumber Manufacturers Association, Washington, D. C. (1937). 22. Wood as a Structural Material, by F. J. Hanrahan, Roads and Streets, November and December 1940. 23. Built-Up Wood Columns Conserve Lumber, by J. A. Scholten, Engineering News-Record, August 27, 1931. 24. Plywood Bonding with Resin Adhesives, by the Resinous Products and Chemical Company, Philadelphia, Pa. (1942). 25. Technical Data on Plywood, by Douglas Fir Plywood* Association, Tacoma, Wash. (1942). 26. Construction Glues, by I. F. Laucks, Inc.-, Seattle, Wash. (1942). 27. Designing Timber Connector Structures, by Timber Engineering Company, Washington, D. C. (1940). 28. Fabricating Teco Timber Connector Structures, by Timber Engineering Company, Washington, D. C. (1942). 29. Typical Designs of Timber Structures, by Timber Engineering Company, Washington, D. C. (1942). 30. Blue Ox Series of Typical Designs, by West Coast Lumbermen’s Association, Seattle, Wash. (1940-42). 31. A Course in Modern Timber Engineering, by H. J. Hansen, Southern Pine Association, New Orleans, La. (about 1941). 32. Modern Timber Highway Bridges, by Timber Engineering Company, Washington, D. C. (1942). 33. Highway Structures of Douglas Fir, by West Coast Lumbermen’s Association, Seattle, Wash. (1941). 34. Typical Highway Bridges of Pressure-Treated Timber, by The Wood Preserving Corporation, Pittsburgh, Pa. (about 1940). 35. Acceptable Bridge Plans and Standard Lookout Structure Plans, by Division of Engineering, Forest Service, U. S. Department of Agriculture (about 1940). 36. Reports of Committee 7 on Wood Bridges and Trestles, American Railway Engineering Association, Chicago, Ill. 37. Heavy Timber Construction Details, by National Lumber Manufacturers Association, Washington, D. C. (1943). 38. Lumber Grade-Use Guide for Softwood and Hardwood Lumber in Building and General Construction, by National Lumber Manufacturers Association, Washington, D. C. (1943). 39. Lumber Literature (a bibliography of literature available from various lumber manufacturers associations), by - 62 - FOR STRESS GRADE LUMBER National Lumber Manufacturers Association, Washington, D. C. (1942). 40. Redwood Technical Data Series, California Redwood Association, San Francisco, Calif, (current). 41. Experience in Maintenance of Large Timber Structures, by John J Gould, Engineering News-Record, August 15, 1940. 42. End Seals for West Coast Lumber, by West Coast Lumbermen’s Association, Seattle, Wash. (1942). 43. Fabrication of Laminated Timber Members, by Verne Ketchum, Civil Engineering, February 1943. 44. Timber Structures, by L. P. Keith, Civil Engineering, October 1942. - 63 -