Report, Tema 1903U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, 1951 |
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12-percent moisture content applied average Baldcypress basic stress beams bending boards bolt cedar coating color column compression compression members connector construction creosote cubic foot decay defects diameter Douglas-fir eastern eastern hemlock effect face factor fiber finish flooring foot at 12-percent Forest Products Laboratory FOREST SERVICE formula glue glued grade growth ring hardwoods heartwood heat hemlock hickory illus inches insulation joints knots laminated load lumber manufactured maple material moderately modulus of elasticity nails paint panels parallel to grain percent moisture content perpendicular piece piling plies plywood poles ponderosa pine pounds per cubic Products Laboratory Report redwood Rept resin resistance sapwood seasoned shear shrinkage side softwoods southern yellow pine species specific gravity spruce stain Standard strength properties strength ratio structural surface temperature tests thickness timber treated treatment U. S. Dept values veneer weight Western redcedar width Wood Preservers zinc chloride
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Página 20 - I the moment of inertia of the section about the neutral axis in (inches)4. § 4. Theorem of Three Moments. Suppose fig. 84 represents a part of a loaded beam resting on a number of supports of which three are indicated (A, B and C). It will be justifiable to discuss the effect of the loading by concentrating attention on any portion of it provided the effect of the remainder...
Página 6 - Association. Nomenclature of Commercial Softwoods The names of lumber adopted by the trade as American lumber standards are not always identical with the names adopted as official by the Forest Service. Where the names are not identical some confusion may...
Página 27 - Surfaced and matched; that is, surfaced one or two sides and tongued and grooved on the edges. The match may be center or standard.
Página 5 - If butt joints are used in compression members, the effective crosssectional area should be computed by subtracting from the gross cross-sectional area the area of all laminations containing butt joints at a single cross section. In addition, laminations...
Página 3 - Compreg is extremely useful for aluminum drawing and forming dies, drilling jigs, and jigs for holding parts in place while welding because of its excellent strength properties, dimensional stability, low thermal conductivity, and ease of fabrication.
Página 2 - Moisture content is the weight of the water contained in the wood expressed as a percentage of the weight of the oven-dry wood. The moisture content given for green wood is the average for specimens taken from the pith to the circumference of the log.
Página 5 - Butt joints generally can transmit no tensile stress and can transmit compressive stress only after considerable deformation or if a metal bearing plate is tightly fitted between the abutting ends. In normal assembly operations such fitting would not be done, and it is therefore necessary to assume that butt joints are ineffective in transmitting both tensile and compressive stresses. Because of this ineffectiveness, and because butt joints cause concentration of both shear stress and longitudinal...
Página 1 - Equilibrium Moisture Content Any piece of wood will give off or take on moisture from the surrounding atmosphere until the moisture In the wood has come to a balance with that In the atmosphere. The moisture In the wood at the point of balance Is called the equilibrium moisture content.
Página 21 - ... not exceed 30 to 1. The following rules for lateral deflection are conservative and can be used to check a design for lateral stability: (1) If the ratio of the moment of inertia of the cross section about the neutral axis to the moment of inertia about the axis perpendicular to the neutral axis does not exceed 5 to 1 , no lateral support is required. (2) If the ratio of the moments of inertia is between 5 to 1 and 10 to 1, the ends of the beam should be held in position at the bottom flange...
Página 9 - The size of knots on wide faces may increase proportionately from the size permitted at the edge to the size permitted along the center line.