Chapter 05 Wood PDF

WOOD by Engr. Alexis T. Belonio Department of Agricultural Engineering and Environmental Management College of Agriculture Central Philippine University Iloilo City [email protected]  Introduction Wood is one of the mo...

WOOD by Engr. Alexis T. Belonio Department of Agricultural Engineering and Environmental Management College of Agriculture Central Philippine University Iloilo City [email protected]  Introduction Wood is one of the most common construction materials. They are very difficult to classify, select, and use correctly due to the great variation in the properties of the different species and to the influence of defects in growth and seasoning.  Advantages of Wood In proportion to weight, wood is stronger than other materials Easily worked out with tools and fabricated into many shapes, sizes, and design. Excellent non-conductor of heat. Abundant is many shapes, color, sizes, and as renewable resources. Does not deteriorate if properly handles and protected  Wood Properties Strong material Durable Light in weight Ease of working and fastening With artistic and natural beauty 1. Soft Wood – It comes from the needle-leaved, cone bearing trees 2. Hard Wood – It Comes from the deciduous or broad leaf tree. Classifications of Wood  Wood Defects Compression Wood Decay Pitch Pocket Shake Mineral Streaks Mold and Staining Fungi Knots Cross Grain Wood Processing  Wood Surfaces Face End Edge  Lumber Lumber – term applied to wood after it was sawed or sliced into boards, planks, sticks, etc for commercial purposes.  Some Definitions Surfaced or Dressed Lumber – is a planed lumber having at least one smooth side S2S and S4S – planed or dressed lumber of which the number connotes the smooth side. S2S smooth on two sides while S4S smooth on four sides. Rough Lumber - is the term applied to newly sawed lumber.  Timber – is a piece of lumber five inches or larger in smallest dimension. Plank – is a wide piece of lumber from 2 to 5 inches thick Board – is a piece of lumber less than 1-1/2 in thick and at least 4 inches wide Flitch – is a thick piece of lumber Slab - kind of rough lumber cut tangent to the annual rings of wood running the full length of the log and containing at least one flat surface.  Measuring Wood Board Foot – it means the one square foot of wood one inch thick or 144 cubic inches. Formula: Bd-Ft = T(in) x W(in) x L(ft) / 12 Bd-Ft = T(in) x W(ft) 1 ft x L (ft)/144 1 ft 1 in.  Compute the total cost of 50 pcs-2 x 3 x 12 lumber at P27/bd ft. Given: No. of pieces of lumber - 50 pieces Size of lumber - 2” x 3” x 12’ Price per bd ft - P 27 / bd ft Required: Total cost of lumber Solution: bd ft = (2” x 3” x 12”) 12 = 6 bd ft total bd ft = 6 bd ft/piece x 50 pieces = 300 bd ft Total cost of lumber = (300 bd ft) ( P27 / bd ft) = P8, 100 Determine the number of board foot of wood having the following dimension and number of stocks: (a) 40 pcs - 2 in. x 4 in. x 10 ft; (b) 120 pcs - 1 in. x 2 in. x 12 ft; (c) 500 pcs - 2 in. x 2 in x 8 ft; and (d) 20 pcs - 1 in. x 1 ft x 10 ft. Also compute the total cost of the stocks of wood if the cost per board foot is P30.00. Given: Wood sizes and stocks 40 pcs - 2 in. x 4 in. x 10 ft 120 pcs - 1 in. x 2 in. x 12 ft 500 pcs - 2 in. x 2 in x 8 ft 20 pcs - 1 in. x 1 ft x 10 ft Price per board foot - P30.00 Required: Total number of board foot and cost of the materials Solution: Bd-ft (A) = 2 in. x 4 in. x 10 ft /12 = 6.07bd-ft/pc x 40 pcs = 266.67 bd-ft Bd-ft (B) = 1 in. x 2 in x 12 ft / 12 = 2 bd-ft/pc x 120 pcs = 240 bd-ft Bd-ft (C) = 2 in x 4 in x 8 ft / 12 = 2.67 bd-ft/pc x 500 pcs = 1,333 bd-ft Bd-ft (D) = 1 in. x 1 ft x 10 ft / 144 = 0.869 bd-ft x 20 pcs = 1.39 bd-ft Total Bd-ft = 266.67 bd-ft + 240 bd-ft + 1,333 bd-ft + 1.39 bd-ft = 1,841.06 bd-ft Cost = 1,841.06 bd-ft x P30.00 /bd-ft = P55,231.80  Lumber and Related Products Veneer and Plywood – light in weight and strong. Thickness available from 1/8 to ¾ in. Standard length and width are 8 ft x 4 ft, respectively. Types includes – Soft plywood – Harwood plywood – Exterior or marine plywood  Hardboard – are pressed wood made from wood chips exploded into fibers under high pressured steam. Particle Board – manufactured from wood chips, curls, fibers, flakes, strands, shaving, etc bound together and pressed into sheets and other molded shapes. Samples of Hardboard  References: Fajardo, M. B. 2000. Simplified Methods on Building Construction. 5138 Merchandizing. 389pp. Velasco, R. A. 1977. Handbook of Construction Estimate. Loacan Publsihing House. Manila. 147pp.