INTERIM TRANSITION: Are there any questions about the demonstration? If not, let’s move on. (On SLIDE #27) e. Vertical reinforcement bars are placed in the cores, and filled with concrete or mortar. When block walls will be supporting heavy structural loads, cores will be filled with a 1:2:4 concrete mix ratio at places where girders will rest. The cores must be filled from the footing to the bearing surface of the wall. f. Horizontal truss type reinforcement is placed every second course (16 inches) vertically up the wall to reduce shrinkage and settlement cracks. g. In walls 20 feet and longer, 8" x 16" vertical pilasters are placed every 10' and filled with concrete to make the walls more rigid. (On SLIDE #28) TRANSITION: We have just covered the fundamental characteristics of masonry building materials. Are there any questions? OPPORTUNITY FOR QUESTIONS: 1. QUESTIONS FROM THE CLASS: Do you have any questions concerning the characteristics of masonry building materials? (Answer student’s questions.) 2. QUESTIONS TO THE CLASS: a. What are the two types of concrete block? ANSWER: Heavyweight, and Lightweight. b. What size are CMU’s manufactured? ANSWER: Full and Half block sizes. (BREAK 10 Min) TRANSITION: Before the we covered the fundamental characteristics of masonry building materials. Do you have any questions? If not, let’s discuss the fundamental characteristics of wooden building materials. (On #29) trial
4. WOOD: (60 Min) Materials made of wood come in a variety of species, grades, and All wooden members must be carefully selected to serve their intended purpose when designing a structure. a. The particular species of wood dictates its intended use in the construction of a structure. INSTRUCTORS NOTE: Use wood species in outline to clarify. WOOD SPECIES AND USES TYPE USES CHARACTERISTICS BIRCH Cabinet work, interior finishes, plywood Hard, durable, fine grain, heavy, stiff, strong, works easily, but is not durable when exposed to the elements. DOUGLAS FIR Building construction of structural members requiring higher strengths. Excellent structural lumber, strong, easy to work, clear straight grained, soft but brittle. Best structural timber. MAHOGANY Furniture, decks, interior trim. Most useful for cabinet work, hard, durable, but checks, swells, shrinks, and warps slightly. RED OAK Interior finish, cabinets, millwork Tends to warp, coarse grain, does not last well when exposed to weather, Heavy, tough, and strong. WALNUT Furniture, cabinets, interior woodwork Fine cabinet wood, coarse grained but takes finish well, medium weight, hard, strong, easily worked but brittle. Does not warp or check. WHITE CEDAR Shingles, siding, posts, poles Soft, light weight, close grained, very durable when exposed to water, not strong enough for building construction, generally knotty. WHITE OAK Framing for buildings, furniture, fence posts. Heavy, hard, strong, medium coarse grain, tough, dense, most durable of all hardwoods. Easy to work, but shrinks, and checks. WHITE PINE Interior trim, cabinets, millwork Easy to work, fine grain, free of knots, durable when exposed to water expands when wet, shrinks when dry. Soft, does not split when nailed.
MH Poor Medium to Very High Not suitable Poor to Fair CH Poor to Very Poor Medium Not suitable Practically Impervious OH Poor to Very Poor Medium Not suitable Practically Impervious PT Not suitable Slight Not suitable Poor to Fair d. There are three basic types of foundations used for the construction of any type of structure. As the mission dictates, these types of foundations can be combined. (On SLIDE #45) (1) “T” foundations have a trench footing with a concrete wall or concrete block wall resting on top of it. This type of foundation is used if the structure requires a basement or crawl space. (On #46) (2) Slab foundations are prevalent in construction where a basement or crawl space is not required. This type of foundation consists of a concrete slab which is poured directly on the ground, with trench footings poured at locations where additional support is required. (On SLIDE #47) (3) Pier-and-Column foundations consist of individual footers with a column placed on top of it. This type of foundation combination is used primarily for the support of girders and beams which support structural floor members. (Off #48) TRANSITION: We have just covered foundation systems. Are there any questions? OPPORTUNITY FOR QUESTIONS: 1. QUESTIONS FROM THE CLASS: Do you have any questions concerning foundation systems? (Answer students’ questions.)
(On SLIDE #69) (3) Type III (a) Type III slabs are constructed over problem soils. They are reinforced and stiffened to transmit structure loads to the foundation soil. (b) Type III slabs can be built on problem soils such as CL, OL, CH, OH. High organic soils (PT) should not be used to support Type III slabs. (On SLIDE #70) (4) Type IV (a) Type IV slabs are greater than 4" nominal thickness. The base course (slab bed) material functions as only as a form to provide temporary support during curing. (b) They do not depend on the foundation soil for support. (c) The soil for Type IV slabs can be CL, OL, CH, OH, and PT. (d) Type IV slabs must be designed by professional structural engineers. Structurally supported slabs are independently supported and rest on foundation walls, and piers. They are structurally reinforced, and can be used over very poor soils and are designated as Type IV. (On #71) b. The type of slab to be poured falls into 6 specific classifications for projects requiring slab work. These classifications enable us to design the minimum thickness required for a slab to carry a load without failing. (On SLIDE #72) (1) Class 1: (a) Light foot traffic. (b) Used for light frame structures. (c) Minimum of 4” thick. (d) 28 day compressive strength of 3,500 psi.
(6) Class 6: (a) Heavy foot and steel tire traffic. (b) Used for heavy industrial structures. (c) Over 8” thick (d) 28 day compressive strength of 5,000 to 8,000 psi. (On SLIDE #78) c. The excavation for the slab foundation is made for the footings only. The depth of the footings is dictated by the depth required to ensure the bottom of the footing is below the frost line. If bearing walls are erected on the slab, the width of the footing base is twice the width of the wall itself. On SLIDE #79) (On SLIDE #80) d. The slab itself is placed on the ground surface and is formed using either 2" x 4" or 2" x 6" form material. e. Slab foundations must have a base course lift of a minimum of 4" of compacted gravel, sand, or crushed rock under the concrete slab to act as an insulator and provide additional stability for the slab itself. f. A polyethylene vapor barrier of at least .006 mil plastic is placed between the gravel base course and the concrete slab to prevent
24 21-3 16-11 18-3 16-6 13-1 14-2 2 x 12 12 16 24 33-5 30-0 25-10 29-1 25-2 20-6 31-4 27-2 22-2 26-6 24-4 20-0 22-6 19-6 15-11 24-4 21-1 17-2 MAXIMUM RAFTER SPANS Selected Species Southern Yellow Pine Yellow Pine Fir Yellow Pine White Pine Fir Grades NO. 1 NO. 2 NO. 2 NO. 1 NO. 2 NO. 2 HIGH SLOPE (Over 3:12) Size Spacing O.C. 20# Live Roofing 40# Live Load-Heavy Roofing 2 x 4 12 16 24 11-6 10-5 8-6 10-3 9-1 7-4 11-0 9-6 7-9 8-5 7-3 5-11 7-4 6-4 5-2 7-8 6-8 5-5 2 x 8 12 16 24 18-1 16-4 13-4 15-0 13-0 10-7 16-2 14-0 11-5 13-2 11-5 9-4 10-6 9-1 7-5 11-4 9-10 8-0 2 x 10 12 16 24 23-8 21-6 17-7 19-9 17-1 13-11 21-4 18-5 15-1 17-5 15-1 12-4 13-10 12-0 9-9 14-11 12-11 10-7 2 x 12 12 16 24 30-3 27-5 22-5 25-2 21-10 17-10 27-2 23-7 19-3 22-2 19-3 15-8 17-8 15-3 12-6 19-1 16-6 13-6 INTERIM TRANSITION: Any questions on what we just covered before the demonstration. INSTRUCTORS NOTE: Use dry erase board to illustrate “birds-mouth” cut. (On SLIDE #116) DEMONSTRATION. (5 min) Gather the students attention to the dry erase board and chosen table/desk for a brief demonstration of the cut technique. STUDENT ROLE: Observe the cut technique. INSTRUCTOR(s) ROLE: Visually demonstrate, by illustration and/or actual samples, to the students’, the “birds-mouth” cut fastening technique.