Author: workhouse123
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CONCRETE STAIRS
A concrete stair (Figure 14.40) may be thought of as an inclined one-way solid slab with additional concrete added to make risers and treads. The underside of the formwork is planar. The top is built with riser forms, which are usually inclined to provide greater toe space and make the stair more comfortable to users.…
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TWO-WAY FLOOR AND ROOF FRAMING SYSTEMS
Two-way concrete framing systems are generally more economical than one-way systems in buildings where the columns can be spaced in bays that are square or nearly square in proportion. A two-way solid slab is a rarely seen system, occasionally used for very heavily loaded industrial floors, in which the slab is supported by a grid of beams…
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ONE-WAY FLOOR AND ROOF FRAMING SYSTEMS
One-Way Solid Slab System A one-way solid slab (Figures 14.16–14.19) spans across parallel lines of support furnished by walls and/or beams. The walls and columns are poured prior to erecting the formwork for a one-way slab, but the forms for the girders and beams are nearly always built continuously with those for the slab, and girders, beams,…
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CASTING A CONCRETE WALL
A reinforced concrete wall at ground level usually rests on a poured concrete strip footing (Figures 14.5–14.7). The footing is formed and poured much like a concrete slab on grade. Its cross-sectional dimensions and its reinforcing, if any, are determined by the structural engineer. A key, a groove that will form a mechanical connection to the…
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Pouring and Finishing the Slab on Grade
Pouring (casting) of the slab commences with placing concrete in the formwork. This may be done directly from the chute of a transit-mix truck, or with wheelbarrows, concrete buggies, a large crane-mounted concrete bucket, a conveyor belt, or a concrete pump and hoses. The method selected will depend on the scale of the job and…
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CASTING A CONCRETE SLAB ON GRADE
A concrete slab on grade is a level surface of concrete that lies directly on the ground. Slabs on grade are used for roads, sidewalks, patios, airport runways, and basements or ground floors of buildings. A slab-on-grade floor usually experiences little structural stress except a direct transmission of compression between its superimposed loads and the ground beneath,…
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GLASS AND THE BUILDING CODES
Building codes are concerned with several functional aspects of glass: its structural adequacy against wind and impact loads; its role in providing natural light in habitable rooms; its breakage safety; its safety in preventing the spread of fire through a building; and its role in determining the energy consumption of a building. The International Building…
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GLASS AND ENERGY
Glass is a two-way pipeline for the flow of both conducted and radiated heat. As noted previously, glass, even when doubled or tripled, conducts heat rapidly into or out of a building. It can also collect and trap large amounts of solar heat inside a building. In residential buildings, the conduction of heat through glass…
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GLAZING
Glazing Small Lights Small lights of glass are subjected neither to large wind force stresses nor to large amounts of thermal expansion and contraction. They may be glazed by very simple means (Figure 17.16). In traditional wood sash, the glass is first held in place by small metal glazier’s points and then sealed on the outside with glazing…
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THE MATERIAL GLASS
The major ingredient of glass is sand (silicon dioxide). Sand is mixed with soda ash (sodium hydroxide or sodium carbonate), lime, and small amounts of alumina, potassium oxide, and various elements to control color, then heated to form glass. The finished material, while seemingly crystalline and convincingly solid, is actually a supercooled liquid, for it…