BSCI2300 031124 Steel (Slides 205) PDF

Intro to Steel Division 05 00 00 Metals In Pre-Modern Building Construction Iron tie rods and cramps in masonry construction, Pantheon, Paris, 1789 Crystal Palace, 1851 Coalbrookdale Bridge, 1779 Home Insurance Company Building, 1885, Modern Steel is one of three commonly used noncombustible structu...

Intro to Steel Division 05 00 00 Metals In Pre-Modern Building Construction Iron tie rods and cramps in masonry construction, Pantheon, Paris, 1789 Crystal Palace, 1851 Coalbrookdale Bridge, 1779 Home Insurance Company Building, 1885, Modern Steel is one of three commonly used noncombustible structural materials. (Concrete and masonry are the others.) Suitable for construction of buildings of all sizes, from single family residences to the tallest skyscrapers. THE MATERIAL STEEL Carbon content is the crucial determinant of the properties of the steel. Too much carbon makes a hard but brittle metal Too little carbon results in a relatively soft and malleable metal Mild steel (low carbon steel) Utilized for structural steel members Not more than 0.3% carbon Small amounts of other alloys, such as nickel, chromium, molybdenum, manganese, vanadium, and silicon improve strength, toughness, and other qualities Reasonably strong, highly ductile, and easily welded Equally strong in tension and compression MAKING STEEL Two primary methods to process steel` Basic Oxygen Process = 40% http://www.youtube.com/watch?v=iRss4r0f7Hk 2. Electric Arc = 60% https://www.youtube.com/watch?v=8J3bMtX9Wqo 1. Steelmaking: Mini Mill Scrap metal is charged into the furnace. Electrodes are lowered into the scrap. An electric current flows through the electrodes creating an arc that melts the metal. Large amounts of externally supplied energy are required. Oxygen is injected to oxidize impurities and enhance heating. Flux is added to draw off impurities. Once the charge is fully melted, additional scrap may be added. The mixture is sampled, and ingredients and the process are adjusted as needed. Molten steel and slag are separately poured off. Additional alloying elements may be added to the steel. Steelmaking: Casting Steel is cast into a variety of shapes, ranging from plain rectangles or rounds to more complex cross sections, such as beam blanks or blooms, that approximate the shape of finished beam products. Right: In the continuous casting process, casting begins once the outer shell of the steel mass has solidified, while the inner portion is still molten. http://www.youtube.com/watc h?v=d-72gc6I-_E Production of Structural Shapes Structural shapes are produced in a rolling mill. Prior to rolling, the beam blanks are reheated to the necessary temperature. Blanks then pass through a series of rollers in which they are progressively deformed into the desired final shape. Production of Structural Shapes Wide-Flange (WShape) : The most commonly used shape for beams and columns; Not an "Ibeam"! Channels, angles, tees: For trusses, lighter weight framing, and other miscellaneous uses American Standard: Traditional I-beam with a shape that is less structurally efficient than a contemporary wide-flange of the same weight Wide-Flange Shapes Example designation: W10 x 30 W: Wide-flange shape 10: Nominally 10 inches deep 30: weighing 30 pounds per lineal foot The unshaded portions of the diagrams illustrate how a variety of weights of beams can be rolled from the same set of rollers by opening up the space between the rollers. Which W Shape would weigh more per lineal foot? W10 x 30 B. W10 x 112 A. Steel Alloys By adjusting the chemistry, alloying, and forming processes of steel, a multitude of different steel types with varying physical properties can be made. Example: ASTM A913 steel High-strength, low-alloy, steel that has been modified by thermal processes after rolling to impart a particularly desirable combination of strength, weldability, and toughness characteristics Especially suited for welded, heavy weight members and for use in structures in areas of high seismic risk Heart Tower New York City used ASTM A913 High Strength Steel Steel Alloys Traditional mild steel ASTM A36 Minimum 36 ksi (36,000 lb per sq. in.) yield strength Contemporary high- strength, low alloy steels ASTM A992: W shapes ASTM A572: other shapes Produced economically in mini-mills Minimum yield strength 50 to 65 ksi Use of stronger steel allows savings in weight and reductions in the size of structural elements, reducing overall costs. ASTM A992 steel columns lay stacked in a fabricator yard. Note the holes predrilled for connections that will be completed in the field. More Steel Alloys Weathering steel ASTM A588 Surface rust adheres to base metal, limiting further rusting Mostly used in highway and bridge structures, eliminating the need for a protective coating Right: 365-ft span highway arch bridge made principally of weathering steel Cor-Ten steel (a proprietary trade name for weathering steel) Stainless steel ASTM A240, A276 Added nickel and chromium Forms self-protecting oxide layer that provides long lasting protection against corrosion Cold-Worked (ColdFormed) Steel Deforming steel in its cold state causes realignment of the steel crystals and increases its strength. Examples: Corrugated steel decking, rolled from steel sheet (right) Steel studs and joists (Chapter 12) High-strength wire for concrete prestressing strands (Chapter 13) http://www.youtube.com/watc h?v=1SFvvTZAPn0 Hollow Structural Sections (HSS) Hollow square, rectangular, round, and elliptical shapes Made by cold- or hotforming steel strip (sheet) and welding longitudinally Example designation: HSS 8 x 8 x ½ Hollow structural section 8" x 8" nominal size ½" wall thickness HSS shapes are used for trusses, structurally efficient column sections, and where the simple outside profile is desirable. Open-Web Steel Joists (OWSJ) Lightweight trusses, manufactured in standard configurations Made from both hot- and cold-formed components Depths range from 8 in. to 6 ft Traditionally spaced 2 to 10 ft on center; more recently, wider spacings are being used for greater economy Right: Note the deeper joists for the two floor levels, which carry greater loads than the more shallow roof joists above. Steel LIGHT GAUGE STEEL Light Gauge Steel Framing Members C-Studs Light gauge steel C-studs web depths range from 2 ½” to 14” Light gauge steel C-studs return depths include 3/8”, ½”, 5/8”, 1” Flange sizes range from 1 3/8” to 3” Tracks U-channels Used for bridging, blocking, and other reinforcing and bracing Standard sizes Depth ¾ to 2-1/2 in. Width ½ in. Example designation: 075U50-54 0.75 in. deep U-channel 0.50 inches wide 54 mils metal thickness Bridging Furring Channels Light gauge steel members are also used for furring Also called hat channels Standard sizes Depth 7/8 or 1-1/2 in. Width 1¼ in. at raised surface, 2½ in. at base Furring cont. Furring: Allows for the installation of flat wall finish over an irregular surface Provides a concealed space for installing plumbing, wiring and thermal insulation Other members used for furring are: Z-furring channel (Bottom left) Adjustable Furring brackets (bottom right) Framing Accessories L-Headers Section View Special Products Jamb Stud Specialized Channels Sheet Metal Thickness Minimum thickness of steel sheet Loadbearing Gauge framing Nonloadbearing framing 12 0.097 in. (2.46 mm) 14 0.068 in. (1.73 mm) 16 0.054 in. (1.37 mm) 0.054 in. (1.37 mm) 18 0.043 in. (1.09 mm) 0.043 in. (1.09 mm) 20 0.033 in. (0.84 mm) 0.030 in. (0.75 mm) 22 0.027 in. (0.69 mm) 25 0.018 in. (0.45 mm) Cutting Light Gauge Sheet Metal Fastening Light Gauge Plug Weld Slot Weld Flare Vee Weld Framing Framing methods parallel wood light frame platform construction. Steel joists spaced from 12 to 24 in. o.c. are framed into tracks or channels. Web stiffeners or reinforcing are inserted where concentrated loads might cause joist webs to buckle. Construction panels are fastened with mastic adhesive and screws. Light Gauge Steel Compared to Light Wood Framing Advantages Like wood light framing: versatile, flexible, simple to construct Noncombustible and immune to insect attack Dimensionally stable, with consistent material properties Lighter weight Disadvantages Members require more frequent bracing Readily conducts heat and requires extra attention to eliminating thermal bridging effects Smaller labor pool Steel Joining Division 05 00 00 Riveting White-hot fastener is inserted through holes in members to be fastened. Fastener is hammered to produce a head on the plain end. Mostly found in historical structures. Not used in modern building construction. Bolting Carbon steel bolts Relatively low strength Limited use; for fastening light framing elements or temporary connections Also called common, or unfinished bolts High-strength bolts Stronger than common bolts Used for fastening primary structural members Bolting Bearing-type connection (left) Body of bolt resists movement between connected members by bearing directly against sides of bolt holes. Bolt is stressed in shear. Connection will experience some slippage before reaching full strength. Allow slight movement Slip-critical connection or Friction-type (right) Bolt is tensioned to such an extent that movement between members is resisted by friction between the adjoining "faying" surfaces of the members themselves. Bolt is stressed in tension. Under normal loads, no slippage occurs. No movement is allowed Slip-Critical Connections Adequate bolt tension must be assured. Turn-of-nut method: Nut is tightened some additional fraction of a turn after achieving a snug condition. Bolt tension is verified by checking selected fastener tightness with a torque wrench. Load indicator washers (right): When bolt is adequately tightened, protrusions on the washer are flattened. Bolt tension is verified by inserting a gauge between bolt head and washer. Slip-Critical Connections Tension control bolt (right): When bolt is adequately tightened, the splined end snaps off. Bolt tension is verified by visually inspecting for splines. An additional advantage of this bolt type is that a second worker is not required to hold the bolt head on the opposite side of the connection during tightening. Welding The joining surfaces of steel members are heated to a molten state, additional molten metal is added, and the members are fully fused. After welding is complete, two members can be joined as if they are one monolithic element. Welding Fillet welds are relatively easy to make, as little preparation of the joint is required. Groove welds require properly shaped and spaced joints. Puddle welds are used to fasten metal decking to structural steel members. Testing Welds Welds that are critical to the stability of the structure can be inspected using a variety of techniques to ensure their soundness and freedom from hidden flaws. DETAILS OF STEEL FRAMING Is this most likely a beam or a column? Shear Connections Joins the web of the beam with bolts The flanges are not connected This pair of lightweight beam-column shear connections rely on shear tabs welded to the column in the fabricator's shop and bolted to the beam webs in the field. The beams are purposely cut slightly short to make it easier to swing them into position between the columns and to allow for minor deviations in column locations. Moment Connections ‘Dog bone’ Cut End Plate Connection Beam-Girder Connection Column Splice Stabilizing the Building Frame The rectangular geometry of the building frame must be made stable against lateral forces by one of three methods: Diagonal bracing and Eccentric Bracing 2. Moment-resisting frame 3. Shear Walls 1. Stabilizing the Building Frame The rectangular geometry of the building frame must be made stable against lateral forces by one of three methods: Stabilizing the Building Frame Inverted vee diagonal bracing in a steel building frame. These bucklingresistant braces are specially designed to deform plastically in a controlled manner during an extreme seismic event and protect the building from the energy of the earthquake. The beam-to-column connections are also moment connections. Exercise What are the members involved? Beam-to-Column Beam-to-Beam Identify the type of connection? Moment vs Shear Identify the type of connection? Rigid (Fully Restrained), Semi-Rigid (Partially Restrained), or Simple What type of loads are resisted? Vertical Bending 9 STONE AND CONCRETE MASONRY CONRETE MASONRY Division 4 Concrete Masonry Concrete Masonry Units (CMUs) Stiff concrete mix pressed into metal molds Concrete Masonry Steam curing in autoclaves accelerates curing Concrete Masonry Standard nominal size: 8" x 8" x 16" Actual size is 3/8-inch less in each dimension. Concrete Masonry Other common sizes: 4", 6", 10", and 12" width 8" in length Concrete Masonry CMU Weight Classifications Heavier weight blocks Less expensive to manufacturer More durable Less moisture absorbent Higher compressive strength Better acoustical isolation between adjacent spaces Lighter weight blocks Less expensive to transport and lay Lower thermal conductivity Higher fire-resistance rating Concrete Masonry ASTM C90 Classifications Lightweight and medium weight are most common. Concrete Masonry Depending on the type of measurement, the number of joint widths in the dimension may be one more, the same, or one less, than the number of blocks. Concrete Masonry https://www.youtube.com/watch?v=rWofXX WOhck Corner leads are laid first. String lines and levels are used to keep walls straight, plumb, and level. Concrete Masonry Joints are tooled and the face of the blocks cleaned as work progresses. Concrete Masonry Vertical reinforcing in grouted cells Lightweight horizontal reinforcing in horizontal mortar joints Concrete Masonry Vertical steel reinforcing in a fully-grouted concrete block wall Concrete Masonry Spanning Openings Structural steel Steel reinforced concrete block Precast concrete Concrete Masonry Decorative or Architectural Units Split-face block Two or more blocks are cast as a single unit. During the curing process, the blocks are split with knifelike blades. Concrete Masonry Ribbed split-face units Concrete Masonry Ground-face block After curing, block surface is ground smooth, creating a polished surface. In any architectural block, the color of aggregates and cement can also be varied. Concrete Masonry Concrete Masonry Concrete Masonry BRICK Division 04 Mortar Stone and brick masonry are the strongest and most durable of preindustrial building materials. Lion’s Gate, 13th C. BCE Mortar Mortar Cushions masonry units, ensuring uniform bearing Seals joints between the units, minimizing the flow of air and water Mortar Portland Cement-Lime Mortar Ingredients: 1. Portland cement 2. Aggregate 3. Hydrated lime 4. Water Mortar Mortar Mix Sand provides the basic structural body of the hardened mortar. There is almost one cubic foot of sand in a cubic foot or mortar. Admixtures Mortar Property Specification Defined by minimum strength and other properties. Any mix of ingredients may be used if strength and other property requirements are met. Performance is established through laboratory testing for the proposed mix. Concrete Masonry Raw Materials Natural clays are excavated from the earth, ground up, and screened to control particle size. Water is added to achieve a plastic consistency ready for molding into bricks. B RICK MASONRY Concrete Masonry Brick Forming Molded Soft mud process Dry-press process Extruded Stiff mud process Concrete Masonry Brick Firing Formed bricks are dried and then kilnfired, where they pass through various stages of drying and chemical transformation. Firing: 10 to 40 hours. Concrete Masonry Fly Ash Brick Made from fly ash (industrial waste product), sand, and water. Formed by molded process. Concrete Masonry Brick Sizes Bricks are available in many sizes. Standard sizes vary regionally. Example Modular–Sized Brick Sizes Nominal Dimensions, in. Joint Thickness, in. W H L Vertical Coursing 3/8 1/2 3 5/8 3 1/2 2 1/4 7 5/8 7 1/2 3 courses = 8 in. 8 3/8 1/2 3 5/8 3 1/2 2 3/4 2 13/16 7 5/8 7 1/2 5 courses = 8 in. 4 8 3/8 1/2 3 5/8 3 1/2 3 5/8 3 1/2 7 5/8 7 1/2 1 course = 4 in. 4 2 12 3/8 1/2 3 5/8 3 1/2 1 5/8 1 1/2 11 5/8 11 1/2 2 course = 4 in. 4 4 16 3/8 1/2 3 5/8 3 1/2 3 5/8 3 1/2 15 5/8 15 1/2 1 course = 4 in. W H L Modular 4 2 2/3 8 Engineer Modular 4 3 1/5 Closure Modular 4 Roman Meridian Actual Dimensions, in. Concrete Masonry Special Shapes Used to form arches, water tables, and other forms and features. Concrete Masonry Solid Brick Cored, solid bricks are lighter in weight than fully solid units. Frogged, solid bricks are less prone to shifting on a wet mortar bed. Concrete Masonry Brick Nomenclature Course: One horizontal row of bricks Bed Joint: Horizontal joint between courses Head Joint: Vertical joint between bricks in same course Concrete Masonry Brick Nomenclature Wythe: One vertical stack of bricks Collar Joint: Vertical joint between wythes Concrete Masonry Dimensioning To the greatest extent possible, brick masonry wall dimensions should conform to the brick module, minimizing the need to cut bricks or work with very small pieces. Concrete Masonry http://www.youtube.com/watch?v=2xTw5sJCdzg Brick Laying Corner leads are constructed ahead of the rest of the wall. Levels and string lines are used to keep the wall straight and true. Concrete Masonry Joint Tooling Examples Concave Mortor Joints Brick Curtain Wall Shelf angle is installed on the structural frame Soft joint or horizontal expansion joint is maintained below the shelf angle a. Silicon Soft Joint b. Compressible Backing Ro Mortar d. Compressible Filler Vertical Expansion Joints Brick curtain walls must be divided vertically by movement joints called vertical expansion joints. Allow the frame and the cladding to expand and contract independently of one another Prevent cracking caused by temperature, moisture expansion, and settlement Back Up Wall CMU wall The brick cladding is laid up from a starting course at each shelf angle. Every six courses, a wire brick tie is attached with two screws through the sheathing. Waterproofing Brick Ties Scaffolding Chicken Salad Chick at Foy Hall Concrete Masonry Spanning Openings Lintels (steel angle, stone, precast concrete, reinforced) Arches Corbelling ROOFING MATERIAL Division 07 Steep Roofs Roof Details Roof Deck Roof Membrane Thermal Insulation Vapor Retarder Flashing STEEP ROOFS Steep Roofs Life expectancy: 15 to 25 years Install roof sheathing (roof deck) – OSB/Plywood Lay underlayment of asphalt-saturated felts or synthetic membranes (30#) Metal Flashing to prevent water intrusion Asphalt or Composition Shingles Shingles – small overlapping units with staggered vertical joints Installed starting from the eaves and working up the slope of the roof, to achieve an overlapping that naturally sheds water off the roof. Valley Installation Types of Roof Coverings Clay and Concrete Tile Slate Tile Metal Roof System Types of Roof Coverings Clay and Concrete Tile Barrel or Cuban Tile Flat Roof Tile Roofing Elements Clay and Concrete Tile Soffit Roofing Flashings & Tools Clay and Concrete Tile Roof Deck Wood: OSB or Plywood Corrugated Steel Purpose: The structural surface that supports the roofing system Concrete: Sitecast or Precast Composite Deck: Corrugated Steel & Concrete Roof Deck The deck must be strong and stiff enough to resist loads from ?: A roof deck must not deflect under the weight of water accumulating on it to the extent that water can accumulate, leading to possible overloading and collapse. Roof Deck A substrate board fastened over a wood roof deck provides a suitable surface for hot asphalt to be applied The substrate board is fastened with screws and oversized washers. The largediameter washers are needed to resist wind uplift forces. Gypsum substrate boards can also contribute to the fire-resistance of the finished roof assembly. Thermal Insulation Batt Insulation Cellulose Fiberboard Purpose: Slow the passage of heat into and out of the building Perlite Foam Insulation Thermal Insulation Vapor Retarders Plastic sheets Bituminous membranes Purpose: Restrict the passage of water vapor and humidity Roofing felts embedded in hot Vapor Retarders Example: Entrapped moisture within the roofing system Flashing & Misc Items Placed around edges and at penetrations to prevent water penetration http://www.youtube.com/watch?v=Bxostp3 _H4Q Pitch Pan Roof Membrane Built Up System Built Up System Modified Bitumen Built Up System Cold Applied Roof Membrane http://www.youtube.com/watch?v=e_tOpY2 CWHE Parapet Wall Detail Where the membrane meets a vertical parapet wall, the membrane and base flashings are turned up and sealed to the wall. Metal counterflashing covers the roof membrane termination, protecting this vulnerable condition from physical damage and leakage. Counter Flashing Base Interior Drain Detail Roof Elements Scupper Drain Lamb’s Tongue Drain Roof Elements Parapet Flashing Paver protection Roof Elements Exterior Wall Treatment BSCI 2300: Construction Methods and Materials Load Bearing Wall – Until late in the 19th century all large buildings were built with loadbearing walls – They were poor insulators, developed water leaks and heavy requiring large foundations – Modern day loadbearing walls have been brought up to date with higher strength masonry and concrete with components such as steel reinforcing, insulation, cavities, flashings, air barriers, vapor retarders. They are used in low and medium rise buildings Curtain Wall The concept of curtain wall was introduced in late 19th century with the advent of skyscrapers It is an exterior wall supported at each story by a frame and derives from the idea that the wall is thin and hangs like a curtain on the structural frame It bears no vertical load and can be thin and light in weight Curtain walls may be constructed in place or prefabricated of masonry, concrete, metal and glass Protection From the Weather The structure is closed in or made "tight to the weather" as soon as possible, so that it may begin to dry Roofing underlayment is installed first, to provide temporary protection from rain until the finish roof covering is installed. The rake metal drip edge has also been installed in this photo. Wall Moisture Barrier The wall moisture barrier may be installed shortly after the framing and sheathing are completed Installed before interior finish work begins Windows and doors can be installed before or after the moisture barrier Moisture Barrier Residential Applications video Self-adhered Waterproofing membrane Building Sealant aka POOKIE Silicone v. Urethane Primary Functions of Cladding Keeping water out Preventing air leakage Controlling light Controlling the radiation of heat Controlling conduction of heat Controlling sound Modern Day Glass and Metal Curtain Wall Secondary Functions of Cladding Resisting wind forces Controlling water vapor Movement – thermal expansion and contraction Movement - moisture expansion and contraction Movement – Structural Resisting Fire Weathering gracefully Glass Siding Board Batten strip Brick Stone Stucco Board siding: Different attachment and overlap provisions allow expansion and contraction of boards. Painted wood clapboard installation over synthetic house wrap Corner board Wood and Hardie Siding Horizontal board siding with corner board Vinyl and cedar shingle siding Vinyl Cedar Shake Close-up of stucco work in progress around a garage opening: to the right, the first scratch coat, and to the left, the second brown coat Windows and Doors Chapter 19 Division 8 http://www.youtube.com/watch?v=xVrJ8DxECbg Window Nomenclature Types of Windows Fixed windows – Hung windows – – Least expensive and least likely to leak air or water Maybe single hung or double hung depending on one or two moving sashes Sashes were hung by counterweights in the past but now use springs Sliding windows – – Essentially like a single hung window on the side Inherently stable operable windows because of tracks Types of Windows Window Frames Aluminum Framed Window Aluminum Clad Wood Framed Window Wood Framed Window Windows Installing Windows Shim Window Frames Comparisons Impact of Window Frame to Overall U Values of Windows Overall U-Factor1 Window Frame Single-glazed Double-glazed, clear Double-glazed, low-e, argon gas Aluminum, without thermal break 1.2 6.8 0.76 4.3 0.60 3.4 Thermal break aluminum 1.0 5.7 0.63 3.6 0.48 2.7 Steel 0.92 5.2 0.55 3.1 0.41 32.3 Wood, clad wood, vinyl 0.84 4.8 0.49 2.8 0.35 2.0 GFRP 0.65 3.7 0.44 2.5 0.27 1.5 1 2 o 2 o U-Factor: Btu/ft -hr- F followed by W/m - K Coefficients of Thermal Expansion Door Nomenclature Types of Doors Glass doors – French doors – – – Open fully and are more welcoming Not easy to regulate air into the room because it can’t be kept partially open Prone to more air leakage Sliding doors – – Large glass doors may slide on tracks or swing open on hinges Can be partially opened to regulate air Can only open half its area Terrace doors – Half leaf can swing open Modes of Door Operation Door Categories Exterior doors Interior doors Weather resistance is an important criteria Solid entrance doors, doors with glass, screen doors, vehicular doors, revolving doors. Most common are swinging doors Passage of sound and fire are important criteria Modes of door operations Swinging, bifold, accordion, sliding, overhead, coiling Types of Doors Performance Many other issues that need to be taken into account in choosing fenestration – – – – – – – – – – Fire Egress Accessibility Accidental breakage Emergency escape Structural performance Resistance to wind and rain Thermal performance Impact resistance Blast resistance GLASS AND GLAZING Division 08 80 Early Glass Production: Crown Glass 10th century A.D. the Venetian Island of Murano had become major center for glassmaking CROWN GLASS PROCESS CYLINDER GLASS PROCESS Early Glass Production: Plate Glass Lack of optical quality of crown and cylinder glass gave way to introduction of plate glass in 17th century France Float Glass Production Process Float Glass In 1959 Pilkington started producing float glass which is the basis of all modern day glass Annealing Lehr gradually cools the glass to avoid locked-in stresses Automatic cutting can produce glass to desired sizes Glass Terminology Annealing cools the glass to avoid locked-in stresses Glazing is the installation of glass or the transparent material in a glazed opening Installer of glass is called Glazier. Individual pieces are called Lights or lites. The Material: Glass Glass is made from – Sand (silicone dioxide) – Lime (calcium) – Soda ash (sodium hydroxide or sodium carbonate) – Alumina – Potassium oxide Glass is supercooled liquid and in sheet form strength is impacted by imperfections in glass Thicknesses is determined by the size of the lite and wind loads Range from 1/8” used for small windows in low buildings up to 1” for larger lites in high rise buildings Annealed and Heat Treated Annealed Cooled slowly to avoid locked in thermal stresses which might cause it to behave unpredictably Used in doubled-glazed windows Heat-Strengthened – Produced by reheating annealed glass and cooled rapidly – Use for windows exposed to heavy wind pressures, impact, intense heat and cold – 2x as strong as annealed glass in bending strength – Breaks like annealed Tempered Glass is Used in Store Front For Strength and Breakage Safety Tempered Glass Produced by cutting annealed glass to required size, reheating and then cooling rapidly Higher residual stresses than heat-treated glass 4x as strong in bending as annealed glass Used for glass doors without frames More costly than annealed Noticeable optical distortions Safety glazing Laminated Glass Laminated Glass Used in Sloped Glazing Provides Safety Against Falling Shards Glass Types by Architectural Treatment Fritted Patterned Spandrel Tinted & Reflective Coated Glass VT and SHGC VT = visible light transmittance is the transparency of glass to visible light Example, clear glass has a VT of 0.80 to – 0.90 means 80-90% of light passes through Remaining 10-20% either reflected or absorbed by the glass and converted to heat Solar Heat Gain Coefficient (SHGC) Measures the effectiveness of glass in reducing heat gain from solar radiation Ratio of solar heat admitted through a piece of glass to total heat energy striking the glass Accounts for solar radiation that passes through the glass + heat that is conducted or radiated Example, clear glass ranging from 0.90 to 0.70 Light to Solar Gain Ratio (LSG) Measure of overall energy-conserving potential of the glass Visible light transmittance divided by the solar heat gain coefficient Impact of Glass Type on Control of Visible Light and Solar Radiation Effect of Three Different Glazing Assemblies on Incoming Sunlight – Outside is on Left Glass and Thermal Considerations IGU – Insulating Glass Unit Made of multiple glass panes with sealed air space reducing conductance – Double glazing is two sheets and triple glazing is three sheets of glass – Space filled by air or inert gas in a sealed cavity – Different spacers used including warm-edge spacer – Performance given in terms of U values Low Emissivity coated glass (Low-e) – Formed with transparent metallic coating to improve thermal performance – Located on surface 2 and sometimes on surface 3. – Improves thermal performance Two Methods of Sealing Edge of Double Glazing Glazing Small Lights Not subject to excessive wind force or stresses due to thermal expansion Glass first held in place by Glazier’s points and then sealed on outside with putty followed by painting Factory glazed units employ improved putties or glazing compounds which stay elastic for longer period of time Alternative Methods of Single Glazing Small Lights – Outdoor Side on Left Glazing Large Lights Lockstrip gasket is a dry glazing method It is faster, easier and less dependent on workmanship then wet glazing method Wet glazing with good workmanship is more effective Lockstrip Gasket Installation in Progress and Completed Advanced Glazing Systems Butt-joint glazing system – Head and sill of the glass sheets are supported conventionally in metal frames, but vertical mullions are eliminated – The vertical joints between sheets of glass are made by injection of colorless silicone sealant Mullionless Butt-Joint Glazing With Single Glazing Advanced Glazing Systems Glass Suspended from Above With Vertical Glass Stiffeners Suspended Glazing Systems and Glass Mullion System – – – – Used primarily for high walls of glass around building lobbies Tempered glass sheets are suspended from above and stabilized by tempered glass perpendicular stiffeners Metal fittings are used to join multiple sheets of glass Stainless steel cables and fittings are used in roof applications Interior Walls Fire Walls A fire wall is a wall that – – Forms a required separation against spread of fire Extends continuously from foundation to roof, often above the roof and beyond the exterior walls along the plane of the wall A fire wall is used to divide a single building into smaller fire compartments which may be considered separate buildings when calculating allowable heights and areas as per the code Openings in fire walls are restricted in size and aggregate area and must be closed with fire doors or fire-rated glass Shaft Walls A shaft wall is used to enclose a multistory opening through a building such as an elevator shaft or a shaft for ductwork, conduits or pipes Rating of shaft wall depends on number of connected floors Walls for elevator shafts designed to – – Withstand air pressure and suction Prevent noise of elevator machinery from reaching other spaces Framed Partition Systems Partition Framing Wood framing – – Metal – Generally dictated by building code where combustible construction is allowed Heavy timber and fire retardant treated wood are permitted in some instances Light gauge steel studs with runner channels is most common and works similar to wood Masonry can be used with wood or metal furring strips Installation of Furring on Concrete Blocks Furring allows: – – 2 For the installation of flat wall finish over an irregular masonry surface, Provides a concealed space for installing plumbing, wiring and thermal insulation Furring can be created by – – – Z-furring channel (1) Hat shaped metal furring (2) Adjustable furring brackets (3) 3 1 Gypsum Board It is a prefabricated plaster sheet material – – – – 4 feet wide by 8 to 14 feet long (1220mm x 2440-4270mm) It is also called gypsum wallboard, plasterboard, gyp board, sheetrock, and drywall Least expensive requiring less labor than plaster Core of gypsum is slurry of calcined gypsum, starch, water, pregenerated foam, and additives sandwiched between special paper facing Sheets of Gypsum Board Roll off Manufacturing Line, Trimmed and Ready for Packaging Types Gypsum Board – – – – – – – – – – – Regular Type X for fire rated assemblies consists of glass fibers in core Type C for fire rated assemblies but thinner than Type X Water resistant gypsum backing board with facings of water repellant paper or glass matt and moisture resistant core Abuse resistant or impact resistant may have heavier facing paper, glass fiber mesh, polycarbonate film and core reinforced with cellulose fibers Mold-resistant gypsum with alternates to paper facings Ceiling gypsum board, sag resistant, ½ inch (13mm) thick Predecorated gypsum board Weather-resistant exterior gypsum soffit board Gypsum lath and gypsum veneer base Boards are available in many thicknesses and various edge treatments Gypsum Board Installation Gypsum Board Installation Finishing – – Surface can be smooth or have texture Ceilings are textured to conceal minor irregularities in workmanship Finishing Standards Level 0, minimum standard mostly unfinished – temporary Level 1 only joints are covered with tape set in joint compound – attics, service corridors Level 2 finish coat of joint compound is applied over accessories and fasteners – garages, warehouses, storage areas Level 3 adds a full second coat of compound after the first has dried - surfaces that will be textured or covered Level 4 is designed for surfaces to be finished with flat paints Level 5 is the highest quality and adds a very think skim coat of joint compound over the entire surface of the board – surfaces that will receive gloss or semigloss paints Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Wall and Partition Facings 1 Facings Ceramic – – Stone – Ceramic tile facings are often added to the walls for reasons of appearance, durability, sanitation, or moisture resistance Tiles can be mounted to gypsum base with adhesive and to concrete/masonry base with mortar with joints filled with grout Facings of granite, limestone, marble or slate are used in public areas of building Wood – Wood wainscotting and paneling may be used in limited quantities in fire-resistant buildings. They are mounted on backing of plaster or gypsum board Wall Cover Examples Finishes, Ceilings & Flooring Chapter 24 Millwork Materials Hardwood Softwood MDF Tools Saw Finish Nailer Caulk Gun Sandpaper Base Shoe Mould Casing Sill Apron Mouldings Casing Base Crown General Moulding Countertops Materials Granite Corian Concrete Formica/laminate Wood Tools Saw Adhesives Caulk Coatings Binder + Solvents +Pigments + Additives Solvent-based Oil or Alkyd Water-based Latex paints VOC (Volatile Organic Compounds) Coatings Roller Brush Paints contain a high amount of pigment Stains Clear Coatings Shellac Lacquers Varnishes Spray Tightly Attached Ceiling Exposed Structural and Mechanical Components Suspended Ceilings Ceiling that is suspended on wires Eggcrate Decorative Example of exposed grid lay-in-panels Ceiling Elements Hard Flooring Materials Hard flooring materials are often chosen for their resistance to wear and moisture They are not comfortable but are very beautiful and desirable Concrete – – – – Can have many different finishes Used for garages, industrial buildings, commercial and institutional buildings Color can be added It has low initial cost and high durability but requires proper workmanship Stone – – – Many types with different surface textures are used in buildings Installation is simple but requires high skill for bedding Require clear sealer coating and periodic maintenance Hard Flooring Materials Bricks and Brick Pavers Quarry Tiles Hard Flooring Materials Ceramic Tiles – – – – – Fired clay tiles smaller than quarry tiles are called ceramic tiles. They are usually glazed and available in many colors and shapes Grout color has a significant influence on the appearance of the surface A slip sheet or cleavage membrane is used over substrate that are prone to deflection Crack isolation membranes or uncoupling membranes are used in thin set application over problem areas Terrazzo – – It is very durable and made by grinding and polishing concrete that consists of marble or granite chips There are many different methods of installing terrazzo Hard Flooring Materials Installation Wood and Bamboo Flooring Wood is used in several different forms as finish flooring material – – – – – – – Solid wood tongue-and-groove strip flooring made from many hardwood and softwood species. They are blind nailed in place Plank flooring is solid wood flooring which comes in wider strips. They are fastened by screws which are countersunk and then plugged Engineered wood flooring refers to a factory made wood flooring of many different types Parquet is wood flooring of varying hues arranged in patterns Floating floors are wood floors that are not nailed or glued Plastic laminate flooring is composed of planks or large tiles that have wood composite core Wood block flooring is made of small blocks of wood set in adhesive with their grain oriented vertically Resilient Flooring The oldest resilient flooring is linoleum – a sheet material made of ground cork Asphalt tiles were developed as an alternate Today’s market resilient sheet flooring and tile market is made of vinyl or rubber They are available in wide range of colors and have good durability with low initial cost Vinyl composition tile (VCT) has the lowest installed cost. Other tile products include luxury vinyl tile (LVT) and rubber floor tile. More ornate colors, texture and patterns. Resilient sheet flooring materials are vinyl and rubber Most resilient flooring is glued to the substrate sometimes using underlayment Various flooring accessories are available Carpet Carpets are manufactured in many different types of fibers, styles and patterns for indoor or outdoor use Carpets are tough enough to wear for years or soft enough for intimate interiors Majority of carpet in North America is made with nylon fibers with remainder being made from polypropylene, synthetics and natural fibers Four ways to install carpet – – – – Direct glue-down installation With carpet pad or cushion and tackless strip at edges (stretch-in installation) Double glue-down installation Attached cushion installation Carpet material is also manufactured as tiles