Metals

Introduction u Metal is used in various places in the construction process including: –rebar = reinforcing steel in round shapes –flashing = thin metal –door & window frames = in shapes of frames –connectors = used to attach or connect members –fasteners = to join construction parts –structural steel = shapes of steel for various building parts

Reinforcing Bar - Rebar u Embedded in concrete to strengthen –concrete - strong in compression, weak in tension –steel rebar - strong in both tension and compression –together strengthens overall material makeup –both concrete & steel have the coefficient of expansion similar to each other, making materials compatible to each other

Reinforcing Bar Sizes and Shapes u Rebars (reinforcing bars) are designated by 1/8” intervals u Sizes available in 1/8” diameter increments –range in size from #3(3/8”) to #18(2 1/4”) –#3 bar = 3/8” –#4 bar = 1/2” (most common in residential) –#5 bar = 5/8” –#6 bar = 3/4” –#7 bar = 7/8” –etc.

Rebar Representation u Heavy dot in section view u Heavy dashed line in elevation/plan view

Rebar Callout u Typical callout:#4 24” OC u Material: made from billet steel & old rail steel u Shape--Plain & Deformed bar

Dowels - Short lengths of Rebar u Used to unite 2 concrete elements –tie footing to foundation wall –tie concrete slab to foundation wall

Compression vs. Tension u Compressive force is one that pushes or tends to shorten Compressive Force

Compression vs. Tension u When a load is placed on a concrete surface, both tensile and compressive forces develop Load

Compression vs. Tension u This can be better understood by looking at an exaggerated deformation of the part Load Compression - elements shortened, top portion Tension - elements are lengthened, bottom portion Center axis Note: rebar is placed in area of tension

Loads on Concrete u Dead loads u Frost u Rebar in areas of tension

Flashing u Sheet metal that covers intersection of 2 or more building members

Purpose of Flashing u Protects against water & dirt infiltration, leakage & rot u Provides a protective covering for wood members u Seals a joint of 2 intersection members

Flashing Material u Typically galvanized iron –Callout:#26 GA. G.I. FLASHING Gauge # Thickness 111/8” 161/16” 221/32” ”

Flashing u No. 26 (3/160” =.01875”) most common –24 Gauge used for commercial work u Heavy gauges require special tools for bending

Foundation Flashing Flashing to protect sill plate

Metal Door Frames u More common in commercial than residential construction u Increased durability u May be required by code u Same as wood counterparts, except usually all one piece

Thresholds u Member below the bottom of door that is secured to floor

Thresholds u Used to prevent water & air from entering building u Commonly made from oak or aluminum –aluminum thresholds are extruded shapes u Tread patterns used to minimize slipping

Metal Threshold Sections

Metal Connectors u Used to join wood framing members securely together –joist hangers –beam connectors

Beam Connectors Good to prevent wind uplift

Nails u Used to fasten members together –common vs. box –d = penny –8d - sheathing –16d - studs –“d” stands for penny in the English monetary system, the price of 100 nails, d nails were 16 pence (pennies)

Nail Usage u Perpendicular vs. Toe nailing GOOD BAD

Lag Bolts u Threaded –wood screw type u More sturdy than nails –predrilled hole necessary u Used in larger members

Foundation Anchor Bolts u Used to fasten sill plate to foundation u L-shaped & threaded u Spacing set by code –usually 4’- 8’ OC

Machine Bolts u Material--steel –galvanized or bright plate finishes u Heads –hexagonal and square u Used for the fastening of wood members when heavy metal connectors are involved. –Diameter Size Length »1/2” to 1 1/2” 3 1/2” to 30 “

Structural Steel Shapes u Wide Flange (W) u Standard (S) u Miscellaneous (M) u Channels (C) u Angles (L) u Pipe, sq. & round u Tee (T)

Light Gauge Steel Framing u Steel Stud materials: Studs, runners(for plates) and floor and ceiling joist u Roof and Floor Decking u Metal Siding and Roofing

Example of Light Steel Framing Head Detail over a Door

Steel Decking u Corrugated steel decking supported by steel channels or open-web joist u Common shapes shown u Common depths: –1 1/2”, 2”, 3” & 4 1/2” u Minimum concrete coverage: 1 1/2” u Application Detail:

Open-Web Steel Joist and Steel Decking Example

Metal Grating u Several applications: 1--ventilation (sometimes called a grille or register) within a building 2--a cover for a drainage system interior or exterior of buildings

Metal Stair Handrail drawing u Additional Info: 1--Handrail is a C 1 1/2x 2.4 channel, draw to given size, attached with 1/16 fillet weld all around tube 2--Lower horizontal bar is a C 1 1/4x 1.3 (1 1/4” x 1/2” x 1/8”) channel, attached with 1/16 fillet weld three sides draw 7” above deck 3--Support channel is a C6x8.2 (12 GAGI) 4-- Weld leader lines with dot() is replaced by a darkened flag Scale: 3” = 1’-0” Support Channel 7”7”

Assignment