a - d i-introduction

8/2/2019 A - D I-Introduction

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Design and Inspectionof Cold-Formed Steel Framed Structures

STEEL FRAMING WORKSHOP:Purpose of Presentation

Provide the basic information needed toassure that cold-formed steel structuresare:

Designed in accordance with the AISIPrescriptive Method Standard, 2003 IRC andindustry recommendations

Constructed per plan and industry standards

Today's presentation will be based on the AISIToday's presentation will be based on the AISIPrescriptive Method StandardPrescriptive Method Standard


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Outline for Todays Presentation

Introduction Introduction to Cold-Formed Steel Framing Use of Cold-Formed Steel framing Tools and Fasteners

General Provisions Floor Framing Wall Framing Roof Framing (Ceiling Joists and Roof

Rafters)

Steel in Residential Applications


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Homes

Steel, Wood, Concrete

Introduction to Cold-Formed SteelFraming Members


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Steel, The Material

~ Is recyclable, using old cars, buildings, bridges, steelcans, etc.

~ Steel is the worlds most versatile material to recycle~ Yearly, steelmakers recycle about 500 million tons of

steel world-wide~ It takes at least 60% less energy to produce steel from

scrap than it does from iron ore~ It takes 6 old cars to produce enough steel to frame a

basic residential dwelling

The Environment

~ The average landfill consists of approximately 60%construction debris, mostly concrete, wood and plastic.~ Less than 6% of landfill is steel - such as staples, nails

in wood and steel rebar inside concrete chunks~ Every ton of steel recycled conserves 2,500 pounds of

iron ore, 1,400 pounds of coal and 120 pounds of limestone.

~ Debris from a typical wood-framed home accounts for 50 ft 3 of landfill waste, compared to only 2 ft 3 from asteel-framed house


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Advantages of Steel

~ Consistent Material Quality~ Superior Seismic Performance~ Non-Combustible Material~ Dimensionally Stable in anyClimate~ Insect Resistance~ Steel will not Rot

Advantages of Steel

Steel providesthe possibility

for largespans andopen spaces.


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Advantages of Cold-Formed Steel

~ High Strength to Weight Ratio~ Ease of Handling and Transportation~ Ease of Fabrication and Mass Production~ Speed of Erection~ Flexibility in Design~ Engineering Not Required for

Common Residential Houses(Prescriptive Method, 2000/2003 IRC)

What is Light Gauge, or more

accurately, Cold-Formed Steel?

Cold Forming is A process where light gauge steelmembers are manufactured by rolling or shaping the steel

after it is cold. This process makes the steel stronger.


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Manufacturing Of Cold-FormedProducts

~ Press or Break Forming~ Roll Forming (most common method

for mass production)~ Stamping (more common in the

automotive industry)

Manufacturing Of Cold-Formed Products

Each coil weighsapproximately 13 tons


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Studs are roll shaped for production speed


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Studs may be formed by a break press processas well.

Press BrakeShapes And Profiles

Surface-Panel MaterialSidingRoofingComposite Deck

Individual MembersPurlinsGirtsStuds and JoistsBuilt-up Sections

Endless Geometric Possibilities


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Generic Light Gauge Steel Members

S t u d s

( a n d

J o i s t s

)

T r a c k s

U - c h a

n n e l s

F u r r i n

g

C h a n

n e l

Cold-Formed C-Shape


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Studs Structural studs

Carry Axial loads 1-5/8 flanges and 1/2 return

lips. Thickness from 33-97 mil G60 galvanized coating

Non-structural studs Not expected to carry loads 1-1/4 flanges and 1/4 return

lips, typical Thickness often less than 33 mil G40 galvanized coating

2 x 4 Wood Steel Stud

Track

Flange: 1-1/4(Typical)

web

Studs madeto fit in tracks


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Floor/Ceiling Joists and Roof Rafters

Same elements as studs Webs typically 6, 8, 10, or

12

lip

flange

web

Cold-Rolled Channel

used for wall bridgingand fits through web

punch outs in studs and joists


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Furring (Hat) Channel

Similar to purlins in metalbuildings

Straps

bridging lateral bracing


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Bracing and Blocking

Specialty Connectors

(used in accordance with manufacturersspecs.)

Strap Tie strap Joist hanger Beam hanger Hold-down


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Connectors

JOIST HANGERHURRICANE CLIP

By-Pass Deflection ClipSome common clips for by-passconnections.


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Deflection Tracks

Typical choices are: Deep leg track w/

mechanical connections -GWB floats.

Slotted proprietary deep legtrack - GWB directlyattached.

Double track system - (1)deep leg track over a stdtrack.

Tools and Fasteners


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Tools of the Trade Screw Guns


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ET&F TrimFast

Makita Screw GunGrabber

Chop Saw


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Circular Saw Power Shears


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Plasma Cutter Plasma Cutter


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Torch Cutting

Not Permitted

Clamps and Snips


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Hole Punchers

NEW TOOLS


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Fasteners And Drives

LOX

Fasteners Screws

The Only Permitted Fastening Method To Be UsedWith Other Prescriptive Provisions in the PM.

Most Commonly Used.

Alternate Fastening Methods (ApprovalRequired) Welds Pneumatically-Driven Pins Powder Actuated Fasteners Clinches

Others


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Screws: Tips

Self-Drilling

Self-PiercingMax. steel thickness43 mil (18 GA)

drill point prevents jacking

d

For SI: 1 inch = 25.4 mm.

0.25001/4

0.2160 No. 12

0.1900 No. 10

0.1640 No. 8

0.1380 No. 6

Nominal ScrewDiameter, d, in.

ScrewNominal Size

Note: #12 Screws can

self drill into 3/16 thick red iron Steel

Note: The most common allpurpose framing screw size is a #8.

Typical screw heads

& drive types

Pan Head Oval Head

Round Head

Truss Head

TrimWasher

Hex Washer

Hex Head

Flat Head

RoundWasher

Mod. Truss(Lath)

Bugle Head

Wafer Head

PancakeHead

Flat

Hex Pan

OvalRound

Truss


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Welds (Structural Welding Code: AWS- Section D1.3)

No burn-throughPermitted

Touch-up welds withzinc enriched paint

Note: Welding as thin as 18 gauge is common,20 gauge is difficult however still possible .

Welds


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Pneumatically Driven Pins

1/4 penetration

Evaluation Reports are Typically Available from Supplier

Clinches

proprietary technology (see manufacturers evaluation report)


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Rivets & Bolts

(see manufacturers evaluation report)

Construction Methods


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The same basic principlesinvolved with wood-framedconstruction are applicableto steel-framedconstruction,except for how the materialis cut and joined.


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Screw Gun (instead of Nail Gun)

Proper screw guns atthe lower RPMs willprotect against overheating the drill tip.Protects against threadstripping.


shears: electric or hydraulicsnipschop and circular sawsplasma cutter


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Fire Rated AssembliesSFA Publication

Fire Rated Assemblies

Photos courtesy Atlanta Journal-Constitution

Highlands on Ponce fire,

Atlanta, April 31, 2001


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Steel and Fire

Steel is Non-CombustibleSteel Does Not Add Fuel to FireSteel Looses Strength Under High TemperaturesSteel Should be Protected in Accordance withCode Requirements By:

Gypsum BoardOther Approved Material

Fire and Sound Details


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Insulation

rigid foam on the exterior (if required)batt insulation in the wall cavityAISI Thermal Design Guide

(www.steelframingalliance.com)

Hybrid Construction

www.huduser.org


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Hybrid Construction

www.huduser.org

Hybrid Construction


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Misconceptions About Steel

More prone to

lightning strikes

TV reception isadversely affected

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