Transcript Slide 1

12 LIGHT GAUGE STEEL CONSTRUCTION
THE CONCEPT OF
LIGHT GAUGE STEEL
CONSTRUCTION
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Light Gauge Steel Framing Members
• Steel components are cold-rolled from steel sheet.
• Cold-forming increases metal strength.
• Members are essentially noncombustible equivalents of wood light
frame construction.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
C-Studs and Joists
• Used as vertical studs, and
horizontal joists, rafters,
and headers
• Standards sizes
– Depth 1-5/8 to 12 in.
– Width 1-1/4 to 2-1/2 in.
– Metal thickness 18 to 97
mils (0.018 to 0.097 in.)
• Example designation:
600S162-54
– 600: 6.00 inches deep
– S: Stud or joist
– 162: 1.625 (1-5/8) inches
wide
– 54: 54 mils (.054 inches)
metal thickness
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Tracks
• Used at top and bottom of
wall framing and at ends of
floor framing, to hold
studs or joists
• Analogous to wall plates
and rim joists in light
wood frame construction
• Standard sizes
– Depth to match studs or
joists
– Width 1-1/4 to 2 in.
• Example designation:
600T125-33
–
–
–
–
6.00 inches deep
Track
1.25 in. wide
33 mils metal thickness
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Channels
• Used for bridging,
blocking, and other
reinforcing and bracing
• Also called cold-formed
channels
• 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
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Furring
• Used for bridging,
backing, 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
• Example designation:
087F125-30
– 0.875 in. deep
– Furring channel
– 1.25 inches wide at raised
surface
– 30 mils metal thickness
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
L-Headers
• Used for simplified header
construction over openings
in loadbearing walls
• Break-formed angles (sheet
metal bent in fabricator's
shop to the specified size)
• Standard sizes
– Long leg 6 to 10 in.
– Short leg 1½ in.
• Example designation:
2-800L150-43
–
–
–
–
–
2 (doubled) angles required
8.00 in. long leg length
L-Header
1.5 in. short leg length
43 mils metal thickness
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Section View
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Framing Accessories
• Various sheet metal clips,
stiffeners, bracing, and
hangers are used to make
connections and reinforce
framing.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Special Products
• Many manufacturers offer
proprietary members that
offer various performance
advantages or efficiencies.
• Example right: The heavy
dimpling or extra
corrugation result in
framing members that are
stiffer than their
conventional counterparts
of the same metal
thickness.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Special Products
• Slip track: A top track with
extra deep legs and slotted
holes
• Allows fastening of
nonloadbearing studs to track
while permitting deflection in
the track
• Studs are intentionally cut
short so that a deflection gap
remains.
• Deflection in the slab above
does not impart unintended
loads into the wall framing.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Special Products
• A jamb-stud, a single, deeper
framing member designed to
replace two conventional studs
at either side of a framed
rough opening
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Sheet Metal Thickness
• Thicker members are
stronger and stiffer, but
also heavier and more
expensive.
• Thickness is traditionally
expressed as metal gauge
(or gage), with lower
numbers corresponding
to thicker metal.
• Translation of gauge
numbers to metal
thickness is not always
consistent.
• Contemporary ASTM
standards specify metal
thickness in decimal
inches.
Minimum thickness of steel sheet
Loadbearing
Gauge 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)
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Nonloadbearing
framing
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Cutting Light Gauge Sheet
Metal
• Tin snips (aviator's snips):
quiet, clean, slower than
power methods
• Power shears
• Power saw with abrasive or
carbide-toothed blade
• Torch cutting
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Fastening Light Gauge Sheet
Metal
• Self-drilling, self-tapping
screws are most common.
(top)
• Crimping tools mutually
deform parts to be joined.
(middle)
• Nail-like pins are powerdriven. (bottom)
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
THE CONCEPT OF LIGHT Gauge STEEL CONSTRUCTION
Fastening Light Gauge Sheet
Metal
• Welded joints can achieve
higher strengths but are
more labor intensive to
make than mechanically
fastened joints.
• Welding is best suited to
thicker sheets that are less
susceptible to meltthrough (burn through)
than thinner sheets.
• Top: Plug welds
• Middle: Slot welds
• Bottom: Flare vee weld
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
12 LIGHT GAUGE STEEL CONSTRUCTION
FRAMING
PROCEDURES
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
FRAMING PROCEDURES
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.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
FRAMING PROCEDURES
Framing
• Heavier beam equivalents,
such as the ridge beam in the
top illustration, can be
constructed by nesting
standard joists.
• Simple angles or end clips
facilitate joining of
perpendicular members.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
FRAMING PROCEDURES
Framing
• Joist hangers, gusset plates, and
folded track ends are other
connection methods.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
FRAMING PROCEDURES
Framing
• Window header connection to
supporting studs
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
FRAMING PROCEDURES
Bracing
• Slender steel members require
bracing at regularly spaced
intervals to reduce the
tendency to buckle.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
LIGHT GAUGE STEEL CONSTRUCTION
Specifying Light Gauge Steel
Framing
• Division 5 Metals,
Section 05 40 00—ColdFormed Metal Framing
– Structural, loadbearing framing
– Exterior wall framing (subject to
wind loads)
• Division 9 Finishes
Section 09 22 16—NonStructural Metal Framing
– Interior nonloadbearing framing
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
LIGHT GAUGE STEEL CONSTRUCTION
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
– Susceptible to corrosion
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.