(3) Masonry Base Details. The base of the masonry wythe must be placed on a
shelf angle or a foundation ledge that is lower than the base channel of the steel stud wall
by at least 102 mm (4 "). The width of this shelf angle or a foundation ledge will include
the width of the masonry wythe and the cavity. This width will not be less than two thirds
of the unit thickness plus the minimum air space. Masonry units set on shelf angles may
use a formed lip to reduce the depth of the horizontal joint that is created at the shelf
b. Steel Studs and Framing. Designers specifying cold-formed studs and framing will
use a minimum base metal thickness of 1.21 mm (0.0478 ") and not refer to the metal thickness
as 1.146 mm (0.0451"). While the base metal thickness is to be specified to match the design,
designers can use table 1-1 as a guide to selecting commonly referred base metal thickness.
Designers should be aware that the minimum delivered thickness specified for steel studs will be
no less than shown in table 1-1 when materials are specified to the minimum design thickness
and delivered in accordance with AISI. The minimum depth of members will be 89 mm (3-1/2 ")
and the minimum flange width of 35 mm (1-3/8 ") will have a minimum return lip of 6.4 mm (1/4 ").
Shop drawing submittals will need to present the calculations that show the effective flange, with
the return lip provided. The actual required stud depth, thickness and spacing will be determined
prior to completion of the contract documents. In some cases, the use of a minimum stud depth
of 152 mm (6") yield a more efficient design. Steel studs and framing will be hot-dipped
galvanized metal with a minimum ASTM A 653, G60 coating.
(1) Welding. Welding of steel studs requires the use of qualified welders
experienced in the welding of cold-formed steel. When welding is used, the contractor
needs to provide Qualification documents for each welder working on the project.
Welded connections to steel framing members will be touched-up with zinc-rich paint
after welding. Normally welded connections are not required in curtain-wall construction
but may be used for attachments.
(2) Connections. Connections of studs to runners and other framing members
will be made with screws or welds. When the thickness of the thinner connected parts is
less than 4.8 mm (3/16 ") the capacity of the connected parts will be in accordance with
AISI. For bolted connections when the thickness of the thinner material is equal to or
greater than 4.8 mm (3/16 ") use AISC. Normally the minimum top and bottom channel
connections in curtain-wall construction will require a single #10-16 self-drilling, self-
tapping screw in each flange of the bottom runner for either system and the top channel
of the double track system. Welding of studs may be used in lieu of screws or bolts.
Slide clip connections will be used when parapets extend above the roof line of the
structure. These slide clips connectors need to be welded to a structural element and the
details and the capacity of the manufacturers system will need to be included in the shop
drawing review. The minimum edge distance of shot-in anchors for top and bottom
runners to concrete is 76 mm (3 ") and the minimum fastener spacing is 102 mm (4 ").
Contract plans will show anchorage details of the steel studs and other framing members
to the building structural system, and the extra steel stud wall framing members required
around openings. The required strength capacities of framing weld and screw
connectors will be in accordance with ML/SFA 540-87 and ML/SFA 920-91.
(3) Openings. Window and door frames will be attached to the steel stud
system, not the masonry veneer.
(4) Top Track and Bottom Runner. A single track or double track top (slip joint)
connection will be used at the top of stud walls to permit the vertical movement of the
structural framing system to prevent the loading of the steel studs. Both flanges of the
steel stud will be attached to the inside top channel for the double track system and the
bottom runner of either system. Mechanical bracing of the single track systems should