Page 326 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch07.qxd 9/29/05 5:16 PM Page 7.10

FLOOR AND ROOF SYSTEMS

7.10 CHAPTER SEVEN

means with a field-operated seaming machine provided by the deck manufacturer. Some deck types
utilize an additional cap piece over the seam, which is mechanically seamed in the field (Fig. 7.10).
Frequently, the seams contain a factory-applied sealant for added weather protection.
Thicknesses of standing-seam roof decks usually range between 26 and 20 ga. Typical spans range
1
between 3 and 8 ft. A roof slope of at least / 4 in per ft should be provided for drainage of rainwater.
Standing-seam systems are typically attached to the supporting members with concealed anchor
clips (Fig. 7.11) that allow unimpeded longitudinal thermal movement of the deck relative to the
supporting structure. This eliminates buildup of stresses within the system and possible leakage at
connections. However, the effect on the lateral bracing of supporting members must be carefully
evaluated, which may result in a need for supplementary bracing. An evaluation method is presented

FIGURE 7.10 Standing-seam roof deck with cap installed over the seams. (a) Channel cap with flanges
folded over lip of seam. (b) U-shaped cap clamps over clips on seam. (c) Steps in forming a seam with
clamped cap.

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