CEMP-ET
EI 01S908
1 June 1998
(1) Steel. AISI Specification for the Design of Cold-Formed Steel Structural Members.
(2) Aluminum. AA SAS-30, Aluminum Construction Manual Series-Section 1
Specifications for Aluminum Structures.
(3) Tests for Determining Structural Performance. The approved methods for testing the
panel assemblies are included in ASTM E 1592 for roof panels of SSSMR system.
6. DESIGN LOADS.
Design loads will be in accordance with ASCE 7. The design loads for the metal roofing will
include snow, dead, live, concentrated, thermal, and wind loads. The minimum roof live load will
not be less than 960 Pa (20 psf). Midspan deflections under maximum design live loads will be
limited to L/180. The design wind pressure loads should be converted to maximum net inward
and outward pressures for the roof system and will be shown on the contract drawings in
diagrams or tables. This includes all areas of the roof, i.e., ridges, edges, corners, and midfield.
A minimum design concentrated load of 1,335 N (300 pounds) will be used to simulate a
construction load on roof panels. The concentrated load will be applied at the panel midspan
and will be resisted by a single standing seam metal roof panel, or a 610-mm (24-inch) -wide
corrugated metal panel, assumed to be acting as a beam. The undeformed shape of the panel
will be used to determine the section properties. Down-slope forces should be considered for all
roof slopes and for all roofing systems. Of particular concern are the roofs that have snow
guards attached to the panel system since they have the potential for greatly increasing the
down-slope forces.
7. SSSMR DESIGN REQUIREMENTS.
a. General Design Philosophy. SSSMR systems are procured using a performance
specification. The system is designed by the manufacturer and a designated Registered
Professional Engineer based on loads and other design requirements furnished in the contract
documents. The structural designer for the project will show the design loads and structural
support framing on the contract drawings. The contractor is responsible for the quality of the
metal roofing system. The contractor may be required to install additional subframing members
to meet design requirements for the roof panel assembly chosen for the stated project.
b. Seams. SSSMR systems with panels wider than 300 mm (12 in.) will have mechanically
crimped side lap seams at panel-to-panel connections rolled during installation by an electrically
driven seaming machine.
c. Fasteners. Fasteners for structural connections will provide both tensile and shear
ultimate strengths of not less than 3,340 N (750 pounds) per fastener. Screws for attaching
anchor devices will not be less than 6 mm (No. 14) diameter. Bolts will not be less than 6 mm
(1/4 in.) diameter; bolts will be shouldered or plain shank as required with locking washers and
nuts. Blind screw-type expandable fasteners will not be less than 6 mm (1/4 in.) diameter. Blind
(pop) rivets will be not less than 7 mm (9/32 in.) diameter. Clips with two (2) fasteners will be
capable of resisting the tributary area load of the clip times the design wind pressure applicable
to that portion of the roof multiplied by a safety factor of 2.25. Clips with a single fastener with a
minimum diameter of 9 mm (3/8 in.) will be allowed when the supporting structural members are
pre-punched or pre-drilled. Clip spacing should be set so that single fasteners are capable of
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