*Note: No live load reductions are taken in this example to be conservative
Metal Roof Decking
Note: Since the Government cannot procure proprietary materials and systems, the following reference is provided.
To select the metal decking, refer to and use the Steel Joist Institute (SJI) LOAD TABLES in the current SDI Design
Manual. Select the deck rib type (narrow, intermediate, or wide) and the gage thickness that will be given on the
contract documents.
For this example the metal roof decking is chosen based on the given live and dead loads from any metal deck
manufacturer' catalog. The manufacturer' catalog used for this example lists allowable loads based on the
s
s
expected service loads.
Dead Loads to Deck:
13 psf
Live Loads to Deck:
20 psf
33 psf (1.58 KN / m2)
Total:
Entering the catalog with the 33 psf load and assuming that the deck will span 6' 8" between each open-web joist a
-
20 gage deck is selected.
Roof Joists
Note: Since the Government cannot procure proprietary materials and systems, the following reference is provided.
To select the open web joists, refer to and use the Steel Joist Institute (SJI) K-Series STANDARD LOAD TABLE in
the current edition of the SJI publication, STANDARD SPECIFICATIONS, LOAD TABLES AND WEIGHT
TABLES. (Note: The assumptions for joist selection from the K-Series STANDARD LOAD TABLE are parallel
chord simple span joists that are uniformly loaded and are placed on a slope not greater than inch / foot. If any of
these conditions do not exist, the joist loading diagram, the span, the slope, and the desired joist depth must be given
on the contract documents. With this information, the required K-Series joist chord size will be determined and
certified by the manufacturer.)
For this example the open-web steel joists are chosen from a manufacture' catalog. The allowable loads for the
s
joists are listed for unfactored service loads
Dead Loads to Joists:
15 psf
Live Loads to Deck:
20 psf
35 psf (1.68 KN / m2)
Total:
Running Load = Load (psf) x tributary width (6' 8" or 2.03m)
-
Running Load = (35 psf)(6.67' = 233 plf (3.40 KN / m)
)
Entering the catalog with a 40'span and running load of 233 plf a 24K7 joist is selected. The design and details of
the bridging and weld connections to the supporting beams shall be as per manufacture' specs in the design
s
catalogs.
Edge Beams of Gravity System
The beams of the gravity system are designed in accordance with the AISC LRFD specifications.
Tributary width = 20' (6.10m)
Dead Loads:
Dead Load:
17psf
Roll-up Doors:
1200 lb. / door (5.34KN)
Total = (17psf)(20' + (1200 lb. / 20' = 400 plf (5.84 KN / m)
)
)
Live Loads:
Live Loads:
(20psf)(20' = 400 plf (5.84 KN / m)
)
H1-9
Previous Page
