B-1 Calculate fundamental period, T
Ta = CT h3/4 where CT = 0.020 and hn = 28.25 ft. (ave. roof ht.)
(FEMA 302 Eq. 5.3.3.1-1)
n
Ta = (0.020)(28.25) 3/4 = 0.25 seconds for both the transverse and longitudinal directions.
B-2 Determine the dead load, W
Sloped Upper Roof Level*
Sloped Lower Roof Level*
Finish
1.0
Psf
Built-Up Roofing
5.0 psf
20 Gage Metal Deck
2.0
Psf
2" Rigid Insulation
3.0 psf
Roof Purlins
1.5
Psf
20 Gage Metal Deck
2.0 psf
Rigid Frame Beams
2.0
Psf
Horizontal Bracing
2.0 psf
Rigid Frame Columns
1.0
Psf
Ceiling / Covering
1.0 psf
Ceiling / Covering
1.0
Psf
Misc. (Mech., Elec.&
3.0 psf
Misc. (Mech., Elec. & Framing)
3.0 Psf
Total:
16.0 psf
Total:
11.5 Psf
Roof at Sacristy (Horizontal)
Sloped Roof at Entrance*
Finish
1.0
Psf
Built-Up Roofing
5.0 psf
Concrete Slab (Assume 4" Thick)
50.0
Psf
2" Rigid Insulation
3.0 psf
Ceiling / Covering
1.0
Psf
20 Gage Metal Deck
2.0 psf
Misc. (Mech, Elec.)
1.0
Psf
Steel Beams
1.0 psf
Total:
53.0
Psf
Ceiling / Covering
1.0 psf
Misc. (Mech, Elec. &
1.0 psf
Total:
13.0 psf
Reinforced Concrete Shear Walls
Normal Weight Concrete (8" Thick) 100 Psf
*Note: The weights of the sloped roofs are calculated based on the sloped area. In order to calculate the weight
based on the horizontally projected area the loading on the sloped roof must be adjusted.
Upper roof level:
(11.5)(12.65/12) = 12.12 psf
Sloped lower roof level:
(16.0)(12.65/12) = 16.87 psf
Roof at entrance:
(13.0)(12.65/12) = 13.70 psf
1 psf = 47.88 N/m2
H3-13
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