Problem 2.1

 

 

Dead Loads

 

roof + ceiling: 3:12 pitch

 

Component	D (psf)	Reference	D (psf)	Reference
asphalt shingles	2.0/layer	Appendix B.3	2	ASCE 7 table C3-1
roofing felt/paper (not mentioned)	--	--	--	--
3/8" plywood	3.0/in.	Appendix B.1	0.4 per 1/8"	ASCE 7 table C3-1
plywood clips (not mentioned)	--	--	--	--
2x6 @ 16" O.C.	1.4	Appendix A.1	?	?
5-1/2" fiberglass loose insulation	0.5/in.	Appendix B.2	?	?
1/2" gypsum wall board	5.0/in.	Appendix B.4	0.55 per 1/8"	ASCE 7 table C3-1
framing, sheathing & roofing nails (not mentioned)	--	--	--	--

 

D (3:12 pitch, 1 layer of shingles) = 1 * 2.0 + 3/8 * 3.0 + 1.4 + 5-1/2 * 0.5 + 1/2 * 5.0 = 9.775 psf
D (3:12 pitch, 2 layers of shingles) = 2 * 2.0 + 3/8 * 3.0 + 1.4 + 5-1/2 * 0.5 + 1/2 * 5.0 = 11.775 psf
D (3:12 pitch, 3 layers of shingles) = 3 * 2.0 + 3/8 * 3.0 + 1.4 + 5-1/2 * 0.5 + 1/2 * 5.0 = 13.775 psf

 

 

D (0:12 pitch, 1 layer of shingles) = sqrt (3² + 12²)/12 * 9.775 = 10.08 psf
D (0:12 pitch, 2 layers of shingles) = sqrt (3² + 12²)/12 * 11.775 = 12.14 psf
D (0:12 pitch, 3 layers of shingles) = sqrt (3² + 12²)/12 * 13.775 = 14.20 psf

 

wall: 8'-0" height

 

Component	D (psf)	Reference
7/8" stucco	10.0	Appendix B.4
2x4 @ 16" O.C.	0.9	Appendix A.1 & B.3
1/2" gypsum wall board	5.0/in.	Appendix B.4

 

D = 10.0 + 0.9 + 1/2 * 5.0 = 13.4 psf  (pressure)

w_D = 13.4 psf * (8 ft) = 107.2 lb/ft  (distributed load)

 

Live Loads

 

roof

 

Term	Value	Reference	Value	Reference
L0	20 psf (at 0:12)	ASCE 7 table 4-1	20 psf (at 0:12)	IBC table 1607.1
R1	1 (assume AT ≤ 200 ft2)	ASCE 7 section 4.9.1	?	IBC section 1607.11
R2	1 (F ≤ 4)	ASCE 7 section 4.9.1	1 (F ≤ 4)	IBC section 1607.11

 

L_r = 1 * 1 * 20 psf = 20 psf  (this is true for 3:12 and 4:12)