Earthbag Village Updated_Final Loft Design - New Spreadsheet

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1	Note: This spreadsheet is for initial calculations only. All numbers should be confirmed by an engineer licensed in your state/country to assure safety.
2	Aesthetically improved verion (linked from website) is here: https://docs.google.com/spreadsheets/d/1CcfdC2OiWtEsmudWuqefXakA2VlH72j_6B-OiShada4/edit?ts=6031c2e3#gid=343079329
3	ABOUT:	Updated loft deisgn for a dome in the 3-dome cluster.
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5	Using the Sheets:
6	1. Only edit highlighted (yellow) sections / cells.
7	2. Blue cells show summarized results.
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9	Current Loft Design Being Tested:		Wood Species & Grade:		DFL No. 1
10				Wood Section:	3x10
11				Spacing O.C.:	1	ft
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14	Preliminary Info:					Table 1. Nominal vs. Actual Dimensions			Reference Design Values (Table 4a [p.34] in NDS Supplement)			Bending Design	(LRFD)		Shear Design	(LRFD)		Deflection Design
15	Interior Dome Height		15	feet		Joist Sizes	Actual Depth (in.)	Actual Width (in.)	Species & Commercial Grade:		DFL No. 1	Preliminary Analysis			Preliminary Analysis			Allowable Deflection
16	Interior Loft Height Above Ground:		8	feet		2x4	3.5	1.5	Fb =	1000	psi	F'b = CdFb =	1000	psi	F'v = CdFv =	180	psi	△allowable (live) = L/240		0.675	in
17	Height of Loft Structural System:		9.25	inches		2x6	5.5	1.5	Fv =	180	psi	Sreq'd = M / F'b =	21.69	in^3	Areq'd = 3V / 2F'v =	4.46	in^2	Condition for an attic floor with limited storge - ASCE 7-16 Table 4.3-1.
18	Bottom Width of Loft (Longest):		13.5	feet		2x8	7.25	1.5	Fc,perp. =	625	psi
19	Top Width of Loft (Longest):		13.0	feet		2x10	9.25	1.5	Fc =	1500	psi	Is the section adequate?		Yes	Is the section adequate?		Yes	w [lb/in] =	3.33
20	Interior Base Radius:		7.5	feet		2x12	11.25	1.5	E =	1700000	psi
21	Ceiling Thickness:		0.625	inches		3x8	7.25	2.5				Corrected Stress	-NDS Table 4.3.1		Corrected Stress	-NDS Table 4.3.1		Required Section Properties
22	Decking Thickness:		0.75	inches		3x10	9.25	2.5				F'b = ØλKFFbCMCtCLCFCfuCiCr			F'v = ØλKFFvCMCtCi			EIreq'd (live) = 5wl^4 / 384△ =		44286750	psi*in^4
23	Interior Height From Loft to Top of Dome:		6.11	feet		4x6	5.5	3.5	Section Properties (Table 1B [p.14] in NDS Supplement)			F'b =	1911.8	psi	F'v =	272.16	psi
24						4x8	7.25	3.5	Section:	3x10		Is the section adequate?		Yes	Is the section adequate?		Yes	EI,chosen section =		280330000	psi*in^4
25	Design Loads								Sxx =	35.65	in^3							Is the section adequate?		Yes
26	Dead Load				Notes:				Ixx =	164.9	in^4
27	Joists (Self Weight):		5.14	lb/ft^2	DFL Density = 32 lb/ft^3 (need to acct for sxn dimensions - Table 1)				A =	23.13	in^2	Inherent LRFD Safety Factor =	1.2		Inherent LRFD Safety Factor =	1.3		Deflection (in) = (5wl^4) / (384EI) =		0.107	in
28	Decking (3/4" OSB):		2.4	lb/ft^2	As per ASCE 7-16 Table C3.1-1a							Additional Safety Factor =	3.1		Additional Safety Factor =	7.8
29	Mech / Elec:		2.5	lb/ft^2	As per ASCE 7-16 Table C3.1-1a
30	5/8" Gypsum Drywall Ceiling		2.75	lb/ft^2	As per ASCE 7-16 Table C3.1-1a
31		Total DL:	12.79	lb/ft^2					Geometric Parameters (Section 4 in NDS)
32	Live Load								CD =	1
33	Estimated for Loft:		40	lb/ft^2					CM =	1
34		Total LL:	40	lb/ft^2	As per ASCE 7-16 Table 4.3-1.				Ct =	1	*For application in less than 100F.
35									CL =	1	*Compression edge must be supported throughout its length to prevent lateral displacement, and the ends at pts of bearing have lateral support to prevent rotation
36									CF (Fb) =	1.1
37	Load Combinations								CF (Ft) =	1.1	*See 'Reference Tables' sheet for CF values (Based on section dimensions).
38	Case 1:	1.4D =	17.90	lb/ft^2					CF (Fc) =	1
39									Cfu =	1
40									Ci =	1
41	Case 2:	1.2D + 1.6L =	79.35	lb/ft^2					Cr =	1.15
42		Governing Load =	79.35	lb/ft^2					CP =	1
43									Cb =	1	*Bearing area must be at least 6" in length parallel to grain.
44											Cb (the bearing area factor) is a factor that is multiplied into the bearing strength equation that we used to determine the required bearing width.
45	Factored Design Load										See Table 3.10.4 on the Reference Tables tab for how to determine Cb
46	Tributary Width:		1	feet							I chose to have Cb = 1 for simplicity in calculations
47	Factored Gravity Load:		79.35	lb/ft
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50	Demand Loads
51	Max Shear =	535.6	lb
52	Max Moment =	1807.6	lb-ft
53	Modelling as a simply-supported beam.
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56	Unfactored Loads for Serviceablility
57	Unfactored Live Load:		40	lb/ft
58	Unfactored Dead Load:		12.8	lb/ft
59	Unfactored D + L:		52.8	lb/ft
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62	Load capacity per 6.25 ft^2 =		250	lb (concentrated)
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