The Earthbound System® - Compression Member Design

Wood Compression Members:
●	Vertical members required to support the compressive load transfer from the holdown system.
●	The EB System takes advantage of 16" o.c. standard framing as a part of the compression requirements.
●	All members are sized on the lower capacity of axial buckling parallel to grain (Pr) or compression perpendicular to grain (Qr) on floor plate.
●	The minimum amount of compression members must equal or exceed the tension force required on each level.
●	The capacities shown below are based on CSA O86-05.

COMPRESSION MEMBER SELECTION - DOUGLAS FIR LARCH (DF-L)
FRAMING	LUMBER SIZE (SINGLE MEMBER)	LUMBER GRADE	PERP. TO GRAIN (Qr)	PARALLEL TO GRAIN, (Pr) OR PERPENDICULAR TO GRAIN (Qr) LIMITATION - EACH MEMBER
				8 FT (2.44 m)		9 FT (2.74 m)		10 FT (3.05 m)		11 FT (3.35 m)		12 FT (3.66 m)
				(LBS)	(kN)	(LBS)	(kN)	(LBS)	(kN)	(LBS)	(kN)	(LBS)	(kN)
4-inch Wall	2x4	No.1/2	6,130	5,235	23.29	4,089	18.19	3,204	14.25	2,530	11.26	2,018	8.98
	4x4	No.1/2	12,959	12,215	54.34	9,540	42.44	7,476	33.26	,5904	26.26	4,709	20.94
	4x6	No.1/2	12,929	19,195	85.38	14,992	66.69	11,748	52.26	9,278	41.27	7,399	32.91
	4x8	No.1/2	19,778	23,701	105.43	19,762	87.91	15,487	68.89	12,230	54.40	9,753	43.69
	4x10	No.1/2	23,701	30,240	134.51	25,214	112.16	19,759	87.89	15,603	69.41	12,444	55.35
	4x12	No.1/2	30,240	36,778	163.60	30,666	136.41	24,031	106.9	18,977	84.41	15,135	67.32

6-inch Wall	2x6	No.1/2	9,632	9,632	42.85	9,632	42.85	9,632	42.85	9,632	42.85	9,700	38.70
	6x4	No.1/2	20,318	20,318	90.38	20,318	90.38	20,318	90.38	20,318	90.38	20,299	90.29
	6x6	No.1/2	31,080	31,080	138.25	31,080	138.25	31,080	138.25	31,080	138.25	31,080	138.25
	6x8	No.1/2	37,245	37,245	165.27	37,245	165.27	37,245	165.27	37,245	165.27	37,245	165.27
	6x10	No.1/2	47,519	47,519	211.38	47,519	211.38	47,519	211.38	47,519	211.38	47,519	211.38
	6x12	No.1/2	57,794	57,794	257.08	57,794	257.08	57,794	257.08	57,794	257.08	57,794	257.08

COMPRESSION MEMBER SELECTION - SPRUCE PINE FIR (SPF)
FRAMING	LUMBER SIZE (SINGLE MEMBER)	LUMBER GRADE	PERP. TO GRAIN (Qr)	PARALLEL TO GRAIN, (Pr) OR PERPENDICULAR TO GRAIN (Qr) LIMITATION - EACH MEMBER
				8 FT (2.44 m)		9 FT (2.74 m)		10 FT (3.05 m)		11 FT (3.35 m)		12 FT (3.66 m)
				(LBS)	(kN)	(LBS)	(kN)	(LBS)	(kN)	(LBS)	(kN)	(LBS)	(kN)
4-inch Wall	2x4	No.1/2	4,641	4,635	20.62	3,658	16.27	2,889	12.85	2,296	10.21	1,839	8.18
	4x4	No.1/2	9,789	9,789	43.55	8,534	37.96	6,741	29.99	5,356	23.83	4,292	19.09
	4x6	No.1/2	14,975	14,975	66.61	13,411	59.66	10,594	47.12	8,417	37.44	6,744	30.00
	4x8	No.1/2	17,945	17,945	79.82	17,679	78.64	13,964	62.12	11,095	49.35	8,890	39.54
	4x10	No.1/2	22,896	22,896	101.85	22,555	100.33	17,817	79.25	14,156	62.97	11,342	50.45
	4x12	No.1/2	27,846	27,846	123.87	27,432	122.02	21,669	96.39	17,216	76.58	13,795	61.36

6-inch Wall	2x6	No.1/2	7,293	7,293	32.44	7,293	32.44	7,293	32.44	7,293	32.44	7,293	32.44
	6x4	No.1/2	15,383	15,383	68.43	15,383	68.43	15,383	68.43	15,383	68.43	15,383	68.43
	6x6	No.1/2	23,532	23,532	104.68	23,532	104.68	23,532	104.68	23,532	104.68	23,532	104.68
	6x8	No.1/2	28,200	28,200	125.44	28,200	125.44	28,200	125.44	28,200	125.44	28,200	125.44
	6x10	No.1/2	35,979	35,979	160.04	35,979	160.04	35,979	160.04	35,979	160.04	35,979	160.04
	6x12	No.1/2	43,758	43,758	194.65	43,758	194.65	43,758	194.65	43,758	194.65	43,758	194.65