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

NOTES:

TABLE IS BASED ON CSA S86-01. SPF PROPERTIES PER 5.3.1a
PERPENDICULAR AND PARALLEL TO GRAIN LOADS INCLUDE K_D = 1.15 LOAD INCREASE.
PERPENDICULAR TO GRAIN VALUES INCLUDE BEARING FACTOR K_B AND SIZE FACTOR K_Zcp.
FINAL VALUES SHOWN ARE THE LOWER OF PERPENDICULAR TO GRAIN (Qr) OR COMPRESSION PARALLEL TO GRAIN (Pr)
EFFECTIVE LENGTH OF STUD OR POST HEIGHT USED IS NOMINAL PLATE HEIGHT SUBTRACTING 4.5 INCHES FOR (3) 2x WALL PLATES.
PLYWOOD SHEATHING AND NAILING PATTERN REQUIREMENTS PROVIDED BY THE ENGINEER OF RECORD.

Earthbound SlackJack: a seismic, snow and wind load holdown system for wood framed structures.