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Symmetrical Compression Posts

Strong-Rod Systems

Compression Posts

Compression posts play an integral role in designing a Strong-Rod Anchor Tiedown System for shearwall overturning restraint. As tension loads are resisted by the Strong-Rod ATS steel rods, adequate compression elements are crucial in the opposite end of the shearwall. Compression posts are either single members or multiple members. A Designer may use either a symmetrical or an asymmetrical post configuration. These elements are specified by the Designer. Simpson Strong-Tie offers guidance by providing standard tables for compression elements.

Symmetrical Posts

An equal number of posts or studs on each side of the Strong-Rod. End of the shearwall requires extra framing to maintain edge-of-wall line.

Moment Arm = Center of Rod to Center of Rod

Nailing Example: (4) total compression members: 2" o.c. edge nailing x 4 = 8" o.c. nailing at each compression member.

Compression Member Selection

Compression Post Perpendicular and Parallel to Grain Allowable Loads for Douglas Fir-Larch (Solid Lumber Sizes)
Solid Lumber Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	6,565	6,685	5,330	4,335	3,590	3,020
	1-3x4	10,940	11,145	8,880	7,225	5,985	5,035
	1-4x4	15,315	16,730	13,320	10,830	8,970	7,545
	2-3x4	21,875	22,290	17,760	14,450	11,975	10,075
	1-4x6	24,065	26,195	20,880	16,990	14,075	11,840
	1-4x8	31,720	34,400	27,445	22,350	18,525	15,590
	1-4x10	40,470	43,700	34,905	28,445	23,590	19,860
	2-4x6	48,125	52,395	41,755	33,980	28,150	23,685
	1-4x12	49,220	53,145	42,455	34,595	28,690	24,155
	2-4x8	63,440	68,795	54,890	44,695	37,045	31,180
6-inch Wall	1-2x6	10,315	22,060	18,455	15,475	13,075	11,145
	1-3x6	17,190	36,765	30,760	25,795	21,790	18,580
	1-4x6	24,065	55,685	46,420	38,835	32,760	27,900
	1-6x6	37,815	71,865	62,220	53,405	45,820	39,470
	1-6x8	51,565	95,800	83,445	71,945	61,915	53,455
	1-6x10	65,315	118,340	103,750	89,895	77,635	67,185
	1-6x12	79,065	143,255	125,590	108,820	93,980	81,330
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Compression Post Perpendicular and Parallel to Grain Allowable Loads for Douglas Fir-Larch (Multiple 2x Sizes)
Multiple 2x Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	6,565	6,685	5,330	4,335	3,590	3,020
	2-2x4	13,125	13,375	10,655	8,670	7,185	6,045
	3-2x4	19,690	20,060	15,985	13,005	10,775	9,065
	4-2x4	26,250	26,745	21,315	17,345	14,365	12,085
	5-2x4	32,815	33,435	26,645	21,680	17,960	15,110
	6-2x4	39,375	40,120	31,970	26,015	21,550	18,130
	7-2x4	45,940	46,805	37,300	30,350	25,145	21,155
	8-2x4	52,500	53,495	42,630	34,685	28,735	24,175
	9-2x4	59,065	60,180	47,955	39,020	32,325	27,195
6-inch Wall	1-2x6	10,315	22,060	18,455	15,475	13,075	11,145
	2-2x6	20,625	44,120	36,910	30,955	26,150	22,295
	3-2x6	30,940	66,180	55,365	46,430	39,225	33,440
	4-2x6	41,250	88,240	73,825	61,905	52,300	44,590
	5-2x6	51,565	110,300	92,280	77,385	65,375	55,735
	6-2x6	61,875	132,360	110,735	92,860	78,450	66,885
	7-2x6	72,190	154,420	129,190	108,335	91,525	78,030
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Compression Post Perpendicular and Parallel to Grain Allowable Loads for Spruce-Pine-Fir (Solid Lumber Sizes)
Solid Lumber Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	4,460	5,865	4,675	3,805	3,155	2,655
	1-3x4	7,440	9,775	7,795	6,345	5,260	4,425
	1-4x4	10,415	13,685	10,910	8,885	7,360	6,195
	2-3x4	14,875	19,550	15,590	12,690	10,515	8,850
	1-4x6	16,365	21,420	17,100	13,930	11,550	9,720
	1-4x8	21,570	28,115	22,475	18,320	15,195	12,795
	1-4x10	27,520	35,705	28,575	23,315	19,350	16,300
	2-4x6	32,725	42,840	34,200	27,860	23,095	19,440
	1-4x12	33,470	43,420	34,750	28,355	23,530	19,820
	2-4x8	43,135	56,235	44,945	36,640	30,390	25,590
6-inch Wall	1-2x6	7,015	19,200	16,110	13,540	11,450	9,770
	1-3x6	11,690	31,995	26,855	22,565	19,085	16,285
	1-4x6	16,365	44,795	37,595	31,590	26,720	22,800
	1-6x6	25,715	54,005	47,670	41,530	36,005	31,245
	1-6x8	35,065	71,720	63,710	55,790	48,550	42,240
	1-6x10	44,415	88,250	78,910	69,485	60,725	52,990
	1-6x12	53,760	106,830	95,520	84,115	73,505	64,145
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Compression Post Perpendicular and Parallel to Grain Capacities for Spruce-Pine-Fir (Multiple 2x Sizes)
Multiple 2x Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	4,460	5,865	4,675	3,805	3,155	2,655
	2-2x4	8,925	11,730	9,355	7,615	6,310	5,310
	3-2x4	13,390	17,595	14,030	11,420	9,465	7,965
	4-2x4	17,850	23,460	18,705	15,230	12,620	10,620
	5-2x4	22,315	29,320	23,385	19,035	15,775	13,275
	6-2x4	26,775	35,185	28,060	22,840	18,930	15,930
	7-2x4	31,240	41,050	32,735	26,650	22,085	18,585
	8-2x4	35,700	46,915	37,415	30,455	25,240	21,235
	9-2x4	40,165	52,780	42,090	34,265	28,395	23,890
6-inch Wall	1-2x6	7,015	19,200	16,110	13,540	11,450	9,770
	2-2x6	14,025	38,395	32,225	27,075	22,905	19,545
	3-2x6	21,035	57,595	48,335	40,615	34,355	29,315
	4-2x6	28,050	76,790	64,445	54,150	45,810	39,090
	5-2x6	35,065	95,990	80,560	67,690	57,260	48,860
	6-2x6	42,075	115,185	96,670	81,230	68,710	58,635
	7-2x6	49,090	134,385	112,780	94,765	80,165	68,405
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Column Perpendicular and Parallel to Grain Allowable Loads for Hem-Fir (Solid Lumber Sizes)
Solid Lumber Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	4,255	5,485	4,355	3,540	2,925	2,460
	1-3x4	7,090	9,145	7,260	5,895	4,875	4,100
	1-4x4	9,925	14,855	11,825	9,615	7,960	6,695
	2-3x4	14,175	18,285	14,525	11,790	9,755	8,200
	1-4x6	15,595	23,265	18,535	15,080	12,495	10,510
	1-4x8	20,555	30,550	24,370	19,840	16,440	13,835
	1-4x10	26,225	38,815	30,995	25,250	20,940	17,625
	2-4x6	31,185	46,530	37,075	30,160	24,985	21,020
	1-4x12	31,895	47,210	37,695	30,710	25,465	21,435
	2-4x8	41,110	61,105	48,735	39,675	32,880	27,670
6-inch Wall	1-2x6	6,685	18,765	15,470	12,850	10,790	9,165
	1-3x6	11,140	31,275	25,780	21,420	17,985	15,275
	1-4x6	15,595	49,610	41,300	34,525	29,110	24,785
	1-6x6	24,505	59,530	51,230	43,780	37,450	32,200
	1-6x8	33,415	79,455	68,780	59,030	50,640	43,625
	1-6x10	42,325	98,280	85,620	73,830	63,540	54,860
	1-6x12	51,235	118,970	103,645	89,370	76,920	66,410
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Column Perpendicular and Parallel to Grain Capacities for Hem-Fir (Multiple 2x Sizes)
Multiple 2x Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	4,255	5,485	4,355	3,540	2,925	2,460
	2-2x4	8,505	10,970	8,715	7,075	5,855	4,920
	3-2x4	12,760	16,455	13,070	10,615	8,780	7,380
	4-2x4	17,010	21,940	17,425	14,150	11,705	9,840
	5-2x4	21,265	27,430	21,785	17,690	14,630	12,295
	6-2x4	25,515	32,915	26,140	21,225	17,560	14,755
	7-2x4	29,770	38,400	30,500	24,765	20,485	17,215
	8-2x4	34,020	43,885	34,855	28,300	23,410	19,675
	9-2x4	38,275	49,370	39,210	31,840	26,340	22,135
6-inch Wall	1-2x6	6,685	18,765	15,470	12,850	10,790	9,165
	2-2x6	13,365	37,535	30,935	25,700	21,585	18,325
	3-2x6	20,050	56,300	46,405	38,555	32,375	27,490
	4-2x6	26,730	75,065	61,875	51,405	43,165	36,655
	5-2x6	33,415	93,830	77,340	64,255	53,960	45,820
	6-2x6	40,095	112,600	92,810	77,105	64,750	54,980
	7-2x6	46,780	131,365	108,280	89,955	75,540	64,145
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Compression Post Perpendicular and Parallel to Grain Allowable Loads for Southern Pine (Solid Lumber Sizes)
Solid Lumber Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	5,930	5,905	4,700	3,820	3,165	2,660
	1-3x4	9,890	9,845	7,835	6,370	5,275	4,435
	1-4x4	13,845	15,675	12,475	10,145	8,400	7,065
	2-3x4	19,775	19,690	15,670	12,740	10,550	8,870
	1-4x6	21,750	24,515	19,535	15,895	13,170	11,080
	1-4x8	28,675	32,230	25,700	20,925	17,340	14,590
	1-4x10	36,585	41,000	32,725	26,655	22,095	18,595
	2-4x6	43,505	49,030	39,070	31,795	26,340	22,160
	1-4x12	44,495	49,710	39,710	32,360	26,835	22,595
	2-4x8	57,350	64,455	51,405	41,845	34,680	29,180
6-inch Wall	1-2x6	9,325	19,810	16,470	13,755	11,590	9,865
	1-3x6	15,535	33,020	27,445	22,925	19,315	16,440
	1-4x6	21,750	52,160	43,460	36,355	30,660	26,110
	1-6x6	34,185	60,045	53,640	47,195	41,220	35,950
	1-6x8	46,615	81,880	73,145	64,355	56,205	49,025
	1-6x10	59,045	103,715	92,650	81,520	71,195	62,100
	1-6x12	71,475	125,550	112,155	98,680	86,185	75,175
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Compression Post Perpendicular and Parallel to Grain Allowable Loads for Southern Pine (Multiple 2x Sizes)
Multiple 2x Sizes
Framing	Lumber Size (each side of Rod)	Allow. Perp. To Grain, Pc (lbs.)	Allowable Parallel to Grain, Pc (lbs.)
			Plate Height (ft)
			8	9	10	11	12
			(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-2x4	5,930	5,905	4,700	3,820	3,165	2,660
	2-2x4	11,865	11,815	9,400	7,645	6,330	5,325
	3-2x4	17,800	17,720	14,105	11,465	9,495	7,985
	4-2x4	23,730	23,630	18,805	15,290	12,660	10,645
	5-2x4	29,660	29,535	23,505	19,110	15,825	13,305
	6-2x4	35,595	35,440	28,205	22,935	18,990	15,970
	7-2x4	41,525	41,350	32,910	26,755	22,155	18,630
	8-2x4	47,460	47,255	37,610	30,580	25,320	21,290
	9-2x4	53,395	53,160	42,310	34,400	28,485	23,955
6-inch Wall	1-2x6	9,325	19,810	16,470	13,755	11,590	9,865
	2-2x6	18,645	39,625	32,935	27,505	23,175	19,725
	3-2x6	27,965	59,435	49,405	41,260	34,765	29,590
	4-2x6	37,290	79,245	65,875	55,015	46,355	39,450
	5-2x6	46,615	99,055	82,340	68,770	57,945	49,315
	6-2x6	55,935	118,870	98,810	82,520	69,530	59,180
	7-2x6	65,255	138,680	115,280	96,275	81,120	69,040
See Compression Members: General Notes for additional information. Shaded Cells are limited by Parallel to Grain loads.

Column Perpendicular and Parallel to Grain Capacities for Parallam® PSL
Framing	Lumber Size (each side of Rod)	DF Sill Plate Allow Perp. To Grain Pc (lbs)	SP Sill Plate Allow Perp. To Grain Pc (lbs)	Allowable Parallel to Grain, Pc (lbs.)
				Plate Height (ft)
				8	9	10	11	12
				(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-3 1/2x3 1/2	15,315	13,845	25,420	20,100	16,270	13,430	11,265
	1-3 1/2x5 1/4	22,970	20,765	38,125	30,150	24,405	20,145	16,900
	1-3 1/2x7	30,625	27,685	50,835	40,200	32,540	26,860	22,535
6-inch Wall	1-5 1/4x3 1/2	22,970	20,765	79,445	64,540	53,015	44,150	37,255
	1-5 1/4x5 1/4	34,455	31,145	119,170	96,805	79,520	66,220	55,885
	1-5 1/4x7	45,940	41,530	158,890	129,075	106,030	88,295	74,510
See Compression Members: General Notes for additional information. PSL Grade = 1.8E with F_c=2500 psi. F_{c perp}= 625 psi for Douglas-Fir Larch (DF) sill plate. F_{c perp}= 565 psi for Southern Pine (SP) sill plate. Shaded columns are limited by Parallel to Grain loads.

Parallam® is a registered trademank of Trus Joist® by Weyerhaeuser.

Column Perpendicular and Parallel to Grain Loads for LSL
Framing	Lumber Size (each side of Rod)	DF Sill Plate Allow Perp. To Grain, Pc (lbs)	SP Sill Plate Allow Perp. To Grain, Pc (lbs)	Allowable Parallel to Grain, Pc (lbs.)
				Plate Height (ft)
				8	9	10	11	12
				(160)	(160)	(160)	(160)	(160)
4-inch Wall	1-3-1/2x3-1/2	15,315	13,845	18,110	14,380	11,670	9,645	8,105
	1-3-1/2x5-1/4	22,970	20,765	27,160	21,570	17,505	14,470	12,155
	1-3-1/2x7	30,625	27,685	36,215	28,760	23,340	19,295	16,205
6-inch Wall	1-5-1/4x3-1/2	22,970	20,765	53,900	44,880	37,345	31,330	26,555
	1-5-1/4x5-1/4	34,455	31,145	80,850	67,320	56,020	46,995	39,835
	1-5-1/4x7	45,940	41,530	107,805	89,760	74,695	62,655	53,110
See Compression Members: General Notes for additional information. LSL Grade = 1.3E with F_c=1400 psi. F_{c perp}= 625 psi for Douglas-Fir Larch (DF) sill plate. F_{c perp}= 565 psi for Southern Pine (SP) sill plate. Shaded columns are limited by Parallel to Grain loads.