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Hold-Down Eccentricity and Capacity of the Vertical Wood Member

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In my pervious email I tried to include the table mentioned in the
letter. The copied and pasted version went through fine in my
inter-office test, but it appears to not have worked in the email I
submitted to seaint. I am trying again in this email. If this does not
work you can request the excel file from Norm at  Norm(--nospam--at)NSSE.com. 

Thank You,

Terri Schneider PE


The following tables discusses eccentricity effects on wood tension
members.  2x4 and 4x4 wood

members are check for their design capacity for single and double shear
installations.  This includes

checking for its design capacity at the critical net section, reducing
the gross section properties

for holes or other removed wood and for tensile stresses, based on the
following formulas proposed

by I.C.B.O.

SINGLE SHEAR				DOUBLE SHEAR

Ptmax = 1/[(1/F'tAnet) + (e'/F*bSnet)]				Ptmax =
F'tAnet					
								
Ptmax on 2x4 WOOD MEMBER
SIMPSON	
SINGLE SHEAR				DOUBLE SHEAR
tabulated	
	No. 1	No. 2	Standard	No. 1	No. 2	Standard
values	
HD2A	786	684	288	4284	3645	1582		1555	
HD5A	586	511	215	4094	3483	1512		1870	
HD6A	580	506	213	3903	3321	1441		2275	
HD8A	580	506	213	3903	3321	1441		3220	
HD10A	580	506	213	3903	3321	1441		3945	
								
Ptmax on 4x4 WOOD MEMBER
SIMPSON	
SINGLE SHEAR				DOUBLE SHEAR
tabulated	
	No. 1	No. 2	Standard	No. 1	No. 2	Standard
values	
HD2A	2644	2296	971	9996	8505	3691		2775	
HD5A	2153	1872	791	9552	8127	3527		4010	
HD6A	2105	1830	773	9108	7749	3363		5105	
HD8A	2105	1830	773	9108	7749	3363		7460	
HD10A	2105	1830	773	9108	7749	3363		9540	
								
Reference NDS: Douglas Fir-Larch Table 4A (p.20)

	2x4 MEMBER				4X4 MEMBER

	No. 1	No. 2	Standard		No. 1	No. 2	Standard

Fb=	1000	875	550		1000	875	550		
Ft=	677	576	375		677	576	375		
F't=FtxCF 	1016	864	375		1016	864	375

F*b=FbxCFxCfuxCD	1995	1746	732		1995	1746
732		
xm = 	0.75	0.75	0.75		1.75	1.75	1.75		
t =	1.5	1.5	1.5		3.5	3.5	3.5		
CF = 	1.5	1.5	1.0		1.5	1.5	1.0		
Cfu = 	1.0	1.0	1.0		1.0	1.0	1.0		
								
Reference Simpson Wood Construction Connectors

	2x4		4x4			2x4	4x4		
	Anet	Snet	Anet	Snet	e (in)	e' (in)	e' (in)		
HD2A	4.2188	1.05	9.8438	5.74	1.4375	2.1875	3.1875		
HD5A	4.0313	1.01	9.4063	5.49	2.1875	2.9375	3.9375		
HD6A	3.8438	0.96	8.9688	5.23	2.0625	2.8125	3.8125		
HD8A	3.8438	0.96	8.9688	5.23	2.0625	2.8125	3.8125		
HD10A	3.8438	0.96	8.9688	5.23	2.0625	2.8125	3.8125		
								


NOMENCLATURE:

								
								
Ptmax = 	Wood member tension design capacity at critical net
section, [lbs. (N)].

F't = 	Allowable design tensile stress (Ft x CF), [psi (Pa)].

F*b =	allowable design bending stress (Fb x CF x Cfu x CD), [psi
(Pa)].								
Anet =	Net area at hole, [inch2 (mm2)].

Snet = 	Net section modulus at hole, [inch3 (mm3)].

e' =	Eccentricity (connector offset from center of the hole for the
anchor rod to face of

	wood member plus xm), [inch (mm)].

xm = 	Distance from the face of the wood member to the location of the
maximum moment 								
	due to dowel bearing or dowel bending (<t/2) [inch (mm)].

t =	Length of bolt in wood member; or thickness (breadth) of wood
member, [inch (mm)].

CF = 	Size factor.

Cfu = 	Flat use factor.