Anchors deisgn to ACI 349.2R97 appendix B

1. Design of anchors according to ACI 349.2R97 appendix B
Appendix B of ACI 349 was developed to better define the design requirements for steel embedmnts
revisions are periodically made to the code as a result of on-going research and testing. As with
other concretebuilding codes, the design of embedments attempts to assure a ductile failure mode
sothat the reinforcement yields before the concrete fails. In embedments designed for direct loading,
the concrete pullout strength must be greater than the tensile strength of the steel.
Vu  6kip
fy  50000psi fut  60000psi
fc  4000psi Must be in psi
Anchor diameter d s  0.5in
Anchor head diameter d h  1in
Anchor head thickness Th  0.312in
Anchor length Ld  10 d s  5  in
ϕ  0.85 μ  0.9
Vu
Vn   7.059  kip
ϕ
Determine the required area of steel of the anchor
Use the shear friction provision of Section 11.7 with = 0.85, = 0.9.
Equate the external (required strength) and internal (design strength)
forces and solve for the required steel area for the stud.
Vu 2
Avf   0.157  in
ϕ μ fy
2
π d s 2
As   0.196  in
4
 
check1  if As  Avf "ok" "no good"  "ok"

2. Check Anchor head bearing
Area of the anchor head (Ah ) (including the area of the tensile stress
component) is at least 2.5 times the area of the tensile stress
component.
2
π dh 4 2
Ah   5.067  10 m
4
Ah
4 Must be more than 2.5
As
dh  ds
c1   0.25 in
2

check2  if Th  c1 "ok" "no good"  "ok" 
Determine the embedment of the stud
The design pullout strength of the concrete, Pd , must exceed the minimum specified
tensile strength (Asfut ) of the tensile stress component.
As fut  11.781 kip
0.65 4 psi fc  164.438  psi
Acp = [(Ld + dh /2)^2– (dh /2)^2]

 dh 
2 2

 dh 
Pc  π  Ld        0.65 4  psi fc  15.498 kip
 2  2 

check3  if Pc  As fut "ok" "no good"  "ok" 
By Khaled Eid, PE email khaled_eid@yahoo.com