CEMP-E
TI 809-02
1 September 1999
strength design is used, the required strength, and the design of the anchors will be in
accordance with FEMA 302. When allowable stress design (ASD) is used, the allowable
service load for headed anchors in shear or tension, assuming the anchor bolts conform to
ASTM 307 or an approved equivalent can be assumed equal to that indicated in Table 4-4.
For ASD design, when anchors are subject to combined shear and tension, the following
relationship will be used:
Ps
Vs
5/3
5/3
+
≤1
Pt
Vt
Where:
Ps = applied tension service load
Pt = allowable tension service load from Table 4-4
Vs = applied shear service load
Vt = allowable shear service load from Table 4-4
The allowable service loads in tension and shear specified in Table 4-4 are for the edge
distances and spacing specified. The edge distance and spacing can be reduced to 50
percent of the values specified with an equal reduction in allowable service load. Where edge
distance and spacing are reduced less than 50 percent, the allowable service load will be
determined by linear interpolation. Increase of the values in Table 4-4 by one-third is permitted
for load cases involving wind or earthquake. Where special inspection is provided for the
installation of anchors, a 100 percent increase in the allowable tension values of Table 4-4 is
permitted. No increase in shear value is permitted.
c. Expansion Anchors. Expansion anchors will be designed in accordance with the
provisions of ACI Committee 449 Report, "Concrete Nuclear Structures," Appendix B, "Steel
Embedments." The engineer will review expansion anchor design features, failure modes, test
results and installation procedures prior to selecting a specific expansion anchor for an
application. Expansion anchors will not be used to resist vibratory loads in tension zones of
concrete members unless tests are conducted to verify the adequacy of the specific anchor
and application. Expansion anchors will not be installed in concrete where there is obvious
signs or cracking, or deterioration.
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