2.0 SHEAR
2.3 Steel Failure Mode
Results ϕ concrete
Results ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
ϕ concrete
17.5.3 Strength reduction factor ϕ for anchors in concrete shall be in accordance with Tables ……… …….. 17.5.3 ( c )…………………
Table 17.5.3 ( c ) — Anchor strength governed by concrete pullout , or pryout strength
Type of anchor installation
Anchor Category [ 1 ] from ACI 355.2 or ACI 355.4
Tension ( concrete pullout )
Strength reduction factor ϕ
Shear ( concrete pryout )
Cast-in anchors Not applicable 0.70 0.70
Post-installed anchors
1 0.65 2 0.55 3 0.45
Example of a post-installed adhesive anchor system strength reduction factor ( ϕ-factor ) corresponding to concrete breakout failure in shear .
ICC-ES ESR-3187 Table 12
DESIGN INFORMATION Symbol Units
Strength reduction factor for shear , concrete failure modes , Condition B
3 / 8 or # 3
1 / 2 or # 4
0.70
Nominal rod diameter ( in ).
5 / 8 or # 5
3 / 4 or # 6
ϕ - 0.70
7 / 8 or # 7
1 or # 8
# 9
1 / 4 or # 10
ACI 318-19 strength design provisions for pryout failure in shear require calculation of a nominal pryout strength ( V cp or V cpg
). The nominal strength is multiplied by a strength reduction factor ( ϕ-factor ) to obtain a design strength ( ϕV cp or ϕV cpg ). Only one ϕ-factor is applied to V cp or V cpg
. The 0.75 seismic strength reduction factor required per Section 17.10.5.4 is only relevant to tension calculations , and is therefore not applied to V cp or V cpg when the anchorage is being designed for seismic shear load conditions .
PROFIS Engineering designates the ϕ-factor corresponding to pryout failure for shear load conditions “ ϕ concrete
”, since pryout is considered a concrete failure mode . When designing cast-in-place anchors , PROFIS Engineering uses the ϕ-factors given in ACI 318-19 Table 17.5.3 ( c ). The ϕ-factors in Table 17.5.3 ( c ) are only intended to be used as guide values for post-installed anchors in the absence of product-specific data .
Post-installed mechanical anchors can be qualified for recognition under the International Building Code via testing per the ICC-ES acceptance criteria AC193 in conjunction with the ACI standard ACI 355.2 . Post-installed adhesive anchor systems can be qualified for recognition under the International Building Code via testing per the ICC-ES acceptance criteria AC308 in conjunction with the ACI standard ACI 355.4 . For pryout calculations , PROFIS Engineering uses the ϕ-factors derived from AC193 / ACI 355.2 or AC308 / ACI 355.4 testing , as given in the ICC-ES evaluation report ( ESR ) for the anchor . These ϕ-factors correspond to the ϕ-factors noted in Table 17.5.3 ( c ).
Reference the Results section of the PROFIS Engineering report for more information on the following parameters :
V cp or V cpg : nominal pryout strength in shear . ϕV cp or ϕV cpg
: design pryout strength in shear .
279 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions