PROFIS ENGINEERING REPORT SHEAR LOAD
Concrete Breakout Failure Mode
Results ϕ concrete
Results 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ϕ concrete
17.3.3 Strength reduction factor ϕ for anchors in concrete shall be as follows when the load combinations of 5.3 are used :
……………………………………………………………………………………………………
( c ) Anchor governed by concrete breakout , side-face blowout , pullout , or pryout strength Condition A
Condition B ( i ) Shear loads 0.75 0.70
……………………………………………………………………………………………………
Condition A applies where supplementary reinforcement is present except for pullout and pryout strengths .
Condition B applies where supplementary reinforcement is not present and for pullout and pryout strengths .
Example :
Example of a post-installed mechanical anchor strength reduction factor ( ϕ-factor ) corresponding to concrete breakout failure in shear .
ICC-ESR-1917 Table 3
DESIGN INFORMATION Symbol Units
Nominal anchor diameter ( in .) 3 / 8 1 / 2 5 / 8 3 / 4
Effective min . embedment h ef in . 1-1 / 2 2 2-3 / 4 2 3-1 / 4 3-1 / 8 4 3-1 / 4 3-3 / 4 4-3 / 4
Strength reduction o factor for shear , concrete failure modes , Condition B
Example :
Example of a post-installed adhesive anchor system strength reduction factor ( ϕ-factor ) corresponding to concrete breakout failure in shear .
ICC-ESR-3187 Table 12
0.70
ACI 318-14 strength design provisions for concrete breakout failure in shear require calculation of a nominal concrete breakout strength ( V cb or V cbg
). The nominal strength is multiplied by a strength reduction factor ( ϕ-factor ) to obtain a design strength ( ϕV cb or ϕV cbg ). Only one ϕ-factor is applied to V cb or V cbg
. The 0.75 seismic strength reduction factor required per Section 17.2.3.4.4 is only relevant to tension calculations , and is therefore not applied to V cb or V cbg when the anchorage is being designed for seismic shear load conditions .
PROFIS Engineering designates the ϕ-factor corresponding to concrete breakout failure for shear load conditions “ ϕ concrete
”. When designing cast-in-place anchors , PROFIS Engineering uses the ϕ-factors given in ACI 318-14 Section 17.3.3 . The ϕ-factors in Section 17.3.3 are only intended to be used as guide values for postinstalled anchors in the absence of product-specific data .
Post-installed mechanical anchors can be shown compliance 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 shown compliance under the International Building Code via testing per the ICC-ES acceptance criteria AC308 in conjunction with the ACI standard ACI 355.4 . When Condition B is selected as a post-installed anchor design parameter , PROFIS Engineering uses the ϕ-factors derived from AC193 / ACI 355.2 or AC308 / ACI 355.4 testing , as given in the ICC-ESR for the anchor . The ϕ-factors in the ICC-ESR correspond to Condition B .
PROFIS Engineering defaults to Condition B when calculating concrete breakout strength in shear . If Condition A is selected as a design parameter for either castin-place or post-installed anchors , PROFIS Engineering uses the Condition A ϕ-factor given in ACI 318-14 Section 17.3.3 ( c ) ( i ) to calculate the design concrete breakout strength in shear .
Reference the Results section of the PROFIS Engineering report for more information on the following parameters :
V cb or V cbg : Nominal concrete breakout strength in shear ϕV cb or ϕV cbg : Design concrete breakout strength in shear
DESIGN INFORMATION Symbol Units
Strength reduction o factor for shear , concrete failure modes , Condition B
3 / 8 or # 3
1 / 2 or # 4
Nominal Rod Diameter ( in ).
5 / 8 or # 5
3 / 4 or # 6
ϕ - 0.70
7 / 8or # 7
1 or # 8
# 9
1 / 4 or # 10
200 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions