PART 3 TENSION LOAD
Pullout Failure Mode
Results ϕ concrete
Results ACI 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
( ii ) Tension loads Cast-in headed studs , headed bolts , or hooked bolts
Condition A
Condition B
0.75 0.70
Post-installed anchors with category as determined from ACI 355.2 or ACI 355.4
Category 1 |
0.75 |
0.65 |
( Low sensitivity to Installation and high reliability ) |
|
|
Category 2 |
0.65 |
0.55 |
( Medium sensitivity to Installation and medium reliability ) |
|
|
Category 3 |
0.55 |
0.45 |
( High sensitivity to Installation and lower reliability ) |
|
|
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 and pullout failure in tension .
ICC-ES ECR-1917 Table 3
DESIGN INFORMATION
Effective min . embedment
Symbol
Units
Strength reduction ϕ factor for tension , concrete failure modes , or pullout , Condition B
Nominal anchor diameter ( in .) 3 / 8 1 / 2 5 / 8 3 / 4 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
0.55 0.65
Excerpt from ICC-ESR-3187 Table 10 showing the strength reduction factor ( ϕ-factor ) corresponding to pullout failure in tension for HIT-Z / HIT-Z-R threaded rods used with HIT-HY 200 adhesive .
ICC-ESR-3187 Table 10
DESIGN INFORMATION Symbol Units
Permissible installation conditions
Dry concrete , water saturated concrete
Anchor Category
Nominal rod diameter ( in .) 3 / 8 1 / 2 5 / 8 3 / 4
- 1 ϕ d ϕ ws
- 0.65
ACI 318-14 strength design provisions treat pullout failure in tension as a “ concrete ” failure mode . The nominal pullout strength ( N pn
) is multiplied by one or more strength reduction factors ( ϕ-factors ) to obtain a design pullout strength ( ϕN pn
). The ϕ-factors given in ACI 318-14 Section 17.3.3 are used to calculate the design strength for pullout failure , concrete breakout failure and side-face blowout failure in tension . These ϕ-factors are relevant to static load conditions . An additional strength reduction factor (= 0.75 ) is used to calculate the design strength for these failure modes if the anchorage design is based on seismic load conditions .
PROFIS Engineering designates the ϕ-factor corresponding to “ concrete ” failure modes for static load conditions “ ϕ concrete
”, and applies this ϕ-factor to the nominal pullout strength , concrete breakout strength and side-face blowout strengths in tension to obtain a design strength . If seismic load conditions are being modeled , PROFIS Engineering also applies the 0.75 seismic reduction factor to the design strength .
When designing cast-in-place anchors , PROFIS Engineering uses the ϕ-factors given in ACI 318-14 Section 17.3.3 ( c )( ii ) to calculate the design pullout strength . The ϕ-factors given in Section 17.3.3 ( c )( ii ) for post-installed anchors are only intended to be used as guide values 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 . 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 ( ICC-ESR ) for the anchor , to calculate the design pullout strength for the postinstalled anchors in its portfolio . The ϕ-factors in the anchor ICC-ESR correspond to Condition B .
As noted in ACI 318-14 Section 17.3.3 , only Condition B ϕ-factors are used to calculate a design pullout strength . PROFIS Engineering defaults to the Condition B ϕ-factor relevant to the anchor that has been selected when calculating design pullout strength . If Condition A is selected as a design parameter , PROFIS Engineering only uses the Condition A ϕ-factors given in ACI 318-14 Section 17.3.3 to calculate the design concrete breakout strength in tension .
PROFIS Engineering designates the 0.75 reduction factor noted in ACI 318-14 Section 17.2.3.4.4 for seismic load conditions “ ϕ seismic
”.
Reference the Equations section of the PROFIS Engineering report for more information on the following parameters :
ϕN pn or ϕN pn , f ́c
: Design pullout strength in tension
Reference the Results section of the PROFIS Engineering report for more information on the following parameter :
ϕ seismic
: Strength reduction factor for seismic tension
96 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions