2.0 SHEAR
2.2 Pryout Failure Mode
Results ϕ seismic
Results ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
ϕ seismic
17.10.5.4 The anchor design tensile strength shall be calculated from ( a ) through ( e ) for the failure modes given in Table 17.5.2 assuming the concrete is cracked unless it can be demonstrated that the concrete remains uncracked :
( a ) ϕN sa for a single anchor or for the most highly stressed individual anchor in an anchor group
[ ϕN sa corresponds to steel failure ( tension ) in Table 17.5.2 ] ( b ) 0.75ϕN cb or 0.75ϕN cbg except that N cb or N cbg need not be calculated if anchor reinforcement satisfying 17.5.2.1 ( a ) is provided [ ϕN cb or ϕN cbg correspond to concrete breakout failure ( tension ) in Table 17.5.2 ]
( c ) 0.75ϕN pn for a single anchor or for the most highly stressed individual anchor in an anchor group [ ϕN pn corresponds to pullout failure ( tension ) in Table 17.5.2 ] ( d ) 0.75ϕN sb or 0.75ϕN sbg
[ ϕN sb or ϕN sbg correspond to side-face blowout failure ( tension ) in Table 17.5.2 ]
When designing an anchorage for ACI 318-19 seismic tension load conditions , non-steel nominal strengths are multiplied by two strength reduction factors ( ϕ-factors ): one ϕ-factor for the ( non-steel ) tension failure mode being considered , and one ϕ-factor for seismic tension load conditions .
PROFIS Engineering designates the 0.75 seismic tension reduction factor noted in ACI 318-19 Section 17.10.5.4 “ ϕ seismic
”. This reduction is only considered with respect to non-steel tension failure modes when calculating tension design strengths for both cast-in-place and post-installed anchors subjected to seismic tension loads . The PROFIS Engineering report always shows “ ϕseismic ” equal to 1.0 when designing for ACI 318-19 shear load conditions .
Reference the Results section of the PROFIS Engineering report for more information on the following parameters :
V cp or V cpg : nominal concrete breakout strength in shear ϕV cp or ϕV cpg
: design concrete breakout strength in shear
ϕ concrete
: strength reduction factor for shear concrete failure .
( e ) 0.75ϕN a or 0.75ϕN ag
[ ϕN a or ϕN ag correspond to bond failure ( tension ) in Table 17.5.2 ] where ϕ is in accordance with 17.5.3 .
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
0.70
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
Nominal Rod Diameter ( in ).
5 / 8 or # 5
3 / 4 or # 6
ϕ - 0.70
7 / 8 or # 7
1 or # 8
# 9
1-14 or # 10
238 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions