PART 3 TENSION LOAD
Pullout Failure Mode
Results ϕ seismic
Results ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ϕ seismic
17.2.3.4.4 The anchor design tensile strength for resisting earthquake forces shall be determined from consideration of ( a ) through ( e ) for the failure modes given in Table 17.3.1.1 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 a group of anchors [ ϕN sa corresponds to steel failure ( tension ) in Table 17.3.1.1 ] ( b ) 0.75ϕN cb or 0.75ϕN cbg except that N cb or N cbg need not be calculated where anchor reinforcement satisfying 17.4.2.9 is provided [ ϕN cb or ϕN cbg correspond to concrete breakout failure ( tension ) in Table 17.3.1.1 ]
( c ) 0.75ϕN pn for a single anchor or for the most highly stressed individual anchor in a group of anchors [ ϕN pn corresponds to pullout failure ( tension ) in Table 17.3.1.1 ] ( d ) 0.75ϕN sb or 0.75ϕN sbg
[ ϕN sb or ϕN sbg correspond to side-face blowout failure ( tension ) in Table 17.3.1.1 ]
( e ) 0.75ϕN a or 0.75ϕN ag
[ ϕN a or ϕN ag correspond to bond failure ( tension ) in Table 17.3.1.1 ] where ϕ is in accordance with 17.3.3 .
PROFIS Engineering calculations for pullout failure in tension when seismic load conditions are being modeled :
single anchor : design pullout strength = ϕ seismic ϕ concrete
( N pn or ϕN pn , f ́c
).
ACI 318-14 strength design provisions for pullout failure in tension require calculation of a nominal pullout strength ( N pn
). The nominal strength is multiplied by one or more strength reduction factors ( ϕ-factors ) to obtain a design pullout strength ( ϕN pn
). ϕ-factors are relevant to static and seismic load conditions .
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
”. This reduction is applied to non-steel failure modes when calculating tension design strengths for both cast-inplace and post-installed anchors .
When calculating the design pullout strength in tension for cast-in-place anchors , the parameter “ ϕ concrete
” in the PROFIS Engineering report is taken from Section 17.3.3 , and corresponds to the parameter “ ϕ ” shown in Section 17.2.3.4.4 .
When calculating the design pullout strength in tension for post-installed anchors , the parameter “ ϕ concrete
” in the PROFIS Engineering report corresponds to the parameter “ ϕ ” shown in Section 17.2.3.4.4 . Values for ϕ concrete in the pullout section of the PROFIS Engineering report are relevant to “ Condition B ”, and are taken from the ICC-ESR for the anchor .
Reference the Results 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 ϕ concrete
: Strength reduction factor for concrete failure
97 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions