1.0 TENSION
1.1 Bond Failure Mode
Results ϕ nonductile
Results ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
ϕ nonductile
ACI 318-19 Section 17.5.2 17.5 . 2 For each applicable factored load combination , design strength of anchors shall satisfy the criteria in Table 17.5.2 .
Table 17.5.2 — Design strength requirements of anchors
Failure Mode Single Anchor
Individual anchor in a Group
Steel strength in tension ( 17.6.1 ) ϕN sa ≥ N ua ϕN sa
≥ N ua , i
Concrete breakout strength in tension ( 17.6 . 2 ) ϕN cb
≥ N ua
Pullout strength in tension ( 17.6.3 ) ϕN pn ≥ N ua ϕN pn
≥ N ua , i
Concrete side-face blowout strength in tension ( 17.6.4 )
Bond strength of adhesive anchor in tension ( 17.6.5 ) ϕN sb
≥ N ua
ϕN a
≥ N ua
Anchor Group
Anchors as a group
ϕN cbg
≥ N ua , g
ϕN sbg
≥ N ua , g
ϕN ag
≥ N ua , g
ACI 318-14 Section 17.10.5.4 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 : ………………………………..
( b ) 0.75 ϕN cb or 0.75 ϕN cbg except that Ncb or Ncbg 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 ] ………………………………..
ACI 318-19 strength design provisions for bond failure in tension require calculation of a nominal bond strength ( N a or N ag
). The nominal strength is multiplied by one or more strength reduction factors ( ϕ – factors ) to obtain a design strength ( ϕN a or ϕN ag
). ϕ – factors are relevant to static and seismic load conditions .
The ϕ – factors referenced in Table 17.5.2 correspond to tension design strengths calculated for static load conditions . The PROFIS Engineering report designates the ϕ – factor corresponding to bond failure for static load conditions “ ϕ bond
”. PROFIS Engineering uses the ϕ – factors derived from AC308 / ACI 355.4 testing , as given in the ICC-ES evaluation report ( ESR ) for the adhesive anchor system , for the parameter “ ϕ bond
”.
ACI 318-19 Section 17.10.5.4 contains provisions to calculate tension design strengths for seismic load conditions . PROFIS Engineering designates the 0.75 reduction factor noted in this section as “ ϕ seismic
”. This reduction is applied to non-steel tension failure modes . When calculating tension design strengths for adhesive anchors , the relevant non-steel tension failure modes to which this reduction is applied include concrete breakout failure ( 0.75 ϕN cb or 0.75 ϕN cbg ) and bond failure ( 0.75 ϕN a or 0.75 ϕN ag
), as referenced in the excerpt to the left .
The parameter “ ϕ nonductile
” is a reduction factor for seismic load conditions that is given in Part D . 3.3.6 of the anchoring-to-concrete provisions in ACI 318-08 Appendix D . This reduction factor can range from a value of 0.4 to 1.0 , depending on the application , and PROFIS Engineering designates this factor “ ϕ nonductile
”.
“ ϕ nonductile
” is not a relevant parameter for seismic design per ACI 318-19 Chapter 17 ; therefore , it is always referenced in the PROFIS Engineering report for ACI 318-19 calculations as equal to 1.0 .
Reference the PROFIS Engineering Design Guide for ACI 318-08 anchoring-toconcrete provisions for more information on ϕ nonductile
.
( e ) 0.75 ϕN a or 0.75 ϕN ag
[ ϕN a or ϕN ag correspond to bond failure ( tension ) in Table 17.5.2 ]
ACI 318-08 Part D . 3.3.6 D . 3.3.6 — As an alternative to D . 3.3.4 and D . 3.3.5 , it shall be permitted to take the design strength of the anchors as 0.4 times the design strength determined in accordance with D . 3.3.3 . For the anchors of stud bearing walls , it shall be permitted to take the design strength of the anchors as 0.5 times the design strength determined in accordance with D . 3.3.3 .
46 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions