PART 3 TENSION LOAD
Side-Face Blowout Failure
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 ) ϕ N 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 ]
ACI 318-14 strength design provisions for side-face blowout failure in tension require calculation of a nominal side-face blowout strength ( N sb or N sbg
). The nominal strength is multiplied by one or more strength reduction factors ( ϕ-factors ) to obtain a design side-face blowout strength ( ϕN sb or ϕN sbg
). 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 castin-place and post-installed anchors .
PROFIS Engineering only calculates side-face blowout strength for the cast-in anchors in its portfolio . This portfolio is as follows :
• AWS D1.1 Type B headed studs : ( 1 / 2 ” – 7 / 8 ” nominal diameter )
• ASTM F1554 hex head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” – 1 1 / 2 ” nominal diameter )
• ASTM F1554 heavy hex head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” – 2 ” nominal diameter )
• ASTM F1554 square head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” – 1 1 / 2 ” nominal diameter )
• ASTM F1554 heavy square head bolt , Gr . 36 , Gr . 55 , Gr . 105 : ( 1 / 2 ” – 1 1 / 2 ” nominal diameter )
( 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 side-face blowout failure in tension when seismic load conditions are being modeled :
single anchor : design side-face blowout strength = ϕ seismic ϕ concrete
N sb
. anchor group : design side-face blowout strength = ϕ seismic ϕ concrete
N sbg
.
When calculating the design side-face blowout strength in tension for cast-inplace 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 .
Reference the Results section of the PROFIS Engineering report for more information on the following parameters :
ϕN sb or ϕN sbg
: Design pullout strength in tension
ϕ concrete
: Strength reduction factor for concrete failure
125 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions