PROFIS Design Guide: US-EN Summer 2021 | Page 99

PART 3 TENSION LOAD

Pullout Failure Mode
Results ϕN pn
Results ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering cast-in anchors
ϕN pn
17.4.3.1 The nominal pullout strength of a single cast-in , post-installed expansion , and postinstalled undercut anchor in tension , N pn
, shall not exceed
N pn
= ψ c , p
N p
( 17.4.3.1 )
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
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 .
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 :
( c ) 0.75ϕN pn for a single anchor or for the most highly stressed individual anchor in a group of anchors where ϕ is in accordance with 17.3.3 .
ACI 318-14 strength design provisions for tension define the parameter “ design strength ” as the product of a “ nominal strength ” ( N N
) and one or more strength reduction factors ( ϕ-factors ). Nominal pullout strength in tension ( N pn
) is always calculated for a single anchor when designing with the provisions of ACI 318-14 . PROFIS Engineering calculates the nominal pullout strength ( N pn
) for the cast-inplace anchors in its portfolio using Eq . ( 17.4.3.1 ).
The PROFIS Engineering cast-in-place anchor portfolio includes the following anchors :
• 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 )
When modeling static load conditions for a cast-in anchor , PROFIS Engineering uses the strength reduction factor ( ϕ-factor ) for “ Condition B ” given in ACI 318-14 Section 17.3.3 to calculate the design pullout strength . This ϕ-factor is designated “ ϕ concrete
” in the PROFIS Engineering report , and the report parameter “ ϕN pn ” corresponding to “ design pullout strength ” is calculated as “ ϕ concrete
N pn
”. If seismic load conditions are being modeled ; PROFIS Engineering applies the additional 0.75 reduction factor to “ ϕ concrete
N pn
” per Section 17.2.3.4.4 , and designates this factor
“ ϕ seismic ”. The report parameter “ ϕN pn
” corresponds to “ ϕ seismic ϕ concrete
N pn
”.
Reference the Equations and Calculations section of the report for more information on the parameter N p
.
Reference the Results section of the report for more information on the parameters ϕ concrete and ϕ seismic
.
When modeling post-installed anchors in PROFIS Engineering , Reference the Equations section of the report for information on the following anchor-specific pullout parameters :
• ϕN pn , f ́c if mechanical anchors are being modeled
• ϕN pn if HIT-HY 200 with HIT-Z and HIT-Z-R threaded rods is being modeled
99 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions