1.0 TENSION
1.3 Pullout Failure Mode
Results ϕN pn
Results ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering cast-in anchors
ϕN pn
17.6.3.1 Nominal pullout strength of a single cast-in anchor , or a single post-installed expansion , screw , or undercut anchor in tension , N pn
, shall be calculated by :
N pn
= ψ c , p
N p
( 17.6.3.1 ) ………………………………………………………
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 )
Cast-in anchors Not applicable 0.70
Post-installed anchors
1 0.65 2 0.55 3 0.45
Strength reduction factor ϕ
Shear ( concrete pryout )
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 :
…………………………………………………………………………………………………… ( 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 ] ……………………………………………………………………………………………………
where ϕ is in accordance with 17.5.3 .
0.70
ACI 318-19 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 318-19 . PROFIS Engineering calculates the nominal pullout strength ( N pn
) for the cast-inplace anchors in its portfolio using Eq . ( 17.6.3.1 ).
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 ) given in ACI 318-19 Table 17.5.3 ( c ) 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 17.10.5.4 , 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 , ƒ ́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 .
101 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions