1.0 TENSION
1.3 Pullout Failure Mode
Variables N p
Variables ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
HIT-Z / HIT-Z-R anchor with HIT-HY 200
N p
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 , Npn , shall be calculated by :
17.6.3.2 Basic single anchor pullout strength , N p .
N pn
= ψ ( c , p )
N p
( 17.6.3.1 ) ………………………………………….
17.6.3.2.1 For post-installed expansion , screw or undercut anchors , the values of N p shall be based on the 5 percent fractile of results of tests performed and evaluated according to ACI 355.2 . It is not permissible to calculate the pullout strength in tension for such anchors .
Excerpt from ESR-3187 for Hilti HIT-HY 200 adhesive , referencing provisions for calculating nominal pullout strength in tension ( N pn
) with HIT-Z ( carbon steel ) or HIT-Z-R ( stainless steel ) threaded rods .
4.1.4.1 Static Pullout Strength in Tension : Hilti HIT-Z and HIT-Z-R Anchor Rods : The nominal static pullout strength of a single anchor in accordance with ACI 318-14 17.4.3.1 and 17.4.3.2 or ACI 318-11 D . 5.3.1 and D . 5.3.2 , as applicable , in cracked and uncracked concrete , N p , cr and N p , uncr , respectively , is given in Table 10 . For all design cases , ψ c , p
= 1.0 .
Pullout strength values are a function of the concrete compressive strength , whether the concrete is cracked or uncracked , the drilling method ( hammer drill , including Hilti hollow drill bit , diamond core drill ) and installation conditions ( dry or water-saturated ). The resulting characteristic pullout strength must be multiplied by the associated strength reduction factor ϕ nn as follows :
Hilti HIT-Z and HIT-Z-R threaded rods
DRILLING METHOD
Concrete type
Permissible installation conditions
Pullout strength
Associated strength reduction factor
PROFIS Engineering calculates nominal pullout strength in tension ( N pn
) per ACI 318-19 Eq . ( 17.6.3.1 ). Although not referenced in ACI 318-19 Section 17.6.3.2.1 , pullout failure in lieu of bond failure must be considered for Hilti HIT-HY 200 used with HIT-Z ( carbon steel ) or HIT-Z-R ( stainless steel ) threaded rods . A characteristic pullout strength in tension ( N p
) derived from testing is used to calculate a nominal pullout strength ( N pn ) for HIT-HY 200 when used with HIT-Z /
Z-R threaded rods .
N p
-values for HIT-Z and HIT-Z-R threaded rods derived from testing per the ICC-ES acceptance criteria AC308 in conjunction with the ACI standard ACI 355.4 ( a ) are provided in ESR-3187 Table 10 , ( b ) are specific to the concrete condition ( cracked or uncracked ), and ( c ) are specific to anchor diameter . N p
-values in the
ESR are valid for concrete compressive strengths 2500 psi ≤ ƒ ́c ≤ 8000 psi .
N p
-values for HIT-Z and HIT-Z-R threaded rods shown in the Variables section of the PROFIS Engineering report are taken from ESR-3187 Table 10 .
Reference the Variables section of the report for more information on the following parameters :
• λ a
— lightweight concrete modification factor .
• α N , seis
— seismic modification factor . Reference the Results section of the report for more information on the parameter
N pn
.
When modeling cast-in anchors , PROFIS Engineering calculates the nominal pullout strength in tension ( N pn
) per ACI 318-19 Eq . ( 17.6.3.1 ), and the parameter
N p per ACI 318-19 Eq . ( 17.6.3.2.2a ). Reference the cast-in anchor report sections relevant to pullout strength in tension for more information .
Hammer-drill ( or Hilti TE-CD or TE-YD Hollow Drill Bit ) or Diamond Core Bit
Uncracked
Cracked
Dry |
N p , uncr
|
ϕ d
|
Water saturated |
N p , uncr
|
ϕ ws
|
Dry |
N p , cr
|
ϕ d
|
Water saturated |
N p , cr
|
ϕ ws
|
Excerpt from ESR-3187 Table 10 showing values for Np , cr and Np , uncr derived from testing per AC308 / ACI 355.4 .
ICC-ES ESR-3187 Table 10
DESIGN INFORMATION Symbol Units
Nominal rod diameter ( in .) 3 / 8 1 / 2 5 / 8 3 / 4
Temperature Range A
Pullout strength in cracked concrete N p , cr lb 7,952 10,936 21,392 27,930
Pullout strength in uncracked concrete N p , uncr lb 7,952 11,719 21,931 28,460
91 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions