PART 3 TENSION LOAD
Pullout Failure Mode
Equations N pn
Equations ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering cast-in anchors
N 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 where ψ c , P is defined in 17.4.3.6 .
N pn
= ψ c , p
N p
( 17.4.3.1 )
17.4.3 . 2 For post-installed expansion and 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 .
Nominal pullout strength ( N pn
) is a possible tension failure mode for cast-in-place anchors and post-installed mechanical anchors . Generally speaking , bond failure is considered for adhesive anchor systems in lieu of pullout failure ; however , the Hilti adhesive anchor system “ HIT-HY 200 ” includes a proprietary anchor element known as a HIT-Z threaded rod , for which a nominal pullout strength is calculated in lieu of a nominal bond strength .
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 )
Section 17.4.3.2 notes that testing per the ACI test standard ACI 355.2 must be used to derive the pullout strength of a single anchor ( N p
) for a post-installed mechanical anchor ( e . g . expansion or undercut anchor ). N p is one of the parameters used to calculate the nominal pullout strength ( N pn
). Mechanical anchor N p
-values can be derived from testing per the ICC-ES acceptance criteria AC193 in conjunction with the ACI standard ACI 355.2 . N p
-values for HIT-Z threaded rods used with HIT-HY 200 adhesive can be derived from testing per the ICC-ES acceptance criteria AC308 in conjunction with the ACI standard ACI 355.4 . Post-installed anchor N p
-values are provided in an ICC-ESR . PROFIS
Engineering uses the N p -values that are given in the ICC-ESR to calculate N pn for relevant post-installed anchors in its portfolio . The parameter ψ c , p is a modification factor for cracked or uncracked concrete conditions . PROFIS Engineering determines ψ c , p per Section 17.4.3.6 for the cast-in anchors in its portfolio . PROFIS Engineering always uses a ψ c , p
-value equal to 1.0 when calculating N pn for the post-installed anchors in its portfolio .
When modeling cast-in anchors in PROFIS Engineering , reference the Equations and Calculations section of the report for more information on the parameter
N p
. Reference the Variables section of the report for more information on the parameter ψ c , p
.
When modeling post-installed anchors in PROFIS Engineering , Reference the Equations section of the report for information on the following anchor-specific pullout parameters :
• N pn , f ́c if mechanical anchors are being modeled
• N pn if HIT-HY 200 with HIT-Z and HIT-Z-R threaded rods is being modeled
79 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions