PART 3 TENSION LOAD
Sustained Tension Load — Bond Strength
Equations ϕN ba
Equations ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering 0.55 ϕN ba
≥ N ua , s
17.3.1.2 For the design of adhesive anchors to resist sustained tension loads , in addition to 17.3.1.1 , Eq . ( 17.3.1.2 ) shall be satisfied .
0.55 ϕN ba ≥ N ua , s
( 17.3.1.2 )
Where N ba is determined in accordance with 17.4.5 . 2 . 17.4.5 . 2 The basic bond strength of a single adhesive anchor in tension in cracked concrete , N ba
, shall not exceed
N ba
= λ a т cr π da h ef
( 17.4.5 . 2 )
PROFIS Engineering parameters for calculating N ba :
N ba
= λ a т k , c α N , seis πd a h ef
PROFIS Engineering calculations for N ba when used to calculate the sustained load parameter 0.55 ϕN ba for threaded rods , reinforcing bars and HIS-N and HIS-RN inserts :
N ba
=
( λ a т xxxx α N , seis πd a h ef
) α N , seis
PROFIS Engineering calculations for N ba when used to calculate the sustained load parameter 0.55 ϕN ba
: for HIT-HY 200 used with HIT-Z and HIT-Z-R threaded rods :
N ba
= λ a
N p
The provisions given in ACI 318-14 Section 17.3.1.2 are used to perform a check for adhesive anchors subjected to sustained tension loads . The check consists of calculating a capacity ( 0.55ϕN ba
), and comparing it to the highest ( factored ) sustained tension load ( N ua , s
) acting on a single anchor within the anchor group . The strength reduction factor
( ϕ-factor ) in Eq . ( 17.3.1.2 ) corresponds to the parameter “ ϕ bond
” in the PROFIS
Engineering report . The parameter “ N ba
” corresponds to the “ basic bond strength ” for a single adhesive anchor without any fixed edge influences . N ba is calculated per Eq . ( 17.4.5.2 ); but an additional seismic modification factor that is derived from testing per the ICC-ES acceptance criteria AC308 is not given in Eq . ( 17.4.5.2 ), and must also be considered in the N ba
-calculation . This seismic modification factor is designated “ α N , seis ”, and is included in PROFIS Engineering N ba
-calculations when seismic conditions are being modeled . However , since seismic load is not considered a sustained load , PROFIS Engineering divides out any α N , seis
-value when calculating N ba per Eq . ( 17.3.1.2 ).
Reference the Equations , Calculations and Results section of the report for more information on :
N ba
:
Basic bond strength parameters and calculations for the sustained tension load check
Reference the Results section of the report for more information on :
ϕ bond
:
N ua , s
:
Strength reduction factor for bond Sustained factored tension load
Reference the Design Guide sections about pullout for more information about the HY 200 / HIT-Z parameter N p
.
146 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions