PART 4 SHEAR LOAD
Stand-off Failure Mode
Variables α M
( continued )
Variables 318-14 Chapter 17 Provision Comments for PROFIS Engineering
α M
5.2.3.2 Steel failure b ) Shear load with lever arm
The characteristic resistance of an anchor , V Rk , s , is given by Equation ( 5.5 ).
If full fixture rotational restraint exists , the fixture cannot rotate freely . PROFIS Engineering defaults an α M
-value = 2.0 when the “ stand-off with grouting ” option is selected .
V Rk , s
= α M M Rk , s [ N ] ( 5.5 ) l where α M
= see 4.2.2.4 l = lever arm according to Equation ( 4.2 )
M Rk , s
= M 0 ( 1 - N / N ) [ Nm ] ( 5 . 5a )
Rk , s Sd Rd , s
PROFIS Engineering modifies ETAG 001 Equation ( 5.5 ) to use the following nomenclature :
ϕV s
M
= ϕ α M
M s
L b where : “ ϕV sM ” corresponds to “ V Rk , s
”
“ M s ” corresponds to “ M Rk , s
”
“ L b
” corresponds to “ l ” “ ϕ ” is a strength reduction factor for steel failure
Utilizing a nut / washer assembly to permit proper torqueing of an anchor ( reference ETAG 001 Figure 4.8b ) should not automatically be assumed to provide any rotational restraint . PROFIS Engineering defaults to an α M
-value = 1.0 when the “ stand-off with clamping ” option is selected .
Likewise , per ETAG 001 Section 4.2.2.4 and Table 4.1 , full rotational restraint should not be assumed if the hole clearance between the anchor element and fixture is significant .
PROFIS Engineering users can input any α M
-value between 1.0 ( no rotational restraint ) and 2.0 ( full rotational restraint ) corresponding to the amount of fixture rotational restraint that exists for their stand-off application .
Reference the Calculations section of the report for more information on the following PROFIS Engineering parameters .
M s
: Internal bending resistance
L b
: Internal lever arm
Reference the Results section of the report for more information on the following PROFIS Engineering parameters .
V s
M
: Nominal shear strength for bending
ϕV s
M
: Nominal shear strength for bending
326 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions