PART 4 SHEAR LOAD
Steel Failure Mode
Results ϕ eb
Results 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ϕ eb
17.5.1.1 The nominal strength of an anchor in shear as governed by steel , V sa
, shall be evaluated by calculations based on the properties of the anchor material and the physical dimensions of the anchor . Where concrete breakout is a potential failure mode , the required steel shear strength shall be consistent with the assumed breakout surface .
17.5.1.2 The nominal strength of an anchor in shear , V sa , shall not exceed ( a ) through ( c ):
( a ) For cast-in headed stud anchor
V sa
= A se , V f uta
( 17.5.1.2a ) where A se , V is the effective cross-sectional area of an anchor in shear , in . 2 , and f uta shall not be taken greater than the smaller of 1.9fy a and 125,000 psi .
( b ) For cast-in headed bolt and hooked bolt anchors and for post-installed anchors where sleeves do not extend through the shear plane
V sa
= 0.6 A se , V f uta
( 17.5.1.2b ) where A se , V is the effective cross-sectional area of an anchor in shear , in . 2 , and f uta shall not be taken greater than the smaller of 1.9fy a and 125,000 psi . ( c ) For post-installed anchors where sleeves extend through the shear plane , V sa shall be based on the results of tests performed and evaluated according to ACI 355.2 . Alternatively , Eq . ( 17.5.1.2b ) shall be permitted to be used .
17.5.1.3 Where anchors are used with built-up grout pads , the nominal strengths of 17.5.1.2 shall be multiplied by a factor 0.80 .
ACI 318-14 Section 17.5.1.2 contains provisions for calculating the nominal steel strength of an anchor in shear ( V sa
). Section 17.5.1.3 requires the value for V sa to be multiplied by a 0.80 reduction factor if the anchor application consists of a grouted stand-off . This reduction factor is only relevant with respect to ACI 318 anchoring-to-concrete provisions when a grouted stand-off is being designed , i . e ., no guidance or provisions are given in ACI 318 for stand-off applications that are not grouted . PROFIS Engineering designates this 0.8-factor “ ϕ eb
”.
PROFIS Engineering also includes functionality to consider anchor bending when modelling non-grouted stand-offs subject to shear load . This functionality is explained in the Design Guide section for “ steel failure with lever arm ”.
Reference the Results section of the PROFIS Engineering report for more information on the parameters ϕV sa and ϕV sa , eq
.
312 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions