PART 4 SHEAR LOAD
Stand-off Failure Mode
Equations
1 ‒
N ua
ϕN sa
Equations 318-14 Chapter 17 Provision Comments for PROFIS Engineering
1 ‒ N ua
ϕN sa
ETAG 001 reduction for tensile force acting simultaneously with a shear force on the anchor
resultant flexural resistance of anchor
5.2.3.2 Steel failure b ) Shear load with lever arm
( 1 ‒ N Sd / N Rd , s
)
M Rk , s
= M 0 ( 1 ‒ N / N ) [ Nm ] ( 5 . 5a )
Rk , s Sd Rd , s
The characteristic resistance of an anchor , VR k , s , is given by Equation ( 5.5 ). where
V Rk , s
= α M M Rk , s [ N ] ( 5.5 ) l 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
N Rd , s
= N Rk , s / γ Ms
N Rk , s
, γ Ms to be taken from the relevant ETA
The figures below illustrate ETAG 001 design assumptions with respect to bolt bending . PROFIS Engineering nomenclature for ACI 318 calculations is used in the illustrations .
Shear and tension load act on an anchorage with standoff .
PROFIS Engineering uses the provisions given in the European Technical Approval Guideline ( ETAG ) titled ETAG 001 Metal Anchors for Use in Concrete Annex C : Design Methods for Anchorages to consider bolt bending as a possible shear failure mode .
The ETAG 001 parameter M 0 corresponds to a calculated internal
Rk , s
“ characteristic bending resistance ” for the anchor element . This parameter is designated M 0 in PROFIS Engineering . The ETAG 001 parameter M s Rk , s corresponds to a calculated internal “ characteristic bending resistance ” that is modified to account for both tension and shear load acting on the anchor element . If only a shear load acts on the anchor , M Rk , s
= M 0 . If both tension and shear
Rk , s load act on the anchor , ETAG 001 provisions require a reduction factor ( 1 – N sd
/ N Rd , s
) to be applied to M 0 to obtain M . Therefore , if tension and
Rk , s Rk , s shear act on the anchor , M Rk , s
= M 0 ( 1 – N / N ) per ETAG 001 Equation ( 5 . 5a ).
Rk , s sd Rd , s
PROFIS Engineering designates the parameter corresponding to M Rk , s as “ M s
”.
The parameters “ N sd ” and “ N Rd , s
” in the ETAG 001 reduction factor ( 1 – N sd / N Rd , s
) correspond to the “ design steel tension force ” and the “ design resistance steel force ”, respectively . This reduction factor is designated ( 1 – N ua
/ ϕN sa ) in PROFIS
Engineering , where “ N ua
” corresponds to the highest factored tension load acting on an individual anchor and “ ϕN sa
” corresponds to the calculated steel design strength in tension for a single anchor . When both tension load and shear load act on an anchor with standoff , PROFIS Engineering calculates the internal bending resistance for the anchor as follows :
M s
= M 0 s ( 1 – N ua / ϕN sa ).
Reference the Variables section of the report for more information on the following PROFIS Engineering parameters :
N ua
: Factored tension load
ϕN sa
: Design steel strength in tension
PROFIS Engineering calculation . ϕV s
M
= ϕ α M
M s
L b
320 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions