PART 4 SHEAR LOAD
Stand-off Failure Mode
Calculations M s
Calculations 318-14 Chapter 17 Provision Comments for PROFIS Engineering
M s
resultant flexural resistance of anchor |
|
|
|
M Rk , s
= M 0 ( 1 ‒ N / N )
Rk , s Sd Rd , s
|
[ Nm ] |
( 5 . 5a ) |
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 ). 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 M 0 = characteristic bending resistance of an individual anchor
Rk , s
The value of M 0 for anchors according to current experience is obtained from Equation ( 5 . 5b ).
Rk , s
M 0 Rk , s = 1 . 2 W el f uk
[ Nm ] ( 5 . 5b )
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 . If both tension and shear loads act on the anchor , ETAG 001 provisions require a reduction factor ( 1 – N sd
/ N Rd , s
) to be applied to M 0 , and the resulting parameter is designated
Rk , s
“ M Rk , s ” per Equation ( 5.5a ). The parameters “ N sd
” and “ N Rd , s
” in Equation ( 5.5a ) correspond to the “ design steel tension force ” and the “ design resistance steel force ”, respectively .
PROFIS Engineering designates the parameters in Equation ( 5.5a ) as follows : “ M Rk , s
” is designated “ M s
” “ M 0 Rk , s ” is designated “ M0 s ” “ N sd
” is designated “ N ua ”
“ N Rd , s ” is designated “ ϕN sa
”
Reference the Equations and Calculations section of the PROFIS Engineering report for more information on the parameter M 0 s .
Reference the Variables section of the PROFIS Engineering report for more information on the parameters N ua and ϕN sa .
PROFIS Engineering calculations
ϕV Ms
= ϕ [( α M
M s
)/ L b ) modified ETAG 001 Equation ( 5.5 )
|
M s
= M 0 ( 1 - N / ϕN ) s ua sa
|
modified ETAG 001 Equation ( 5 . 5a ) |
M 0 = ( 1 . 2 )( S )( f ) s u , min |
modified ETAG 001 Equation ( 5 . 5b ) |
338 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions