PART 4 SHEAR LOAD
Stand-off Failure Mode
Results ϕ nonductile
Results 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ϕ nonductile
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 ).
V Rk , s
= α M M Rk , s [ N ] ( 5.5 ) l PROFIS Engineering calculations for shear resistance of an anchor subjected to bending :
ACI 318-08 Part D . 3.3.6
ϕV s
M
= ϕ [( α M
M s
)/ L b ] modified ETAG 001 Equation ( 5.5 )
D . 3.3.6 – As an alternative to D . 3.3.4 and D . 3.3.5 , it shall be permitted to take the design strength of the anchors as 0.4 times the design strength determined in accordance with D . 3.3.3 . For the anchors of stud bearing walls , it shall be permitted to take the design strength of the anchors as 0.5 times the design strength determined in accordance with D . 3.3.3 .
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 steel failure mode in shear . When a standoff condition exists for an anchorage , an applied shear load can create bending in the anchors . A shear resistance ( V Rk , s
) for the anchor element is calculated per ETAG Equation ( 5.5 ). ACI 318 anchoringto-concrete provisions require calculation of a “ nominal strength ” which is then multiplied by a strength reduction factor ( s ) ( ϕ-factor ) to obtain a “ design strength ”. The parameter “ V sM
” in PROFIS Engineering corresponds to the “ nominal shear strength ” with respect to bending , and is calculated as follows :
V s
M
= ( α M
M s
)/ L b
The parameter “ ϕV sM
” in PROFIS Engineering corresponds to the “ design shear strength ” with respect to bending , and is calculated as follows :
ϕV s
M
= ϕ [( α M
M s
)/ L b ] where “ ϕ ” corresponds to the PROFIS Engineering parameter “ ϕ steel
” for steel failure in shear . Therefore , the PROFIS Engineering parameter “ ϕ steel
V sM
”, corresponds to the parameter “ V Rk , s
” in Equation ( 5.5 ). The parameter “ ϕ nonductile
” is a reduction factor for seismic load conditions that is given in Part D . 3.3.6 of the anchoring-to-concrete provisions in ACI 318-08 Appendix D . This reduction factor can range from a value of 0.4 to 1.0 , depending on the application , and PROFIS Engineering designates this factor “ ϕ nonductile
”.
“ ϕ nonductile
” is not a relevant parameter for seismic design per ACI 318-14 Chapter 17 ; therefore , it is referenced in the PROFIS Engineering report for ACI 318-14 calculations ( including steel failure with lever arm calculations ) as equal to 1.0 .
Reference the PROFIS Engineering Design Guide for ACI 318-08 anchoring-toconcrete provisions for more information on ϕ nonductile
.
344 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions