PART 4 SHEAR LOAD
Stand-off Failure Mode
Variables n ( continued )
Variables 318-14 Chapter 17 Provision Comments for PROFIS Engineering n PROFIS Engineering calculations for stand-off with clamping
t plate
= plate or fixture thickness z = standoff + 0.5 ( t plate )
L b
= z
Torque-controlled expansion anchors must be torqued via a nut / washer assembly at the concrete surface . If clamping via a nut / washer assembly occurs , there will be no local spalling at the concrete surface when the anchor is subjected to bending ; therefore , n equals 0 . When “ stand-off with clamping ” is selected in PROFIS Engineering , ( n )( d 0
) = 0 . For a non-grouted stand-off , expansion anchors must be modeled in PROFIS Engineering for “ stand-off with clamping ”.
Reference the Variables section of the report for more information on the following PROFIS Engineering parameters z and d 0
.
Reference the Equations and Calculations section of the report for more information on the PROFIS Engineering parameter L b
.
Variables d 0
Variables 318-14 Chapter 17 Provision Comments for PROFIS Engineering
d 0
4.2.2.4 Shear loads with lever arm
If the conditions a ) and b ) of 4.2.2.3 are not fulfilled the lever arm is calculated according to Equation ( 4.2 ) ( see Figure 4.8 )
with l = a 3 + e 1
( 4.2 ) e 1
= distance between shear load and concrete surface
a 3
= 0.5d
a 3
= 0 if a washer and a nut are directly clamped to the concrete surface ( see Figure 4.8b ) d = nominal diameter of the anchor bolt or thread diameter ( see Figure 4.8a )
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 parameter “ l ” in ETAG 001 Equation ( 4.2 ) is designated “ L b
” in
PROFIS Engineering . “ L b
” corresponds to the “ lever arm ”, i . e . distance from where the shear resistance V Rk , s
( ϕV s
M in PROFIS Engineering ) acts , to the “ point of fixity ” where the internal bending moment M Rk , s
( M s in PROFIS Engineering ) acts .
Mechanical and adhesive anchors are installed into a hole drilled in concrete . When the anchor is subjected to bending , local concrete spalling can occur if it comes in contact with the side of the drilled hole . ETAG 001 provisions assume this spalling occurs at the surface of the concrete to a depth of one half the nominal anchor diameter . This depth is defined as “ a 3
” in ETAG 001 Equation ( 4.2 ), and as “( n )( d 0
)” in PROFIS Engineering . The value for “ n ” in PROFIS Engineering depends on whether “ stand-off without clamping ”, “ stand-off with clamping ” or “ stand-off with grouting ” is selected
334 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions