PART 4 SHEAR LOAD
Stand-off Failure Mode
Variables n
Variables 318-14 Chapter 17 Provision Comments for PROFIS Engineering n
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 .
PROFIS Engineering stand-off calculations : without clamping and with grouting
t plate
= plate or fixture thickness z = standoff + 0.5 ( t plate ) n = 0.5 L b = z + ( 0.5 )( d 0
) d 0
= nominal anchor diameter
When “ stand-off without clamping ” or “ stand-off with grouting ” are selected in PROFIS Engineering , ( n )( d 0
) = ( 0.5 )( d 0 ) and L b
= z + ( 0.5 )( d 0 ).
ETAG 001 Annex C : Figure 4.8 Definition of lever arm
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
333 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions