PROFIS ENGINEERING REPORT SHEAR LOAD
Concrete Breakout Failure Mode
Results V cb
Results 318-14 Chapter 17 Provision Comments for PROFIS Engineering
V cb
17.5 . 2.1 The nominal concrete breakout strength in shear , V cb of a single anchor
……………………………………………………….. shall not exceed : ( a ) For shear force perpendicular to the edge on a single anchor
V cb
=
A vc ψed , V ψ c , y ψ h , V
V b
( 17.5.2.1a )
A vc0
…………………………………………………….. ( c ) For shear force parallel to an edge V cb
………… shall be permitted to be twice the value of the shear force determined from Eq . ( 17.5 . 2.1a ) ……………………………………………….. with the shear force assumed to act perpendicular to the edge and with ψ ed , V taken equal to 1.0
( d ) For anchors located at a corner , the limiting nominal concrete breakout strength shall be determined for each edge , and the minimum value shall be used
PROFIS Engineering includes an additional modification factor ( ψ parallel , V ) in Eq . ( 17.5.2.1a ).
PROFIS Engineering calculations for V cb :
V cb
=
A Vc ψed , V ψ c , V ψ h , V ψ parallel , V
V b
A Vc0
PROFIS Engineering calculations for shear load acting at a corner . Check ( V ua
/ V cb , x ) versus ( V ua
/ V cb , y ) and take the highest utilization (%).
ACI 318-14 Eq . ( 17.5.2.1a ) is used to calculate the nominal concrete breakout strength in shear for a single anchor ( V cb
).
Concrete breakout in shear is calculated for shear load acting towards ( i . e . perpendicular to ) a fixed edge . If shear load acts parallel to a fixed edge , Section 17.5.2.1 ( c ) requires V cb to be calculated as if the shear load acts towards the fixed edge , and the value calculated for V cb to be doubled . The PROFIS Engineering parameter that is designated in the report as “ ψ parallel , V
” indicates whether the software is calculating concrete breakout for shear load acting towards a fixed edge ( ψ parallel , V
= 1.0 ) or parallel to a fixed edge ( ψ parallel , V
= 2.0 ).
If a shear load acts at an angle with respect to two fixed edges , Section 17.5.2.1 ( d ) requires V cb to be calculated with respect to each fixed edge . The calculated value for V cb is checked against the component of the shear load that acts towards each fixed edge . PROFIS Engineering calculates V cb for load acting towards each fixed edge as well as load acting parallel to each fixed edge . The software then checks the calculated V cb value for each load condition ( towards the edge and parallel to the edge ) against the resultant shear load rather than the shear load component acting on each edge . This is a conservative design assumption .
Reference the Equations section of the PROFIS Engineering report for more information on V cb
.
Reference the Calculations section of the PROFIS Engineering report for more information on the following parameters :
A Vc
: Area of influence for anchors in shear
A Vc0
: Area of influence for single anchor in shear
ψ ed , V
: Shear modification factor for edge distance
ψ h , V
: Modification factor for thin slabs
V b
: Basic concrete breakout strength in shear
Reference the Variables section of the PROFIS Engineering report for information on : ψ c , V
: Modification factor for cracked concrete
ψ parallel , V
: Modification factor for shear parallel to a fixed edge calculate V cb , x calculate V cb , y
197 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions