PROFIS ENGINEERING REPORT SHEAR LOAD
Concrete Breakout Failure Mode
Equation V b
= 9λ a
Equation ACI 318-14 Chapter 17 Provision Comments for PROFIS Engineering
|
V b
= 9λ a
|
( c f ́c a1
) 1 . 5
|
17.5.2.2 The basic concrete breakout strength in shear of a single anchor in cracked concrete , V b , |
|
|
shall be the smaller of ( a ) and ( b ): |
( a ) V b = 7 l e
0.2 d a d a λ a f ́c
( c a1 ) 1 . 5 ( 17.5.2.2a )
……………………………………………………………
( b ) V b = 9λ a f ́c ( c a1 ) 1 . 5 ( 17.5.2.2b )
V b corresponds to concrete breakout in shear for a single anchor without any geometry influences .
ACI 318-14 Chapter 2 defines the parameter V b as the “ basic concrete breakout strength in shear of a single anchor in cracked concrete ”. V b calculated using Eq . ( 17.5.2.2a ) can be considered relevant for anchors that are not rigidly attached to the fixture , i . e . an annular space exists between the anchor element and the hole in the fixture through which the anchors are located . V b calculated using Eq . ( 17.5.2.2b ) is a limiting value . PROFIS Engineering calculates V b using both equations , and shows the controlling equation in the Equations section of the report , and the V b
-value calculated using the controlling equation in the Calculations section .
Consider a single anchor installed near a fixed edge with a shear load acting on the anchor towards that edge . Assuming there are no fixed edges perpendicular to the direction of the applied shear load , and the concrete has an “ infinite ” thickness ; if concrete breakout occurs , it could be defined by the calculated capacity V b using either Eq . ( 17.5.2.2a ) or Eq . ( 17.5.2.2b ). V b is calculated using both equations and the smaller calculated value is used to calculate the nominal concrete breakout strength in shear ( V cb or V cbg ). Geometry influences are considered via the parameters A vc , ψ ed , V and ψ h , V
. Reference the Design Guide sections for these parameters for more information .
Reference the Variables section of the PROFIS Engineering report for more information on the following parameters :
λ a
: f ́c :
c a1
:
Lightweight concrete modification factor Concrete compressive strength Edge distance in the direction of the shear load
Reference the Calculations section of the PROFIS Engineering report for more information on the following parameters :
V b calculated per Eq . ( 17.5.2.2a )
V b calculated per Eq . ( 17.5.2.2b ).
171 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions