COMBINED TENSION AND SHEAR LOAD
Parabolic
Equations β NV
= β E N + βE V ≤ 1 . 0 ( continued )
Equations 318-14 Chapter 17 Provision Comments for PROFIS Engineering β NV
= β E N + βE V ≤ 1 . 0
17 . 3 . 1 . 3 When both N and V are present , interaction effects shall be considered using an ua ua interaction expression that results in computation of strength in substantial agreement with results of comprehensive tests . This requirement shall be considered satisfied by 17.6
Excerpt from Table 17.3.1.1 showing the tension failure modes considered in ACI 318-14 anchoringto-concrete provisions .
Table 17.3.1.1 — Required strength of anchors , except as noted in 17.2.3
Failure Mode Single Anchor
Individual anchor in a Group
Steel strength in tension ( 17.4.1 ) ϕN sa ≥ N ua ϕN sa
≥ N ua , i
Concrete breakout strength in tension ( 17.4.2 ) ϕN cb
≥ N ua
Anchor Group
Anchors as a group
ϕN cbg
≥ N ua , g
Part 4 of the PROFIS Engineering report shows the ratio of factored shear load ( V ua
) to shear design strength ( ϕV N ) via the parameter β V
. For the example below , concrete edge failure in direction x + is the governing failure mode for shear because it has the highest utilization ( β V
= 60 %).
4 Shear load Load V ua
[ lb ]
Capacity ϕV n [ lb ]
Utilization
β N
= V ua / ϕV n
Status
Steel strength * 1,500 4,540 33 OK
Steel failure with lever arm *
Pryout ( bond strength controls )*
Concrete edge failure in direction x + **
* highest loaded anchor ** Anchor group ( relevant anchors )
N / A N / A N / A N / A
6,000 52,765 12 OK
6,000 10,080 60 OK
Pullout strength in tension ( 17.4.3 ) ϕN pn ≥ N ua ϕN pn
≥ N ua , i
Concrete side-face blowout strength in tension ( 17.4.4 )
Bond strengh of adhesive anchor in tension ( 17.4.5 ) ϕN sb
≥ N ua
ϕN a
≥ N ua ϕN sbg
≥ N ua , g
ϕN ag
≥ N ua , g
For the examples above , PROFIS Engineering would perform the combined interaction check using the parabolic interaction equation as follows :
β NV
= ( β N ) 5 / 3 + ( β V
) 5 / 3 check : β NV
≤ 1.0
= ( 0.51 ) 5 / 3 + ( 0.6 ) 5 / 3 = 0.752 check : 0.752 < 1.0 OK
Excerpt from Table 17.3.1.1 showing the shear failure modes considered in ACI 318-14 anchoringto-concrete provisions .
Table 17.3.1.1 — Required strength of anchors , except as noted in 17.2.3
Reference the PROFIS Engineering design guide section on the trilinear interaction equation for additional information about PROFIS Engineering interaction calculations .
Failure Mode Single Anchor
Individual anchor in a Group
Anchor Group
Anchors as a group
Steel strength in shear ( 17.5.1 ) ϕ steel
V sa
≥ V ua ϕ steel
V sa
≥ V ua , i
Concrete breakout strength in shear ( 17.5 . 2 )
Concrete pryout strength in shear ( 17.5.3 ) ϕ concrete
V cb
≥ V ua ϕ concrete
V cp
≥ V ua ϕ concrete
V cbg
≥ V ua , g ϕ concrete
V ag
≥ V ua , g
349 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions