PART 4 SHEAR LOAD
Steel Failure Mode
Results ϕV sa
Results 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ϕV sa
17.3.1.1 The design of anchors shall be in accordance with Table 17.3.1.1 . In addition , the design of anchors shall satisfy 17.2.3 for earthquake loading and 17.3.1.2 for adhesive anchors subject to sustained tensile loading .
Excerpt from ACI 318-14 Table 17.3.1.1 showing provisions for shear calculations . Table 17.3.1.1 — Required strength of anchors , except as noted in 17.2.3
Failure Mode
Steel strength in shear ( 17.5.1 )
Concrete breakout strength in shear ( 17.5 . 2 )
Concrete pryout strength in shear ( 17.5.3 )
Single Anchor
ϕ steel
V sa
≥ V ua ϕ concrete
V cb
≥ V ua ϕ concrete
V cp
≥ V ua
Individual anchor in a group
ϕ steel
V sa
≥ V ua , i
Table 17.3.1.1 |
|
|
Failure Mode |
Single Anchor |
Individual Anchor in a Group |
Steel Strength in Shear |
ϕ V sa ≥ V ua
|
ϕ V sa ≥ V ua , i
|
Anchor Group
Anchors as a group
ϕ concrete
V cbg
≥ V ua , g ϕ concrete
V cng
≥ V ua , g
ACI 318-14 strength design provisions for anchors in shear check a calculated design strength ( ϕV N
) against a factored shear load ( V ua
). The parameter “ design strength ” is defined as the product of a “ nominal strength ” ( V N
) and one or more strength reduction factors ( ϕ-factors ). If ϕV N ≥ V ua for all relevant shear failure modes , the ACI 318-14 shear provisions are satisfied . When designing with ACI 318-14 anchoring-to-concrete provisions , nominal steel strength in shear ( V sa
) is always calculated for a single anchor , and multiplied by the ϕ-factor for steel failure .
For applications consisting of only one anchor in shear , the design strength ( ϕV sa ) is checked against the shear load acting on that anchor ( V ua ). If ϕV sa
≥ V ua
, the ACI
318-14 provisions for steel failure in shear are satisfied . If an application consists of a group of anchors in shear , V sa is calculated for a single anchor , and the design strength ( ϕV sa ) is checked against the highest individual loaded anchor in shear ( V ua , i ). If ϕV sa
≥ V ua , i
, the ACI 318-14 provisions for steel failure in shear are satisfied . The PROFIS Engineering report section for steel failure in shear uses the generic designation “ V ua
” to reference either the only shear load acting on an anchor in shear , or the highest shear load acting on an individual anchor within an anchor group in shear .
PROFIS Engineering designates the strength reduction factor for steel failure
ϕ steel
. When modeling an anchor element in PROFIS Engineering using ACI 318-14 provisions , the calculated design steel strength in shear for static load conditions equals ϕ steel
V sa
; however , if a grouted standoff is being modeled , an additional reduction factor (= 0.80 ) is applied to the nominal steel strength per Section 17.5.1.3 . PROFIS Engineering designates this reduction factor “ ϕ eb
” and shows it in the Results section of the report . The calculated design steel strength in shear for static load conditions and a grouted stand-off equals ϕ steel ϕ eb
V sa
Reference the Equations section of the PROFIS Engineering report for more information on :
ϕV sa
: Design steel strength in shear .
Reference the Results section of the PROFIS Engineering report for more information on the following parameters :
ϕ steel
: Strength reduction factor for steel failure
ϕ eb
: Strength reduction factor for grouted standoffs
V sa
: Nominal steel strength in shear ( static load conditions )
V ua
: Factored load acting on anchors in shear
A summary of calculated shear design strength versus the factored shear load for each shear failure mode relevant to the application is given in Part 4 Shear Load of the PROFIS Engineering report
314 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions