PART 4 SHEAR LOAD
Steel Failure Mode
Equation ϕV steel
≥ V ua
Equation 318-14 Chapter 17 Provision Comments for PROFIS Engineering
ϕV steel
≥ V ua
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 .
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
|
ACI 318-14 strength design provisions for 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 . Nominal steel strength in shear ( V sa
) is always calculated for a single anchor when designing with the provisions of ACI 318-14 . If an application consists of a group of anchors in shear , V sa is calculated for a single anchor , and the design strength is checked against the highest loaded anchor in shear .
PROFIS Engineering designates the strength reduction factor for steel failure
ϕ steel
. ACI 318-08 anchoring-to-concrete provisions include an additional seismic reduction factor that is used to calculate anchor design strengths corresponding to brittle failure modes . Anchor elements can be defined in ACI 318 as “ ductile ” or “ brittle ” steel elements . Steel failure for a brittle steel anchor element is a “ brittle ”, i . e . “ nonductile ” failure mode ; therefore , design steel strength calculated for a brittle steel anchor element using ACI 318-08 seismic provisions includes an additional strength reduction factor . PROFIS Engineering designates this seismic reduction factor “ ϕ nonductile
”, and shows it in the results section of the report .
Since ϕ nonductile is only relevant to seismic calculations with ACI 318-08 provisions , PROFIS Engineering always shows the parameter “ ϕ nonductile
” equal to 1.0 in the
Results section of reports for ACI 318-14 provisions .
When modeling an anchor element subject to shear loads using ACI 318-14 provisions , PROFIS Engineering calculates design steel strength for static load conditions as “ ϕ steel
V sa
”, and the design steel strength for seismic load conditions as “ ϕ steel
V sa , eq
”. Reference the Calculations and Results section of the PROFIS Engineering report for information on :
V sa
: Nominal ( static ) steel strength in shear
V sa , eq
: Nominal ( seismic ) 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
ϕV s a : Design ( static ) steel strength in shear
ϕV sa , eq
: Design ( seismic ) steel strength in shear
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 .
300 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-14 Provisions