Concrete Punching Shear Calculator to AS3600

This calculator computes the shear capacity of a suspended flat slab at a concentrated load. This situation is often referred to as 'Punching Shear'. 
📝 This template has been designed in accordance with AS 3600:2018 Section 9 - Design of slabs for strength and serviceability, Section 9.3 - Strength of Slabs in Shear.
CalculationRefer to the diagrams in the toggle below to illustrate the parameters used in this calculator.
Punching shear diagrams in AS3600 Section 9.3
InputsOpen each toggle block below to input required values.
Slab Properties
Design selections
Column Details
Ultimate Design Loads
﻿
The following inputs are optional if they apply to the slab design being considered. If they are not applicable, they can be left as is or set to zero. 
Critical Penetration Details (if applicable)
Spandrel Beam Details (if applicable) 
Fitment/Shear Reinforcement Details (if applicable)
Effective Prestress Details (if applicable)
OutputsThe critical shear perimeter and shear capacity is provided for every type of situation, regardless of the user input, see toggles below.
Calculated ﻿u
 Values
Slab Shear Capacity when ﻿M∗v
 is zero
Slab Shear Capacity when ﻿M∗v
 is not zero
﻿
The shear capacity relevant to your slab design is provided in the toggle below.
Slab Shear Capacity (Punching Shear Capacity), ﻿ϕVu
﻿
﻿
ExplanationWhat is punching shear?Punching shear is a failure mechanism in structural members like slabs and foundations by shear under the action of concentrated loads, such as columns. 
﻿
Punching shear failure mechanism
In analysis we are only concerned about the load that is transferred to the column at the slab level in consideration. That is, do not include the axial forces in the column above this level.
﻿
Punching shear zones on a traditional concrete flat slab
How do I design for punching shear?Punching shear capacity of a slab is dependent on the assumed failure length, also known as the "critical shear perimeter" or "punching shear surface". This is the perimeter of a shape formed by outlining the loaded area with a clear gap of ﻿dom​/2
, refer Figure 4.16 of AS3600.
﻿
Critical shear perimeter (or punching shear surface) shown in (a) isometric and (b) section
The calculation method adopted for punching shear design depends on whether any moment, ﻿M∗v
 is being transferred from the slab to the support in the direction being considered. This calculator considers situations where ﻿M∗v
 is zero and non-zero.
See the toggles below for the code formulas used in this calculator.
AS 3600 formulas for when M*v is zero
AS 3600 formulas for when M*v is not zero
﻿
AcknowledgementsThis calculation was built in collaboration with Brooke Reynolds. Learn more.
Related ResourcesConcrete Slab-on-Grade Designer to AS3600
Concrete Beam Design Calculator to AS3600
Concrete Column Design Calculator to AS 3600

Calculation

Punching shear diagrams in AS3600 Section 9.3

Inputs

Slab Properties

Design selections

Column Details

Ultimate Design Loads

Critical Penetration Details (if applicable)

Spandrel Beam Details (if applicable)

Fitment/Shear Reinforcement Details (if applicable)

Effective Prestress Details (if applicable)

Outputs

Calculated

$u$
Values

Slab Shear Capacity when

$M^{*} v$
is zero

Slab Shear Capacity when

$M^{*} v$
is not zero

Slab Shear Capacity (Punching Shear Capacity),

$ϕ V u$

Explanation

What is punching shear?

How do I design for punching shear?

AS 3600 formulas for when M*v is zero

AS 3600 formulas for when M*v is not zero

Acknowledgements

Related Resources

Calculation

Punching shear diagrams in AS3600 Section 9.3

Inputs

Slab Properties

Design selections

Column Details

Ultimate Design Loads

Critical Penetration Details (if applicable)

Spandrel Beam Details (if applicable)

Fitment/Shear Reinforcement Details (if applicable)

Effective Prestress Details (if applicable)

Outputs

Calculated ﻿u Values

Slab Shear Capacity when ﻿M∗v is zero

Slab Shear Capacity when ﻿M∗v is not zero

Slab Shear Capacity (Punching Shear Capacity), ﻿ϕVu﻿

Explanation

What is punching shear?

How do I design for punching shear?

AS 3600 formulas for when M*v is zero

AS 3600 formulas for when M*v is not zero

Acknowledgements

Related Resources

Calculated

$u$
Values

Slab Shear Capacity when

$M^{*} v$
is zero

Slab Shear Capacity when

$M^{*} v$
is not zero

Slab Shear Capacity (Punching Shear Capacity),

$ϕ V u$