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AS 3600:2018 (Amdt 2)Australia

Concrete Wall

Design reinforced concrete walls to AS 3600:2018 (Amdt 2) with the correct method selected automatically - simplified wall design or column design based on slenderness. Axial compression capacity, in-plane shear (Clause 11.6), and P-M interaction are all shown with code references for load-bearing and shear walls in multi-storey structures.

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What it calculates

Design reinforced concrete walls to AS 3600:2018 (Amdt 2) with the correct method selected automatically - simplified wall design or column design based on slenderness. Checks axial compression capacity, in-plane shear (Clause 11.6), and P-M interaction with full control over horizontal and vertical reinforcement.

Code standards

  • AS 3600:2018 (Amdt 2)

Who uses this calculator

Design reinforced concrete walls to AS 3600:2018 (Amdt 2) with the correct method selected automatically - simplified wall design or column design based on slenderness. Axial compression capacity, in-plane shear (Clause 11.6), and P-M interaction are all shown with code references for load-bearing and shear walls in multi-storey structures.

Automates AS 3600 code checks and applies the correct design method whether the element behaves as a wall or a column - load-bearing walls in multi-storey buildings, shear walls for wind and seismic resistance, and basement or sloped-site retaining walls. Full control over horizontal and vertical reinforcement inputs with in-plane shear capacity rigorously evaluated against Clause 11.6 limits, removing the need to switch between tools.

How it calculates

The Concrete Wall calculator designs reinforced concrete walls subjected to axial loads and horizontal demands to AS 3600:2018 (Amdt 2). It automatically selects between the simplified wall design method (Cl. 11.4) and the more detailed column design method (Cl. 10) based on the wall's slenderness and moment demand.

Design method selection

The calculator evaluates two conditions to determine which method applies:

  • If the design eccentricity e ≤ 0.05t and the wall's effective height-to-thickness ratio is within stocky limits (Hwe/t), the simplified method (Cl. 11.4) is used
  • Otherwise, the column method (Cl. 10) is applied, treating the wall as a slender column with full P-M interaction

When the column method applies, moment magnification for slenderness is applied per Cl. 10.4.

Simplified wall design (AS 3600:2018, Cl. 11.4)

Axial compression capacity for a unit length of wall is:

phi × N_wn = phi × (t_w - 1.2e - 2e_a) × 0.6 × f'c

where e is the design eccentricity, e_a = H_we² / (2500 t_w) is the additional eccentricity for slenderness, and phi = 0.65. This is checked against the factored axial demand N*.

Column design - P-M interaction (AS 3600:2018, Cl. 10)

For walls requiring the column method, the full P-M interaction is evaluated:

utilization (axial) = N / (phi × N_n) ≤ 1.0* utilization (moment) = M / (phi × M_n,axial) ≤ 1.0*

Biaxial bending is checked using the Bresler load contour method when moments about both axes are present.

In-plane shear capacity (AS 3600:2018, Cl. 11.6)

In-plane shear demand V* is checked against the wall shear capacity:

phi × V_wn = phi × (f_cv × b_w × L_w/2 + A_sh × f_sy / s)

where f_cv is the concrete shear stress contribution, A_sh is the area of horizontal reinforcement per spacing s, and phi = 0.75. Maximum in-plane shear stress limits per Cl. 11.6 are also checked.

Fire resistance and environment (AS 3600:2018, Cl. 5.7)

The calculator also checks minimum cover requirements for the specified fire resistance period (FRP) and exposure classification, and reports whether the section satisfies structural adequacy for the selected load level.

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Frequently asked questions

What design standard does this calculator use?
The calculator designs reinforced concrete walls to AS 3600:2018 (Amdt 2), the current Australian standard. It follows the simplified design method for walls (Cl. 11.4) where applicable, and automatically switches to the column design method (Cl. 10) when the wall is slender or subject to significant bending, as required by the standard.
What are the key inputs?
Key inputs are wall height, length, and thickness; concrete compressive strength; horizontal and vertical reinforcement bar size, spacing, and cover on each face; restraint conditions at the top and bottom (floor or free); axial load (dead and live); and in-plane horizontal shear load. Soil class and fire resistance period can also be set.
What does the calculator check and output?
For walls designed by the simplified method: axial compression capacity (Cl. 11.4) and in-plane shear capacity (Cl. 11.6). For walls requiring column design: axial squash capacity, buckling capacity, moment capacity about each axis, biaxial moment and axial interaction (P-M diagram), tension capacity, and in-plane shear capacity. Utilization ratios and code references are shown for each limit state.
How does the calculator decide between the simplified wall method and the column method?
AS 3600:2018 requires the column design method when the design bending moment exceeds the eccentricity limit for the simplified method (e > 0.05t for stocky walls) or when the wall is classified as slender (Hwe/t exceeds 30/12 depending on restraint). The calculator evaluates these conditions automatically and flags which design path applies.
Can this calculator handle in-plane shear loads (shear walls)?
Yes. In-plane shear demand is checked against the shear capacity per AS 3600:2018 Cl. 11.6, which considers both the concrete contribution and horizontal reinforcement contribution. Minimum horizontal reinforcement ratios and maximum spacing limits are also verified. The calculator covers both wind-loaded and seismically loaded shear wall configurations.

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