AS 3600 Concrete Shear
Beam shear to AS 3600, the Australian concrete code. The concrete contribution depends on the cube root of the longitudinal steel ratio and on the effective depth — a size effect that the older ACI expressions handle differently.
| Depth (mm) | φVuc (kN) |
|---|---|
| 300 | 93 |
| 400 | 113 |
| 500 | 131 |
| 600 | 148 |
| 800 | 143 |
Vuc = β1β2β3·bv·do·(Ast/bv·do)^(1/3)·√f'c · AS 3600 cl. 8.2.4.1.
β1 = 1.1(1.6 − do/1000) · Clamped to 0.8–1.1.
A clear path from inputs to results.
Beam shear to AS 3600, the Australian concrete code. The concrete contribution depends on the cube root of the longitudinal steel ratio and on the effective depth — a size effect that the older ACI expressions handle differently.
How to use
- Set web width bv (mm).
- Set effective depth do (mm).
- Set longitudinal steel ast (mm²).
- Set concrete f'c (mpa).
- Read the headline metrics, then check the table for the detail.
The formula
Reference: AS 3600 cl. 8.2.4.1 concrete shear with the β1 size effect.
Worked example
At the default inputs
- Web width bv (mm): 300; Effective depth do (mm): 500; Longitudinal steel Ast (mm²): 1200; Concrete f'c (MPa): 32; Design shear (kN): 200
- 1
φVuc: 131 kN · Steel ratio: 0.80% · β1: 1.100 · Utilisation: 153%
φVuc: 131 kN · Steel ratio: 0.80% · β1: 1.100
Interpreting the result
The concrete contributes 131 kN to AS 3600.
Assumptions & limitations
- No axial load or prestress.
- No stirrups in the concrete term.
Frequently asked questions
What is β1?
A size-effect factor that reduces the concrete contribution as the effective depth grows.
Does the steel ratio matter?
Yes — the cube root of Ast/(bv·do) is in the formula.
Methodology last reviewed 2026-10-22. Results are informational and not financial or engineering advice — see our disclaimer.