Steel · Bases, anchors & embedded plates
Embedded plate with headed studs (anchor group) calculator
Steel plate cast into a concrete element with a rectangular group of welded headed studs, loaded in tension and in shear toward the nearest edge. Characteristic resistances for every failure mode of AS 5216 / EN 1992-4 are reduced by the material factors, the lowest governs in each direction, and tension and shear are combined with the 1.5-power interaction.
Standard: AS 5216:2021 / EN 1992-4 headed fasteners: steel, concrete cone (k1 = 8.9 cracked, 12.7 uncracked), pull-out, pry-out (k8 = 2), concrete edge (k9), N–V interaction (exponent 1.5)
Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Stud rows | 2 | |
| Studs per row | 2 | |
| Spacing along a row | 150 | mm |
| Row spacing | 150 | mm |
| Stud shank diameter | 19 | mm |
| Head diameter | 32 | mm |
| Effective embedment | 125 | mm |
| Stud fu | 410 | MPa |
| Concrete f′c | 32 | MPa |
| Concrete condition | Cracked | |
| Edge distance (shear acts toward this edge) | 300 | mm |
| Member thickness | 300 | mm |
| Design tension N* | 60 | kN |
| Design shear V* | 30 | kN |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Steel tension φNRk,s | 372.0 | kN |
| Concrete cone N⁰Rk,c (single) | 70.4 | kN |
| Group cone Ac,N / A⁰c,N | 1.96 | |
| Concrete cone φNRk,c | 91.9 | kN |
| Pull-out φNRk,p | 266.6 | kN |
| Design tension capacity | 91.9 | kN |
| Steel shear φVRk,s | 223.2 | kN |
| Pry-out φ·2NRk,c | 183.9 | kN |
| Edge breakout φVRk,c | 50.7 | kN |
| Design shear capacity | 50.7 | kN |
| Interaction (N/NRd)^1.5 + (V/VRd)^1.5 | 0.98 |
- ✓ N* ≤ NRd — 65 %
- ✓ V* ≤ VRd — 59 %
- ✓ Combined interaction ≤ 1
- ✓ Spacing ≥ 4d and edge ≥ 1.5hef for the full cone
Method, formulas and assumptions
- Cone: N⁰Rk,c = k1√f′c·hef^1.5 (k1 = 8.9 cracked, 12.7 uncracked), × Ac,N/A⁰c,N (A⁰ = 9hef²) × ψs,N = 0.7 + 0.3c/1.5hef; pull-out 6·Ah·f′c (× 1.4 uncracked).
- Shear: steel 0.6·As·fu, pry-out 2NRk,c, edge V⁰ = k9·d^α·lf^β·√f′c·c^1.5 with α = 0.1(lf/c)^0.5, β = 0.1(d/c)^0.2, × Ac,V/A⁰c,V × ψh.
- Factors: steel 0.8 (γMs = 1.25), concrete 1/1.5. Supplementary reinforcement, eccentricity and plate bending are not included.
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.