Steel · Connections: bolts & welds
Fin plate (shear tab) connection calculator
Single vertical line of bolts with eccentricity, plate shear yield and rupture, block shear, plate bending and the support fillet welds.
Standard: AS 4100 Cl 9.3, 9.1.9, 9.7 (simplified)
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 |
|---|---|---|
| Design shear V* | 180 | kN |
| Bolts in the line | 4 | |
| Bolt pitch | 70 | mm |
| Eccentricity (weld to bolt line) | 60 | mm |
| End distance (vertical) | 35 | mm |
| Edge to bolt line (horizontal) | 35 | mm |
| Bolt size | M20 | |
| Bolt category | 8.8/S | |
| Plate grade | Grade 250 plate | |
| Plate thickness | 10 | mm |
| Beam web thickness | 7.3 | mm |
| Beam web fu | 440 | MPa |
| Fillet weld leg (both sides) | 8 | mm |
| Weld category | SP (φ = 0.8) |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Bolt diameter df | 20.00 | mm |
| Bolt tensile strength fuf | 830.0 | MPa |
| Tensile stress area As | 245.0 | mm² |
| Core area Ac (threads) | 225.0 | mm² |
| Shank area Ao | 314.0 | mm² |
| Plate yield stress fy (AS/NZS 3678) | 260.0 | MPa |
| Plate tensile strength fu | 410.0 | MPa |
| Plate depth | 280.0 | mm |
| Hole diameter | 22.00 | mm |
| Σy² about centroid | 24,500 | mm² |
| Resultant on top bolt √((V/n)² + (V e ymax/Σy²)²) | 64.56 | kN |
| Bolt capacity min(φVf, φVb plate, φVb web) | 92.63 | kN |
| Plate gross shear 0.9·0.6 fy hp tp | 393.1 | kN |
| Plate net shear 0.9·0.6 fu (hp − n dh) tp | 425.1 | kN |
| Block shear φRbs (9.1.9, kbs 1.0) | 360.5 | kN |
| Plate bending φ fy tp hp²/6 | 30.58 | kNm |
| V* × e | 10.80 | kNm |
| Weld capacity 2 φ 0.6 fuw tt hp | 745.1 | kN |
- ✓ Bolts
- ✓ Plate gross shear
- ✓ Plate net shear
- ✓ Block shear
- ✓ Plate bending
- ✓ Welds
- ✓ Plate thin enough for rotation (tp ≤ 0.5 df)
Method, formulas and assumptions
- Bolt diameter df = CHOOSE(3,12,16,20,24,30,36) = 20 mm
- Bolt tensile strength fuf = IF(2=1,400,830) = 830 MPa
- Tensile stress area As = CHOOSE(3,84.3,157,245,353,561,817) = 245 mm²
- Core area Ac (threads) = CHOOSE(3,76.2,144,225,324,519,759) = 225 mm²
- Shank area Ao = CHOOSE(3,113,201,314,452,707,1018) = 314 mm²
- Plate yield stress fy (AS/NZS 3678) = CHOOSE(1,IF(10<=8,280,IF(10<=12,260,250)),IF(10<=8,320,IF(10<=12,310,IF(10<=20,300,280))),IF(10<=12,360,IF(10<=20,350,340))) = 260 MPa
- Plate tensile strength fu = CHOOSE(1,410,430,450) = 410 MPa
- Plate depth = (4-1)*70+2*35 = 280 mm
- Hole diameter = 20+2 = 22 mm
- Σy² about centroid = 70^2*(4-1)*4*(4+1)/12 = 24500 mm²
- Resultant on top bolt √((V/n)² + (V e ymax/Σy²)²) = SQRT((180/4)^2+(180*60*(4-1)*70/2/24500)^2) = 64.555 kN
- Bolt capacity min(φVf, φVb plate, φVb web) = MIN(0.8*0.62*830*225/1000,0.9*3.2*20*10*410/1000,0.9*3.2*20*7.3*440/1000) = 92.628 kN
- Plate gross shear 0.9·0.6 fy hp tp = 0.9*0.6*260*280*10/1000 = 393.12 kN
- Plate net shear 0.9·0.6 fu (hp − n dh) tp = 0.9*0.6*410*(280-4*22)*10/1000 = 425.09 kN
- Block shear φRbs (9.1.9, kbs 1.0) = 0.75*MIN(0.6*410*(280-35-(4-0.5)*22)*10+410*(35-22/2)*10,0.6*260*(280-35)*10+410*(35-22/2)*10)/1000 = 360.45 kN
- Plate bending φ fy tp hp²/6 = 0.9*260*10*280^2/6/1E6 = 30.576 kNm
- V* × e = 180*60/1000 = 10.8 kNm
- Weld capacity 2 φ 0.6 fuw tt hp = 2*IF(1=1,0.8,0.6)*0.6*490*8/SQRT(2)*280/1000 = 745.08 kN
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.