Bolt Shear Capacity Calculator
Design shear and tension capacity of a bolt from its stress area, grade and the number of shear planes.
Results
What this tool does
A bolt in a lap joint carries load across one plane; put it in a splice with plates either side and it carries across two, doubling the capacity for no extra bolt. The rest is the grade and the partial safety factor the code imposes. What this does not do is check the plate: bearing, edge distance and block tearing very often govern the connection long before the bolt itself does.
Formula
Fv = α fub As n ÷ γ
Variables
| Symbol | Meaning | Unit |
|---|---|---|
as | Tensile stress area | mm² |
fu | Bolt ultimate strength | MPa |
al | Shear coefficient | — |
np | Shear planes | — |
gm | Partial safety factor | — |
FV | Shear capacity | kN |
FN | Shear capacity | N |
FT | Tension capacity | kN |
TS | Shear stress | MPa |
Worked example
- Tensile stress area245 mm²
- Bolt ultimate strength800 MPa
- Shear coefficient0.6
- Shear planes1
- Partial safety factor1.25
- Shear capacity94.080 kN
- Shear capacity94,080 N
- Tension capacity141.120 kN
- Shear stress384.00 MPa
Limitations
- For work that must comply with a standard or be signed off, check the result against the applicable code and have it reviewed by a qualified engineer.
- Mixing units is the most common source of error. Convert every input to the units shown next to each field before calculating.
Frequently asked questions
Should the coefficient be 0.6 or 0.5?
In Eurocode 3 it is 0.6 for grades 4.6, 5.6 and 8.8, and 0.5 for grades 4.8, 5.8, 6.8 and 10.9. It also matters whether the shear plane passes through the threaded part, in which case the tensile stress area is used, or through the plain shank, where the gross area applies. Bearing on the plate and block tearing are separate checks this does not cover.