BIZOMAT MAKEOS · Fasteners
Riveted Joint Design (Balanced Pitch and Rivet Count)
What rivet pitch balances plate and rivet strength, how efficient is the joint, and how many rivets carry the load?
Design of a riveted lap or butt joint: strength of the rivets per pitch in shear and crushing, the balanced pitch at which plate tearing equals the rivet strength, joint efficiency at that pitch (as the riveted joint tool), the number of pitches along the joint length and the joint capacity against the load, with the minimum pitch of three diameters.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Plate thickness | mm | Thickness of the (thinner) plate. |
| Rivet hole diameter | mm | Diameter of the rivet hole (the driven rivet fills it). |
| Rivet rows | Number of rivet rows within one pitch. | |
| Shear planes per rivet | choice | Shear planes each rivet carries. |
| Allowable tensile stress of the plate | MPa | Allowable tensile stress of the plate. |
| Allowable rivet shear stress | MPa | Allowable shear stress of the rivets. |
| Allowable crushing (bearing) stress | MPa | Allowable bearing stress between rivet and plate. |
| Joint length | mm | Length of the joint across the load. |
| Load on the joint | kN | Total load the joint must carry. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Plate thickness
- What it is
- The thickness of the plate the rivets pass through. In a joint of unequal plates use the thinner one, which governs tearing and crushing.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 10 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Crushing strength and plate tearing strength rise in proportion to thickness.
- Get it right
- For a butt joint use the main plate thickness, not the strap thickness.
What this means: Rivet hole diameter
- What it is
- The diameter of the drilled or punched rivet hole. The driven rivet swells to fill it, so this is the diameter that carries load.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 17 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Rivet shear strength rises with the square of the hole diameter; the minimum pitch is three diameters.
- Get it right
- Use the hole diameter, not the nominal shank diameter of the rivet before driving.
What this means: Rivet rows
- What it is
- How many rows of rivets fall within one pitch length of the joint, each row adding one rivet per pitch.
- Units and format
- Enter a plain number with no unit. The form accepts 1 to 6. Use a whole number. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 2 as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- More rows raise the rivet strength per pitch, allowing a wider balanced pitch.
- Get it right
- For a butt joint count the rows on one side of the butt only.
What this means: Shear planes per rivet
- What it is
- How many shear planes each rivet carries: one in a lap joint, two in a butt joint with a strap on each side.
- Units and format
- Choose one of 2 options from the list: Single shear (lap joint); Double shear (butt joint with two straps).
- Example
- The form opens with “Single shear (lap joint)” selected as a worked example. Choose the option that matches your case.
- Effect on the result
- Double shear doubles the rivet shear strength per pitch.
- Get it right
- A butt joint with a single strap is still single shear.
What this means: Allowable tensile stress of the plate
- What it is
- The tensile stress you allow in the plate between rivet holes, from your design code or design basis.
- Units and format
- Enter a number in MPa: megapascals (1 MPa = 1 N/mm²). The form accepts 0.000001 MPa to 2000 MPa. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 150 MPa as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A higher allowable shortens the balanced pitch and raises plate tearing strength.
- Get it right
- Use the allowable working stress, not the tensile strength of the material.
What this means: Allowable rivet shear stress
- What it is
- The shear stress you allow across the rivet shank, from your design code for the rivet material.
- Units and format
- Enter a number in MPa: megapascals (1 MPa = 1 N/mm²). The form accepts 0.000001 MPa to 2000 MPa. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 100 MPa as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Rivet shear strength per pitch is directly proportional to it.
- Get it right
- Use the allowable working stress for rivets, not the shear strength of the material.
What this means: Allowable crushing (bearing) stress
- What it is
- The bearing stress you allow where the rivet presses on the side of its hole, from your design code.
- Units and format
- Enter a number in MPa: megapascals (1 MPa = 1 N/mm²). The form accepts 0.000001 MPa to 3000 MPa. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 250 MPa as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Crushing strength per pitch is directly proportional to it.
- Get it right
- This acts on the projected area, hole diameter times plate thickness, not on the rivet cross-section.
What this means: Joint length
- What it is
- The length of the seam along which the rivets are laid out, measured at right angles to the load.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 500 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- The joint capacity grows in whole pitch steps as the length increases.
- Get it right
- Measure along the rivet line, not in the direction of the load.
What this means: Load on the joint
- What it is
- The total force the whole joint must carry across its length, which is compared with the joint capacity.
- Units and format
- Enter a number in kN: kilonewtons (1 kN = 1000 N). The form accepts 0.000001 kN to 10000000 kN. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 300 kN as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- It does not change the pitch or efficiency, only the capacity check.
- Get it right
- Enter the total load on the joint, not the load per rivet or per pitch.
Method and formulas
- Per pitch: rivet shear = rows × planes × π d² ÷ 4 × τ; crushing = rows × d t σ_c; rivet value R = the smaller.
- Balanced pitch: (p − d) t σ_t = R, so p = d + R ÷ (t σ_t); not less than 3d.
- Efficiency = R ÷ (p t σ_t) (as the riveted joint tool); pitches = ⌊L ÷ p⌋; capacity = pitches × weakest per pitch.
- Example: 2 rows of 17 mm rivets in 10 mm plate balance at a 51 mm pitch, 59.341% efficient.
Limitations
- Static design by allowable stresses; fatigue and slip need separate checks.
- Edge distances and gauges must follow the applicable code.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Lay out a riveted lap or butt joint
- Choose rows and rivet size for a load
- Check an old riveted structure
Who it is for
- Structural engineers
- Fabrication supervisors
- Maintenance engineers
What you get
- Rivet strength per pitch
- Balanced pitch and efficiency
- Joint capacity against the load
Interpreting the result
- More rows raise the rivet value and allow a wider pitch, increasing efficiency.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1735–1745. Topic reference; no source tables or recommended settings are reproduced.
BIZOMAT tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Riveted Joint Design (Balanced Pitch and Rivet Count) calculator