Steel Bolted Connection Calculator (AISC)

Use the AISC bolted connection calculator to estimate shear capacity for structural steel connections.

Connection inputs

How to use

Enter the bolt diameter, applied shear force, and select the bolt grade. Click Calculate or let the live update handle recalculation after input changes.

Methodology

Shear capacity is based on the AISC connection design formula \(V_n = 0.75 F_v A_b\). Bolts are assumed to be double-shear with areas computed from the nominal diameter.

  • Nominal shear strength \(F_v\) depends on the bolt grade (A325 or A490).
  • Bolt area \(A_b\) uses the gross area formula \(π d^2 / 4\).
  • Utilization compares applied shear to the calculated capacity.

Full original guide (expanded)

Data Source and Methodology

Formulas come from the AISC Steel Construction Manual; shear values follow the AISC bolt database.

The Formula Explained

\(V_n = 0.75 × F_v × A_b\)

\(A_b = \frac{π d^2}{4}\)

Glossary of Terms

  • Bolt Diameter: Diameter of the bolt in inches.
  • Shear Force: Applied load parallel to the bolt axis.
  • Bolt Area: Gross cross-sectional area of the bolt.
  • Bolt Strength: Nominal shear strength based on grade.
  • Utilization: Ratio of applied shear to nominal capacity.

Example Calculation

For a 0.75" A325 bolt with 20 kips shear: \(A_b = π × 0.75^2 / 4 = 0.442\,in²\). \(V_n = 0.75 × 90 ksi × 0.442 in² = 29.8 kips\).

Frequently Asked Questions (FAQ)

What is a bolted connection?

A structural junction using bolts to transfer shear between plates.

How do I pick the bolt grade?

Choose the grade based on required strength and corrosion resistance.

What does utilization tell me?

Utilization shows how much of the nominal capacity is consumed by the applied load.

Formulas

\(V_n = 0.75 × F_v × A_b\)

\(A_b = \frac{π d^2}{4}\)

Citations

AISC Steel Construction Manual (latest edition).

NIST — https://www.nist.gov/pml/weights-and-measures

FTC — https://consumer.ftc.gov/

Changelog
  • 0.1.0-draft — 2026-01-19: Initial audit spec draft generated from HTML extraction.
  • Verify formulas match the calculator engine and convert text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the methodology.
Verified by Ugo Candido
Last Updated: 2026-01-19
Version 0.1.0-draft