Bolted Connection Calculator

Checks a single non-preloaded structural bolt for shear, bearing, tension, and combined shear+tension resistance to Eurocode 3.

Standards used on this page:
  • BS EN 1993-1-8:2005+A1:2014 (Eurocode 3, Part 1-8) — Table 3.4, design resistances for individual fasteners
  • UK National Annex to BS EN 1993-1-8 — partial factor γM2 = 1.25
  • BS EN 10025-2 — nominal ultimate tensile strength (fu) of connected steel grades
Accuracy & scope note:
  • Covers standard non-preloaded ("bearing-type") bolted connections only — not slip-resistant/friction-grip (preloaded) connections
  • Checks a single bolt — bolt groups, prying action, and load distribution across multiple bolts are not covered
  • Shear resistance conservatively assumes the shear plane passes through the threaded portion of the bolt
  • Bearing resistance uses the edge-bolt k1 formula — appropriate for a single row of bolts at a plate edge; multi-row layouts need the "inner bolt" variant, not included here
  • Does not check the connected plate itself (net section resistance, block tearing) — this is a bolt-only check
  • Standard clearance holes assumed (2mm for bolts up to M24)
This tool provides preliminary, indicative structural calculations only, intended to assist with initial sizing and understanding. It is not a substitute for assessment by a qualified structural engineer, and cad-steel.co.uk accepts no responsibility for its use in any final design. Always have connection designs checked and approved by a competent engineer before construction.