Short answer
Connection design determines how steel members are joined — the plates, bolts and welds that transfer forces from one member to another. Members can be perfectly sized and the frame still fail at its joints, so connections are designed for the actual forces they carry: shear, moment, axial tension or compression, and often a combination. Typical connections include fin plates, flexible end plates, moment end plates, splices, base plates and bracing gussets. Design also considers fabrication, fit-up, erection access, tolerance and corrosion protection.
Branded guidance note, prepared for project records and circulation to your team.
Typical connection types
- Fin plate and flexible end plate — simple shear connections
- Moment end plate — transfers bending as well as shear
- Column splices and column bases with holding-down bolts
- Bracing gussets and bolted lap connections
- Beam-to-beam notched connections at level soffits
What the design checks
- Bolt shear, bearing and tension, including prying
- Weld capacity and effective throat
- Plate bending, block tearing and notch effects
- Local capacity of the supporting member's web and flange
- Buildability — access for the erector's spanner
How BES is typically involved
- BES prepares connection designs for new frames and for alterations to existing steelwork.
- Fabricator-proposed connections can be checked and approved.
- Details are issued in a form fabricators can detail and price from.
Typical process
- 01Extract design forces from the frame analysis
- 02Select an appropriate connection type
- 03Design bolts, welds and plates
- 04Check the supporting member locally
- 05Issue details for fabrication
Common misconceptions
Commonly assumed
“Standard connections always work.”
In practice
Standardised tables are excellent starting points but need checking against the actual forces and geometry.
Commonly assumed
“Connections are the fabricator's problem.”
In practice
Responsibility must be defined explicitly. Where the fabricator designs, the engineer should still check.
Related tools and services
Resource Centre tool
Steel Section Capacity Checker
Verify a steel section you have already selected — bending, shear, deflection, web bearing, web crushing and approximate lateral-torsional buckling, with utilisation and reserve capacity.
Open Capacity Checker →Resource Centre tool
Preliminary Beam Sizing
Explore an indicative steel beam size using bending, lateral-torsional buckling, shear and deflection criteria.
Open Beam Sizing Tool →Related questions
Discuss your project
General guidance only goes so far. Describe your building and what you are planning, and you will receive project-specific advice from a Chartered Structural Engineer.
Discuss Your Project →Next scheduled review August 2027
Disclaimer
Indicative result only. The calculation depends on the assumptions and information entered and does not constitute structural design or professional advice. Do not use the result for construction, procurement, Building Regulations submissions or safety-critical decisions. All results must be independently verified by a suitably qualified structural engineer before being used for design, construction or regulatory purposes. Bebbington Engineering Studio Ltd accepts no responsibility for reliance placed on unverified results.