18 Steel Connections and Joints Worked Examples | Eurocode 3 Steel Design series

Summary

The tutorial explains how to size and check simple bolted end-plate connections under Eurocode 3, then applies the process to a beam-to-column example.

Connection types

• Simple joints transfer shear but are intended to allow rotation; they do not transfer significant bending moment. They may use partial- or full-depth end plates. In a building frame, bracing resists lateral loads.
• Moment-resisting joints, such as extended end-plate connections, are designed to transfer moments as well as forces. They are mentioned for comparison but are not the focus of the tutorial.

Initial sizing and design considerations

The presenter refers to NCCI guidance for the initial sizing of simple end-plate connections. The rules discussed apply to typical, non-preloaded bolted connections.

Key guidance includes:

• Choose a partial- or full-depth end plate based on the applied shear relative to the beam’s shear resistance. The tutorial cites a threshold of about 0.75 times the beam shear resistance; the worked example describes the threshold as 0.7, so the exact value should be checked against the referenced guidance.
• For a supported beam less than 500 mm deep, an initial end-plate thickness of 8 or 10 mm may be used. A plate width of 150 mm and a gauge of around 90 mm are given as typical starting dimensions.
• A common initial plate-height estimate is around six times the beam height. The worked example instead uses a partial plate depth of 0.6 times the beam depth.
• M20, grade 8.8 bolts are presented as a common choice. A simple preliminary bolt-count rule is based on the applied shear divided by 75 kN, with the result adjusted upward.
• Bolt positions and spacing must satisfy Eurocode minimum and maximum edge-distance and spacing rules.
• For S275 steel, the example checks the weld throat size against a minimum derived from the beam-web thickness. The chosen weld has a 4 mm throat, corresponding to a 6 mm leg.

Main connection checks

The tutorial emphasizes checking several possible failure modes:

1. Bolt shear resistance — whether the bolts can resist the applied shear without failing in shear.
2. End-plate bearing/crushing resistance — whether the plate around the bolts can resist the bearing force.
3. Beam-web shear resistance — whether the beam web can resist the shear transferred through the connection.
4. Bolt tensile resistance / tying capacity — a robustness check intended to help prevent local failure from causing progressive collapse.

The presenter notes that bolt shear, end-plate bearing, and beam-web shear are especially important in the worked example, although other checks may also be required for a complete design.

Worked example: Flexible end-plate beam-to-column joint

The example is taken from SCI Steel Building Design Example SCI 387, Example 10.

Given and selected details

• Column: 254 × 254, grade S275
• Beam: 457 × 191 × 82 UKB
• Beam web thickness: 9.9 mm
• Beam flange thickness: 16 mm
• Applied design shear: 230 kN
• Initial connection: partial-depth end plate, 280 mm deep, with six M20 grade 8.8 bolts
• Bolt layout: The presenter assumes edge distances and pitches, including 85 mm vertical pitch, 55 mm and 50 mm edge distances, and 100 mm horizontal spacing, then checks them against Eurocode limits.

Checks and reported results

• The selected bolt positions satisfy the minimum distances and spacing discussed, based on the assumed 22 mm hole diameter.
• The plate’s ductility limit is calculated as approximately 12 mm; the selected 10 mm plate passes.
• The weld throat requirement is calculated as about 3.86 mm; the selected 4 mm throat passes.
• Bolt shear resistance: approximately 75 kN per bolt, or 451 kN for the six-bolt group.
• End-plate bearing/crushing resistance: approximately 928 kN for the group.
• Beam-web shear resistance: approximately 396 kN.
• Governing resistance: The beam-web shear resistance of 396 kN is the lowest of the reported shear resistances. It exceeds the applied 230 kN, so the connection passes the checks presented.
• Robustness check: The calculated bolt tensile/tying resistance is reported as 962 kN, exceeding the cited minimum tying requirement of 75 kN.

The video ends while the presenter is wrapping up the conclusion. The calculations shown indicate that the connection is adequate for the stated applied shear.

Speakers and sources featured

Speaker: Dr Jawed (also rendered in the subtitles as “Jave”) Qureshi, who introduces himself as a senior lecturer at a university in London.

Design references mentioned: Eurocode 3, including provisions and tables for bolt distances and resistance; NCCI guidance on the initial sizing and resistance of simple end-plate joints; an NCCI steel-weld-design guide for S275; and SCI 387, Example 10. No other speakers are identified.