Steel Buildings in Europe Verification Problem Example
Fin Plates – Beam to Beam Left Beam Connection

Problem Statement

This document presents a comparative study between the published Joints in Steel Construction: Simple Joints to Eurocode 3 and the results generated by SDS2 version 2025.01 connection software for the left beam connection of Example 1 – Fin plates – Beam to beam. The central problem statement is to verify the available strength of a fin plate connection between a beam and a supporting beam web. This connection involves a 406x178x74 UKB beam and a 610x229x140 UKB supporting beam. Shear reaction on the beam to fin plate connection is 200kN with both beams using Grade S275 steel. The connection uses M20 8.8 bolts and grade S275 steel for the fin plate. The connection detail is shown in Figure 1.

Figure 1. Example 1 – Fin plate – Beam to beam

Connection design report output from SDS2 for this connection:

• Eurocode 3 UK.pdf

Note: To view the 3D model (U3D) of the structural joint in the PDF files, open the PDF using Bluebeam or Adobe Acrobat Reader.

Validation Method

The connection as shown in the Simple Joints to Eurocode 3, section 5.6, page 137, Example 1 – Fin plates – Beam to beam (see reference 1) was modeled in SDS2 and a connection design report was generated.

The core of this report features a comparison table for each connection limit state, displaying the calculated capacities from both SDS2 and the cited document. The order of the limit state table generally mirrors the sequence in which it was presented in the Simple Joints to Eurocode 3 example problem. This table also highlights the percent difference (% Δ) between these calculated values, providing a clear measure of any discrepancy, if any.

To further enhance understanding, this report includes relevant notes that discuss any differences or assumptions made during the calculation process. This comparative study's goal is to evaluate the precision and efficiency of the SDS2 connection design software in contrast to the published Eurocode 3 UK design example and serves as a guide for better understanding and application of these design calculations.

Comparison

A comparison of the limit state checks is presented in Table 1. The limit state checks and calculated values aligned well between the published Eurocode 3 UK design example document and the calculation generated by SDS2. The minor differences in calculated values, except where noted, were a result of rounding differences.

Other minor differences are discussed in the comparison table notes.

Table 1. Capacity comparison table for Eurocode 3 UK
Limit state on left fin plate connection	SDS2 Capacity	SCI Capacity	%Δ	Notes
Supported beam-bolt shear	94.0 kN / bolt	94.0 kN / bolt	0.0%
Supported beam-bearing on fin plate	326.0 kN	332.0 kN	-1.8%	1
Supported beam-bearing on web	285.7 kN	291.0 kN	-1.9%	1
Supported beam-fin gross shear	362.5 kN	363.0 kN	-0.1%
Connection-net shear rupture	434.7 kN	435.0 kN	-0.1%
Supported beam-fin block shear	346.5 kN	347.0 kN	-0.1%
Supported beam-fin bending & LTB	764.0 kN	771.0 kN	-0.9%	2
Supported beam-gross web shear	568.2 kN	561.0 kN	1.3%	3
Supported beam-net web shear	590.2 kN	581.0 kN	1.6%	3
Supported beam-web block shear	312.3 kN	312.0 kN	0.1%
Supported beam-resistance at notch	89.1 kN-m	89.1 kN-m	0.0%
Supported beam-stability at notch				4
Supporting member-welds				4
Supporting beam-local shear	603.2 kN	603.0 kN	0.0%

Table Notes

Note 1: The α_b value calculated inside of SDS2 is 0.606061 and the value calculated in Simple Joints to Eurocode is 0.61.

Note 2: SDS2 uses a ‘z’ value (Distance from the weld to the centroid of the bolt group) of 50.4mm and the example in Simple Joints to Eurocode uses 50mm.

Note 3: When calculating the area of the coped beam, SDS2 includes the area of the fillet between the beam flange and web. SCI calculates the area assuming rectangular cross section elements.

Note 4: These checks are performed in both SDS2 & Simple Joints to Eurocode 3 but no capacity is calculated.

References

1. Joints in Steel Construction: Simple Joints to Eurocode 3, Publication P358, The Steel Construction Institute & The British Constructional Steelwork Association Limited. 2014