A flitch beam combines timber and steel with connections intended to transfer forces between them. RSJ.info does not provide a validated flitch-beam design calculator. The name of this page previously suggested more functionality than was available.
Why the UB model does not apply
Our steel tools assume one prismatic steel section with a tabulated inertia and a single elastic modulus. A built-up timber and steel member involves different material properties and the behaviour of its connections. Entering the outside dimensions into a steel-only formula would not establish how the parts share load.
Information for the designer
Provide timber grade and condition, proposed steel plates, overall geometry, span, support details, load sources and constraints on connector placement. For an existing assembly, provide drawings and any evidence of alterations rather than assuming it matches a typical example.
Ask the engineer to specify the member and connections together, including supports and construction requirements. Do not use an online bolt-spacing rule as a substitute for that work.
SCI’s steel-timber guidance provides context for combined systems; it does not validate this site’s calculators for flitch design. Our methodology states the restricted scope of the available tools. A chartered structural engineer and the applicable Building Control approval are required for the actual structural work.
Structural work must be designed by a chartered structural engineer and receive the applicable Building Control approval. This article is educational and has not received an independent engineering review.