Technical Guidance Note (Level 2, No. 21): Design and detailing of base plates to steel columns

Since the invention of medium-storey framed structures in the late 1800s, there has been a need to clad them with a reasonably robust material that acts as an efficient barrier to the external environment. Masonry delivers the performance required of a cladding system on multiple fronts. It has therefore developed from a load-bearing element within structures to become a component of an envelope to larger framed buildings.

This Technical Guidance Note introduces structural engineers to the interfaces between a primary structure that is principally formed from steelwork and a masonry cladding system.

This Technical Guidance Note addresses the design of timber elements that are unrestrained against lateral torsional buckling. It explains how such beams are analysed and designed. The impact of notching the supports of beams is also considered with respect to the shear capacity of the beam.

For clarity and brevity, this note only covers solid and glued laminated (glulam) timber elements; compound and composite beams, such as flitch beams, are not considered. The connections within timber frame assemblies will be addressed in a future note.

Readers should also be aware that this note forms part of a trio of Technical Guidance Notes leading to the design of bespoke timber trusses – assemblies made from unrestrained timber beams and posts. Notes on the design of timber posts and bespoke timber trusses will follow later in the series.

Although retaining walls have been the subject of two earlier Technical Guidance Notes; No. 8 (Level 1): Derivation of loading to retaining structures and No. 33 (Level 1): Retaining wall construction, their design has not been covered. This guidance note focuses specifically on the design of reinforced concrete gravity retaining walls.

There are three different forms of this type of wall, all of which are designed to resist overturning and sliding failure. The primary difference between them is their height. The taller the retaining wall, the more likely that counterforts and beams spanning between them will be necessary. This note describes how all of these forms of retaining wall can be designed.

(This article was updated in October 2016 to reflect errata issued since its original publication.)