Technical Guidance Note (Level 2, No. 23): Design of triangular timber trusses

This Technical Guidance Note is intended to act as an aide to those seeking to design an unreinforced masonry retaining wall. Following this guidance will prevent cracking and ensure that the wall performs as originally intended. The note will not cover the design of reinforced masonry retaining walls and variants of that form. Such reinforcement typically strengthens the wall itself against induced bending stresses and the wall’s geometry will therefore be somewhat different to that of an unreinforced retaining wall. The note will also not discuss the applied actions that a retaining wall will be subjected to, nor the construction of retaining walls. These subjects have previously been covered in the following Technical Guidance Notes: Level 1, No. 8: Derivation of loading to retaining structures and Level 1, No. 33: Retaining wall construction. It is assumed that the reader is familiar with the content of both these notes.

Piled foundations are one of the first aspects of scheme design a structural engineer needs to consider during a project's development. It is at this crucial stage that, without any specialist input, the structural engineer must make recommendations based on the typically limited knowledge they have on the subject. This Technical Guidance Note describes the method by which bored piles are designed using the current UK codes of practice, i.e. BS EN 1997 (Eurocode 7). It explains how to interpret soil conditions and design piles to match what has been discovered following a site investigation. The note does not address the types of piling systems that are available, nor the technical issues concerning their installation; these questions are covered in Technical Guidance Note Level 1, No. 23 Introduction to piling . The note explains how to design what is essentially a buried column of concrete to resist forces from the superstructure that are applied to it. It concerns the design of a single pile and not one that is part of a group. For information on how grouped piles differ in their design approach, the reader is directed to Cl. 6.3.3 of BS 8004:2015. (This article was update on 9 March 2018 to correct an error in Table 6.)

A significant-sized opening in a masonry wall will always require a lintel to bridge over it. This note offers advice on the different types of lintel that are available, their detailing requirements and their design.