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

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.)

This Technical Guidance Note concerns the design of pile-caps for small groups of piles e.g. 2-4 piles. It relies on the strut and tie method to determine the amount of reinforcement required in the pile-cap; which is dependent upon the depth of the cap, the magnitude of the axial load being placed upon it, the cap’s concrete strength and the pile size and spacing.

The purpose of a pad foundation is to spread a concentrated force into soil. They are one of the most simple and cost effective types of footings for structures. Provided the founding soil is of sufficient strength and is not too deep to reach, pad foundations are the preferred solution for foundations due to the straight forward nature of their design and construction. This Technical Guidance Note covers the design of concrete pad foundations, both mass and reinforced concrete forms. It will not, however, discuss how the bearing capacity of the soil is determined, as that is explained in Technical Guidance Note 19 (Level 1) Soil bearing capacity. It is suggested that you read that text in conjunction with this, in order to gain a more comprehensive understanding of the topic. (This article was updated in October 2016 to reflect errata issued since its original publication.)