Author: C. O'Regan (AECOM)
2 January 2019
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C. O'Regan (AECOM)
These panels are quite slender to the point where they usually require additional horizontal support to make them stable. The same can also apply to cavity walls, where both skins are incapable of resisting lateral loads.
The element that provides this support to masonry panels is a vertical prop known as a ‘windpost’. Its principal role is to provide lateral support against destabilising horizontal forces that typically originate from wind pressure – hence, the name.
Windposts are typically steel elements – either open sections, such as channels or angles, or closed sections, such as rolled hollow rectangular sections. This Technical Guidance Note provides guidance on the design and detailing of windposts relating to their incorporation into building structures.
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.)
Until relatively recently, masonry was the major load bearing component in a building structure. With the advent of steel and concrete frame technologies, masonry has become a part of a building’s cladding envelope and as such is more prone to being exposed to lateral loads than vertical ones. This Technical Guidance Note concerns the design of masonry walls that are subject to lateral loads i.e. they are being used as a cladding element. It will discuss the way in which the material is assessed against how it is being restrained and its geometry. All of these factors have an impact on the design of masonry walls as well as the mortar within them and the exposure conditions. This is discussed in Technical Guidance Note 27 (Level 1) and should be read in conjunction with this guide. (This article was updated in October 2016 to reflect errata issued since its original publication.)
Portal frames are a simple and very common type of framed (or skeleton) structure. Steel portal frames, in particular, are a cost-effective structural system to support building envelopes (such as warehouses and shopping complexes) requiring large column-free spaces. In general, the loads and consequent deformations for these frames are in the plane of the structure, and hence these are a 2D (or plane) frame structure. Due to the practical requirement of having a clear space between the supports of a portal frame, providing in-plane bracing is generally not feasible. Consequently, these frames undergo larger deflections and are prone to sway laterally, even under the vertical loads. The concept of sway frames is addressed in more detail in Technical Guidance Note No. 10 (Level 1) Principles of lateral stability. Thus, in spite of the inherent simplicity of portal frames, many aspects of their analysis, design and detailing require careful consideration. Portal frames can be made from concrete, timber and even glass but the vast majority, in the UK certainly, are constructed from steel. This Technical Guidance Note gives an introduction to steel portal frames and their preliminary analysis. Steel portal frames usually have pinned bases and moment connections at the column/rafter interface and mid-span apex splice in the rafter. Although there are other forms of portal frame (described in Elastic Design of Single- Span Steel Portal Frame Buildings to Eurocode 3), for the sake of brevity and clarity this note will be dedicated to this particular form. (This article was updated in October 2016 to reflect errata issued since its original publication.)