Chapter 1
General Matters
Contents
1.1 Introduction
1.2 Codes and Standards
1.3 Loads and Actions
1.4 Limit State Design Philosophy
1.5 Determining Loads on Individual Structural Elements
1.6 Structural Mechanics
1.7 Design of Beams for Bending Moment
1.8 Compression Members
1.9 Material Properties
1.10 Summary
1.1 Introduction
Eurocode 0 ‘Basis of Structural Design’ states:
‘A structure is an organised combination of connected parts designed to carry loads and provide adequate rigidity.’
Structural engineering is the study of how the various components of a building or other structure act together to transmit forces down to the foundations. Stages in the process are:
Structural planning stage: When a structural scheme is devised to suit both the purpose of the building and the site conditions.
Structural analysis stage: When the loads on the structure are determined and the way that the loads disperse through the structure is analysed using the principles of structural mechanics.
Structural element design stage: When the size and properties of each member are determined.
Structural detailing stage: When detail drawings are produced to illustrate how the structure is to be constructed on site.
Structural specification stage: When specification clauses are compiled to define the standard of materials and workmanship to be used.
Construction stage: When the structure is built, with appropriate supervision, inspection and testing to ensure that it complies with the drawings and the specification.
This book is primarily about the third of these stages, although some aspects of the other stages are also covered.
Although structural design should be carried out by structural engineers, other construction professionals require some knowledge of structural behaviour. Architects, quantity surveyors, building control officers, clerks of works and site staff will all benefit from studying the design of structural elements in different building materials.
1.2 Codes and Standards
Guidelines for the use of structural materials are found in many published codes, and this manual is mostly based on a set of codes produced for use throughout the European Union – the Eurocodes. Each country in the European Union defines how each code is to be used by publishing a National Annex for each code, and this manual is based on the UK National Annexes.
The various Eurocodes make extensive use of Greek letters, details of which are given in the respective sections of this manual.
Designs which accord with the Eurocodes are both safe and economic, and are deemed to satisfy UK Building Regulations. The codes do not inhibit the exercise of engineering judgement or the production of exciting structures, but they set out sound and well understood limits to which various materials can be taken.
In relation to structural design, the codes and standards are in two groups:
- Those relating to materials and components
- Those relating to loading and to the design of structures.
Tables 1.1 and 1.2 list a selection of these codes and standards.
Table 1.1: Codes relating to materials and components
| Material | BSI reference | Title |
| Timber | BS EN 336 | Structural timber – sizes, permitted dev... |