There are statutory regulations and guideline codes, which all consulting civil and structural engineers must follow in design work regardless of the size of the project.  I will try here to provide clarity on understanding the codes and bring you up to date with changes.  If you ever need to employ an engineer, surveyor or architect to perform services for you, this article may help explain the rules and perhaps even correct the occasional error in coding.  The Building Regulations 2000 require buildings to be stable, loadings assessed and structurally sound.   This may appear rather obvious and even flippant but in reality it is a very serious statement. 

Civil and structural consultancy, project management, design, specification and supervision work should only be performed out by a civil or structural engineer who will be designated under the Royal Charter as a Chartered Engineer (CEng).  This rank indicates a high level of professional expertise, supervised training, excellent qualifications and high moral values with a strict code of conduct. The engineer will in almost all cases at least have a batchelor’s (BSc/BEng) or even a master’s (MSc/MEng) university degree and either be a Member or Fellow of the Institution of Civil Engineers (MICE/FICE) or the Institution of Structural Engineers (MIStructE/FIStructE).  Finally all engineers will carry expensive professional indemnity insurance if they wish to practise.

In this article, I will try to cover the changes and differences in simple terms between the present and incoming or new codes and their implications.  It is and never will be a simple subject so please bear with me.  In small works design and construction, as far as property owners are concerned, timber and steel will remain the main materials.

Previous structural timber stress grades were called SC3 and SC4 for the two grades mostly used.  But now those grades have been replaced in BS 5268 by C16 and C24 respectively.  Grade C16 refers to the typical timber supplied if no grade is requested.  Grade C24 indicates timber is of better quality than C16, e.g. with less knots, warping, splits, etc.  Personally I prefer to specify the C24 grade if and wherever I can.  Like the SC3/4 grades the C16/C24 timbers are stress graded.  It will often be seen on architect’s and surveyor’s drawings that Grade SC3 is still referred to and specified.  This is clearly incorrect and may indicate the designer’s lack of knowledge in relation to the latest codes and regulations and in keeping up to date with changes.

Steel members over openings are often called RSJ’s by my clients and many builders or even just steels. I do not like that casual description ‘steels’. It belies an inherent lack of respect for a complex material. The correct term is steel beam. An RSJ means a rolled steel joist. It is an old section and not specified or used anymore really. You can detect an RSJ by the internal sloping flange, thicker at the web. Nowadays we use universal beams, columns, channels, etc.; more modular sizes and shapes for universal use. The reason we do that is very simple and as much to do with connections as with other factors. Many aspects of engineering come down to connections or how to fix two items together, viz. welding, bolting, screwing, reinforcing, fusing, etc. The concept of squaring off the flange cross section has enabled us to connect steel members so much more easily into some now complex shapes. But more importantly it has reduced installation time and reduced costs and also to have more confidence in the connection.

The old material grades such as Grades 43 and 50 still mentioned by many people in the construction industry have now been replaced by Grades S275 and S355 respectively for mild steel and high tensile steel materials. The latter should be specified and referred to on drawings and in calculations.

The Eurocodes shown in the table, with their present counterpart, will come into full force in 2010, by which time most if not all civil and structural engineers will have some knowledge of how to use them. You can see the simplification by the general reduction of several existing codes into one single code. The codes will be used by engineers across Europe in all 27 EU countries. An enormous effort is being made by everyone in the profession to become as familiar as possible with the new codes before 2010. There are books out, codes to be bought and courses on how to understand them and what to do. They are complicated but then engineering always was and always will be.

James Dale
Consulting Civil/Structural Engineer
www.dale-consulting.co.uk
22 November 2008