Trussed rafters were introduced to the UK from America in the early 1960s. Market share increased steadily, and they are now used for over 90% of domestic roof construction. The main attractions are clear spans with fast construction times and reduced reliance on skilled site-based roof carpenters. M. Milner
A vast number of engineering products are protected, or capable of being protected by English law. The design of the product is or may be protected by copyright, or by the registration of the design at the Patent Office, or by the relatively new Unregistered Design Right, or else the invention itself is capable of being patented if new and if it can be made to work. Philip J. Harris
Serving on construction-industry awards panels is almost invariably interesting but can be disappointing if assessors are aware of some other projects well worthy of an award, which were just not entered. In terms of numbers the engineering entries are frankly disappointing when compared with the very many architects who enter. These notes are written in the hope of future redress in this and also to reduce possible mystique surrounding the subject of awards. S.B. Tietz
In the design of reinforced concrete slabs the Wood-Armer equations are used extensively. However; their direct application to assessment can result in a conservative estimate of structural capacity. Equations based on the same fundamental principles are derived which provide a more precise measure ofthe ability of a given slab to withstand an imposedfield of moments. Application of these equations will lead, in many cases, to an improved assessment for bridges previously analysed using the Wood-Armer equations and found to require a load restriction. S.R. Denton and C.J. Burgoyne
Changes to Codes of Practice and their supporting Standards are being made as a consequence of the introduction of European standards in the United Kingdom. When a European Standard (designated EN xxxxx) is published by the European Standards Committee (CEN) each nation is required to withdraw any conflicting parts of a corresponding national standard and implement the EN within a given period of time. This time period can be as short as 6 months but standards for the construction industry are usually implemented in batches because of the interdependence of the standards. P.J. Steer