The last edition of this book identified the ever advancing sophistication of computer programs on offer to the trussed rafter manufacturers. The continuing need to be competitive will drive the plate system owners on to further advances both in the degree of roof shape complexity possible to process and in the simplicity of operating the programs produced.
Mi-Tek and Wolf now have available laser projection equipment which as this book goes to press is in limited use but will undoubtedly become more widespread in the future. Doubtless this type of feature will be further developed and in the next edition of this book we may well be reporting on the use of robotics in the selection and placement of the plates and the timber components of a trussed rafter. Systems already exist to program the actual pressing machine to stop and press the plates at each node point on the truss. With the programming time necessary to achieve this degree of control, and therefore the cost of input, falling all the time, the economics of using this technology on relatively small batches of trusses becomes viable.
Eurocode 5 is now upon us and over the next few years British Standard 5268 will gradually change to be its equivalent. The basis on which timber structural design is undertaken in the UK will change as Europe moves towards an integrated method based on limit state design.
Finger jointed timber for trussed rafter construction has not become popular, presumably for economic reasons, but the process is structurally sound and when the economic balance between finger jointing and the splice joint reverses, things may well change. This is likely to be driven by fabricators seeking cost reductions because it must be remembered that those responsible for designing the computer programs, that is the nail plate manufacturers, must have a vested interest in keeping the splice plate in use.
Customer and architectural requirements will push forward trussed rafter design to achieve their aesthetic ends, thus advancing the boundaries of trussed rafter roofs and making them even more common in the future for non-domestic structures.
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