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The design of steel and composite bridges: part 1

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The design of steel and composite bridges: part 2

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Conceptual choice


To introduce the designer to the principal conceptual choices that have to be addressed for the design of successful, economic steel and composite bridges.


This lecture emphasises the importance of the correct conceptual design of bridges. After a brief introduction on the different types of bridges, it highlights the influences that the bridge function and other factors may have on the selection of correct structural form. It also addresses the more detailed choices that have to be made as the design is developed.


"If you get the concept right, the design will be right." A trite statement, but one which contains a considerable element of truth (provided, of course, that the development of the concept is carried out correctly). If the concept is wrong, it will lead at best to a less than optimum design or at worst to much abortive work or a design quite unsuited to its location. Conceptual design does not involve detailed calculations; indeed, in most circumstances, an experienced designer would probably be able to produce a safe and economic design from previous experience and would only use detailed calculations as a final check or for 'fine tuning'.

The purpose of this lecture is to give an inexperienced designer some guidance on the conceptual choices which have to be made. It is deliberately expressed in general terms and makes no specific use of particular national or international standards for bridge design. In addition, many of the concepts described could be designed in either steel or concrete; in such cases, the emphasis is placed on steel construction.

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