ABSTRACT
The specific aim of structural design is, for a given framing arrangement, to determine the member sizes to support the structure's loads. This chapter discusses design theories and design methods given in BS 5950: Part 1. Elastic theory was the first theoretical design method to be developed. The behaviour of steel when loaded below the yield point is much closer to true elastic behaviour than that of other structural materials. Plastic theory was the next major development in design. Plastic analysis is based on determining the least load that causes the structure to collapse. Collapse occurs when sufficient plastic hinges have formed to convert the structure to a mechanism. The design of steel structures may be made to any of the design methods set out in Clause 2.1.2 of BS 5950. There are: simple design; continuous design or rigid design; semi-continuous design or semi-rigid design; and experimental verification.
