Optimization of Cover Plated Steel Frames by Linear Programming

Structural engineers are required to design economical, reliable, and aesthetic structures which conform to given requirements and constraint conditions. To do this requires a knowledge of structural analysis methods and behavior of structural materials. In principle, structural engineers can work with any kind of structural material and any type of structure such as a two dimensional structure (frames, plates, . . . , etc.) or a three dimensional structure (shells, plates, . . . , etc.) in order to fulfill the requirements. There exists an infinite number of possible ways to design a proposed structure as well as a multitude of difficulties in design. The determination of an indeterminate structural system of specified topology that can withstand prescribed loading or environmental conditions is a problem without a unique solution. However, if the system satisfies some criterion, such as minimum weight or minimum weight or minimum costs, then a unique design is sought and the problem becomes correspondingly more difficult. The usual method of designing a statistically indeterminate structure consists of a trial and error procedure in which a first design is assumed, the structure is then analyzed, and the design is revised on the basis of the results of the analysis. This cycle may be repeated until, hopefully, each member is fully stressed under at least on loading condition. This procedure will not necessarily result in the best design, and it is even possible that the best design is to develop a method by which an optimum design can be obtained with a reasonable mathematical certainty. The greatly expanded computational facilities and optimizing procedures1 being used in management and in other areas of engineering are providing structural engineers with possibilities of new approaches to optimum structural design. With this background the theoretical description of a method for optimizing a structural design with particular reference to the conventional methods of analysis is presented. In this thesis, the optimization of a framed structure using wide flange sections and cover plates is considered. The working stress method of analysis and the American Institute of Steel Construction code have been adopted throughout this investigation. (see more in text