ABSTRACT
Buildings are designed within various economic constraints. Whatever the economic conditions, engineering ethics define a certain approach to the subject of economy. Structural engineering methods, which can be analytical or computational, help designers to find ways of improving the performance of structures whilst decreasing their cost. Possible approaches to the economy of structures can be explained by using the concepts of structural efficiency and optimization. The history of long-span and high-rise structures is related to developments in increased structural efficiency through evolutionary structural optimisation by inventing new structural systems. Designing for evolutionary structural optimisation, designing for the optimum structure, optimisation of the designed structure and designing for symbolic capital are all professional approaches to building economy. The percentage of design for symbolic capital and design for evolutionary structural optimisation is very small in comparison with other architectural approaches to economy. The structural engineer should try to achieve the architectural characteristics given by the architect.
