ABSTRACT
The initial phase in proportioning a structure, modestly called preliminary design, is the most important one in the conception of a structure. Preliminary design, mostly an art, exerts a strong inuence on the nal product that results from generally analytical evaluations of the initially chosen framing type and section dimensions. Perhaps the best witness to the relative importance of preliminary design is contained in the engineering adage that if a calculation produces a result that differs by more than 15% from the engineer’s initial guess, then there is likely to be something inadequate in the engineer’s judgment, in the calculation, or in both. A careful check or consultation with an experienced engineer is in order.
