ABSTRACT
The overall aim for the design of a given structure is to identify critical loads, estimate design actions and select sections. Preliminary design is needed for four reasons: to obtain sections and weights for cost estimation; to compare alternative proposals; to obtain initial sections for computer analysis; and to check a completed design. The design concept should express clear force paths. It should include, where possible, repetition of members, floor panel sizes, column stacks, frames and bracing. The chapter sets out some points relevant to modelling for preliminary design. The purpose of analysis is to determine the critical actions for design. The chapter provides some methods that can be used in preliminary analysis. Element design is the process of sizing sections to resist actions obtained from analysis. Member design is required for members subjected to: axial load, bending and shear, and axial load and bending.
