Essential Knowledge Text No.12 Flexure and flexural structures

Some form of approximate analysis remains essential for both the conceptual design of structures and verification of final (computer) analysis. This text presents simple approaches to the approximate analysis of two-dimensional skeletal structures.

This is an introduction to the understanding of structural behaviour - applied to two-dimensional, mainly redundant frames. It demonstrates a qualitative approach, with an emphasis on a diagrammatic solution consisting of the detected shape, reactions and bending moment diagrams. A clear convention is established for the axes and diagrams, which is key to understanding structural behaviour.

Stability is one of two fundamental requirements of a structure, the other being equilibrium. Lack of stability during construction or service life can cause catastrophic structural failure. Stability is necessary against horizontal loads, asymmetric loading, out-of-plane loading and the effects of geometric imperfections, loading eccentricities and tolerances.