Essential Knowledge Text No.5 Lessons from failures

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.

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.

This text is an introduction to the most important aspects of flexure in structures. A description of the widespread use of flexural elements and structures is followed by an introduction to the modelling and analysis of beams, slabs and frames. The text then discusses the use of four common structural materials in flexural elements and structures.