Strategies for mitigating risk to buildings from abnormal load events

Abstract

Building structures customarily are designed to withstand loads from their occupants and the natural environment. The normal design process provides a measure of structural integrity that is also available to withstand events that traditionally have been outside the design envelope, including accidents, misuse, and sabotage. Changes in design and construction practices over the past several decades have lessened inherent robustness in certain modern structural systems, making them vulnerable to such events. Social and political factors also have led to an increase in hazardous events that may pose a risk to buildings. Finally, public awareness of building safety has increased as a result of well-publicised natural and man-made disasters. Building practices to mitigate the risk of abnormal loads and ensuing unacceptable damage or collapse can be improved using concepts of structural reliability and risk analysis. This paper summarises the basis for such practices, from the perspective of a structural engineer.