A new system for preventing bridge collapses

Bridge safety is receiving renewed attention because of the growing appreciation of how separate load effects can combine to increase hazards. There are five categories of extreme events listed in order of approximate likelihood, a simple event in which one extreme event exerts a single load, a combined multihazard event in which a single extreme event exerts multiple load effects, a consequent multihazard event, and a subsequent multihazard event, two unrelated extreme events separated in time. A progress in bridge safety an be made by modeling the reliability relationship between loads and resistance and by developing improved structural modeling and materials. Incident reporting systems are now required for airplane accidents and near-misses and are routinely recommended for the study of medical errors and construction site incidents. Such a system will track stresses, strains and other conditions on the structure and its components and will identify, locate, and measure the effects.