Geoscience Reference
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subjected to fault rupture, piles affected by landslides, and soil failure imposed on
underground facilities by explosions, flooding, and the collapse of voids. Such condi-
tionsinducelargeplastic,irrecoverablestructuraldeformationthatinvolvesbothmaterial
andgeometricnonlinearbehavior.Hence,analyticalandexperimentalmodelingforsoil-
structureinteractionundertheseconditionsrequiresthecoupledpost-yieldsimulationof
bothsoilandstructuralresponse.Suchbehaviorgenerallyposessignificantchallengesto
our analytical capabilities, thus requiring large-scale experimental and case history data
toimprove the simulationprocess and validate themodels.
Extreme loading conditions, especially those associated with natural hazards and severe
humanthreats,mayaffectlargesystemsofstructures.Consider,forexample,Figure17.1,
which is a photograph of the corner of Wall and Williams Streets in New York City in
1917. The congestion shown in this photograph has not improved in the last 90 years,
and is indicative of the situation in a multitude of cities worldwide. The photo illustrates
atleasttwoimportantfeaturesofthebuiltenvironment.First,muchofcriticalinfrastruc-
ture is located underground, and its fate is intimately related to that of the surrounding
ground. Second, the crowded nature of urban and suburban developments increases risk
due to proximity. Damage to one facility, such as a cast iron water main, can rapidly
cascade into damage in surrounding facilities, such as electric and telecommunication
cables and gas mains, with system-wide consequences. Soil surrounding critical under-
ground infrastructure is frequently both the perpetrator and mediator of loading that can
affect thesystemicperformance of an entire city.
Fig. 17.1. Underground infrastructureat Wall and WilliamsStreets
in New York City, 1917
