185 Recent Improvements in Earthquake Performance

Much of the damage that has occurred during recent earthquakes was the result of the failure of the surrounding soil or structural elements. Not surprisingly, most of the recent improvements to the earthquake resistance of structures have focused on methods of improving poor soil, on soil-structure interaction, and on structural elements and systems that increase strength, stability, ductility, etc.

There has also been some work to prevent secondary earthquake damage. For instance, California has begun to retrofit bridges that cross over active faults. On the Colton Interchange, a bridge was provided with additional supports to catch the superstructure if it is pulled off its piers. Another California bridge was provided with large galleries at the abutments to accommodate large movements. A couple of bridges have even been provided with gates that close the bridge when the ground begins to shake.

Some effort has also been made to improve lifeline performance, most notably in Wellington, New Zealand, where facilities are carefully planned and located to prevent disruptions in service during large earthquakes.

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