UTILIZATION OF NEW TECHNOLOGIES
The NEP embraces testing the usefulness of promising new technologies forunderstanding earthquakes and reducing earthquake-caused loss that haveemerged since the original formation of NEHRP. Space-based technologiessuch as Global Positioning System (GPS) technology can be utilized to providecontinuous-in-time measurements of how the ground is deforming in areasof earthquake risk, and Synthetic Aperture Radar remote sensing applicationsare being developed to provide a spatially continuous image of crustal deformation.Other new geophysical methods include high-performance seismometers andseismographs for recording broadband, high-dynamic-range ground motion whichare being installed world-wide. These stations are particularly importantfor emergency response to damaging earthquakes and for recording the strongmotion data needed for building design. Borehole tiltmeters, borehole strainmeters,and laser-ranging instrumentation measure ongoing distortion of the earth'scrust and may eventually aid earthquake prediction. Paleoseismic methodshave rapidly advanced in the last decade and enable identification of pre-historicearthquakes and improved estimates of earthquake recurrence intervals. Probabilisticseismic hazard methods have been developed to provide estimates of earthquakeground motion in areas of low recurrence (such as the eastern U.S.). NewGeographic Information System (GIS) technology will be used to integratethe information from these and a variety of other data sets.
New technologies in the area of earthquake engineering include advancedmodeling and simulation of the dynamic, non-linear response of constructedfacilities to earthquake effects, use of energy absorption systems, andpassive and active control systems for reduction of structural responseto ground shaking with resulting reduction in damage and interruption offunctions, and innovative structural materials and systems such as high-performancecomposites for strengthening existing structures:
- Advanced non-destructive evaluation methods such as ultrasonic, acousticemission, infrared thermography techniques have been developed to monitorand assess structures and detect flaws which could make them more susceptibleto ground shaking.
- Optic-fiber sensors and innovative embedment techniques have provento be extremely effective in sensing the dynamic response of structuresunder seismic conditions.
- Neural networks and fuzzy logic-based mathematics techniques are veryuseful in identifying the properties and damage potential of large, complexstructures.
- Hydraulic, electromagnetic-based actuators, or their hybrids, arebeing developed to produce the required control forces to counter-balanceimpeding earthquake loads.
- High-performance materials, including high-strength, highly ductileand weldable steel and alloys and cement-based materials which can be madesuper strong, tough, and durable--properties of importance to earthquakeresistance--are becoming common for construction of critical buildings andinfrastructures in seismic zones.