In any given year, the world can expect 18 earthquakes of magnitude greater than 7.0, most of which (more than 80%) will likely occur on the so-called Ring of Fire, which circumscribes the Pacific Plate and includes a portion of the California coast. If the epicenter is in a populated area, an earthquake of this magnitude can cause devastating damage. The study of earthquake hazards and what can be done to reduce the associated risks is a field known as earthquake engineering. Earthquake engineering draws on the disciplines of structural engineering, structural dynamics, seismology, materials engineering, geotechnical engineering, risk and decision analysis, and probability and reliability theory to holistically address infrastructure performance in an uncertain seismic future.
The focus of our Earthquake Engineering practice is two-fold: post-earthquake investigations of causative mechanisms resulting in structural damage, failure, or collapse; and earthquake planning and risk mitigation, which includes identification, quantification, and mitigation of risk through optimal repair strategies, performance-based upgrades, and customized solutions. We offer multi-faceted holistic support to property owners, insurance and legal communities, and government agencies, both in the aftermath of earthquakes and in pre-earthquake planning and mitigation.
An important aspect of earthquake engineering is investigation of damaged structures after a seismic event. The magnitude 6.7 Northridge Earthquake in 1994 caused more than $20 billion of damage and provided many opportunities for earthquake engineers to study why some buildings suffered more than others. It is by studying earthquake damage, as well as structures that were not damaged, that engineers learn how to design and build more reliable structures. Since it is not economically feasible to construct buildings that will not be damaged in major earthquakes, some damage is expected. However, sometimes engineers discover design or construction features that make a building more susceptible to earthquake damage. For instance, the engineer may have underestimated earthquake loads, or the contractor may not have built important components correctly. Occasionally, engineers discover surprising damage mechanisms—for example, the cracking of welded steel connections observed after the Northridge Earthquake. This is a potentially serious damage mode that affects some of our most modern, well-designed, and well-constructed buildings.
Other aspects of earthquake engineering include understanding the nature of seismic hazards, such as understanding the chances of a large earthquake, and assessing whether the site soil will amplify the shaking or if liquefaction will weaken the site soils. Reliable assessment of potential structural damage that will result from ground shaking often requires sophisticated computer simulation.
Our services include:
- Post-earthquake safety and damage assessment
- Seismic hazard and risk assessment
- Disaster management
- Investigation protocol development
- Risk mitigation through optimal retrofit and performance-based upgrade strategies
- Development of web-based GIS systems for post-earthquake portfolio loss assessment and adjustment
- Evaluation of existing structural and non-structural systems
- Structural analysis
- Geologic and geotechnical hazards and risk assessment: geologic conditions, faulting, subsidence, landslides (due to earthquakes)
- Geotechnical analysis and soil laboratory testing
- Performance-based design and peer reviews
- Post-earthquake fault and ground deformation reconnaissance
- Earthquake-induced permanent ground displacement analyses: fault rupture, settlement, liquefaction, slope instability
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