An innovative method for liquefaction mitigation based on inducing partial saturation (IPS) is studied in this research project. Laboratory tests have led to the conclusion that introduction of gas bubbles in sands, thus reducing its degree of saturation, prevents the occurrence of liquefaction.
Principle Investigator:Mishac K. Yegian, Northeastern University
Principle Investigator:Mourad Zeghal
A number of shape-acceleration arrays (SAA) have recently been installed permanently at the NEES@UCSB Wildlife liquefaction site to monitor low strain response as well as earthquake induced liquefaction, permanent deformation and lateral spreading. It is anticipated that an earthquake in the near future will induce large permanent deformation at this site. The installed arrays would then provide for the first time measurement of the time history of a site lateral spreading profile.
Principle Investigator:Jacobo Bielak, Carnegie Mellon University
The main objective of this research is to develop the capability for estimating the geological structure and mechanical properties both of individual sites and of complete basins, and to demonstrate this capability on the nees@UCSB site at the Garner Valley.
Principle Investigator:Jack Moehle, UC Berkeley
One of the greatest overall seismic risks in the United States is the risk of collapse of older concrete buildings in a major urban earthquake, yet there are no solutions to how to address this in a cost-effective manner. This multi-institution and multi-disciplinary project brings together engineers, educators and policy makers to assess the extent of the risk and develop cost-effective ways to prioritize addressing it.
Principle Investigator:Kenneth Stokoe, University of Texas, Austin
A joint experiment between the USGS/NEHRP external grants program (USGS Grant number 04HQGR0073) and the NSF/NEHRP George E. Brown Jr. NEES program (NSF award number CMS-0402490) began this week.
We report on a pilot field experiment, meant to demonstrate the value of combining resources from multiple earthquake science and engineering facilities. Our initial intent was to employ a mobile shaker truck from a Network for Earthquake Engineering System (NEES) facility with US Geological Survey (USGS) and Incorporated Research Institutions for Seismology (IRIS) seismographic instrumentation in a single study. The final experiment grew into four studies with additional participation from the Los Alamos National Lab and other NSF-sponsored consortia; the MAEC, SCEC, CENS, and HPWREN (see Participants below). The field experiment piggybacked on an earlier planned inaugural demonstration of NEES facilities, held at the NEES Garner Valley Digital Array (GVDA) site in southern California.