9416240 Hushmand On October 9, 1993, new Federal minimum design standards for Municipal Solid waste landfill Facilities (MSWLF) were released which impacted the seismic design of landfills. However, these new standards combined little information and almost no guidelines for establishing the seismic performance of landfills. On January 17, 1994, the Northridge earthquake provided the first recorded set of strong accelerations in the OII landfill, the only landfill in the United States which is instrumented with strong-motion recorders, thus providing a rare opportunity to analyze a well-documented case history, and to develop guidelines for the seismic performance of landfills. The objective of the proposed research is to analyze the strong motion recordings and the surveyed displacements at the OII landfill after the 1994 Northridge earthquake. Several types of dynamic analyses will be used to calculate the ground accelerations, and the permanent ground displacements. The specific objectives are to determine the wave velocity and the damping properties of landfill materials that simulate the landfill response. These backfitted data will be compared to the wave velocities that are measured from geophysical and surface wave measurement techniques, in an effort to assess the applicability of the wave velocity measurements in extremely heterogeneous media. The method of analysis will include conventional engineering methods (e.g. equivalent linear methods such as QUAD4) and more advanced plasticity models and finite element models such as LINOS. Comprehensive models will be developed that include nonlinear behavior of landfill materials, two dimensional geometries, and wave propagation and reflection. Recommendations will be made for the optimal way to monitor the seismic performance of landfills. The data collected and generated during this research will be in digital format to the database of the Southern California Earthquake Center at the University o f Southern California. ***
