Praad Geotechnical has performed numerous site specific and regional studies of seismicity throughout California. Our expertise in earthquake engineering includes the following services:

• Characterization of dynamic soil behavior

• Probabilistic seismic hazard analysis

• Development of site-specific ground motions

• Site response analysis

• Evaluation of liquefaction potential

• Seismic settlement

• Seismic slope stability

• Seismic evaluation of concrete dams

• Dynamic soil-structure interaction

We are skilled in widely used geotechnical earthquake engineering programs such as EQFAULT, EQSEARCH, FRISKSP, and SHAKE as well as more advanced computer programs such as FLAC, QUAD4M, DEEPSOIL, D-MOD_2 and SUMDES.

Predicted liquefaction along the base of a dam

Earthquake damage to apartment complex

Rotation of wooden post in crawlspace

Representative Projects

Ground Response Analyses for Silicon Valley Rapid Transit in San Jose, CA

Praad Geotechnical performed one-dimensional seismic ground response analyses for the tunnel alignment using equivalent-linear and non-linear computer programs. We developed input ground motion and strain-compatible dynamic soil properties to be used for dynamic soil-structure interaction analyses by the Project. We evaluated dynamic soil property data, conducted dynamic laboratory testing, and performed an extensive study of site-specific modulus reduction and damping characteristics of the site soil.

The methodology and results of our seismic analyses were presented at the American Society of Civil Engineers' 4^th Conference on Geotechnical Earthquake Engineering and Soil Dynamics (click here for poster) and published in ASCE's Geotechnical Special Publication 181.

Seismicity Study for New Tract Development in Agua Dulce, CA

Praad Geotechnical performed a seismic hazard assessment for a 908 acre development, including determination of the ground motions for structural design using deterministic and probabilistic methods, development of site specific response spectra for cut and fill areas, evaluation of liquefaction potential, and seismically induced settlement analyses.

Regional Seismicity Studies of Welded Moment Resisting Steel Frame Buildings in Los Angeles County, CA

Praad Geotechnical investigated approximately 200 building structures with welded moment resisting steel frames in Los Angeles County as a result of the 1994 Northridge Earthquake. Our analyses included the quantification of ground motions, correlation between cracking and ground motions, and determination of threshold ground motions for weld cracking. Findings from the project were published in the 2006 Soil Stress-Strain Behavior, Measurement, Modeling and Analysis Proceedings in Rome, Italy.

Foundation damage due to earthquake

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