This project summarizes the results of undrained cyclic direct simple shear (DSS) tests performed on specimens of Ottawa F50 and F65 sand. Experiments were conducted using the GEOTAC Direct Simple Shear testing system available in the Soil Interactions Laboratory at the University of California, Davis. Data are summarized as liquefaction triggering curves (Cyclic Stress Ratio versus Number of Cycles) and as stress strain loops, stress paths, vertical stress versus shear strain, and vertical compliance versus shear strain.The data available is the raw data (without any post-processing or filtering) for all the experiments illustrated in the report.