This action is in response to the NSF Announcement of Program Initiative No. 91-55: "The 'Class A' Prediction Phase of the VELACS (Verification of Liquefaction Analysis by Centrifuge Studies) Project". VELACS is an NSF-funded coordinated study of the effect of simulated earthquake loading on a variety of model geotechnical structures, such as earth dams and embankments, in order to investigate the mechanisms of liquefaction-induced failure, and to acquire data for the verification of the various analysis procedures for the liquefaction problem. The experiments are run on the geotechnical centrifuges at the California Institute of Technology, University of California at Davis, University of Colorado at Boulder, Rensselaer Polytechnic Institute, Princeton University and Cambridge University, England. The "Class A" prediction phase of the VELACS project involves making analytical/computational predictions before the experiments are performed; then the experiments are run, and the measured results compared with the predictions. "Class A" predictions are analogous to "single-blind" studies in medical research. A workshop, scheduled to be held at the University of California, Davis, in September, 1993, will compare the predictions to the experimental results, and conclusions will be drawn regarding the effectiveness of the analytical/computational methods used. Sixteen research groups from around the world (nine in the U.S.; one in Canada; three in Japan; and three in the U.K.) are participating in this prediction exercise. This study at Princeton University is examining the effectiveness of the computer codes DYNA1D and DYNAFLOW for liquefaction analysis.
