LIQUEFACTION RESISTANCE OF SOILS : SUMMARY REPORT FROM THE 1996 NCEER AND 1998 NCEER / NSF WORKSHOPS ON EVALUATION OF LIQUEFACTION RESISTANCE OF SOILSa

Following disastrous earthquakes in Alaska and in Niigata, Japan in 1964, Professors H. B. Seed and I. M. Idriss developed and published a methodology termed the ‘‘simplified procedure’’ for evaluating liquefaction resistance of soils. This procedure has become a standard of practice throughout North America and much of the world. The methodology which is largely empirical, has evolved over years, primarily through summary papers by H. B. Seed and his colleagues. No general review or update of the procedure has occurred, however, since 1985, the time of the last major paper by Professor Seed and a report from a National Research Council workshop on liquefaction of soils. In 1996 a workshop sponsored by the National Center for Earthquake Engineering Research (NCEER) was convened by Professors T. L. Youd and I. M. Idriss with 20 experts to review developments over the previous 10 years. The purpose was to gain consensus on updates and augmentations to the simplified procedure. The following topics were reviewed and recommendations developed: (1) criteria based on standard penetration tests; (2) criteria based on cone penetration tests; (3) criteria based on shear-wave velocity measurements; (4) use of the Becker penetration test for gravelly soil; (4) magnitude scaling factors; (5) correction factors for overburden pressures and sloping ground; and (6) input values for earthquake magnitude and peak acceleration. Probabilistic and seismic energy analyses were reviewed but no recommendations were formulated. JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING / OCTOBER 2001 / 817 This Summary Report, originally published in April 2001, is being ublished so that the contribution of all workshop participants as aurs can be officially recognized. The original version listed only two thors, plus a list of 19 workshop participants. This was incorrect; all individuals should have been identified as authors. ASCE deeply reets the error. Prof., Brigham Young Univ., Provo, UT 84602. Prof., Univ. of California at Davis, Davis, CA 95616. Prof., ; formerly, . PhD, GEI Consultants, Inc., Winchester, MA 01890. PhD, Engrg. Consultant, Waban, MA 02468-1103. Prof., Rensselaer Polytechnic Inst., Troy, NY 12180. Prof., Univ. of British Columbia, Vancouver, BC, Canada. California Dept. of Water Resour., Sacramento, CA 94236-0001. U.S. Army Engr. Wtrwy. Experiment Station, Vicksburg, MS 39180. Prof.,  Experiment Station, Vicksburg, MS 39180.  Boston, MA 02116. PhD, U.S. Army Engr. Wtrwy. Experiment Station, Vicksburg, MS 39180. Prof., Univ. of Southern California, Los Angeles, CA 90089-2531. Prof., Virginia Polytechnic Inst., Blacksburg, VA 24061. PhD, Prin., Geomatrix Consultants, Santa Ana, CA 94612. Geomatrix Consultants, Oakland, CA 94612. Prof.,  Austin, TX 78712. Note.  2002. To extend the closing date one month, a written request must be filed with the ASCE Manager of Journals. The manuscript for this paper was submitted for review and possible publication on January 18, 2000; revised November 14, 2000. This paper is part of the Journal of Geotechnical and Geoenvironmental Engineering, Vol. 127, No. 10, October, 2001. qASCE, ISSN 10900241/01/0010-0817–0833/$8.00 1 $.50 per page.  Oct 2010 to 143.89.22.104. Redistribution subject to ASCE license or copyright.