EARTHQUAKE RESISTANCE OF EARTH AND ROCK-FILL DAMS; REPORT 5, PERMANENT DISPLACEMENT OF EARTH EMBANKMENTS BY NEWMARK SLIDING BLOCK ANALYSIS

In 1965, Newmark described methods for computing permanent displacements of embankments subjected to earthquake loading, and provided a chart for estimating the upper bounds of permanent displacements on the basis of a sliding black model and four earthquake records. Since that time, many additional strong-motion records have been obtained in the western United States, and it was decided to extend the data base for Newmark's chart by making use of these records. For this purpose, a computer program was written to integrate the digitized accelerograms and compute the permanent displacements from the velocity-time history and the resistance coefficients. All records were scaled to 0.5 g peak acceleration and 30-in./sec peak velocity, and the resulting scaled permanent displacements are called standardized maximum displacements. A total of 169 horizontal and 10 vertical corrected accelerograms were processed in addition to several synthetic records. The greatest standardized maximum displacements, computed from records of the magnitude-6.5 San Fernando earthquake of 9 February 1971 on soil sites, were about 1.5 times above Newmark's upper bound, while those for all other earthquakes analyzed were near or below Newmark's upper bound. The maximum values computed from the Jennings et al synthetic record for a magnitude 8+ earthquake were about 1.7 times higher than Newmark's upper bound. Those for the Seed-Idriss synthetic record fell slightly below those for the Jennings et al synthetic records. Ten records from rock sites compared with 47 records from soil sites indicate that permanent displacements on rock sites are about 75 percent of those on soil sites from earthquakes of the same magnitude, peak acceleration, and peak velocity. It was found that standardized maximum displacements were roughly proportional to the duration of shaking, and consequently were positively correlated with earthquake magnitude. /Author/

  • Corporate Authors:

    U.S. Army Waterways Experiment Station

    3909 Halls Ferry Road
    Vicksburg, MS  USA  39180-6199
  • Authors:
    • Franklin, A G
    • CHANG, F K
  • Publication Date: 1977-11

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 59 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00172355
  • Record Type: Publication
  • Report/Paper Numbers: Misc Paper S-71-77
  • Files: TRIS
  • Created Date: Apr 26 1978 12:00AM