CHARACTERISTICS OF VERTICAL STRONG GROUND MOTIONS FOR APPLICATIONS TO ENGINEERING DESIGN

In the near-source region (D </= 10 to 15 km) of large earthquakes, the characteristics of strong ground motions change in stable and predictable ways: durations become significantly shorter, velocity and displacement time histories can increase significantly in amplitude and become more pulse like (depending upon rupture directivity effects), long period fault normal motions show a stable increase over fault parallel motions, and short period vertical motions can exceed horizontal motions at both rock and soil sites. For vertical motions, these recent observations suggest that the commonly adopted vertical-to-horizontal response spectral ratio of 2/3 may be significantly exceeded at short periods in the near-source distance range. With the increase in near-source strong motion recordings at both rock and soil sites to aid in constraining empirical attenuation relationships as well as providing direct estimation of statistical spectral shapes for vertical and horizontal components, it is possible to examine the dependencies of the vertical-to-horizontal response spectral ratio on magnitude, distance, and site conditions. As an additional and important aspect, similarities and differences in the characteristics of the time histories between vertical and horizontal motions can be examined. For design motions, the relative phasing between horizontal and vertical motions can be an important issue, leading to different structural analyses and design decisions depending on whether or not significant energy is expected to occur both vertically and horizontally at nearly the same time.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/10883800
• Corporate Authors:

  National Center for Earthquake Engineering Research

  State University of New York, Buffalo, Red Jacket Quadrangle, Box 610025
  Buffalo, NY  United States  14261-0025
• Authors:
  • Silva, W N
• Conference:
  • FHWA/NCEER Workshop on the National Representation of Seismic Ground Motion for New and Existing Highway Facilities
  • Location: Burlingame, California
  • Date: 1997-5-29 to 1997-5-30
• Publication Date: 1997-9-22

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 205-252
• Serial:
  • National Center for Earthquake Engineering Research
  • Publisher: National Center for Earthquake Engineering Research
  • ISSN: 1088-3800

Subject/Index Terms

• TRT Terms: Distance; Earthquake resistant design; Energy; Magnitude; Ratios; Seismicity; Soils; Structural design; Time periods
• Uncontrolled Terms: Response spectra; Soil conditions; Time history
• Old TRIS Terms: Horizontal orientation; Vertical orientation
• Subject Areas: Bridges and other structures; Design; Energy; Geotechnology; Highways; I24: Design of Bridges and Retaining Walls; I42: Soil Mechanics;

Filing Info

• Accession Number: 00751051
• Record Type: Publication
• Report/Paper Numbers: Technical Report, NCEER-97-0010
• Files: TRIS
• Created Date: Jul 22 1998 12:00AM