SEISMIC DESIGN CHANGES IMPLIED BY REVISED SEISMIC RISK MAP

SINCE 1925 FEDERAL AUTHORITY TO CONDUCT EARTHQUAKE INVESTIGATIONS AND REPORTS HAS RESIDED INTHE U. S. COAST AND GEODETIC SURVEY, NOW KNOWN AS THE NATIONAL OCEAN SURVEY. IN 1947 THAT AGENCY PUBLISHED ITS FIRST ATTEMPT AT A SEISMIC PROBABILITY MAP, DELINEATING THE ENTIRE COUNTRY BY ZONES OF DAMAGE RISK. THIS MAP WAS REVISED IN 1952 AND AGAIN IN 1970. IN THE MEANTIME, THE PACIFIC COAST BUILDING OFFICIALS CONFERENCE, NOW CALLED THE INTERNATIONAL CONFERENCE OF BUILDING OFFICIALS, BEGAN TO EMPLOY THE MAP TO ESTABLISH ITS "UNIFORM BUILDING CODE." IN THE LATE 1950'S THIS ORGANIZATION BEGAN ITS PRACTICE OF ISSUING CODE REVISIONS EVERY THREE YEARS. ONE OF THE EFFECTS OF THE 1970 SEISMIC PROBABILITY MAP REVISION WAS TO UPGRADE PARTS OF UTAH, IDAHO, AND MONTANA FROM MODERATE RISK TO MAJOR RISK. THIS CHANGE IS CONSIDERED FROM THE STANDPOINT OF THE REQUIREMENTS OF THE UNIFORM BUILDING CODE. SEVEN ESPECIALLY VULNERABLE TYPES OF CONSTRUCTION ARE LISTED, ALONG WITH 22 FACTORS THAT MUST BE CONSIDERED IN STRUCTURAL DESIGN IN AREAS OF MAJOR EARTHQUAKE RISK.

Media Info

  • Serial:
    • Issue Number: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00230071
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 17 1972 12:00AM