INCREASING THE SEISMIC RESISTANCE OF EXISTING HIGHWAY BRIDGES

Prior to the 1971 San Fernando Earthquake, bridges in California experienced only minor seismic related damage. The San Fernando event demonstrated that structures designed by AASHTO Specifications in use at that time are vulnerable to seismic shaking. Failure of these bridges during an earthquake could be hazardous to highway users and block vital transportation life-lines. The State of California initiated a bridge retrofitting program in 1971 in order to increase the seismic resistance of bridges built before that time. The most prevalent deficiency of pre-1971 bridges is a lack of longitudinal restraint of girders at hinges and end supports. California has developed devices which will have been used to retrofit more than 649 bridges at a cost of $22 million by 1980. An evaluation of all state owned bridges is currently being made in order to complete the program. Many of the bridge columns which were designed according to specifications prior to 1971 were proven to be seismically deficient because they had too few ties to adequately confine the concrete. This paper and presentation will cover a brief background, philosophy, magnitude of the problem, design criteria, details and costs. /Author/

Media Info

  • Media Type: Print
  • Features: Figures;
  • Pagination: pp 31-36
  • Monograph Title: Bridge Engineering. Volume 2
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00183777
  • Record Type: Publication
  • ISBN: 0309026970
  • Files: TRIS, TRB
  • Created Date: Dec 12 1978 12:00AM