A recent design review of the likely seismic resistance of five New Zealand bridges has been conducted in the light of the experiences gained from the 1989 San Francisco earthquake. The review was to identify potential weaknesses in early structures, making recommendations on methods of rectification. Initially, only drawings were examined; if problem areas were identified, more detailed investigations and testing were recommended. Analysis of bridge failures in San Francisco showed that an amplification of ground movement and the lack of pier continuity caused the collapse of the upper deck of a freeway viaduct. New Zealand motorways are mainly built to 1970 standards when more stringent design codes were in force compared to those used for the damaged San Francisco structures. Base isolation by the use of energy absorbing dampers greatly reduces the transverse forces on a structure by ground shaking. Often base-isolating bearings have been fitted when maintenance work has been required on decks and surfacings. Details are given of elastomeric bearings incorporating energy dissipators at abutments which have been fitted to existing bridges with lightly reinforced open frame piers. (TRRL)

  • Availability:
  • Corporate Authors:

    Technical Publications Limited

    C.P.O. 3047
    Wellington,   New Zealand 
  • Publication Date: 1990-8-1


  • English

Media Info

  • Pagination: p. 11-14
  • Serial:
    • Volume: 45
    • Issue Number: 7
    • Publisher: Institution of Professional Engineers New Zealand
    • ISSN: 0028-808X

Subject/Index Terms

Filing Info

  • Accession Number: 00617442
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Nov 30 1991 12:00AM