Seismic performance of historic bridge piles

Lead Investigator:
Dr. Lucas Samuel Hogan,
Civil and Environmental Engineering, University of Auckland

Research Team:
Dr. Lucas Samuel Hogan, Dr. Max Stephens,
Prof. Liam Wotherspoon, Dr. Pavan Chigullapally
Civil and Environmental Engineering, University of Auckland

Project number: 1979

 

Abstract

Approximately half of the New Zealand State Highway bridges were constructed prior to the development of any specific design for seismic loads. Recent earthquakes have shown that generally these bridges sustain only minor damage when subjected to earthquakes, however, the observable portions of these bridges are all above ground. There is still concern about the ability of the pile foundations that support these bridges to maintain stability of the bridge following an earthquake. To investigate the behaviour of these foundations, this project tested six concrete piles from the Whirokino Trestle Bridge. The Whirokino Trestle Bridge was constructed in 1939 and its pile foundations are identical to a significant number of the bridges on the State Highway system. As the Whirokino Trestle Bridge was being replaced by a new adjacent bridge, six piles were isolated and tested as part of the bridge demolition. The piles were subjected to lateral loads to simulate earthquake demands. All six piles performed similarly and were able to sustain their load capacity even when at significant lateral deformations. This testing shows that these pile foundations on the older bridges on the State Highway network are likely to perform well during an earthquake and help enable a resilient transportation network.

 

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