Liquefaction analysis for foundations of motorway bridges in Hawke’s Bay

The results of in-situ Standard Penetration Testing and Cone Penetration Testing were used to assess the soil liquefaction potential at the bridge sites for the proposed extension of the Napier-Hastings motorway. Published correlations between the in-situ tests and field performance of sites subjected to earthquake shaking were used to identify liquefiable soil layers and to estimate the intensity of ground shaking that is likely to cause liquefaction.

A seismic hazard study was compared with the results of the liquefaction analysis to produce a quantitative estimate of the risk of soil liquefaction. This data can be used in an economic assessment of the various options to mitigate the effects of soil liquefaction on the performance of bridge structures in earthquakes.