In New Zealand over 60% of State Highway bridges were designed and built during eras with low seismic provisions and most of these bridges are supported by pile foundations. An improved understanding of the in-service performance of these bridge foundations is a key aspect of seismic resilience, however there is limited data on the performance of these foundations in the field. A unique opportunity to study bridge foundations from this period has been presented during the replacement and demolition of the Whirokino Trestle in Foxton. A field testing programme involving a series of static cyclic and monotonic pushover tests has been developed in order to characterize the behaviour of isolated pile foundations that are embedded in loose to medium dense sands. Five different loading protocols were defined and applied across ten isolated bridge piles. To better understand the ability of modelling techniques to capture the observed field behaviour, computational models of these piles were developed using OpenSeesPy. The observations and results from this research will be used to improve the assessment approach for existing bridge foundations and seismic design standards.