Abstract:
This research investigated the in-situ behaviour of reinforced concrete bridges and components
that are typical to New Zealand bridge stock based on experimental and numerical modelling
approaches. The behaviour at the component level was characterized by performing field testing
on two separate reinforced concrete bridge pile foundations and developing numerical models
accounting for nonlinear soil response, soil gapping, and material nonlinearities. Piles with
smooth reinforcement tested under cyclic loading were able to maintain their strength through
large displacements and multiple cycles. Numerical models showed bond-slip implementation
improved the representation of the global cyclic response of the pile-soil system with smooth
reinforcement, but this difference was not as significant as that seen for other structural elements
with smooth reinforcement. Monotonic loading and dynamic snapback testing of piles with
deformed reinforcement demonstrated how loading history and magnitude influenced system
damping and the varying contributions of different energy dissipation mechanisms. Bridge pier
response was characterized by analysing the response of an in-service bridge pier during
multiple earthquakes and developing their numerical models. The fundamental period of the
bridge pier varied significantly during these earthquakes due to system softening. A sensitivity
analysis on the effect of input ground motions highlighted the importance of accounting for
ground motion spatial variability and the difficulties involved in post-earthquake back-analysis.
There was a significant system softening observed prior to the onset of any structural damage
across all these examples, with numerical models demonstrating the importance of including
soil and gapping. Sensitivity analyses showed the influence of concrete strength and the top soil
layers on the static response of pile-soil systems and the dynamic response of bridge pier. This
research improved the understanding of in-situ behavior of reinforced concrete bridges through
the field test and monitored data, and suggested modelling approaches that can effectively
capture the response of bridge pile foundations and piers similar to the ones studied under
different loading conditions.