UC San Diego

Reinforced concrete (RC) bridges constitute a significant part of the infrastructure inventory around the world and specifically in California. The understanding of the different failure mechanisms of their components and the development of accurate analysis tools for their simulation are important to assess their nonlinear behavior during earthquake events.

This dissertation presents two studies investigating the nonlinear behavior of RC bridge components and assemblies using large-scale experimental testing and nonlinear finite-element (FE) modeling. For these studies, suitable constitutive models for concrete and the bond-slip behavior of reinforcing bars embedded in concrete have been identified and calibrated, and aconstitutive model that accounts for the low-cycle fatigue behavior of steel has been developed and implemented in a finite element analysis program.

In the first study the impact of the lineal spacing of longitudinal bars on the performance of circular RC piles under lateral loading was investigated. Two full-scale RC pile specimens were tested under lateral loading.

The second study was aimed to determine the minimum development length required for headed bars in slab-column joints of RC bridges, so that the thickness of the slab, and subsequently its cost, would be reduced. Three full-scale RC slab-column specimens, with embedment lengths of the headed bars smaller than the minimum allowed in the current design provisions, were tested under lateral loading.

In both studies, nonlinear FE models were developed to evaluate the performance of the test specimens, and to conduct numerical parametric investigations varying additional design parameters. The capability of the constitutive models in simulating the nonlinear behavior of RC members is established through the FE analyses of the test specimens. Finally, based on the experimental and numerical findings of these studies, recommendations and possible changes in the design of RC components and slab-column joints in bridges are provided.