UC Berkeley

Reinforced concrete arch bridges face unique challenges due to high axial forces that can compromise their ductile flexure response under seismic conditions. Currently, arch bridges in California do not have any special design requirements despite their unique geometry. This dissertation, through experimental testing and numerical model analysis, evaluates the impact of axial loads on displacement capacity, compares it with the current Caltrans design requirements, and aims to recommend transverse reinforcement configurations and detailing for enhanced seismic performance.This dissertation is divided into three sections. The first section is an extensive experimental program consisting of nine 1/3 scale reinforced concrete specimens that replicate the critical region of a bridge arch rib. The represented bridges are arch bridges designed and constructed by the California Department of Transportation. The specimens were tested under moderate and high axial loads with increasing reversed cyclic displacement amplitudes. Observations of the physical tests are presented. Experimental results demonstrate that an increase in the volume of transverse reinforcement proportionally increases the deformation capacity; closer transverse reinforcement spacing is crucial for ensuring ductile behavior; and high axial force reduces the displacement ductility capacity of the member and produces severe damage in the core at large drifts. The second section describes how the physical test data was used to calibrate fiber models of an arch rib segment to perform a parametric study to investigate key variables such as section geometry, transverse reinforcement configuration, and axial force ratio. Results show consistency with the experimental data. Expressions to predict the ultimate drift capacity for circular-confined sections and square-confined sections are presented. The third section introduces a methodology to investigate the dynamic behavior of reinforced concrete arch bridges. Results of the proposed methodology include the development of fragility functions and engineering demand parameters hazard curves using hazard-consistent ground motions.