UC San Diego

Bridge structures are often supported on cast-in-drilled- hole (CIDH) reinforced concrete (RC) piles. Type II CIDH piles, used by Caltrans, have larger diameters than the columns they support. Current Caltrans specifications for the embedment length of column longitudinal reinforcement in a Type II pile are conservative. Thus far, only reduced -scale experiments were conducted on the connection between a column and a Type II pile. In order to understand the system lateral behavior and to provide an improved recommendation for the connection design of such systems, two large-scale specimens were tested at University of California, San Diego. This thesis focuses on the study of the lateral behaviors of RC columns supported on Type II piles. The study presented in this thesis includes three main sections. First, models of prototype column-Type II pile systems were developed with a computer program to examine the influence of the soil- structure interaction on the lateral behavior of these systems. Configurations of test specimens that could adequately simulate the behavior of such a system without soils were determined based on the analysis. Second, test data on total deflection, flexural and shear deformations, and rotation at the column base were collected to assess the column ductility capacity and the extent of the plastic hinge formation at column base. Third, the experimental results are compared to the numerical results obtained with RC column section analysis models and beam- column elements. Additionally, empirical formulas proposed by others to calculate column ductility and equivalent plastic hinge lengths are evaluated using the experimental results