Effect of Displacement Histories on Lightly Confined Reinforced Concrete Bridge Columns

Abstract

This research involved the study of seismic behavior of older reinforced concrete bridge columns. The column reinforcement was modeled on columns used in the state of Washington prior to the mid 1970s. These columns were characterized by small quantities of hoop steel, poor confinement, and non-ductile behavior. The goal of the research was to determine the effects of cyclic load history on the resistance of such columns to lateral loading. Four specimens have been tested in a previous phase of the work, but the displacement histories used did not differ enough to determine the relative importance of two possible characterizing parameters: maximum displacement and cumulative plastic displacement. The current phase of the work involves constructing and testing two additional columns, subjected to very different load histories, to clarify the role of each parameter. Further analysis will be needed to determine the influence of each parameter on the column resistance.