Experimental Seismic Response of Hybrid Fiber-Reinforced Concrete Bridge Columns with Novel Longitudinal Reinforcement Detailing

The experimental seismic response of two bridge columns built using highly flowable hybrid fiber-reinforced concrete under unidirectional static cyclic lateral loading is presented. The objective was to design bridge columns for use in regions of high seismic hazard that (1) sustain the seismic demands in a ductile manner; (2) minimize the concrete spalling that conventional RC bridge columns experience; and (3) avoid tension strain localization in the longitudinal steel bars observed in plastic hinge regions of fiber-reinforced concrete columns. The first column was designed to rock at its base. The second column was designed to form a flexural plastic hinge at its base and used stainless steel bars as longitudinal reinforcement. Both specimens experienced limited concrete spalling up to drift ratios of 4.8% and attained drift ratios of 11.3% without losing their vertical load resistance. The response of the specimens is compared with that of conventional RC columns.