HyFRC Bridge Piers with Different Detailing at Pier–Foundation Interface

This article presents the results of an experimental investigation to evaluate the effectiveness of the use of hybrid fiber-reinforced concrete (HyFRC) along with some additional detailing features at the pier-foundation interface for improved seismic performance. Two different fibers, namely, steel and polypropylene, of appropriate volume fraction were mixed with concrete to obtain HyFRC. Three different detailing strategies were considered at the region of the pier-foundation interface. Whereas normal reinforcement details were followed for Specimen 1, additional reinforcing bars (dowels) were used in the interface region for Specimen 2, and corrugated sheet duct was used below the interface region in Specimen 3. In this study, detailed strain measurements at predefined locations were correlated with the enhancement of displacement ductility and energy dissipation in different test specimens. Hybrid simulation was used with input excitations of different intensity levels to evaluate the seismic performance of HyFRC bridge piers. The simulation was conducted in a manner such that the specimens experienced different levels of damage. Further, after the completion of the hybrid test, cyclic tests were conducted to evaluate the ultimate capacities of these specimens. The piers with dowel reinforcement at the interface region were found to be better than the other two types for the considered seismic performance parameters, such as delayed growth of strain, improved damage tolerance, enhanced energy-dissipation capacity, higher stiffness at any drift ratio, and improved load-carrying capacity. Further, specimens with HyFRC outperformed all the corresponding specimens made of conventional concrete in terms of all of the aforementioned parameters characterizing enhanced seismic performance. (c) 2018 American Society of Civil Engineers.