Shake Table Studies of Energy-Dissipating Segmental Bridge Columns

Five one-third scale segmental bridge columns with plastic hinges incorporating different advanced materials were designed and tested on one of the shake tables at the University of Nevada, Reno. The columns were subjected to the Sylmar Earthquake record with increasing amplitudes until failure. All the models were cantilever with longitudinal steel dowels connecting the base segment to the footing. Unbonded posttensioning was used to connect the segments and to minimize the residual displacements. Energy dissipation took place mostly through the yielding of the longitudinal bars in the base segment. Conventional RC was used in the plastic hinge of a reference column. In one of the models, a built in elastomeric pad integrated with the footing and a concrete segment constituted the plastic hinge. The other two columns incorporated engineered cementitious composite (ECC) and unidirectional carbon fiber reinforced polymer (CFRP) fabrics at the lower two segments. The effectiveness of repair with CFRP wraps was also studied by repairing and retesting the reference column. The test results showed that the proposed models with advanced materials are suitable for accelerated bridge construction in high seismic zones because of their fast construction, high energy dissipation, minimal damage in the plastic hinge zone, and minimal residual displacement.