A research project is currently in progress to investigate the seismic performance of segment-to segment joints of precast segmental concrete bridges. This paper presents the experimental and analytical results of two large-scale tests which model the superstructure response of a prototype precast segmental bridge, post-tensioned with internally bonded tendons, under fully reversed vertical cyclic displacements. The joints of the first test unit were epoxy bonded with no reinforcement crossing the joints other than the prestressing steel. The second test unit had a reinforced cast-in-place deck closure with the remaining portions of the joints connected by epoxy. Both test units were subjected to fully reversed cyclic loads simulating earthquake vertical motions. It was found that both test units could undergo significant seismic displacements, but their failure modes were considerably different. The paper also presents results from nonlinear finite element modeling of the simulated seismic response of the test units. The results showed that segment-to-segment joints could undergo significant repeated opening and closure before failure.
