A three-phase research project is currently in progress to investigate the seismic performance of precast segmental concrete bridges. This paper presents experimental and analytical results of the first phase, which focused on segment-to-segment joints subjected to high flexural moments and low shears. Four large-scale units were tested under fully reversed cyclic displacements. The major test variable was the ratio of internal to external posttensioning of the superstructure. This paper also presents results of nonlinear finite element modeling of the test units. All test units could undergo significant seismic displacements and joint openings before failure. It was found that the use of external tendons improves ductility and displacement capacity and minimizes permanent displacements and permanent openings of segment-to-segment joints. It was also found that internally bonded and external (unbonded) tendons should not be combined in high seismic zones.
