AbstractThe application of prestress is a very effective way to prevent the cracking of the concrete slab in the negative-moment region of continuous composite girders, and using a prefabricated prestressed-concrete slab in this region is an easier option than posttensioning. To elucidate the structural response of a continuous composite box girder with a prefabricated prestressed-concrete slab, two large, 18-m-long specimens were fabricated and tested under short-term loading, and the results are reported in this paper. One, a control specimen, was a conventional composite girder with its concrete slab cast in situ, whereas the other was a composite box girder with a prefabricated prestressed-concrete slab in the negative-moment region. The relative slip between the steel girder and the concrete slab; the load-deflection response; the distribution of strain in the steel girder, reinforcement, and concrete slab; as well as the crack widths in the concrete slab were measured during the tests. The paper sho...