This paper is the second of a two-part series summarizing precast concrete bridge substructure systems and details for seismic regions. Uncertainties associated with seismic behavior and the lack of design specifications have limited full implementation of precast bent cap systems in seismic regions. NCHRP Project 12-74, Development of Precast Bent Cap Systems for Seismic Regions, has been funded to develop design and construction specifications to promote the widespread use of precast bent caps in all seismic regions of the United States. This paper summarizes NCHRP 12- 74, including: 1) background, introducing integral and non-integral systems as well as emulative and hybrid connections; 2) industry survey of the state-of-the-practice for precast bent cap systems; 3) overview of emulative and hybrid connection details; and 4) status of on-going experimental and analytical efforts. Design and construction specifications developed through Project 12-74 are expected to enable bridge engineers to confidently design precast bent cap systems for all levels of seismicity.
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