This report contains the findings of research performed to develop recommended load and resistance factor design (LRFD) procedures for achieving longer spans using precast prestressed concrete bridge girders. Standard details and examples illustrating the design of three typical bridges were also developed. The material in this report will be of immediate interest to bridge designers. Each year, 200 to 300 bridges are built with spans exceeding 160 feet. Generally, these spans are not designed with precast prestressed concrete girders because of limited experience and limited information. In addition, the size and weight of many precast sections precludes land transportation. Limited choices lead to decreased competition between bridge types and materials, which results in higher costs to owners. Solutions to increase the span range of precast prestressed concrete girders used in the United States and abroad include splicing segments for longer simple or continuous spans, connecting simple spans for continuity, and assembling haunched pier segments in the field. However, this experience and the technology for applying these solutions are fragmented and job-specific. The objective of this research was to develop recommended LRFD procedures, standard details, and design examples for achieving longer spans using precast prestressed concrete bridge girders. The report fully documents the research leading to the conclusion that spliced-girders are the design option with the greatest potential for extending span length. Detailed design examples for one-, two-, and three-span spliced girder bridges are included as appendixes. (Author/publisher) This report may be accessed by Internet users at http://gulliver.trb.org/publications/nchrp/nchrp_rpt_517.pdf
Samenvatting