This article discusses the general design considerations, design sequence, conceptual and detailed design requirements, and analysis procedures of segmental prestressed concrete box girder bridges. It is noted that when constructing a large number of prestressed concrete bridges, precasting has a number of advantages over cast-in-place construction. A box girder is considered a better structural shape for long spans than an I-section girder. The box girder is very compact. It is superior to the I-section girder for long spans in that there is no lateral buckling problem so the compressive capacity of the bottom flange is fully utilized, and the torsional rigidity brings about a more even distribution of flexural stresses across the section under a variety of live loads. When box girder bridges are precast, the casting is generally segmental. The most widely used methods may be categorized as construction on flashwork and cantilever construction. Assembly of the segments, the stage-by-stage erection and prestressing of precast segments, the procedures required for closure, and the adjustment of the distribution of stress is described. The most important reason for the slow adoption of segmental bridge construction is the general division of the engineering and construction responsibilities in the concrete industry. There have been rapid developments in the state of the art in precast segmental box girder technology such as the evolution of the jointing and erection process, the multiple key designs, and the use of wider sections resting on single pies. The article concludes by describing the design sequence for a segmental precast concrete box girder bridge. The main elements of the design sequency are as follows: Conceptual design, preliminary design; detailed design; verification analysis; field support analyses; and change order evaluation.

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  • Accession Number: 00173896
  • Record Type: Publication
  • Files: TRIS, USDOT
  • Created Date: May 31 1978 12:00AM