Intermediate Diaphragm and Temporary Bracing Practice for Precast Concrete Girder Bridges

Intermediate diaphragms are used in precast concrete girder bridges for three primary reasons: (1) to prevent torsional girder rotations during girder erection and deck placement operations, (2) to increase vertical load distribution between girders, and (3) to transfer and spread horizontal impact loads from an overheight vehicle to adjacent girders. Significant variation currently exists in intermediate diaphragm specifications between states. The importance of bracing girders after erection and during construction is widely accepted as essential. Although it is clear that intermediate diaphragms have some effect on bridge performance, the benefit is considered by some to be negligible. Increasing numbers of states have adopted permanent steel or temporary intermediate diaphragm alternatives in place of traditional cast-in-place concrete. Wide variations are found between states regarding the configuration, spacing, and transverse alignment of diaphragms. This article presents a detailed survey of United States (US) design practices by individual state bridge design agencies, including all 50 states, and details the usage of steel intermediate diaphragms and temporary bracing methods across the US.


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  • Accession Number: 01598326
  • Record Type: Publication
  • Files: TRIS, ASCE
  • Created Date: Apr 15 2016 8:54AM