Intermediate Diaphragm and Temporary Bracing Practice for Precast Concrete Girder Bridges
Publication: Practice Periodical on Structural Design and Construction
Volume 21, Issue 2
Abstract
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 U.S. 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 United States.
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Acknowledgments
The authors acknowledge the Auburn University Highway Research Center for funding this research, although the findings and conclusions are those of the authors. They also thank the numerous engineers from many departments of transportation who took the time to respond to the survey and, in some cases, follow-up questions.
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Information & Authors
Information
Published In
Practice Periodical on Structural Design and Construction
Volume 21 • Issue 2 • May 2016
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Mar 19, 2015
Accepted: Aug 21, 2015
Published online: Dec 30, 2015
Published in print: May 1, 2016
Discussion open until: May 30, 2016
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