Development of Prefabricated Bridge Railings

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Final Report

Objective
Many organizations are promoting and utilizing Accelerated Bridge Construction (ABC) practices to reduce traffic impacts and to reduce societal costs. One of the most common means to achieve ABC is to utilize prefabricated elements which are brought together, on-site, to construct the in-place bridge. The purpose of this research is to begin the process of developing crash-tested prefabricated bridge railings that have durable anchorage details. The need for this work has been previously identified by the AASHTO SCOBS Technical Committee for Construction.

Scope
The following tasks will be performed to achieve the project goals.

  • Task 1 – Conduct a national literature search to review all bridge railing (cast-in-place and prefabricated railings) designs and details including anchorage systems that have been crash tested for use on the national highway system by state DOTs and private agencies. Survey state DOTs to determine their needs related to prefabricated bridge railing. Iformation from research projects through the NCHRP, SHRP2, FHWA, and other national, state, and pooled-fund sponsored research will be reviewed as part of this task. Railing shapes that meet the current MASH requirements will be considered in this task and in subsequent tasks. As part of this search, consideration will also be given to the different types of elements used in prefabricated bridges. As part of the preparation of this proposal a brief search and review has already been initiated and a brief summary is presented in section G.
  • Task 2 – Based upon the results of the literature search, the research team will develop conceptual prefabricated railings with associated anchorage systems and details. Although the ultimate goal is to develop a system that can be adopted for multiple railing shapes, only one shape will be utilized in the experimental program to be conducted in Task 3 (allowing for a greater breadth of connection system to be considered without adding additional barrier rail geometry factors). At a minimum, the concepts will consist of details for connecting the rails to the deck and for connecting adjacent rails. It is anticipated that a minimum of three different rail-to-deck and three different rail-to-rail systems will be conceptualized.
  • Task 3 – By combining the various connection systems together, a total of nine combinations can be realized. These nine combinations will be narrowed to the five most promising. These systems will then be tested in the laboratory with a pendulum-type testing apparatus. The systems will be evaluated based upon how they impact their individual strengths and how they impacted the performance of the deck overhangs used to support the railing.
  • Task 4 – A final report will be developed that documents the entire project with a special emphasis on the results of Task 3. More importantly, recommendations for rails on which full-scale crash testing should be conducted will be made. If appropriate, the research team will make recommendations for potential modifications to the details.

Research Team:
Principal Investigators: Dr. Terry Wipf and Dr. Sri Sritharan
Research Assistant: Ashley Ecklund

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