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The National Academies

NCHRP Synthesis 20-05/Topic 53-13 [New]

Practices for Steel Bridge Fabrication and Erection Tolerances
[ NCHRP 20-05 (Synthesis of Information Related to Highway Practices) ]

  Project Data
Funds: $45,000
Authorization to Begin Work: 4/30/2021 -- estimated
Staff Responsibility: Jo Allen Gause
Fiscal Year: 2022

Preliminary Scope

Research on tolerances for prefabricated elements used in accelerated bridge construction was completed under NCHRP Project 12-98: “Recommended Guidelines for Prefabricated Bridge Elements and Systems Tolerances and Dynamic Effects of Bridge Moves”. The majority of the work covered precast concrete elements for bridges such as decks, substructure elements, and wall elements. Typical steel bridge elements were not covered because the majority of prefabri-cated elements used to date have been precast concrete. NCHRP Project 12-98 also did not in-clude traditional prefabricated elements such as steel and concrete girders, since there are already specifications for tolerances for these elements NCHRP Project 12-98 research found that large tolerances cause problems with member connections. In precast concrete, large element tolerances require large joints in order to accommodate the tolerances. The AASHTO/National Steel Bridge Alliance Steel Bridge Collaboration group has noted that the use of oversize holes can lead to loss of overall structure geometry and fit-up problems during erection. Tolerances in steel fabrication require special processes such as shop blocking beams to drill field splices to ensure proper fit-up. Some state departments of transportation (DOTs) require full shop erection and fit-up to resolve tolerance issues in connections.

The purpose of this proposed synthesis is to document current state DOT practices of tolerance management for steel bridge elements.

Information to be gathered includes (but is not limited to):
• Current fabrication tolerances;
• Usefulness to state DOTs of current steel bridge fabrication tolerances (e.g., excessive, easily achievable, too small);
• Accuracy of steel fabrication methods (e.g., plate cutting method, drilled holes, camber management);
• Impact of tolerances on connection fabrication;
• Quality assurance issues; and
• Ways that stakeholders are improving tolerance management.

Information will be gathered through a literature review, a survey of state DOTs, and follow-up interviews with selected agencies for the development of case examples. Information gaps and suggestions for research to address those gaps will be identified.

Information Sources (Partial):
• (NCHRP Web-Only Document 243 “Recommended Guidelines for Prefabricated Bridge Elements and Systems Tolerances and Dynamic Effects of Bridge Moves” (
http://www.trb.org/Main/Blurbs/177187.aspx

TRB Staff
Jo Allen Gause
Phone: 202-334-3826
Email: jagause@nas.edu


Meeting Dates
First Panel: October 12, 2021, virtual
Teleconference with Consultant: TBD
Second Panel: TBD

Topic Panel
Joseph Bracken, Pennsylvania Department of Transportation

Lian Duan, California Department of Transportation

Jamie Farris, Texas Department of Transportation

Christina Freeman, Florida Department of Transportation

Rich Karras, Minnesota Department of Transportation

Christine Mizioch, AI Engineers

Sougata Roy, Rutgers University

Dayi Wang, Federal Highway Administration

Nelson Gibson, Transportation Research Board


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