BACKGROUND

There are approximately 800 highway movable bridges in service in the United States per the current National Bridge Inventory database, spread across 33 states. Of the total inventory of existing highway movable bridges in service, over 20 percent are classified as in poor condition and more than 300 exceed 70 years of age.

The lifecycle costs of movable bridges are highly influenced by construction quality, which is, in part, a function of the adequacy of the technical specifications by which a project is executed. The American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Movable Highway Bridges, last updated in 1988, contained limited information on construction, primarily related to machinery. This document was replaced by the AASHTO LRFD Movable Highway Bridge Design Specifications in 2000, which does not contain specifications for construction. Since there are no AASHTO documents that address movable bridge construction, movable bridge owners would benefit from a comprehensive national document. Research is needed to develop comprehensive construction requirements for new and existing movable bridges.

OBJECTIVE

The objective of this research is to develop construction requirements for new and existing movable bridges. It shall cover all components of movable bridges including (1) structural, (2) mechanical, and (3) electrical.

Accomplishment of the project objective will require at least the following tasks.

TASKS

PHASE I—Planning

Task 1. Conduct a literature review of state-of-the-practice documents on movable bridge construction requirements/provisions. The review shall include published and unpublished documentation and research conducted through the NCHRP; the Federal Highway Administration; other national, state, local, and pooled-fund sponsored research; industry groups; and international organizations. 

Task 2. Synthesize the results of the literature review to identify gaps, conflicts, and/or omissions between current information published by AASHTO and/or industry standards and information required to produce a complete set of construction requirements for new and existing movable bridges. These gaps, conflicts, and/or omissions should be addressed in the final product or the recommended future research, as budget permits.

Task 3. Propose the research plan to be executed in Phase II to achieve the research objective. At a minimum, the research plan shall include:

• Recommended movable bridge types and components to be covered by the requirements and those that warrant project-specific requirements.
• A list of existing AASHTO specifications and industry standards and/or specifications that can be utilized as reference documents in movable bridge construction requirements. Identify which requirements can be referenced and do not require further development.
• A preliminary outline and table of contents of the draft language for movable bridge construction requirements for consideration by AASHTO (hereafter called AASHTO Deliverable).
• A template for the proposed requirements to maintain consistency across all sections and subsections. The format shall meet the current AASHTO formatting guidelines and it shall include commentary.
• A plan to identify and engage stakeholders (e.g., industry, organizations, movable bridge owners, etc.) to seek input on the state of the practice and the AASHTO Deliverable.

Task 4. Prepare Interim Report No. 1 that documents Tasks 1 through 3 and provides an updated work plan for the remainder of the research. The updated plan must describe the process and rationale for the work proposed for Phases II through IV.

PHASE II—Execution

Task 5. Execute the research plan according to the approved Interim Report No. 1.

Task 6. Develop a complete sample section of the AASHTO Deliverable to be selected by the NCHRP. This section should be publication-ready with an appropriate level of detail. 

Task 7. Prepare Interim Report No. 2 that documents Tasks 5 and 6 and provides an updated work plan for the remainder of the research. The updated work plan must describe the process and rationale for the work proposed for Phase III.

PHASE III—Draft Language Development

Task 8. Develop the remaining sections of the AASHTO Deliverable according to the approved Interim Report No. 2.

Task 9. Prepare Interim Report No. 3 that documents Task 8 and provides an updated work plan for the remainder of the research. The updated work plan must describe the process and rationale for the work proposed for Phase IV.

PHASE IV—Final Products

Task 10.  Revise the AASHTO Deliverable after consideration of the panel’s review comments.

Task 11. Submit the draft final deliverables, including (1) the AASHTO Deliverable, (2) a final report that documents the entire research effort, and (3) a stand-alone technical memorandum titled “Implementation of Research Findings and Products”.

STATUS: Research In Progress