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Research and Development (R&D) Project Sites

Project Information
Project ID:   FHWA-PROJ-11-0063
Project Name:   Development of Lightweight Floor Replacement Systems
Project Status:   Active
Start Date:  September 1, 2011
End Date:  September 30, 2014
Contact Information
Last Name:  Duwadi
First Name:  Sheila R
Telephone:  202-493-3106
E-mail:  sheila.duwadi@dot.gov
Office:   Office of Infrastructure Research and Development
Team:   Hazard Mitigation Team [HRDI-50]
Program:   National Historic Covered Bridge Preservation Program
Project detail
Roadmap/Focus area(s):   Historic Preservation
Project Description:   The floor systems of covered bridges are typically replaced due to deterioration, structural damage, or excessive wear after approximately 30 to 40 years of service. In many cases, the floor system controls a bridge’s capacity, and replacement operations present a unique opportunity to upgrade the entire structural system. Because covered bridges are so unique, there are a wide variety of general replacement systems currently in use. However, these systems have seen very little change after many years of implementation, thus there exists a need to develop new replacement flooring systems that improve both the deck system itself as well as improve the overall structural performance. It is envisioned that this is most effectively completed through the use of lightweight systems. Another aspect of floor systems is the replacement of floor beams. In any truss bridge, floor beams receive a great deal of abuse and wear. This is also true of covered bridges. Their floor beams are often found to be wanting and are replaced; however, the beams may still be adequate in some of these cases. This area needs to be restudied to better define the problem and replacement criteria developed.
Goals:   The objective is to develop lightweight floor systems for use on historic covered bridges.
Product Type:   Draft standard, specifications, or guidelines
Research report
Test Methodology:   In order to help ensure that the developed systems meet the needs of the varying floor system geometries, it is envisioned that the work will involve categorizing all existing covered bridges by general floor framing types, as well as a review of floor systems used in other types of wood bridges, and the development of preliminary floor systems for covered bridges in general. The behavior and strength of the most promising of these systems need to be verified through controlled laboratory testing. A follow-up phase of this work may involve design and implementation of one or more of the developed systems on actual covered bridges. One additional consideration would be to seek solutions compatible with historic preservation and authenticity.
Other Information:   Funding: $100,000 (Federal Highway Administration) plus $30,000 (Forest Service, Forest Products Laboratory).
Partners:   University of Minnesota Duluth; Role(s): Technical
Expected Benefits:   The expected benefit is the development of lightweight flooring systems that would increase the overall load-carrying capacity of historic bridges.
Deliverables: Name: Lightweight Flooring Systems for Historic Covered Bridges (9/2014)
Product Type(s): Research report, Techbrief, Draft standard, specifications, or guidelines
Description: Publication evaluating the types of floor systems commonly used on covered bridges and the development and testing of a lightweight replacement system.
FHWA Topics:   Roads and Bridges--Structures
TRT Terms:   Covered Bridges
Bridge Decks
Wooden Bridges
FHWA Disciplines:   Design
Subject Areas:   Bridges and other structures


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