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Federal Highway Administration
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Washington, DC 20590
202-366-4000


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Overview

 

Research and Development (R&D) Project Sites

Project Information
Project ID:   FHWA-PROJ-08-0050
Project Name:   Howe Truss Bridge Design and Performance
Project Status:   Active
Start Date:  October 1, 2008
End Date:  March 31, 2015
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:   For a long time, there has been interest in how William Howe built his original Howe Trusses, which had iron verticals. An interesting aspect is that his original design permitted tightening of the metal verticals by turning the nuts to induce compression in the diagonals and tension in the chords. Colonel Long earlier used wedges in the joints of his patented trusses to modify the stresses in the diagonals, verticals, and chords. This research would study the design and performance of Howe truss bridges. A classic Howe truss in relatively decent condition could be selected and then shored, the verticals loosened, instrumentation installed, and the nuts tightened to change the stress levels in the members, the shoring removed, and live loads applied. Data could be gathered throughout this process and a time history of member forces and displacements will be analyzed and documented. The data would be useful in calibrating viscoelastic models for the Howe truss. The final report would provide understandable, practical information on behavior, modeling, and design for Howe truss bridges. The results could have application to many of the 140 Howe trusses in existence, and could also be used in designing new covered bridges.
Goals:   The primary object of this project is to study in a historical context the design of, and determine the performance of, Howe truss bridges.
Product Type:   Research report
Techbrief
Test Methodology:   A classic Howe truss in relatively decent condition would be selected and then shored, the verticals loosened, instrumentation installed, and the nuts tightened to change the stress levels in the members, the shoring removed, and live loads applied. Data will be gathered throughout this process and a time history of member forces and displacements will be analyzed and documented.
Other Information:   Funding of $241,500 is $204,000 from the Federal Highway Administration and $37,500 from the National Park Service.
Expected Benefits:   Educational and practical benefits to bridge engineers, educators, and historians.
Deliverables: Name: Howe Trusses – Design and Performance
Product Type(s): Research report, Techbrief
Description: The product will be a final report providing understandable and practical information on the behavior and modeling and design of Howe truss covered bridges.
FHWA Topics:   Roads and Bridges--Structures
TRT Terms:   Trusses
Covered Bridges
Truss Bridges
Infrastructure
Bridges
Research
FHWA Disciplines:   Design
Structures
Subject Areas:   Bridges and other structures
History
Research

 

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