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Howe Truss Bridge Design and Performance

Project Information

Project ID: 
FHWA-PROJ-08-0050
Project Status: 
Active
Start Date: 
Wednesday, October 1, 2008
End Date: 
Tuesday, March 31, 2015
FHWA Program: 
Infrastructure
FHWA Subprogram: 
Structures
FHWA Topics: 
Roads and Bridges--Structures
TRT Terms: 
Trusses; Covered Bridges; Truss Bridges; Infrastructure; Bridges; Research
FHWA Discipline: 
Design, Structures
TRB Subject Area: 
Bridges and other structures, History, Research

Contact Information

First Name: 
Sheila
Last Name: 
Duwadi
Telephone: 
(202) 493-3106
Email Address: 
Team: 
Infrastructure Analysis and Construction Team
Office:
Office of Infrastructure Research and Development
Office Code: 
HRDI-20

Project Details

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.

Deliverables

Deliverable Name: 
Howe Trusses – Design and Performance
Deliverable Type: 
Research report or guidelines
Deliverable 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.