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


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Research and Development (R&D) Project Sites

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Project Information
Project ID:   FHWA-PROJ-13-0043
Project Name:   Development of Alternate Load Paths Around Blast or Cut Damaged/Destroyed Steel Truss Members
Project Status:   Active
Start Date:  September 30, 2013
End Date:  September 30, 2018
Contact Information
Last Name:  Munley
First Name:  Eric P
Telephone:  202-493-3046
E-mail:  eric.munley@dot.gov
Office:   Office of Infrastructure Research and Development
Team:   Hazard Mitigation Team [HRDI-50]
Project detail
Roadmap/Focus area(s):   Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:   This is a task order in the general research indefinite delivery, indefinite quantity (IDIQ): technical support services for the Hazard Mitigation team. Enabling a steel truss structure to use alternate load paths during an attack, as with many seismic design or retrofit details, is intended to prevent total or, at least, immediate collapse. Although the physical functions are different, the objectives of both seismic and counterterror designs are to limit the damage and to allow rapid repair, if possible, rather than total replacement. The focus of this Task Order will be methods to provide or improve the alternate load path (ALP) function in surviving members, specifically on steel truss bridges (which often lack redundancy). Providing an alternate load path is one of four countermeasure types used to meet this general objective. The others are inertial resistance, strain energy absorption, and momentum transfer. For any ALP being developed in this task order, the other types of countermeasure may be present as secondary effects.
Goals:  
(1) Assessment of steel truss bridge existing members’ ability to provide full or partial Redundancy/Alternate Load Paths (ALPs) to prevent progressive collapse from blast loads or member cutting.
(2) Assessment of currently used seismic retrofit designs’ ability to provide ALPs to prevent progressive collapse of Steel Truss bridges from blast loads or member cutting.
(3) Initiate development of bridge retrofit components to provide full or partial redundancy/alternate load paths to prevent progressive collapse of steel truss bridges caused by local blast failure or by cutting of individual members.        
 
 
Product Type:   Research report
Test Methodology:   This project will first conduct an assessment of existing alternate load paths (ALPs) under dynamic loads. It will assess the adaptability of seismic retrofits on bridges of this type. It will develop preliminary retrofit component performance specifications, and it will recommend candidate steel truss bridge retrofit methods to provide ALPs, and design a laboratory and field test program to develop and implement these recommendations.
Expected Benefits:   American bridges will be able to survive terrorist attacks.
Deliverables:   Bridge retrofit components to provide full or partial redundancy/alternate load paths to prevent progressive collapse of steel truss bridges caused by local blast failure or by cutting of individual members.
FHWA Topics:   Research/Technologies--Turner-Fairbank Highway Research Center (TFHRC)
TRT Terms:   Mitigation
Counterterrorism
Bridges
Research
Infrastructure
Truss Bridges
Steel Bridges
FHWA Disciplines:   Structures
Subject Areas:   Bridges and other structures

 

Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101