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Mid-America Transportation Center

Development of a Guide for Prioritization of Railway Bridges for Repair and Replacement

Final Report
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Researchers

  • Principal Investigator: Anna Rakoczy (arakoczy1@gmail.com 402-617-9451)
  • Co-Principal Investigator: Andrzej Nowak (anowak2@unlnotes.unl.edu 402-472-1376)
  • Project Status
    Complete
    About this Project
    Brief Project Description & Background
    Performance of the railway transportation network depends on the reliability of railway bridges which can be affected by various forms of deterioration and extreme environmental conditions. More than half of the railway bridges in US were built before 1950 and many show signs of distress. Bridge owners need evaluation criteria for existing structures to make a rational decision about repair, rehabilitation or replacement. With limited available resources, the decision making is important with potentially serious financial consequences. The objective of this research is to formulate rational acceptability criteria and develop a guide for evaluation of existing railway bridges
    Research Objective
    The objective of this project is to develop a guide for bridge owners for evaluation and prioritization of existing structures, with rational evaluation criteria. The major contribution of the project is the development of a rating system for bridge condition depending on deterioration, time period, environmental conditions and past, present and future freight train loads. The research work will involve identification of the basic load and resistance parameters, and the development of advanced analytical procedures for modeling the structural behavior.
    Potential Benefits
    The main contribution of this project is formulation of rational acceptability criteria for existing railway bridges and development of a guide for prioritization of railway. The considered forms of deterioration include corrosion and fatigue. The proposed approach will be demonstrated on selected representative railway bridges. The developed Guide will allow for a more rational management of railway bridges and a more efficient utilization of the available resources. A considerable saving can be expected by the bridge owners.
    Abstract
    The objective of this study is to develop a guide for evaluation and prioritization of repair, rehabilitation and replacement for existing railway bridges. The proposed research will involve review and analysis of the major factors that influence structural performance, e.g. degree of corrosion, loss of material (section loss, holes), cracking and spalling of concrete, bearing problems, loose connections, traffic volume (number of cars/trains and tonnage) and bridge importance for the railroad network. However, these factors are random in nature; therefore, it is convenient to consider reliability as a measure of performance. The relationship between various conditions and ability to perform the required function (i.e. carry the freight trains) will be established in form of limit state function(s). The statistical parameters will be determined for each factor using the available data, by Monte Carlo simulations and if needed also by the so called Delphi process. The reliability as a measure of structural performance will be expressed in terms of a reliability index. Reliability indices will be calculated for selected representative railway bridges, and based on the results, a target reliability index will be selected. The sensitivity analysis will be performed to establish the relationship between the load and resistance factors and reliability to be presented in form of graphs and tables. The results will serve as a basis for the development of a decision making spread sheet. The final report will document research and provide a tool for bridge owners for prioritization of structures for repair/rehabilitation or replacement.
    Project Amount
    $ 60,403.5