Civil and Environmental Engineering


Date of this Version

Summer 7-2012


Rakoczy, A. M., "DEVELOPMENT OF SYSTEM RELIABILITY MODELS FOR RAILWAY BRIDGES", PhD Dissertation, University of Nebraska-Lincoln, Summer 2012


A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Engineering (Civil Engineering), Under the Supervision of Professor Andrzej S. Nowak. Lincoln, Nebraska: July, 2012

Copyright (c) 2012 Anna Maria Rakoczy


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. There is a need for efficient methods to evaluate the safety reserve in the railway bridges by identification of the most sensitive parts of the bridge.

An accurate estimation of remaining fatigue life of a structural component is very important in prioritizing bridge rehabilitation and replacement. However, existing procedures to evaluate the fatigue behavior of bridges are based on estimation rather than the exact formulas because the load and the resistance models contain many uncertainties. Therefore, probabilistic methods are the most convenient way to provide levels of safety for various design cases.

The objective of this study is to develop a reliability model for railway bridges, in particular for the fatigue and strength limit states. It will be demonstrated on two through-plate girder structures. The research involved nonlinear finite element method (FEM) analysis of typical railway bridges, development of statistical parameters of live load and resistance, and calculation of a reliability index for various considered conditions. The findings of this research with final conclusions will serve as a basis for the development of more rational provisions for the design and evaluation of railway bridges.

Adviser: Andrzej S. Nowak