Project 1.13: Structural Integrity, Safety, and Durability of Critical Members and Connections of Old Railroad Bridges under Dynamic Service Loads and Conditions

Project 1.13 Summary:

Most of the New England railway bridges were designed and built more than a century ago with
outdated design codes and materials. The objective of this research project is to investigate the
structural behavior of critical members and connections, such as eye-bars, pins, and gusset plates
(Fig. 1 and 2), of old truss-type steel railway bridges in the Northeast region under dynamic
structural response factors such as service load, environmental conditions, and material aging. The
proposed project will establish a systematic framework to apply analytical, computational, and
experimental/field testing techniques to pinpoint, evaluate, and mitigate the damage in the
connections between steel members in old railroad bridges. Starting with a critical review of the
existing data of past connections issues and failure from selected bridges, the research team will
work closely with New England’s Department of Transportation (DOTs) and railroad companies
to generate reliable data recording and evaluation of bridge type versus connections problems,
existing mitigation methods, and current repair techniques. Existing data collected from
operational and maintenance teams, such as images and reports, if available, will also be used.
Updated Finite Element (FE) Models will be used to simulate different operation scenarios, such
as braking and traction, to establish parameters to identify and analyze possible critical member’s
connections under different scenarios. Similarly, the research will focus on the detailed local
analysis of those critical connections, with an emphasis on dynamic behavior, impact, and material
aging. The updated FE Model will be used to establish parameters to identify and evaluate critical
member’s connections. An optimization of the number and location of sensors will be determined
by using an optimization algorithm such as genetic algorithm, and will aim to develop an effective
and efficient method of finding the location and severity of damage using vibration-based methods
such as Modal Strain Energy Change in conjunction with some optimization algorithms. The
output data from strain gauges and other sensors collected in field- and scaled- prototypes will be
used to validate and verify the global, and local, FE model of the critical member’s connections.
Finally, different connection strengthening and anti-wear methods will be evaluated and
implemented numerically and analytically to check their effects on extending a bridge’s future life.

Sponsors:
University Transportation Centers Program, Department of Transportation
University of Connecticut

Implementation of Research Outcomes:
This project is in its initial research phase. Implementation of Research outcomes will be reported upon completion of initial research.

Impacts and Benefits of Implementation:
This project is in its initial research phase. Impacts and benefits of the research will be reported after the implementation phase.

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