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Title:

Modeling and Field Verification of Dynamic Impact in Railroad Bridges

Accession Number:

01476924

Record Type:

Component

Availability:

Transportation Research Board Business Office

500 Fifth Street, NW
Washington, DC 20001 United States

Abstract:

The freight railroad system in the United States facilitates large volume of freight movement cost-effectively. However, recent increase of railcar weight limits from 263,000 lbs (1170 kN) to 286,000 lbs (1272 kN) raised concerns for existing bridges on the passenger rail systems which are occasionally used by many freight railcars. As part of the load rating and evaluation process, there is a need to understand the overall dynamic behavior and the impact of the freight railcar weight on typical bridges. In this paper, a two-dimensional (2-D) dynamic model and field tests were adopted to develop a refined methodology for evaluating the performance of railroad bridges with particular emphasis on the dynamic impact. The field study included instrumentation and testing of various types of bridges under moving freight and passenger railcars and monitoring their dynamic responses (deflection, velocity and strain). Field test results were analyzed to obtain the bridges’ natural frequency and the damping ratio. The bridge structure is modeled as a Bernoulli-Euler beam and the moving train is modeled using rigid-body dynamics method. Modal superposition method is adopted to compute the dynamic interaction of the train-bridge system. The dynamic model was validated with results from the field tests. Using these model simulations, a parametric study is performed to identify the effects of various parameters (such as vehicle speed, girder stiffness, damping ratio of girder, and track roughness) on the impact factor. Results show that the AREMA code overestimates the impact factor for these bridges at normal operating speed.

Supplemental Notes:

This paper was sponsored by TRB committee AR050 Railroad Track Structure System Design.

Monograph Accession #:

01470560

Report/Paper Numbers:

13-4635

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 United States

Authors:

Nassif, Hani
Lou, Peng
Wang, Ying-Jie
Hwang, Eui-Seung

Pagination:

20p

Publication Date:

2013

Conference:

Transportation Research Board 92nd Annual Meeting

Location: Washington DC, United States
Date: 2013-1-13 to 2013-1-17
Sponsors: Transportation Research Board

Media Type:

Digital/other

Features:

Figures; Photos; References (11) ; Tables

Subject Areas:

Bridges and other structures; Maintenance and Preservation; Railroads; I61: Equipment and Maintenance Methods

Source Data:

Transportation Research Board Annual Meeting 2013 Paper #13-4635

Files:

TRIS, TRB, ATRI

Created Date:

Feb 5 2013 12:54PM