Project Number:
01-3
Research Project:
Analysis of Vibrations and Infrastructure Deterioration Caused by High-Speed Rail Transit
P.I. Name & Address:
Hung Leung Wong
Civil Engineering
University of Southern California
216B Kaprielian Hall
Los Angeles, CA 90089-2531
Tel: (213) 740-0574
Fax: (213) 744-1426
Email: hlwong@usc.edu
Project Objective:
The objective of this project is to analyze the effects of a heavy traveling load on the life of rail infrastructures in the Los Angeles area.Analytical models will provide needed information in the area of wave propagation to transit related problems.Areas to be covered are: (1) The effects of geological conditions on ground-borne waves. (2) The effects of railway induced vibration on nearby structures.(3) The stresses on the soil medium created by a heavy traveling load.(4) The possibility of elastic shock waves in the ground when the vehicle speed exceeds the ground wave velocity.Consequences of poor soil condition examined.(5) Create graphs and table of results for future applications and references.
Project Abstract:
Analytical models of ground-borne wave propagation are lacking in Transportation Engineering.Fundamental solutions, or Green's functions, used mainly in seismic engineering can be adapted to analyze train induced waves and clarify many structural vibration problems which exist in high speed rail transit.Experimental data were collected in Europe to provide empirical transfer functions for structural engineers.Analytical models of this project can provide theoretical transfer functions for a much wider range of geological conditions, applicable in the Los Angeles area.
Infrastructure deterioration is noted In many European and Japanese high speed rail systems.As the speed increased, the rate of rail infrastructure failure increased. The objective of this project is to analyze the effects of a heavy traveling load on the soil layers that typically exist in the Los Angeles area.Velocities of operating rail vehicles as well as proposed future vehicles will be used in a parametric study to show the effects of elastic waves on railway infrastructures and on nearby structures and foundations.For selected loads and load velocities, the stresses on the soil medium and the amplitude of the ground-borne waves will be determined.Table of wave attenuation as a function of geological properties will be presented as a guideline for environmental studies and other structural analyses.Analyses on the effects of train acceleration, deceleration and track curvature will also be performed to obtain a full understanding of this vibration problem.
For certain situations where the soil condition is poor, the speed of the traveling loads may exceed the elastic propagation velocities in the soil medium and elastic shock waves would be generated.Elastic shock waves do not attenuate quickly over distance and the repetitive application of these loads can damage the rail infrastructure and urban structures and foundations nearby.In many situations, the waves may not be damaging to structures but the ambient noise generated by passing trains can affect some light industries that require the use of sensitive instruments.The objective of this research is to obtain a comprehensive overview of the environmental impact of ground waves induced by rail transit in the metropolitan areas.
Task Descriptions:
1.Collect experimental data for comparative studies
2.Perform theoretical parametric studies with traveling load Green'sFunctions.
3.Perform soil-structure interaction analysis to estimate vibrations inside nearby structures.
4.Develop numerical methods with stationary Green's Functions and compareresults with traveling load Green's Functions.
5.Estimate stress levels on ground surface due to traveling loads.Estimate wave amplitudes as a function of distance and frequency.
6.Estimate stresses on simplified rail infrastructures subjected to high speed loads.Estimate reduction of infrastructure life due to the dynamic load effects.
7.Organize publishable results.Prepare final report.Present tables and charts on a project website.Present recommendations for design.Show comparisons with available experimental data.
8.Wind up project and send in technical paper for publication.
Milestones, Dates:
Final Draft Report by 5/31/02
Total Budget:
$48,998
Student Involvement:
One Research Assistant @ 25% time for 12 months
Relationship to Other Research Projects:
Project is part of infrastructure focus area
Technology Transfer Activities:
Project report will be posted on website
Potential Benefits of the Project:
Better evaluation of high-speed rail project impacts
TRB Keywords:
Highs-speed rail
Primary Subject:
Measurement, characterization and modeling of system performance and impacts measurement
Goals:
Human and natural environment, Mobility
Enabling Research:
None
Modal Orientation:
Rail
