| Transit Noise and Vibration | ||
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| 1 | Introduction Introduction to course and summary of the need for understanding the material to be presented over the next few days. Overview of course and materials Introduction of main speakers. Acknowledgments. Description of procedures and schedule. Organization of the course. Description of manuals and supplementary handouts. Overview of FTA environmental review processes and FHWA/FTA environmental impact regulations How the noise and vibration analyses relate to the overall planning and development process. |
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| 2 | Basic Noise Concepts Fundamentals of rail noise. Definition of terms and concepts involved in a noise study (Chapter 2, FTA Manual). Fundamentals of sound - loudness, pitch, duration, decibels Defines the building blocks for describing noise. This basic material is not covered in the manual -- how the A-weighting relates to human hearing, for example. Class exercise on decibel addition. Audio demonstration of various sounds and their measured levels with a sound level meter. Descriptors for rail noise A-weighted sound level (dBA), Maximum level (Lmax), Sound exposure level (SEL), Hourly equivalent sound level (Leq), Day-night sound level (Ldn). Rail noise assessment model: sources, paths and receiver response Discussion of the noise source-path-receiver concept. Discussion of community annoyance as determined by EPA and others and how those studies lead to the selection of preferred noise descriptors. |
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| 3 |
Noise Impact Assessment Covers FTA/FRA noise impact assessment methods: how they were developed and how to apply them. Basis of noise impact criteria Discussion based on the manuals, which provide the background for the curves found in Chapter 3. Defining levels of noise impact Discussion of assessment approaches. Land use categories considered noise- sensitive. Impact Assessment Introduction to methods for obtaining existing noise exposure -- measurements and estimates, the final steps associated with application of the noise impact criteria, determining noise impact contours and conducting a noise impact inventory without and with mitigation. Discussion of the limitations of the method for estimating noise mitigation measures at the general assessment stage. |
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| 4 | Noise Sources Locomotive and vehicle noise sources. Wheel/Rail noise generation. Spectral characteristics. STB assessment method for rail mergers. |
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| 5 | High-Speed Rail Noise Noise sources on high-speed trains. FRA assessment method. |
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| 6 | Horn Noise Guidance on estimating horn noise impacts at grade crossings. FRA spreadsheet model. |
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| 7 | Mitigation Noise barriers, wheel/rail interface, sound insulation. |
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| 8 | Existing Noise Exposure Determination of existing noise environment is a key element in applying the noise criteria. Because of its importance, this session will focus on the appropriate methods for measuring and estimating ambient noise. |
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| 9 | Measurement Procedures Measurements for environmental noise assessments. Compliance tests. Demonstrations. |
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| 10 | Basic Ground-Borne Vibration Concepts Because a detailed vibration analysis requires specialized training beyond the scope of this course, we will focus on the general assessment and give guidance on what is involved in a detailed vibration analysis. Fundamentals of vibration Descriptions of vibratory motion and how it is measured. The source-path-receiver concept as it relates to vibration. Relationships between ground-borne vibration and ground-borne noise. Human perception of vibrations and how it differs from airborne sound. Descriptors for transit and construction vibration Vibration is described in terms of RMS velocity levels for environmental assessments and Peak Particle Velocity for construction damage limits. The development of the appropriate descriptors is discussed. The difference between "noise decibels" and "vibration decibels" is illustrated. Frequency spectra of different vibration sources and soil propagation characteristics are shown. Sources of vibration from transit and construction operations Discussion of how vibration is generated by such sources such as steel wheels and rubber tires. Demonstration of Vibration Propagation Test Equipment |
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| 11 | Vibration Criteria Vibration criteria are related to interference with sensitive activities and human response at the lower end, and to potential for damage to structures at the upper end. The foundations of the vibration criteria adopted by FTA including the difference in limits for "frequent" and "infrequent" events will be discussed. |
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| 12 | Vibration Assessment Methods Vibration screening procedure Background for vibration screening distances is presented. General vibration assessment The general vibration assessment of Chapter 10 of the Manual will be the focus of the vibration module. The generalized curve and the detailed adjustments will be discussed. An example will be worked out in class to develop a vibration impact assessment. Detailed vibration analysis The purpose of this session is to describe the tools used by professionals to obtain the best projections of ground-borne vibration and noise impact and how they select vibration mitigation measures. The methods for measuring vibration propagation characteristics will be shown. Mitigation methods, like ballast mats and floating slabs, will be discussed. Class Exercises and Examples on Vibration Solutions to Class Exercises and Examples on Vibration |
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| 13 | Construction Noise and Vibration Method for predicting and assessing noise and vibration impacts from construction operations will be discussed using Chapter 12 as a baseline. Criteria given in the chapter will be described. Examples from HMMH construction projects will be used to illustrate the method. |
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| 14 | Reporting FTA's preferred style of reporting noise and vibration results will be explained. What information to include in the environmental reports and what to reserve for back-up documentation. |
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| 15 | Optional Discussion of Case Studies/ Break Out Sessions | |
