A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity (2012) / Chapter Skim
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Pages 29-47
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29 The FHWA commitment to minimizing noise impacts and enhancing the noise environment is described in Title 23 CFR Part 772 -- Procedures for Abatement of Highway Traffic Noise and Construction Noise. This regulation addresses noise impact assessment and abatement.
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30 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity The problems associated with nighttime construction are location dependent. Nighttime construction can cause nuisances when the work is in residential and commercial areas, whereas few problems arise in rural settings or when resurfacing a highway in an industrial area.
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Nuisances 31 To support agencies in their efforts to control construction noise nuisances, FHWA sponsored development of a Construction Noise Handbook (FHWA 2006a) and associated FHWA Roadway Construction Noise Model (FHWA RCNM)
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32 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity information into a single energy-averaged level. The Leq value is the average acoustic intensity over a defined time period and represents the equivalent energy level of a fluctuating sound, had that sound been steady over the time period.
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Nuisances 33 Tip Effective community awareness techniques: • Personal contact via door-to-door visits or special gatherings. • Personalized letters.
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34 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity Public meetings are important for receiving feedback and in providing early identification of controversial issues. It is imperative to explain the details of construction phasing and methods and the resulting noise, vibrations, and other nuisances.
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Nuisances 35 Tip Provide project inspectors with cell phones to ensure a quick response to citizen inquiries and complaints. In the case of a major project, inquiry calls can be processed through a central control center, which then notifies the correct inspector.
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36 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity Project specifications should require that permanent noise barriers (as in traffic noise barriers) be constructed as early as possible to decrease potential construction noise impacts.
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Nuisances 37 When an agency writes requirements based on Table 4.4 and the associated Tip into a project specification, the contractor must comply with both relative lot-line noise limits and absolute equipment sound emissions. Such source control actions serve as measurable contract performance limits against which noise complaints can be evaluated.
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38 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity • All equipment with backup alarms operated by the contractor, vendors, suppliers, and subcontractors on the construction site shall be equipped with either audible self-adjusting backup alarms or manual adjustable alarms. The self-adjusting backup alarms shall automatically adjust to five decibels over the surrounding background noise levels.
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From page 39... ...
Nuisances 39 Key Take-Away Physical Placement and Height of the Barrier Wall Control Effectiveness When placed properly, a noise barrier can provide 5 to 20 decibels of noise reduction from a listener's perspective. The barrier must intervene and completely break the line of sight between the noise source and the receptor.
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40 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity absorbed within the material of the barrier, and the majority of the sound energy is reflected back toward the source. The ability of a barrier to resist the flow of sound energy is largely determined by its mass.
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Nuisances 41 Figure 4.4 shows an example of a noise barrier specification. Acoustical Curtains.
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42 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity Figure 4.6 shows a sample window treatment program eligibility policy. If a treatment was approved, the CA/T project in Boston issued a task order to a window contractor.
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Nuisances 43 To control or limit project-caused vibrations, it may be necessary to place restraints on construction methods, allowable times, and equipment. However, the determination of acceptable vibration levels is very difficult because of its subjective nature with regard to being a nuisance.
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44 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity the basis of the sensitivity (or vulnerability) of buildings to major structural or minor cosmetic damages from vibration, as shown in Table 4.7.
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Nuisances 45 Figure 4.7. Impact assessment VC curves (Hanson et al.
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46 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity Vibration Mitigation The mitigation techniques for decreasing vibration impacts are similar to those used to lessen noise nuisances. The following are the questions to address concerning vibrations: • Will construction operations cause vibrations?
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From page 47... ...
Nuisances 47 Dynamic Effects of Pile Installations on Adjacent Structures. TRB, National Research Council, Washington, D.C.
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