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MTA New York City Transit Fulton Street Transit Center DEIS

May 2004 13.0 Noise and Vibration 13-1

CHAPTER 13: NOISE AND VIBRATION

13.1 INTRODUCTION

13.1.1 CONTEXT & KEY ISSUES

This chapter considers potential impacts from the Proposed Action upon ambient noise and ground-borne vibration levels. Airborne noise impacts are compared to both pre-September 11 noise levels and existing 2003 noise levels. Vibration levels from each of the analysis years – 2005/2006 (Construction), 2008 (Initial Operation), and 2025 (Full Operation) - are analyzed for potential impacts to sensitive receptors, which includes those defined by Federal Transit Administration (FTA) standards. Within the immediate area of the Existing Complex and in Lower Manhattan in general, the current ambient noise levels are generated by: heavy automobile, city bus, and truck traffic volumes, emergency vehicle sirens, and noise generating construction equipment and outdoor events for example, large gatherings and concerts. Although current noise levels since the events of September 11 have been reduced, monitoring data still indicate that 2003 noise levels remain high. The reductions in noise levels since September 11 are directly related to reductions in office workers, visitors and other activities associated with the central business district in Lower Manhattan. This chapter considers the potential noise and vibration impacts related to increases or decreases in traffic and from the construction and operation of the Proposed Action within the study area. Increases or decreases of on-street traffic are analyzed because traffic is a predominant contributor to ambient (existing and pre-September 11 background) noise levels at the project site. The construction of the Proposed Action is expected to produce temporary noise and vibration impacts. The noise and vibration levels associated with operations of the Proposed Action are also analyzed in this chapter and are compared to the existing and pre-September 11 noise levels to evaluate potential noise and vibration impacts. 13.1.2 CONCLUSIONS

ANALYSIS YEAR 2005/2006

Under the No Action Alternative, existing commercial land uses in the study area would continue and the Existing Complex would be maintained in its current state. No major construction activities related to the Fulton Street Transit Center (FSTC) are anticipated. Construction activities associated with other Lower Manhattan Recovery Projects, with the exception of South Ferry Subway Terminal, would be ongoing in 2005/2006. Minor maintenance and rehabilitation activities associated with the Existing Complex could occur, including typical station and transit infrastructure maintenance and repair during this analysis year. As a result, there would be no adverse impacts from mobile (construction traffic) or stationary (including movable and stationary construction equipment) sources attributable to the No Action Alternative upon noise conditions or vibration levels in the study area. Mobile Sources With other Lower Manhattan Federal Recovery Projects, as part of the background condition, Alternatives 9 and 10 would result in decreases or no change in traffic at two (2) of the receptor locations due to street closures for activities proposed under the FSTC when compared with 2003 existing conditions. Additional traffic would be generated at the eight (8) other locations, seven (7) of which would result in an imperceptible increase of less than two (2) dBA during the AM peak traffic hour. The Century 21 Department Store - Cortlandt Street entrance (Site 4) would experience a Passenger Car Equivalent (PCE) (traffic volume) increase of almost 400 percent resulting in a substantial increase of 6.8



dBAs during the AM peak hour. Using a three (3) dBA increase as the discernable threshold, there would be adverse airborne noise impacts from mobile sources at Site 4 during the AM peak hour. Compared to pre-September 11 conditions, the FSTC would result in decreases in traffic at four (4) of the receptor locations, two (2) of which are due to street closures for activities proposed under the FSTC. Additional traffic would be generated at the five (5) other locations, all of which would result in an imperceptible increase of up to 1.6 dBA during the AM peak traffic hour. Using a three (3) dBA increase as the discernable threshold, there would be no adverse airborne noise impacts from mobile sources at any of the nine (9) locations during the AM peak hour. Stationary Sources Existing conditions reflect an atypical recovery condition. Noise levels were therefore also compared against pre-September 11 levels which reflect a more typical condition for Lower Manhattan. Peak one (1)-hour Leq, eight (8)-hour Leq, and 30-day Ldn were calculated at each of nine (9) sites. The resultant noise level histograms are presented in Appendix J, Part III, Stationary Sources Sections. The maximum one (1)-hour, eight (8)-hour, and 30-day noise levels are summarized and presented in Tables 13-10 through 13-13 below. As presented in Table 13-10, peak one (1)-hour noise levels would exceed FTA criteria of 90 dBA for residences and hotels and 100 dBA for office and commercial at Sites 3, 6, 8 and 9. The eight (8)-hour noise levels would exceed FTA criteria of 80 dBA (for residences and churches) and 85 dBA (office/commercial) at seven (7) of the nine (9) sites. It is noted that the calculated peak-hour and eight (8)-hour noise levels are the maximum expected noise levels at each of the receptor locations. In addition, expected noise levels would only occur during peak construction activities, which are limited to certain time periods and last for short periods of time, e.g. hours or days, over the entire construction duration. The 30-day Ldn levels would exceed FTA criteria at Sites 2, 3, 6, 8 and 9 using the Minimum Distance Method. The Minimum Distance Method presents the most conservative analysis in determining the closest point that pieces of moveable equipment could be located to the receptor. (Stationary equipment would, in fact, be placed as far away as possible within the work zone). In calculating noise levels using the Minimum Distance Method, several of the noise receptors were assumed to be located at relatively short distances from the noise generating source. This was especially the case for noise receptors associated with the construction at the Dey Street Passageway and the mezzanine at Fulton Street. While construction could occur as close as five (5) feet from a building façade, it should be noted that activities would not occur continuously at such proximities, especially for small distances (less than 20 feet). Rather, equipment at such distances would routinely move within different areas of the work site. For stationary sources (construction equipment) utilized for both Alternatives 9 and 10, peak-hour noise levels would equal or exceed FTA criteria of 90 dBA at four (4) of nine (9) receptor sites. These four (4) sites include one (1) hotel and three (3) residential buildings. The peak eight (8)-hour noise levels would exceed the FTA criteria at eight (8) of the nine (9) sites. It should be noted that the calculated peak-hour and eight (8)-hour noise levels would only occur during peak construction activities, which are limited to certain time periods and would last for a short period of time, e.g. hours or days, over the entire construction duration. The 30-day Ldn levels would exceed FTA criteria at five (5) sites based on an assumption that all movable equipment would be operated at the closest distance from the receptor site (pursuant to the Minimum Distance Method) since the exact locations of the construction equipment are not estimable at the current stage of the engineering design. The initial calculation of 30-day Ldn levels was conducted by assuming that equipment would be operating in a single location, close to the receptor, during the entire construction period. In reality, however, within any substantial period of time (e.g. 30 days), construction equipment is moved around the construction site, following the various types of construction activities at different locations around the site. Given the size of the construction zone, the locations of construction equipment thus vary considerably throughout the construction period. To reflect these dynamic construction conditions, the 30-day Ldn levels were also calculated using the average distances between the receptors and construction zones (Average Distance Method). The use of average distances rather than single locations during the entire construction period thus reflects the fact that



movable construction equipment would be moved around throughout the construction areas or zones over an extended period of time, e.g., 30 days. When the Average Distance Method is employed, none of the nine (9) sites would exceed FTA criteria. Vibration and Ground-Borne Noise Under Alternatives 9 and 10, construction vibration at all nine (9) receptor sites would be less than 0.5 inch/sec. which is the New York City Department of Buildings (NYCDOB) Technical Policy and Procedure Notice (PPN) # 10/88 criterion to avoid potential damage to historic structures. Five (5) locations with historical buildings were also analyzed for vibration levels during the peak construction period. Four (4) of the five (5) historical buildings (Sites B, C, D, and E) would experience maximum vibration levels above the FTA criteria of 0.20 for fragile (historic) buildings during the cut-off wall construction using either slurry wall or secant pile wall methods. These buildings include the American Telephone and Telegraph (AT&T) Building at 195 Broadway (Site B), the East River Savings Bank on Church Street (Site C), the Bennett Building at 139 Fulton Street (Site D), and the Corbin Building at 192 Broadway (Site E). It is noted that the vibration levels associated with secant pile wall construction (using augur drill operations) would be substantially lower than those of slurry walls (with clam shell dropping operations). To minimize potential construction impacts, New York City Transit (NYCT) proposes to incorporate Environmental Performance Commitments, or EPCs, into the implementation of the FSTC. NYCT would implement the EPCs as elements of its Construction Environmental Protection Program (CEPP) and related plans by incorporating noise reduction features in design, coordination protocols, and protection plans during construction. EPCs, by way of the CEPP, would be implemented within the design and construction of the FSTC to proactively reduce potentially adverse effects associated with noise and vibration. EPCs would include the following:

• Where practicable, individual project construction activities will be scheduled to avoid or minimize adverse impacts;

• Construction activities will be coordinated with projects under construction in adjacent and nearby locations to avoid or minimize impacts;

• The condition of surrounding buildings, structures, infrastructure, and utilities shall be considered, where appropriate; and,

• Contingency measures such as sequencing of operations, construction alternative methods, and source reduction measures, will be prepared in the event established limits are exceeded.

Several potential measures have been identified to mitigate airborne noise and ground-borne noise and vibration impacts identified in the analyses. A Noise and Vibration Plan (an element of the CEPP) would be developed prior to construction and implemented throughout the construction of the Proposed Action to minimize airborne noise impacts. Typical elements of the Noise and Vibration Plan may include:

• Source Limits and Performance Standards to meet noise level thresholds for daytime, evening, and nighttime hours at sensitive land uses at and/or adjacent to the FSTC;

• Designated Truck Routes; • Establishment of noise monitoring stations for measuring noise prior to and during construction; • Design considerations and project layout approaches including measures such as construction of

temporary noise barriers, placing construction equipment farther from noise-sensitive receptors, and constructing walled enclosures/sheds around especially noisy activities such as pavement breaking. Sequencing operations to combine especially noisy operations to occur in the same time period. Sound proofing of residential homes as determined to be necessary;

• Community Liaison and Complaint Hot Line; and, • Alternative construction methods, using special low noise emission level equipment, and

selecting and specifying quieter demolition or deconstruction methods would also be included in the CEPP.



Other mitigation measures include: sequencing operations, use of alternative construction equipment and instituting other special control measures to reduce the transmission of high vibratory levels to vibration-sensitive areas; a preconstruction survey of any structure or use likely to be adversely affected by the construction activities; and establishing thresholds or limiting values of structures and existing land use. If necessary, underpinning of structures would also be considered and, as appropriate, implemented. A project-wide vibration monitoring program would also be developed and implemented to monitor and identify vibration levels from construction activities at nearby sensitive receptors. This program would be included in the CEPP. In addition to the mitigation measures described above, NYCT would consult with appropriate agencies, such as the NYCDOB, and refer to applicable guidance set forth by the New York State Office of Parks, Recreation and Historic Preservation (NYSOPRHP) and the New York City Landmarks Preservation Commission (LPC) to protect historic resources from increased vibration levels associated with construction activities. The CEPP would be developed in consultation with the NYSOPRHP and implemented before commencement of any excavation or construction. The CEPP would include an overall plan of protection and avoidance of structural and architectural damage for all the potentially affected historic resources. ANALYSIS YEAR 2008 (INITIAL OPERATION)

Under the No Action Alternative, the Existing Complex would be maintained in its current state and configuration. Minor maintenance and rehabilitation activities could occur, including typical station and transit infrastructure maintenance and repair. These activities would not have any significant impacts on noise or vibration levels in the study area. If either Alternative 9 or 10 were constructed, the FSTC would not generate traffic increases. There would be no substantial difference between the No Action Alternative and Alternatives 9 and 10 and no increase in train operations, and associated operational noise levels, would be anticipated for any of the alternatives. The Build Alternatives would not result in any significant noise impacts from stationary sources; heating, ventilation and air conditioning (HVAC) and mechanical systems would utilize noise reduction devices referred in the New York City Noise Code, subchapter 6, Section 24-243, Ambient Noise Quality Zone Criteria and Standards. Under Alternatives 9 and 10, there would be no changes to the existing subway alignments and profiles, in the type of trains using the track (i.e., suspension and wheel conditions would remain the same) and track structure. Therefore, the Alternatives are not anticipated to result in a change in vibration levels at adjacent sensitive receptors, and there would not be any vibration or ground-borne noise impacts. HVAC and mechanical systems would be designed to minimize vibration effects on existing and proposed structures. ANALYSIS YEAR 2025 (FULL OPERATION)

In 2025, the FSTC would be expected to operate with full patronage. For noise and vibration impact analysis purposes, the analysis year 2025 would have no operational differences from analysis year 2008. It is also expected that there would no additional sensitive noise receptor locations within the study area. Because there are no differences in operational activities or receptor locations, it is expected that the Proposed Action would not result in noise and vibration impacts. Table 13-1 summarizes potential noise and vibration impacts associated with the FSTC.



Table 13-1

Summary of Comparison of Alternatives: Airborne Noise & Ground-Borne Vibration

2005/2006 (Construction)

Planned Action (for 2005/2006

Impact)

2008 (Initial Operation)

2025 (Full

Operation) Mobile source noise levels would increase up to 2.1 dBA over year 2003 levels at all 9 receptor locations. Mobile source noise levels would decrease or remain the same at 5 locations and increase at 4 locations by up to 1.6 dBA over pre-September 11 levels at the 9 receptors. Stationary source noise levels would exceed the FTA criteria for peak-hour and 8-hour noise levels at the Millenium Hotel only. Peak 30-day noise levels would not be exceeded.

No impact. No impact. No impact. No Action

Vibration levels would not change under this scenario. No impact. No impact. No impact.

Comparing the Build with No Build conditions in 2005/2006, mobile source noise levels from the FSTC would result in decreases or no change at 5 of 9 locations, 2 of which would be closed due to project-induced street diversions. 4 locations would experience increases, 1 of which would experience a significant 4.6 dBA increase. Compared to the 2003 Existing Condition, Mobile source noise levels in 2005/2006 would have slight (less than 2 dBA) increases over year 2003 at 8 of the 9 locations. The ninth location would experience a 6.8 dBA increase. Compared with pre-September 11, mobile source noise levels would increase at 5 receptors, all of which would have imperceptible increases of up to 1.6 dBA. Stationary Source (equipment) Construction Noise in excess of FTA criteria: - Peak hour std: 4 sites. - Eight 8-hour std: 7 sites. - 30-day std: None using Average Distance Method.

EPCs and CEPP to address work hours, acoustic barriers, equipment noise reducers, monitoring, public outreach, and enforcement.

No impacts. Subway operation would not increase in capacity or frequency and no increases in noise or adverse noise impacts would be anticipated. HVAC and mechanical systems would be enclosed and within the buildings; Cooling equipment would be located on elevated levels in or on top of proposed structures; Noise associated with this system, and with air tempering equipment and ventilation shafts would be designed to minimize audible noise at street level; The HVAC and mechanical systems would utilize noise reduction devices to minimize noise impact. Operation of the retail facilities included in the Entry Facility would not generate substantial noise. Noise generated within FSTC associated with pedestrian movements would not result in adverse noise impacts.

Same as 2008. Alternative

9

Vibration levels at Sites B, C, D, and E would exceed FTA threshold for fragile buildings during peak construction period.

CEPP and MOA provisions apply. No impact. No impact.

Alternative 10 Same results as Alternative 9. Same action as

Alternative 9. Same as Alternative 9. Same as 2008.

Source: The Louis Berger Group, Inc., 2004. 13.2 STUDY AREA The study area was established based on where potential noise and vibration impacts could occur. The study area included construction truck routes and the area around the construction sites. The study area for the analysis of noise and vibration impacts is the project area of the FSTC (see Chapter 1: Purpose and Need) and the surrounding area of Lower Manhattan from the Hudson River to the East River. The northern limit of the study area is Chambers Street, which reflects potential truck traffic effects associated



with the project (see Chapter 6: Traffic and Transportation). There are various sensitive receptors located within the Study Area. These sites include residences, churches, a hotel, commercial office buildings and historic buildings within close proximity to the FSTC (bounded by Broadway, Fulton, Dey, John and Nassau Streets). Noise monitoring locations are located within the vicinity of the sensitive receptor sites and are identified on Figure 13-1. ENVIRONMENTAL PERFORMANCE COMMITMENTS (EPCS)

To minimize potential construction impacts, NYCT proposes to incorporate EPCs into the implementation of the FSTC. The EPCs consist of measures to avoid or minimize potential adverse effects of the FSTC on the environment. NYCT would implement the EPCs as elements of its CEPP by incorporating noise reduction features in design, coordination protocols, and protection plans during construction. EPCs, by way of the CEPP, would be implemented within the design and construction of the FSTC to proactively reduce potentially adverse effects associated with noise and vibration. EPCs would include the following:

• Where practicable, individual project construction activities will be scheduled to avoid or minimize adverse impacts;

• Construction activities will be coordinated with projects under construction in adjacent and nearby locations to avoid or minimize impacts;

• The condition of surrounding buildings, structures, infrastructure, and utilities shall be considered, where appropriate; and,

• Contingency measures such as sequencing of operations, construction alternative methods, and source reduction measures, will be prepared in the event established limits are exceeded.

13.3 NOISE AND VIBRATION BASIC CHARACTERISTICS Noise, or unwanted sound, has numerous sources including airplanes, factories, railroads, power generation plants, construction equipments, and highway vehicles. Noise may have adverse effects on the human population in a variety of ways, depending on how loud and how frequent the source of noise is. The following section provides an overview of the ways that noise is measured and predicted in environmental impact analysis. A discussion is provided below of “decibel” as the unit of measurement of sound levels, the use of a weighting method to account for the way that sound levels are perceived by people and a logarithmic method to project and combine noise levels from different sources and over different time periods. SOUND LEVEL CHARACTERISTICS

Sound pressure is the parameter that is normally measured in noise assessments. People’s hearing responds to “acoustic” pressures that represent the range from the threshold of hearing to the threshold of pain. This vast range is represented as a logarithmic scale. A basic measure of sound is the sound pressure level (SPL), which is expressed in decibels (denoted dB). When the SPL = 0 dB, the acoustic pressure is the same as the threshold of hearing. Therefore, 0 dB corresponds to the threshold of hearing, or the SPL at which people with healthy hearing can just begin to hear a sound. Sound is often measured and described in terms of its overall energy, taking all frequencies into account. However, the human hearing process is not the same at all frequencies. Therefore, noise measurements are often adjusted or weighted, as a function of frequency to account for human perception and sensitivities. The A-weighted adjustment method is the most commonly used. Sound levels measured using this weighting is noted as dBA. The letter “A” indicates that the sound has been filtered to reduce the strength of very low and very high frequency sounds, much as the human ear does. A listing of common noise sources with their associated typical dBA values is shown in Table 13-2.

#

WESTST

BROADWAY

JOHNST

VESEYST

LIBERTYST

PARK R

OWCHURCHST

PINEST

MAIDENLA

NASSAUST

PARKPL

BARCLAYST

TRINITYPL

WALL

ST

ANNST

MURRAYST

BROOKLYN

BR

FULTONST

SOUTHS

FRANKFORTST

GREENWICHST

RECTOR ST

READEST

CLIFF

ST

NEWST

WASHINGTONST

WARREN

ST

SPRUCEST

PLATTST

CENTREST

ELKST

BEEKMANST

CEDARST

WESTBROADWAY

CHAMBERSST

EXCHANGEPL

BROADST

L

FLETCHERST

DUTCHST

GOLDST

THEATREAL

CORTLANDTST

THAMES STLIBERTYPL

RYDERSAL

EXCHANGE AL

EDGAR ST

MORRIS ST

ALBANY ST

WESTST

PEARL ST

WASHINGTONST

CEDARST

FDR

GOLDST

GREENWICHST

BEEKMANST

ANNST

P P

P

P

P

P

P

P

P

PP

P

P

P

P

Generalized Land Use (2003):

Automotive (includessoft-site parking)Commercial

Curb Lines

Legend

NoiseMeasurementLocations

ApproximateProject Location

Fulton Street Transit Center

Noise MeasurementLocations

Open Space/Park/ Plaza

Under Construction

Industrial

Institutional

Residential

Vacant

P On-Site Parking

Ground Floor Retail

Hotel

#S#

Source: NYC DoITT Landbase; NYC DCP

200 0 200Feet

Figure 13-1

WILLIAMST ,.

#

#

#

#

#

# ##

S

S

S

S S

S

S SS

1

2

3

5

6

7 89

4



Table 13-2 indicates that most individuals in New York City are exposed to fairly high noise levels from many sources as they go about their daily activities. The degree of disturbance from unwanted sound depends essentially on three (3) factors:

• The amount and nature of the intruding noise; • The relationship between background noise and the intruding noise; and, • The type of activity occurring where the noise is heard.

Table 13-2 Examples of Common Sounds

(A-Weighted Sound Level in Decibels (dBA))

A-weighted Overall Level Noise Environment

120 Uncomfortably loud (32 times as loud as 70 dBA)

Military jet airplane takeoff at 50 feet.

100 Very loud (8 times as loud as 70 dBA)

Jet flyover at 1000 feet. Locomotive pass-by at 100 feet.

80 Loud (2 times as loud as 70 dBA)

Propeller plane flyover at 1000 feet. Diesel truck 40 mph at 50 feet.

70 Moderately loud Freeway at 50 feet from pavement edge at 10 AM Vacuum cleaner (indoor).

60 Relatively quiet (1/2 as loud as 70 dBA)

Air conditioning unit at 100 feet. Dishwasher at 10 feet (indoor).

50 Quiet (1/4 as loud as 70 dBA)

Large transformers. Small private office (indoor).

40 Very quiet (1/8 as loud as 70 dBA)

Birds’ calls. Lowest limit of urban ambient sound.

10 Extremely quiet Just audible. (1/64 as loud as 70 dBA).

0 Inaudible Threshold of hearing. Source: Federal Agency Review of Selected Airport Noise Analysis Issues, 1992. Modified by The Louis Berger Group, Inc., 2004.

In considering the first of these factors (i.e., amount and nature of the intruding noise), it is important to note that individuals have different sensitivities to noise, relating to loudness, noise patterns, etc. For example, noises occurring during sleeping hours are usually considered to be more of a nuisance than the same noises in the daytime. With regard to the second factor (the relationship between background noise and the intruding noise), individuals tend to judge the annoyance of an unwanted noise in terms of its relationship to noise from other sources. For instance, the blowing of a car horn at night when background noise levels are typically about 45 dBA would generally be more objectionable than the blowing of a car horn in the afternoon when background noises are likely to be 60 dBA or higher. The third factor (the type of activity occurring where the noise is heard) is related to the interference of noise with the activities of individuals. In a 60 dBA environment, work activities requiring high levels of concentration may be interrupted by loud noises, while activities requiring manual effort may not be interrupted by noise to the same degree. Sound is described by a logarithmic scale and sound levels cannot be simply added. In fact, a doubling of the noise source produces only a three (3) dBA increase in the sound pressure (noise) level. For example, two (2) sounds of 50 dBA added together would be equal to 53 dBA, not 100 dBA. In other words, a doubling of sound sources would only increase the total sound level by three (3) dBA. Studies have shown that a three (3) dBA increase is barely perceptible to the human ear, whereas a change of five (5) dBA is readily perceptible. As a general rule, an increase or decrease of 10 dBA in noise level is perceived by an observer to be a doubling or halving of the sound, respectively. One way of describing fluctuating sound is to describe the fluctuating noise heard over a specific period



as if it had been a steady, unchanging sound. For this condition, a descriptor called the “equivalent sound level,” Leq, is used. Leq is the constant sound level that, in a given situation and period, conveys the same sound energy as the actual time-varying sound. Ldn (or DNL), is the day-night average sound level or cumulative noise exposure over a 24-hour period, with events between 10 PM and 7 AM increased by 10 dBA to adjust for greater nighttime sensitivity to noise. The Ldn, which represents 24-hour levels with a 10 dBA penalty for nighttime hours, is useful for evaluating residential land uses and other land uses with sleeping accommodations. VIBRATION DURING CONSTRUCTION

Construction activities and subway operations have the potential for producing high vibration levels that may be perceptible or disruptive. In the case of construction activities, architectural and structural damage could also occur if construction is not properly managed. Even where vibration levels are lower or imperceptible, vibrations can nonetheless produce ground-borne noise. Ground vibrations from most construction activities rarely reach the levels that can damage structures, but may be perceptible close to the construction site. If not properly managed, some heavy construction activities, such as blasting, pile driving, clam shovel drops, pavement breakers, etc., can cause substantial damage to nearby buildings at closer distances depending on geological conditions. Although the perceptibility threshold for ground-borne vibration is about 65 vibration decibels (VdB), human response to vibration is not usually substantial unless the vibration exceeds 70 VdB. In terms of vibration during construction, vibration is described in Peak Particle Velocity (PPV) based on FTA guidelines. PPV relates to the maximum instantaneous peak of the vibration signal, and is often used in measuring the magnitude of vibration. Background vibration is usually well below the threshold of human perception, and is of concern only when the vibration affects very sensitive manufacturing or research equipment. Electron microscopes, high-resolution lithography equipment, and laser and optical equipment are typically sensitive to vibration. Fragile buildings and/or historic buildings may be especially sensitive to vibration. Figure 13-2 presents the vibration analysis sites taking these aspects into consideration. 13.4 REGULATORY FRAMEWORK

13.4.1 INTRODUCTION

The noise analysis of the FSTC was conducted according to FTA noise and vibration guidelines. The analysis followed FTA’s guidelines, Transit Noise and Vibration Impact Assessment 1995, which specifically relates to transit projects. While FTA guidelines were the primary basis for analysis, the City Environmental Quality Review (CEQR) and New York State Department of Environmental Conservation (NYSDEC) guidelines used by nearby Lower Manhattan Recovery Projects are also discussed for understanding the results of the FSTC in the context of analyses conducted for those projects. A discussion of noise impacts relative to criteria used by the Lower Manhattan Recovery Projects is presented in Chapter: Coordinated Cumulative Effects Analysis.


Noise Impact Criteria

Figure 13-2

,.



13.4.2 AIRBORNE NOISE CRITERIA

FTA NOISE GUIDELINES

The FTA guidance manual describes a recommended noise screening and assessment methodology, based on various transportation-related and acoustic professional sources, for assessment of ambient and transit-related noise. As part of the methodology, an initial screening of noise sources and receptors is conducted (the general noise assessment) to determine the need for a more detailed noise assessment. Receptors are noise-sensitive locations where human activity may be adversely affected when noise levels exceed predefined thresholds of acceptability or when noise levels increase by an amount exceeding a predefined threshold of change. The noise analysis begins with the identification of existing receptors in the study area based on existing land use. Should this result in the identification of potentially sensitive receptors, a more detailed investigation is required to assess potential noise impacts (the detailed noise assessment). Land use categories used in the analysis are defined below (Table 13-3). Qualification of a receptor as sensitive under the FTA standards depends on the distance of the receptor from the proposed facility, and on the type of facility. Categories 1 and 3, which include land uses that are noise-sensitive, but where people do not sleep, require examination using the one (1)-hour Leq descriptor for the noisiest peak hour. Category 2, which includes residences, hospitals, and other locations where nighttime sensitivity to noise is significant, requires examination using the 24-hour Ldn descriptor.

Table 13-3 Land Use Categories and Metrics for Transit Noise Impact Criteria

Land Use Category Noise Metric (dBA) Description of Land Use Category

1 Outdoor Leq(H)*

Tracts of land where quiet is an essential element in their intended purpose. This category includes lands set aside for serenity and quiet, and such land uses as outdoor amphitheaters and concert pavilions, as well as National Historic Landmarks with significant outdoor use.

2 Outdoor Ldn Residences and buildings where people normally sleep. This category includes homes, hospitals and hotels where a nighttime sensitivity to noise is assumed to be of utmost importance.

3 Outdoor Leq(H)*

Institutional land uses with primarily daytime and evening use. This category includes schools, libraries and churches where it is important to avoid interference with such activities as speech, meditation and concentration on reading material. Buildings with interior spaces where quiet is important, such as medical offices, conference rooms, recording studios and concert halls fall into this category. Places for meditation or study associated with cemeteries, monuments, museums. Certain historical sites, parks and recreational facilities are also included.

*Leq for the noisiest hour (H) of transit-related activity during hours of noise sensitivity. Source: Federal Transit Administration, Transit Noise and Vibration Assessment, April 1995.

The FTA guidance manual contains criteria for noise levels that, if exceeded, may result in adverse community reaction; these stated criteria are used as the reference impact criteria for the project. These criteria are a function of the land use of the affected areas near a transit project, and day and night, one (1)-hour and eight (8)-hour Leq noise levels, and Ldn noise levels. In the case of construction noise criteria, FTA guidelines identify a screening distance of 1,500 feet between construction noise sources and sensitive receptors. Within this distance, detailed noise assessment is recommended. Detailed noise assessment uses a set of threshold Leq and Ldn levels for various construction activities. In urban areas with very high ambient noise levels (Ldn > 65 dBA), the threshold criteria for impacts occur when Ldn from construction operations exceed existing ambient levels by 10 dBA or more. The noise criteria and the descriptors used to evaluate project noise, including



operation and construction noise are dependent on the type of land use in the vicinity of the proposed project. Table 13-4 presents the FTA’s construction noise criteria for both the general noise assessment and the detailed noise assessment conducted in accordance with FTA methodologies. Using FTA guidelines, an airborne noise impact would occur if noise levels during construction exceed the FTA recommended values in Table 13-4.

Table 13-4 FTA Impact Criteria for Construction

1-hour Leq (dBA)

(General Assessment) 8-hour Leq (dBA)

(Detailed Assessment) Ldn (dBA)

(Detailed Assessment) Land Use Day Night Day Night 30-day Average

Residential 90 80 80 70 75* Commercial 100 100 85 85 80**

Industrial 100 100 90 90 85** * In urban areas with very high ambient noise levels (Ldn > 65 dB), impacts occur when Ldn from construction operations exceed existing ambient noise levels by more than 10 dBA. ** 24-hour Leq, not Ldn. Source: Federal Transit Administration, Transit Noise and Vibration Assessment, April 1995.

FTA operational noise criteria are based on a comparison of the existing noise levels and future outdoor noise levels from a proposed project (see Figure 13-2). There are two (2) noise criteria curves in the FTA guidelines. The curves are defined in terms of the noise exposure resulting from the FSTC and the existing noise exposure. It is the increase in the overall noise level, including existing and project related noise, which forms the basis for the criteria. For airborne operational noise, the FTA guidance manual defines noise criteria based on the specific type of land use that would be affected, with explicit operational noise impact criteria for three (3) land use categories. These impact criteria are based on either peak one (1)-hour Leq or 24-hour Ldn values. The FTA impact criteria for airborne operational noise are based on operational noise generated by the project, termed “project noise exposure”. Impacts are classified as “severe impacts” or “impacts” within each land use category, depending on existing ambient noise levels. A severe impact occurs when a change in noise level would result in strong adverse reactions, while an impact is noticeable to most people but not necessarily sufficient to result in strong adverse reactions from the community. With respect to the threshold for this assessment, an airborne noise impact during operations would occur if noise levels during operation fall in the “impact” or “severe impact” areas of the curve represented in Figure 13-2. For example, based on the operational impact criteria in Figure 13-3, in the case of land use category 2, if subject to an existing noise exposure of 60 dBA, a project noise exposure of 65 dBA would constitute a “severe impact”, a project noise exposure of 60 dBA in this case would result in an “impact”, and a project noise exposure of 55 dBA would not constitute an impact. Inclusion of analysis conducted based on methodologies of other relevant Lower Manhattan Recovery Projects is also provided as a common platform for developing more detailed mitigation measures. In addition to FTA guidelines applicable to transportation projects such as the FSTC, Federal, State and local guidelines are discussed below. Discussion of these guidelines is provided as context for understanding noise and vibration analysis, as it may be assessed by other Lower Manhattan Recovery Projects, including the World Trade Center (WTC) Memorial and Redevelopment Plan.

WESTST

BROADWAY

JOHNST

VESEYST

LIBERTYST

PARK R

OWCHURCHST

PINEST

MAIDENLA

NASSAUST

PARKPL

BARCLAYST

TRINITYPL

WALL

ST

ANNST

MURRAYST

BROOKLYN

BR

FULTONST

SOUTHS

FRANKFORTST

GREENWICHST

RECTOR ST

READEST

CLIFF

ST

NEWST

WASHINGTONST

WARREN

ST

SPRUCEST

PLATTST

CENTREST

ELKST

BEEKMANST

CEDARST

WESTBROADWAY

CHAMBERSST

EXCHANGEPL

BROADST

L

FLETCHERST

DUTCHST

GOLDST

THEATREAL

CORTLANDTST

THAMES STLIBERTYPL

RYDERSAL

EXCHANGE AL

EDGAR ST

MORRIS ST

ALBANY ST

WESTST

PEARL ST

WASHINGTONST

CEDARST

FDR

GOLDST

GREENWICHST

BEEKMANST

ANNST

P P

P

P

P

P

P

P

P

PP

P

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P

Generalized Land Use (2003):

Automotive (includessoft-site parking)Commercial

Curb Lines

Legend

VibrationMeasurementLocations

ApproximateProject Location


Vibration Analysis-

Historical Building Sites

Open Space/Park/ Plaza

Under Construction

Industrial

Institutional

Residential

Vacant

P On-Site Parking

Ground Floor Retail

Hotel

#S

Source: NYC DoITT Landbase; NYC DCP

200 0 200Feet

Figure 13-3

WILLIAMST ,.

A

B

E

D

C



OTHER GUIDELINES

Other Federal, State and local guidelines and criteria are discussed below in acknowledgement of the anticipated inclusion of such methodologies in the separate environmental reviews by other Lower Manhattan Recovery Projects sponsors. Although not applicable for analyses within this chapter, these methodologies were employed in the cumulative effects analyses found in Chapter 20 and to provide the context for comparisons of noise levels of the project with results of other projects. Unlike the FTA guidelines, the NYSDEC noise guidelines for assessing noise in New York State were not specifically developed for transit projects. An overview of the NYSDEC Guidelines is presented below. NYSDEC’s noise exposure guidelines, Assessing and Mitigating Noise Impacts, recommend the following criteria to define a significant noise impact for construction noise associated with both mobile and stationary construction equipment:

• Increases ranging from zero (0) – three (3) dB are considered not to have an appreciable effect on receptors;

• Increases from three (3) – six (6) dBA may have the potential for adverse noise impacts, but only in cases where the most sensitive of receptors are present;

• Sound level increases of more than six (6) dBA may require a closer analysis of impact potential depending on the existing SPL and the character of surrounding land use and receptors; and,

• An increase of 10 dBA deserves consideration of avoidance and mitigation measures in most cases.

Based on NYSDEC guidelines, the noise levels attributable to the FSTC should not exceed the ambient noise levels at the noise sensitive site. In other words, total combined noise levels (including project-related noise) should not exceed the total ambient noise level by three (3) dBA. Therefore, an increase of three (3) dBA or more in overall noise levels resulting from the operation of the FSTC over future noise levels without the FSTC is considered to be the threshold for noise impact determination. Since the FSTC is within a Central Business District (CBD), which already experiences high ambient noise levels (65 dBA or greater), the three (3) dBA increase threshold is applicable to the FSTC. In terms of construction noise, an increase of three (3) dBA or more in overall noise levels from the construction of the FSTC over the ambient (pre-September 11 condition) is also the impact threshold. The CEQR Technical Manual includes guidelines that are frequently used for development projects in New York City, especially where they require City funding or regulatory approvals. The CEQR technical guidelines focus particularly on traffic related noise from operation of new industrial, commercial or land use development. The methodologies in the CEQR Technical Manual are the basis for the WTC Memorial and Redevelopment Plan, a development project located immediately west of the Project Site. For construction noise, the CEQR Technical Manual refers to other guidance documents, including FTA guidelines. Because the CEQR guidelines were not developed for transit projects, FTA guidelines are used for analysis of the FSTC. The U.S. Department of Housing and Urban Development (HUD) noise analysis methodology is used by the WTC Memorial and Redevelopment Plan Draft General Environmental Impact Statement (DGEIS). The methodology is only applicable to the Memorial itself as it is the only receptor site subject to HUD regulatory approval or funding. In addition, the Memorial site is 500 feet or more from the Project Site and noise generated by construction or operation of the FSTC would not affect noise levels at the Memorial site. Therefore, analysis in accordance with HUD guidelines was not deemed warranted. The Route 9A Reconstruction project, located 1,000 feet or more west of the Project Site is expected to include a noise analysis methodology developed by the Federal Highway Administration (FHWA) for highway projects. Because of the distance of the Project Site to Route 9A, noise generated by FSTC



would not affect noise conditions at the Route 9A project site and vice versa. Analyses based on FHWA guidelines were therefore not deemed warranted. 13.4.3 VIBRATION AND GROUND-BORNE NOISE CRITERIA

FTA VIBRATION GUIDELINES

The FTA’s Transit Noise and Vibration Impact Assessment guidelines include a set of threshold criteria for ground-borne vibration and noise during transit operations. Vibration levels for typical human and structural responses and sources are shown in Table 13-5. The threshold criteria are based on past experiences with human sensitivity and community responses to ground-borne vibration and noise. In terms of vibration during construction, FTA defines a set of damage threshold criteria in VdB, a measure that relates to the maximum instantaneous peak of the vibration signal, and is often used in measuring the magnitude of vibration. The FTA-developed criteria for environmental impact from ground-borne vibration and noise from transit operations are based on the maximum levels for a single event. The impact criteria shown in Table 13-6 are used to determine whether a project would result in vibration and ground-borne noise impacts. The criteria are specified for the three (3) land use categories defined below.

Table 13-5 Typical Levels of Ground-Borne Vibration

Human/Structural Response VdB Typical Sources (at 50 feet)

Blasting from construction projects. Threshold, minor cosmetic damage fragile buildings. 100 Bulldozers and other heavy tracked

construction equipment.

Difficulty with vibration-sensitive tasks, such as reading a video screen. 90 Commuter rail, upper range.

Rapid transit rail, upper range. Residential annoyance, infrequent events. 80

Commuter rail, typical range.

Bus or truck over bump. Residential annoyance, frequent events. 70

Rapid transit rail, typical range.

Limit for vibration-sensitive equipment. 60 Bus or truck, typical.

Approximate threshold for human perception of vibration. 50 Typical background vibration.

Source: Transit Noise and Vibration Impact Assessment, FTA, April 1995. Vibration Category 1: High Sensitivity Buildings are considered to have high sensitivity when an environment of low ambient vibration is essential for the operations within the building (e.g., vibration-sensitive research, hospitals). This sensitivity to vibration may be well below levels associated with human annoyance. The criterion limit is based on levels that are acceptable for most sensitive equipment such as optical microscopes. Vibration-sensitive manufacturing or research typically requires detailed evaluation to define the acceptable vibration levels. Ensuring lower vibration levels in a building often requires special design of the HVAC systems and stiffened floors.



Vibration Category 2: Residential This category covers all residential land uses and any buildings where people sleep, such as hotels and hospitals. Because historic structures may include residences, the criteria for high sensitivity and residential vibration categories are considered at the same time. Vibration Category 3: Institutional This category includes schools, churches, other institutions and quiet offices that do not have vibration-sensitive equipment, but still have the potential for activity interference.

Table 13-6 Ground-Borne Vibration and Noise Impact Criteria

(for transit operations)

Ground-Borne Vibration Impact Levels (VdB re: 1 micro inch/second)

Ground-Borne Noise Impact Levels (dBA re: 20 micro Pascals) Land Use Vibration

Category Frequent Events1 Infrequent Events2 Frequent Events1 Infrequent Events2

1: Buildings where low ambient vibration is essential for interior operations.

65 VdB3 65 VdB3 See note4 See note4

2: Residences and buildings where people normally sleep.

72 VdB 80 VdB 35 dBA 43 dBA

3: Institutional land uses with primarily daytime use.

75 VdB 83 VdB 40 dBA 48 dBA

Notes: 1 "Frequent events" are defined as those with more than 70 vibration events per day. Most rapid transit projects fall into this category. 2 "Infrequent events" are defined as those with fewer than 70 vibration events per day. This category includes most commuter rail systems. 3 This criterion limit is based on levels that are acceptable for most moderately sensitive equipment such as optical microscopes. Vibration-sensitive manufacturing or research will require detailed evaluation to define the acceptable vibration levels. Ensuring lower vibration levels in a building often requires special design of the HVAC systems and stiffened floors. 4 Vibration-sensitive equipment is not sensitive to ground-borne noise. However, historic structures may include residences. Therefore ground-borne noise levels for category 1 land use will match those for category 2. Source: Transit Noise and Vibration Impact Assessment, FTA, April 1995, pages 8-2 through 8-3.

NEW YORK CITY DEPARTMENT OF BUILDINGS POLICY AND PROCEDURES (NYCDOB)

NYCDOB has developed a set of policy and procedures (PPN # 10/88) in order to avoid potential damage to historical structures resulting from adjacent construction and for any existing structure designated by the commissioner. The procedures require a monitoring program to reduce the likelihood of construction damages to adjacent historical structures and to detect at an early stage the beginnings of damage so that construction procedures can be changed. PPN # 10/88 includes a threshold of 0.50 inches per second (ips) for potential vibration damage. 13.5 ANALYSIS METHODOLOGY

13.5.1 INTRODUCTION

Noise and vibration analyses were conducted to identify any potential sensitive receptors in the study area that could be impacted as a result of the FSTC. A group of nine (9) sensitive receptor locations, including



residences, parks and churches, were identified within the study area (see Figure 13-1). Both general and detailed noise and vibration analyses were conducted for these receptors. As part of the analyses, existing noise levels were measured for continuous 24-hour periods during normal weekdays at these noise receptors. Future construction noise and vibration levels were calculated for comparison against existing levels for both 2003 and pre-September 11 conditions. Full details of the construction methods and activities analyzed are included in Chapter 4: Construction Methods and Activities. No perceptible noise would be generated during operation of the FSTC, operational noise impacts for project alternatives were therefore assessed in a qualitative manner. FTA noise guidelines compare future conditions with the project’s existing conditions. Existing conditions in 2003 reflect a recovery condition with atypical noise levels due to lower levels of traffic and unusually low traffic-related noise levels. Today, with traffic volumes approximately 15 to 25 percent lower than those of pre-September 11, ambient noise levels have also decreased, although these reductions may not be discernible to the average person. In order to reflect a more typical “existing condition”, the pre-September 11 condition was selected for analysis purposes in addition to the 2003 condition. This pre-September 11 Reference Condition was used to evaluate potential impacts for analysis year 2005/2006 (Construction) and analysis years 2008 (Initial Operation) and 2025 (Full Operation), in addition to the 2003 existing condition. Noise levels for the pre-September 11 Reference Condition (see Chapter 2: Analysis Framework) were estimated by proportionally adjusting the 2003 measured noise levels to reflect the difference in traffic volumes between 2003 and pre-September 11. In general, noise levels are lower than pre-September 11 levels, because of reductions in office workers, visitors and activities that previously catered to both the daytime and residential population. Therefore, the existing baseline year for the study area is defined as pre-September 11 (i.e., Year 2000). NOISE ANALYSIS

Mobile Sources Mobile sources are passenger cars, trucks, buses and other heavy vehicles that travel along the city streets. Ambient noise level changes attributable to mobile sources are directly related to the number of mobile sources, or levels of traffic volume, at a given location. Because of the way sound is perceived, an increase in noise levels by three (3) dBA requires a doubling of the intensity of the noise generating source. In the case of mobile source noise, a three (3) dBA increase therefore relates to a doubling of the traffic volume. To account for trucks, buses and other heavy vehicles creating more noise than passenger cars, CEQR Technical Guidelines provide a method to equate the noise of a truck with that of several passenger cars, known as PCE. For noise analysis purposes, traffic is thus expressed in PCEs, thereby allowing the combination of noise levels from different types of vehicles including trucks and buses. Based on this, a three (3) dBA increase relates to a doubling of PCEs. A screening analysis was conducted to identify intersections where a perceptible increase in noise levels due to mobile sources would occur. Studies have shown that a three (3) dBA increase is barely perceptible to the human ear, whereas a change of five (5) dBA is readily perceptible. Therefore, the doubling of traffic is considered to be the threshold for identifying adverse noise impacts. Adverse impacts were considered to occur when traffic noise levels associated with the project in 2005/2006 were predicted to exceed the pre-September 11 noise levels by more than three (3) dBA. Noise impacts from mobile sources associated with the construction of the FSTC were evaluated based on proposed construction activities of the FSTC. Typical construction activities include truck traffic from deliveries to and from the project site and removal of spoils associated with deconstruction and excavation activities.



Airborne noise from subway operations was also analyzed based on FTA guidance. The subway lines and stations in the Existing Complex are underground and fully covered. The only exception to this is the presence of sidewalk gratings which provide ventilation. Noise from underground fixed-rail operations propagates through these sidewalk gratings to street-level. Station design plans of the FSTC were reviewed to identify any potential areas where changes in station layout and subway operations would increase noise levels at street-level. Stationary Sources Stationary noise sources consist of off-road construction equipment that would be employed during the construction of the FSTC and mechanical equipment for building HVAC systems used during the actual operation of the FSTC. Stationary Construction Equipment Identification of stationary construction equipment to be used during the construction period is the product of a multi-step process that analyzed the foreseeable construction process based on proposed design concepts and available project information. First, construction activities were derived from an overall construction schedule. The duration, scheduling, and location of potential construction activities and sub-activities that would be required to fulfill the construction schedule was then deduced. Other parameters such as working hours (10 effective hours for construction equipment usage) and six (6) working days per week were then included in the analysis. From these assumptions, the types and number of pieces of construction equipment were identified and enumerated. With the identification of the types and number of pieces of equipment, as well as general location, duration and time of usage, typical noise emission levels from construction equipment such as bulldozers, vibratory compactors, generators, and pile driving operations were used as a basis to evaluate potential noise impacts at receptor locations in the study area. Noise and vibration impacts from construction activities (excluding vehicular traffic and truck routing) were assessed based on construction scheduling and the type and quantity of equipment utilized. Another essential input used to calculate construction noise levels at each sensitive receptor was the Acoustical Usage Factor (AUF). This is the percentage that a certain piece of equipment is expected to be utilized during the construction. Since the construction equipment is not expected to be in operation at full power continuously, an AUF was assigned to each piece of the equipment based on equipment usage cycles recommended by the equipment manufacturer. The AUF represents the percent of time a piece of equipment is assumed to be operating at full power while on site. Actual descriptions of data inputs into the noise models are included in Appendix J. The noise levels and AUF were based on FTA guidelines and data from similar construction projects and included equipment expected to be utilized during construction (see Table 13-7). Stationary construction equipment and their noise emissions are analyzed for analysis year 2005/2006 (Construction) only since they would no longer occur during the FSTC’s operation years of 2008 and 2025. In the analysis, noise emissions from construction equipment are analyzed for all three (3) alternatives (No Action, Alternative 9, and Alternative 10). The FSTC would have no construction equipment present under the No Action Alternative. Therefore, all noise emissions would result from other major Lower Manhattan Recovery Projects as discussed in Chapter 20: Coordinated Cumulative Effects Analysis. The analysis of potential noise emissions from construction of both Alternatives 9 and 10 considers the construction equipment anticipated to be utilized during the 2005/2006 peak construction period.



Table 13-7

Typical Construction Equipment Noise Emission Levels And Acoustical Usage Factors

Equipment Description Emission Levels at 50 feet (dBA) Acoustic Usage Factor % All other equipment > 5 HP 85 50

Auger Drill Rig 85 20

Backhoe 80 40

Ballast Equalizer 82 40

Ballast Tamper 83 40

Bar Bender 80 20

Boring Jack Power Unit 80 50

Chain Saw 85 20

Clam Shovel 93 20

Compactor (ground) 82 20

Compressor (air) 81 40

Concrete Batch Plant 83 15

Concrete Mixer Truck 85 40

Concrete Pump 82 20

Concrete Saw 90 20

Concrete Vibrator 76 40

Crane (mobile or stationary) 83 20

Derrick Crane 88 20

Dozer 85 40

Dump Truck 88 40

Excavator 85 40

Flat Bed Truck 84 40

Front End Loader 85 40

Generator 81 100

Generator (25 Kilovolt Amperes (kVA or less) 70 50

Grader 85 40

Horizontal Boring Hydraulic Jack 80 25

Hydra Break Ram 90 10

Impact Wrench 85 20

Insitu Soil Sampling Rig 84 20

Jackhammer 88 20

Mounted Impact Hammer (hoe ram) 90 20

Paver 89 50

Pickup Truck 55 40

Pneumatic Tools 85 50

Pumps 76 50 Source: Transit Noise and Vibration Impact Assessment, FTA, April 1995, MTA NYCT, The Louis Berger Group, Inc., 2004.

Stationary Operation Equipment During operation, stationary operation noise sources located within the FSTC were investigated and inventoried by review of future project design concepts. Mechanical equipment for building HVAC systems resulting from the proposed project was also included in the inventory by reviewing the proposed design concepts. Stationary operation noise sources are analyzed only for the analysis years 2008 (Initial Operation) and 2025 (Full Operation) since they would not be in existence during construction.



Ground-Borne Noise and Vibration Analysis Potential vibration and ground-borne noise from the construction of the FSTC was assessed based on FTA guidelines and criteria by reviewing project construction plans and schedules as described in Chapter 4: Construction Methods and Activities. The construction information utilized in assessing ground-borne noise and vibration included construction activities (see Chapter 4: Construction Methods and Activities) and other factors, such as: time and duration of the construction activities; equipment types; and equipment usage cycle. Typical vibration emission levels from construction equipment and stationary sources were utilized for the evaluation of potential impacts at receptor locations in the study area. Potential vibration and ground-borne noise from construction of other Lower Manhattan Recovery Projects such as the Permanent WTC Port Authority Trans-Hudson (PATH) Terminal was also included as part of the No Action condition.

13.5.2 DATA COLLECTION AND REVIEW

Transportation and land use data pertaining to the proposed study area, construction and operational traffic projections, and engineering plans and construction schedules from the WTC Memorial and Redevelopment Plan, Permanent WTC PATH Terminal and Route 9A Reconstruction Project were reviewed and utilized to determine baseline conditions and projected traffic levels and noise vibration levels. A list of the data and/or information utilized to conduct the analyses is included in Appendix J, and in Chapter 20: Coordinated Cumulative Effects Analysis. Details of construction traffic and equipment are provided in Chapter 4: Construction Methods and Activities, and Chapter 6: Traffic and Transportation. 13.5.3 AGENCY COORDINATION

NYCT coordinated the development of methodologies with the sponsors of the Lower Manhattan Recovery Projects including the Port Authority of New York and New Jersey (PANYNJ), New York State Department of Transportation (NYSDOT), and the Lower Manhattan Development Corporation (LMDC) to allow for data exchange and utilization of analysis results among Lower Manhattan Recovery Projects as detailed in the Environmental Analysis Framework for Lower Manhattan included as Appendix J. This coordination continued as the Lower Manhattan Recovery Project sponsors conducted their technical analysis and developed mitigation measures. In addition to methodologies, the sponsors of Lower Manhattan Recovery Projects have developed a common set of construction assumptions based on conceptual design and construction information. These construction assumptions will be updated as project information is provided by their sponsors. Throughout the development of methodologies and analyses, NYCT coordinated with resource agencies through Technical Advisory Committee (TAC) meetings attended by representatives of NYSDOT, PANYNJ, NYCDEP, LMDC, New York Metropolitan Transportation Council (NYMTC), NYSDEC, FTA, and FHWA. Working sessions among the sponsors of Lower Manhattan Recovery Projects focused on the sharing of project data and analysis results to support the development of a consistent approach to noise analysis that would be applied to other Lower Manhattan projects undertaken in the future. 13.6 AFFECTED ENVIRONMENT The events of September 11 have produced atypical existing conditions in the study area. Several streets within the project vicinity remain closed to traffic with traffic flows still not at pre-September 11 levels. Periodic recovery activities and reconstruction, including utility and street repairs, also contribute to the atypical noise levels and patterns produced in the area. Current land uses and sensitive receptor locations differ from pre-September 11 conditions, as the City’s residential grant program (see Chapter 7: Social and Economic Conditions) has encouraged residential conversion of commercial buildings, resulting in sensitive receptors not present prior to September 11.



13.6.1 AIRBORNE NOISE

Nine (9) sites were selected for noise measurements based on existing and anticipated future land use conditions (see Figure 13-1 and Table 13-6). Generally, the sites were chosen on the basis of proximity to the proposed FSTC site (i.e. Broadway, Fulton, Dey, John and Nassau Streets), proximity to sensitive land uses and potential increase in future noise levels. For example, a location at Fulton Street between Nassau and William Streets was selected due to its close proximity to an existing residential building and the proposed AC mezzanine construction area. In addition, this location may experience a potential increase in future noise levels, since the existing noise levels are relatively low compared to those at intersections. The nine (9) sites are primarily located at mid-block, rather than intersections, in order to better reflect residential, institutional, and other representative receptors in the project area. At the Millenium Hotel (Site 3 in Table 13-8), monitoring was conducted closer to the intersections in order to more closely represent the actual receptor location and provide proximity to the FSTC project construction activities. Detailed descriptions of each noise measurement site are presented in Appendix J, Part I. Based on existing noise level measurement results, existing noise levels (hourly Leq) range between 63 and 85 dBA in the area adjacent to the proposed FSTC site (see Table 13-8). Existing noise levels (hourly Leq) are consistently above 65 dBA during most of the daytime and evening hours and represent typical urban conditions. The major noise sources are vehicular traffic, including commuter buses, delivery and garbage trucks, helicopters, emergency sirens and human voices. The construction activities associated with on-going recovery efforts, such as utilities and street reconstruction, and recovery activities at the WTC site also contribute to the existing noise levels in the Study Area. The noise attributable to the on-going recovery activities were generally limited to areas immediately adjacent to the construction sites and occur only during the time of the construction (day time between 7 AM and 6 PM). 13.6.2 GROUND-BORNE NOISE AND VIBRATION

The primary sources for potential vibration and ground-borne noise in the project area are the existing underground subway facilities including the RW, AC, 45, JMZ and 23 lines which run below Broadway, Church, Fulton, Nassau and William Streets. Field observations conducted at nine (9) receptor locations that were also used during the ambient noise measurements indicated that none of the existing facilities result in any noticeable vibration or ground-borne noise at the nine (9) receptor locations. Ground vibration measurements conducted in the project area indicated that the ambient vibration levels in the vicinity of the Existing Complex were very low and ranged between 32 and 52 VdB (Arup, 2003). Levels measured during train pass-by events were in the range between 61 and 78 VdB. These existing levels exceed FTA criteria for all land use categories for frequent events (see Table 13-6). 13.7 ENVIRONMENTAL IMPACTS

13.7.1 INTRODUCTION

Noise impacts during the peak construction year 2005/2006 and operation years 2008 and 2025 for Alternatives 9 and 10 were evaluated by comparing the noise levels under these alternatives in each of the analysis years against the following conditions:

• No Action condition; • The 2003 existing condition; and, • The pre-September 11 Reference Condition.

The characterization of the noise environment was based on the contribution of mobile (traffic) and stationary (stationary equipment and off-road) sources. For purposes of the analysis, the contribution of both sources to the noise environment is described separately for each analysis year.



Table 13-8

Noise Measurement Results (2003) 24-Hour Measurement Sites

Site ID Site Name & Address Land Use Date Time

Period Leq (dBA)

Hourly

Leq (dBA) 8-hour

Ldn (dBA)

24-hour

1 NW corner of Broadway & Fulton Street Church 8/12/03 &

8/13/03 7 AM - 7 AM

65 – 85 76 80

2 195 Broadway Office/ Commercial

8/12/03 & 8/20/03

6 PM - 6 PM

67 – 79 75 79

3 Hilton Millenium Hotel-Dey Street Hotel 8/13/03 &

8/14/03 7 AM - 7 AM

64 – 72 69 74

4 Century 21– Cortlandt Street entrance Commercial 8/13/03 &

8/14/03 7 AM - 7 AM

63 – 78 72 75

5 180 Broadway Residential 12 Units

8/12/03 & 8/14/03

7 AM - 7 AM

67 – 76 74 79

6 140 Fulton Street between Broadway & Nassau Street

Residential 5 Units

8/14/03 & 8/20/03

8 AM - 8 AM

63 – 81 73 78

7 80 Nassau Street Residential 3 Units

8/14/03 & 8/20/03

8 AM - 8 AM

65 – 74 70 75

8 118 Fulton Street Residential 4

Units and Pace Univ. Dormitories

8/14/03 & 8/20/03

8 AM - 8 AM

63 – 75 70 76

9 10 John Street Residential 6 Units

8/13/03 & 8/14/03

7 AM - 7 AM

67 – 77 72 77

Source: The Louis Berger Group, Inc., 2004.

13.7.2 PRE-SEPTEMBER 11 REFERENCE CONDITION

The events of September 11 resulted in extensive impacts to the economy, transportation infrastructure, and environment in Lower Manhattan. The current 2003 condition represents a “Recovery Condition” with a lower level of economic activity and transit service and demand, as well as different patterns of vehicular traffic and pedestrian activity than existed prior to September 11. Due to the effects of September 11, current 2003 conditions are, therefore, not considered truly representative of normal conditions in Lower Manhattan. It is expected that this recovery condition would continue for several years. It would thus be several years before Lower Manhattan is restored to its pre-September 11 condition, and economic growth resumes, and is restored to the pre-September 11 growth projection condition. For the purposes of the DEIS, it is assumed that current and planned revitalization efforts would be successful so that the level of development and activity in 2025 would reflect the economic growth up to that year, as would have been projected prior to September 11 for 2025 (see Chapter 2). In recognition of this and in conjunction with the environmental analyses being carried out for other major Lower Manhattan projects (see Chapter 2, Section 2.4.4), the analysis of the FSTC includes a pre-September 11 “Reference Condition”, in addition to the Recovery Condition of 2005/2006 and 2008. The Reference Condition is defined as the existing conditions in Lower Manhattan on September 10, 2001. This Reference Condition was defined based on commitments by the project sponsors in the 2003 FTA document Approach to Cumulative Effects Analysis for the Major Lower Manhattan Recovery Projects, July 2003, based on FTA guidance, and reflecting coordination between the FTA and the Environmental Protection Agency (EPA) in the development of this approach. The pre-September 11 Reference



Condition thus provides a context for assessing and understanding noise impacts in addition to the Recovery Condition. Based on a comparison of traffic volume data between pre-September 11 and 2003 existing conditions, noise level data was adjusted from the existing measured noise levels to represent pre-September 11 noise levels. After September 11, traffic volumes decreased by 10 percent or more on Church Street and other local streets in the area. Table 13-9 represents the pre-September 11 noise levels as adjusted based on pre-September 11 traffic conditions. Noise levels measured in 2003 at Sites 1, 2, 5 and 9 were not adjusted to pre-September 11 since there were minimal changes in traffic patterns on Broadway and John Street between pre-September 11 and 2003. Noise levels for Sites 3, 4, 6, 7 and 8 were adjusted by between one (1) dB and five (5) dB based on the traffic volume differences between pre-September 11 and 2003 conditions. The greatest adjustment was at Site 4 on Cortlandt Street, which experienced the greatest traffic volume decrease after September 11. 13.7.3 ANALYSIS YEAR 2005/2006 (CONSTRUCTION)

NO ACTION ALTERNATIVE

Under the No Action Alternative, the Existing Complex would be maintained in its current state. Minor maintenance and rehabilitation activities could occur, including typical station and transit infrastructure maintenance and repair. These activities would not result in any substantial change in noise conditions in the study area. Existing commercial land uses in the study area would continue. Under the No Action Alternative, a number of other major projects would be under construction in the study area in 2005/2006 including the WTC Memorial and Redevelopment Plan, the Permanent WTC PATH Terminal, South Ferry Subway Terminal and Route 9A. The construction activities from these projects would be expected to result in elevated noise levels in the study area in 2005/2006 relative to 2003 and pre-September 11 conditions. Mobile Sources An analysis of mobile source noise impacts under the 2005/2006 No Action Alternative was conducted and compared with existing 2003 noise levels (see Appendix J, Part II). The analysis includes comparison of traffic volumes and PCEs and resultant noise level changes for the 2005/2006 No Action conditions with existing 2003 and pre-September 11 levels. Compared to existing 2003 levels, the No Action Alternative would result in increases at all nine (9) receptor locations due to increased background traffic from existing development, through traffic and construction traffic and equipment associated with the construction of other Lower Manhattan Recovery Projects in the study area. The increases in PCEs for the No Action Alternative between 2003 and 2005/2006 would range between four (4) percent and 64 percent at all nine (9) locations during the AM peak traffic hour (see Appendix JII.1). The increase in PCEs would result in imperceptible dBA increases between 0.2 dBA and 2.1 dBA. As Existing (2003) hourly Leq levels range from 63 to 85 dBA, the increase in noise levels by 0.2 dBA and 2.1 dBA would not result in exceedances of the 90/100 dBA FTA thresholds. A relative increase of less than three (3) dBA is not considered perceptible. In conclusion, there would be no adverse airborne noise impacts from mobile sources in the 2005/2006 No Action Alternative when compared with existing 2003 levels. Compared to pre-September 11 levels, the No Action Alternative would result in decreases at five (5) receptor locations. Additional traffic would be generated at the four (4) other locations, all of which would result in imperceptible increase of up to 1.6 dBA during the AM peak traffic hour (see Appendix JII.1). As pre-September 11 hourly Leq levels range from 64 to 85 dBA, increases in noise levels by up to 1.6 dBA would not result in exceedances of the 90/100 dBA FTA thresholds. A relative increase of less



Table 13-9

Pre-September 11 Noise Conditions

Site ID Site Name & Address Land Use Leq (dBA) Hourly

Leq (dBA) 8-hour

Ldn (dBA) 24-hour

1 NW Corner of Broadway & Fulton Street Church 65 – 85 76 80

2 195 Broadway Office/ Commercial 67 – 79 75 79

3 Hilton Millenium Hotel - Dey Street Hotel 67 – 75 72 77

4 Century 21–Cortlandt Street Entrance Commercial 68 – 82 77 80

5 180 Broadway Residential

12 Units 67 – 76 74 79

6 140 Fulton Street Between Broadway & Nassau Street

Residential 5 Units

64 – 82 74 79

7 80 Nassau Street Residential

3 Units 66 – 75 71 76

8 118 Fulton Street Residential 4

Units and Pace Univ.

Dormitories

65 – 73 72 78

9 10 John Street Residential

6 Units 67 – 77 72 77


than three (3) dBA is not considered perceptible. In conclusion, there would be no adverse airborne noise impacts from mobile sources in the 2005/2006 No Action Alternative when compared with pre-September 11 levels. Stationary Sources Typical noise emission levels from stationary construction equipment were utilized as a basis to evaluate potential noise levels at receptor locations in the study area. Peak one (1)-hour Leq, eight (8)-hour Leq, and 30-day Ldn were calculated at each of nine (9) sites for the twelve months of peak noise conditions within the overall 2005/2006 peak construction period. The resultant noise level histograms are also presented in Appendix J, Part II. The maximum noise levels from stationary sources at nine (9) sites were summarized based on those histograms and are presented in Appendix J, Part II, Stationary Source section. Results demonstrated that peak-hour noise levels would exceed FTA criteria of 90 dBA at Site 3 (Millenium Hotel) only. The peak eight (8)-hour noise levels would exceed FTA criteria of 80 dBA at Site 3 (Millenium Hotel) only. The peak 30-day Ldn levels would not exceed FTA criteria at any of the nine (9) receptor locations. ALTERNATIVE 9

Under this alternative the FSTC would be constructed as described in Chapter 4: Construction Methods and Activities. The traffic volumes, PCEs, percent PCE increases and resultant noise level increases from mobile sources for this alternative are presented in Appendix J, Part III.



To characterize the 2005/2006 noise environment under this Build Alternative, Build Condition noise levels were compared against established FTA criteria thresholds for three (3) conditions: 2005/2006 No Action Condition without FSTC (as discussed in immediately preceding section); Existing (2003) Condition without FSTC; and pre-September 11 Condition noise levels. The comparison of Alternative 9 against the 2005/2006 No Action Noise Condition identifies any incremental increase in noise levels attributable to the construction of the FSTC under this alternative. Mobile Sources Compared to the 2005/2006 No Action condition, the FSTC would result in decreases or no change in traffic at five (5) of the receptor locations, two (2) of which decrease due to street closures for activities proposed under the FSTC. Additional traffic would be generated at the four (4) other locations, three (3) of which would result in an imperceptible increase of less than one (1) dBA during the AM peak traffic hour. Site 4 (Century 21 Department Store) would experience a PCE increase of almost 200 percent resulting in a substantial increase of 4.6 dBAs during the AM peak hour. The increase is a result of construction truck traffic along Cortlandt Street from FSTC construction work zones. Using a three (3) dBA increase as the discernible threshold, there would be adverse airborne noise impacts from mobile sources at Site 4 during the AM peak hour. Compared to the 2003 Existing condition, Alternatives 9 and 10 would result in decreases or no change in traffic at two (2) of the receptor locations due to street closures for activities proposed under the FSTC. Additional traffic would be generated at the seven (7) other locations, six (6) of which would result in an imperceptible increase of less than one (1) dBA during the AM peak traffic hour. Site 4 would experience a PCE increase of almost 400 percent, resulting in a substantial increase of 6.8 dBAs during the AM peak hour. The increase from construction truck traffic is further mitigated in this condition than in the 2005/2006 No Action Alternative because 2003 existing volumes along Cortlandt Street are 64 percent lower than from pre-September 11 levels. As a result, this comparative increase between the 2005/2006 Build and 2003 existing conditions is further exacerbated. Using a three (3) dBA increase as the discernible threshold, there would be adverse airborne noise impacts from mobile sources at Site 4 during the AM peak hour. Compared to the pre-September 11 condition, the FSTC would result in decreases in traffic at four (4) of the receptor locations, two (2) of which are due to street closures for activities proposed under the FSTC. Additional traffic would be generated at the five (5) other locations, all of which would result in an imperceptible increase of up to 1.6 dBA during the AM peak traffic hour. (Site 4 does not experience a substantial increase because pre-September 11 volumes were higher than both the 2005/2006 No Action Alternative and 2003 Existing Conditions along Cortlandt Street. Using a three (3) dBA increase as the discernible threshold, there would be no adverse airborne noise impacts from mobile sources at any of the nine (9) locations during the AM peak hour. Stationary Sources The major components of the construction of the FSTC that would generate noise are listed below. Further details of these activities are provided in Chapter 4: Construction Methods and Activities.

• Deconstruction and Removal of Buildings at 189, 194, 196, 200 and 204 Broadway; • Relocation of Utilities; • Building Stabilization/Underpinning; • Cut-and-Cover Construction for the Dey Street Concourse and AC mezzanine; • Construction of New Buildings and Structures; and, • Tunneling for 45 line, RW underpasses and RW - E Connector.



Table 13-10

2005/2006 Construction Noise Levels During Peak Hour FTA General Analysis

Site ID Site Address Land Use

Distance to Nearest

Construction Activities

(feet)

Pre-September 11 Peak-Hour Leq

(dBA)

FTA Criteria Threshold

(dBA)

2005/2006 Maximum Peak-Hour Leq (dBA)

FTA Adverse Impact

1 NW Corner of Broadway & Fulton Street

Church 50 85 90 88 No

2 195 Broadway Office / Commercial 20 79 100 91 No

3 Hilton Millenium Hotel-Dey Street Hotel 20 75 90 97 Yes

4 Century 21–

Cortlandt Street entrance

Commercial 170 82 100 84 No


12 Units 10 76 90 80 No

6

140 Fulton Street between

Broadway & Nassau Street

Residential 5 Units

20 82 90 100 Yes

7 80 Nassau Street

Residential 3 Units

110 75 90 84 No

8 118 Fulton Street

Residential 4 Units and

Pace Univ. Dormitories

20 75 90 100 Yes


6 Units 40 77 90 90 Yes

Source: The Louis Berger Group, Inc., 2004. As presented in Table 13-10, equipment with higher noise emission levels does not necessarily result in higher hourly Leq levels, since the Leq levels are averaged out over a one (1)-hour period by taking the AUF into consideration. In other words, a piece of equipment with a higher emission level but a small AUF (i.e., typically operating under full power for small portions of time), may result in a lower Leq level than another piece of equipment with middle range of noise emission level but with a very high AUF. Furthermore, noise levels generally decrease as the distances between receptors and sources increase. Noise from construction equipment located at closer distances (e.g., 20 feet) can reach very high levels. However, noise levels, even for louder equipment, decrease substantially over larger distances (e.g., 400 feet). Reflecting the confined urban construction conditions for FSTC, sensitive receptors were located within close distances (within 50 feet) of the proposed construction activities and, therefore, would unavoidably experience high construction noise levels. The measured levels therefore reflect a conservative basis for impact assessment. Peak one (1)-hour Leq, eight (8)-hour Leq, and 30-day Ldn were calculated at each of nine (9) sites. Peak one (1)-hour noise levels would exceed FTA criteria of 90 dBA for residences and hotels and 100 dBA for office and commercial at Sites 3, 6, 8 and 9. The eight (8)-hour noise levels would exceed FTA criteria of 80 dBA (for residences and churches) and 85 dBA (office/commercial) at seven (7) of the nine (9) sites (see Table 13-11). It is noted that the calculated peak-hour and eight (8)-hour noise levels are the maximum expected noise levels at each of the receptor locations. In addition, expected noise levels would only occur during peak construction activities, which are limited to certain time periods and last for short periods of time, e.g. hours or days, over the entire construction duration.



The 30-day Ldn levels would exceed FTA criteria at Sites 2, 3, 6, 8, and 9 using the Minimum Distance Method (see Table 13-12). The Minimum Distance Method presents the most conservative analysis in determining the closest point that pieces of moveable equipment could be located to the receptor.

Table 13-11 2005/2006 Construction Noise Levels During Peak Eight (8)-Hour

FTA Detailed Analysis


Distance to Nearest


(feet)

Pre-September

11 8-hour Leq

(dBA)

FTA Criteria Threshold

(dBA)

2005/2006 Maximum

Peak 8-Hour Leq

(dBA)

FTA Adverse Impact


Church 50 76 80 85 Yes

2 195 Broadway Office/ Commercial 20 75 85 89 Yes

3 Hilton Millenium Hotel-Dey Street Hotel 20 72 80 94 Yes

4 Century 21–

Cortlandt Street entrance



12 Units 10 74 80 78 No

6

140 Fulton Street between

Broadway & Nassau Street

Residential 5 Units

20 74 80 98 Yes

7 80 Nassau Street

Residential 3 Units

110 71 80 81 Yes

8 118 Fulton Street



20 72 80 98 Yes


6 Units 40 72 80 89 Yes


(Stationary equipment would be placed as far away as possible within the work zone). In calculating noise levels using the Minimum Distance Method, several of the noise receptors were assumed to be located at relatively short distance from the noise generating source. This was especially the case for noise receptors associated with the construction at the Dey Street Passageway and the mezzanine at Fulton Street. While construction could occur as close as five (5) feet from a building façade, it should be noted that activities would not occur continuously at such proximities, especially for small distances (less than 20 feet). Rather, equipment at such distances would routinely move within different areas of the work site. The Average Distance Method therefore was also used to reflect the fact that actual locations of the construction equipment would move around throughout the construction areas or zones over an extended period (e.g. 30-days). When computed using the Average Distance Method, the 30-day Ldn levels at all nine locations (see Table 13-13) are substantially reduced and would not exceed FTA criteria at any of nine (9) sites evaluated.



Table 13-12

2005/2006 Construction Noise Levels During Peak 30-Day Period Based on “Minimum Distance” Method



Distance to Nearest


(feet)

Pre-September

11 Ldn (dBA)

Criteria Threshold

(dBA)

2005/2006 Maximum

Peak 30-day Ldn/Leq (dBA)

FTA Adverse Impact


Church 50 80 90 86 No

2 195 Broadway Office/ Commercial 20 75 85 92 Yes

3

Hilton Millenium Hotel-Dey

Street

Hotel 20 77 87 93 Yes

4

Century 21– Cortlandt

Street entrance



12 Units 10 79 89 75 No

6

140 Fulton Street

between Broadway &

Nassau Street

Residential 5 Units

20 79 89 94 Yes

7 80 Nassau Street

Residential 3 Units

110 76 86 76 No

8 118 Fulton Street

Residential 4 Units and Pace

Univ. Dormitories

20 78 88 94 Yes


6 Units 40 77 87 88 Yes


Vibration and Ground-Borne Noise Vibration and ground-borne noise levels were compared with established FTA threshold criteria for stationary construction equipment. Typical vibration levels for construction equipment at various distances are listed in Appendix J, Part IV. In general, the highest vibration levels are associated with clam shovel equipment used in slurry wall construction. Recent research indicates that structures respond differently to vibration depending upon their construction and upon the frequency of the vibration events. NYCDOB PPN # 10/88 and FTA guidelines include the following thresholds for potential vibration damage expressed in movement of ips:

• 0.50 ips for historic structures and structures specifically designated by the Commissioner (NYCDOB);

• 0.20 ips for fragile buildings (FTA); and, • 0.12 ips for extremely fragile historic buildings (FTA).



Table 13-13

2005/2006 Construction Noise Levels During Peak 30-Day Period Based on “Average Distance” Method



Average Distance Between

Construction Activities and

Receptor (feet)

Pre-September

11 Ldn (dBA)

Criteria Threshold

(dBA)

2005/2006 Maximum

Peak 30-day Ldn/Leq (dBA)

FTA Adverse Impact


Church 50 80 90 75 No

2 195 Broadway Office/ Commercial 20 75 85 78 No

3


Street

Hotel 20 77 87 81 No

4

Century 21– Cortlandt

Street entrance


5 180 Broadway Residence 12 Units

10 79 89 72 No

6

140 Fulton Street

between Broadway &

Nassau Street

Residence 5 Units

20 79 89 75 No

7 80 Nassau Street

Residence 3 Units

110 76 86 71 No

8 118 Fulton Street

Residential 4 Units and Pace

Univ. Dormitories

20 78 88 74 No

9 10 John Street Residence

6 Units 40 77 87 77 No

Source: The Louis Berger Group, Inc., 2004. The status of historic buildings in the study area with respect to fragility will be determined as engineering for the FSTC advances. Structural conditions of historic buildings will not be known until the final design stage. For the purposes of the analysis, it was assumed that historic buildings potentially affected by vibration would be considered fragile, and could eventually be determined to be extremely fragile.

The detailed and maximum vibration levels at each receptor site are presented in Tables 13-14 and 13-15, respectively. The potential construction related vibration levels of receptor locations were calculated at each receptor site for the peak 12-month period of construction vibration within the peak 2005/2006 construction period This period was identified as the time period with the greatest possibility for the vibration levels from construction activity occurring. Vibration levels were calculated for both singular and repetitive events at the closest distance equipment would be operating to a receptor location. It is also noted that the vibration levels calculated reflect a conservative estimate, as not all construction elements would be occurring at the same location within this time period. For more details, please see Appendix J, Part IV.



Table 13-14 Peak Period of Maximum Construction Vibration in 2006

PPV Level (ips)

Site Site Address Land Use

NYCDOB/FTA Criteria

Historic/Fragile Buildings)

Distance to Nearest


(feet) Jan

2006

Feb

2006

Mar

200

6

Apr

il 20

06

May

200

6

June

200

6

July

200

6

Aug

200

6

Sept

200

6

Oct

200

6

Nov

200

6

Dec

200

6

1

NW Corner of

Broadway & Fulton Street

Church 0.50/0.20 50 0.022 0.032 0.032 0.032 0.032 0.012 0.012 0.008 0.008 0.012 0.012 0.012

2 195 Broadway

Office/ Commercial 0.50/0.20 20 0.057 0.057 0.057 0.025 0.025 0.025 0.022 0.022 0.022 0.022 0.022 0.022

3


Street

Hotel 0.50/0.20 20 0.099 0.116 0.116 0.003 0.003 0.001 0.001 0.001 0.001 0.001 0.001 0.001

4

Century 21-

Cortlandt Street

entrance

Commercial 0.50/0.20 170 0.005 0.005 0.005 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002

5 180 Broadway

Residential 12 Units

0.50/0.20 10 0.016 0.016 0.016 0.007 0.007 0.007 0.006 0.006 0.006 0.006 0.006 0.006

6

140 Fulton Street

between Broadway & Nassau

Street

Residential 5 Units

0.50/0.20 20 0.124 0.331 0.331 0.331 0.331 0.124 0.124 0.057 0.049 0.124 0.124 0.124

7 80 Nassau Street

Residential 3 Units

0.50/0.20 110 0.008 0.022 0.022 0.022 0.022 0.008 0.008 0.004 0.004 0.008 0.008 0.008

8 118 Fulton Street



0.50/0.20 20 0.124 0.331 0.331 0.331 0.331 0.124 0.124 0.057 0.057 0.124 0.124 0.124

9 10 John Street

Residential 6 Units

0.50/0.20 40 0.100 0.100 0.100 0.044 0.044 0.044 0.038 0.038 0.038 0.038 0.038 0.038




Table 13-15

2005/2006 Maximum Construction Vibration Levels (PPV) of Highest Vibration Generating Equipment

Site Construction Activities Equipment Closest Distance

between Receptor and Construction

Activities (feet)

PPV (inch/sec)

1 AC mezzanine Slurry Wall Crawler Crane with Clam Shell 85 0.032

2 Entry Facility Retaining Walls Crawler Crane with Clam Shell 58 0.057

3 Dey Street Surface Restoration Dozer 21 0.116








Construction vibration at all sites during the peak construction period would be less than 0.5 inch/second, the threshold for potential cosmetic damage of the buildings.

In addition to the nine (9) receptor locations, anticipated construction-related vibration levels were calculated for five (5) nearby historic buildings, the only type of buildings with potential for vibration impacts (see Figure 13-2 and Table 13-16). Use of either the crawler crane with clam shell shovel for excavation in construction of a slurry wall or the auger drill for secant pile wall construction would result in impacts exceeding FTA criteria at four (4) of the five (5) historical buildings including: AT&T Building (Site B - 195 Broadway), East River Savings Bank (Site C - 25 Dey Street/24 Cortlandt Street), Bennett Building (Site D - 140 Fulton Street) and Corbin Building (Site E - 192 Broadway). Vibration levels resulting from construction of a secant pile wall would be substantially lower than levels from construction of a slurry wall using a crawler crane. The buildings would be subject to maximum vibration levels of up to 1.0 ips if drill augers were utilized in secant pile wall construction, exceeding the FTA criteria of 0.12 ips for extremely fragile historical buildings and 0.20 ips for fragile buildings. Slurry wall construction using a crawler crane would result in vibration levels more than twice those calculated for secant pile walls. It is noted that the vibration levels of secant pile wall construction are substantially lower than levels that would occur if pile driving rigs were employed, resulting in up to 2.3 ips, an alternative construction method originally considered but subsequently discarded.

The proposed mitigation would be developed during Final Design and would include a monitoring program to protect historic resources from increased vibration levels. NYCT, through its construction contractors, would implement special vibration protection measures that may include:



• Inspection and report on current foundation and structural conditions of historic resources; • Develop a monitoring program to measure vertical and lateral movement and vibration to historic

structures near construction activities. Details of the frequency and duration of the monitoring program would be determined as part of the project’s ongoing consultation with the New York State Historic Preservation Office (SHPO);

• Establish and monitor construction methods to limit vibrations to levels that would not cause structural damage. Such methods may include underpinning or expansion grouting as an alternative construction method; and,

• Issue “stop work” orders to the construction contractor, as required, to prevent damage to the structures, based on any vibration levels that exceed the design criteria in lateral or vertical direction. Work would not begin until steps proposed to stabilize and/or prevent further damage to the designated buildings were approved.

However, ground-borne noise and vibration impacts may still occur if individual construction activities are located at a close distance, e.g., 10 feet or less, from the receptor sites, and are not properly managed. NYCT would make all efforts, via the use of alternative construction methods and activities, to avoid impacts. A detailed description of such efforts is provided in Chapter 4: Construction Methods and Activities.

Table 13-16 2006 Maximum Construction Vibration Level (PPV) for Historical Buildings

Equipment PPV (ips)

Site Site

Closest Distance Between Building

Façade and Construction

Activities (feet) Crawler Crane

with Clam Shell Drilled Pile for

Secant Pile Wall

A St. Paul's Chapel and Graveyard (Broadway and Fulton Street) 85 0.032 --

B AT&T Building (195 Broadway) 5 2.2581 0.9951

C East River Savings Bank (25 Dey Street/24 Cortlandt Street) 5 2.2581 0.9951

D Bennett Building (140 Fulton Street) 5 2.2581 0.9951

E Corbin Building/ Proposed John Street -Maiden Lane Historic District 5 2.2581 0.9951

1 Vibration impacts would occur when clam shells would be used during slurry wall construction or drill augers would be used during secant pile construction. Source: The Louis Berger Group, Inc., 2004.

ALTERNATIVE 10

Under this Build Alternative, the FSTC would be constructed as described in Chapter 4: Construction Methods and Activities. For the purposes of analysis for potential impacts on ground-borne noise and vibration levels, there would not be any substantive differences between this alternative and the Alternative 9. Potential impacts and mitigation measures associated with this alternative would be similar to those associated with Alternative 9. Construction of Alternative 10 would be conducted in the same way as Alternative 9, with the exception of the Corbin Building. Unlike Alternative 9, which would likely construct a slurry wall on the north side of the Corbin Building, Alternative 10 would require underpinning of the Corbin Building in order to extend the Dey Street Passageway beneath the Corbin Building and into the basement of the Corbin Building. In addition to underpinning, this may also require a slurry wall along John Street. Construction techniques considered for the Corbin Building are described in Chapter 4: Construction Methods and Activities.



13.7.4 ANALYSIS YEAR 2008 (INITIAL OPERATIONAL)


Under the No Action Alternative, the Existing Complex would be maintained in its current state and configuration. Minor maintenance and rehabilitation activities could occur, including typical station and transit infrastructure maintenance and repair. These activities would not result in any substantial change in noise conditions in the study area. Existing commercial land uses in the study area would continue. Under the No Action Alternative, several other Lower Manhattan Recovery Projects would still be under construction in 2008, although the peak of construction would have occurred in 2005/2006 and construction activity would be considerably less in 2008. These projects include the WTC Memorial and Redevelopment Plan, the Permanent WTC PATH Terminal, and Route 9A. The construction activities associated with these projects would result in minimal increases in mobile source noise levels at the analyzed receptor locations relative to existing (2003) and pre-September 11 conditions. The mobile source noise emission analysis for 2008 is described in more detail in Appendix J. Noise level increases attributable to construction related stationary sources would also be minimal, as the intensity of construction in 2008 would be considerably less than the 2005/2006 construction peak of Lower Manhattan Recovery Projects. Construction-related stationary noise increases in 2008 compared to existing (2003) and pre-September 11 conditions would therefore be minimal. ALTERNATIVE 9

Under Alternative 9, the FSTC would be constructed as described in Chapter 4: Construction Methods and Activities) and would be operational in 2008. Mobile Sources During operation, the FSTC would not generate vehicular traffic. Therefore, there would be no substantial difference between the No Action Alternative and Alternative 9. The only potential mobile source associated with operation of the FSTC would be the existing subway station and subway trains. As stated in the FTA’s assessment guidelines, Transit Noise and Vibration Impact Assessment 1995, subway noise is generally not a problem for surrounding sensitive receptors because the ground acts as a barrier to noise transmission. The subway lines and stations are underground and fully covered, with the exception of ventilation gratings and shafts in the sidewalk. As a result, the noise from underground fixed-rail operations propagates through these openings to reach the surface. This alternative would not result in substantial increase in train operations, and operational noise impacts are not anticipated. Stationary Sources Under this alternative, the potential stationary sources of noise would be the FSTC HVAC and mechanical systems. Future noise levels would not be substantially different from existing ambient levels. Under this alternative, buildings would be structurally designed to accommodate HVAC and mechanical within the buildings to minimize noise impacts to adjacent uses and public areas. Cooling equipment would be located on elevated levels in or on top of proposed structures. Noise associated with this system, and with air tempering equipment and ventilation shafts would be designed to minimize audible noise at street level. The HVAC and mechanical systems would utilize noise reduction devices to minimize noise. Retail operations at the FSTC would be similar to those existing and would not substantially change existing noise conditions. In conclusion, the FSTC would not result in any significant adverse noise impacts from stationary sources.



Vibration and Ground-Borne Noise This alternative would not result in any changes to the existing subway alignments and profiles, in the type of trains using the track (i.e., suspension and wheel conditions would remain the same) and track structure. HVAC and mechanical equipment would be placed within buildings that would be designed to withstand vibratory impacts to the structures. Therefore, this alternative is not anticipated to result in a change in vibration levels at adjacent sensitive receptors, and there would not be any vibration and ground-borne noise impacts associated with the operation of Alternative 9. ALTERNATIVE 10

Under Alternative 10, the FSTC would be constructed as described in Chapter 4: Construction Methods and Activities) and would be operational in 2008. Operation of the FSTC under this alternative would be similar to Alternative 9 with the exception that some of the mechanical equipment would be located inside the rehabilitated Corbin Building. The adaptive reuse design of the Corbin Building would take into account any vibrations such equipment may cause and engineer the design accordingly. Alternative 10 would not have any adverse noise and vibration impacts. 13.7.5 ANALYSIS YEAR 2025 (FULL OPERATIONAL)


Under the No Action Alternative, the Existing Complex would be maintained in its current state and configuration. Minor maintenance and rehabilitation activities could occur, including typical station and transit infrastructure maintenance and repair. Existing commercial land uses in the study area would continue. These activities would not result in any substantial change in noise conditions from both mobile and stationary sources in the study area. As no substantial change in noise conditions would result from the continued operation of the Existing Complex, no detailed noise impact analysis is warranted for 2008. Under the No Action Alternative, a number of other major construction projects would be completed in the study area in 2025. The noise level increases from mobile sources over existing 2003 and Pre-September 11 conditions would be minimal. Details of the mobile source emission analysis were conducted for 2025 No-Action alternative and documented in Appendix J. ALTERNATIVE 9

Under Alternative 9, the FSTC would be constructed as described in Chapter 4: Construction Methods and Activities, and would be operational in 2025. Operation of the FSTC would not have adverse noise and vibration impacts, as detailed below. Mobile Sources During operation in 2025, the FSTC would not generate vehicular traffic. Therefore, there would be no substantial difference between the No Action Alternative and Alternative 9. As a result, the only potential mobile source associated with operation of the FSTC would be the existing subway station and subway trains. As stated in the FTA’s assessment guidelines, subway noise is generally not a problem for surrounding sensitive receptors because the ground acts as a barrier to noise transmission. The subway lines and stations are underground and fully covered, with the exception of ventilation gratings and shafts in the sidewalk. As a result, the noise from underground fixed-rail operations propagates through these openings to reach the surface. This alternative would not result in substantial increase in train operations, and operational noise impacts are not anticipated.



Stationary Sources Under this alternative, the potential stationary sources of noise would be the FSTC HVAC and mechanical systems. Future noise levels would not be substantially different from existing ambient levels. Under this alternative, buildings would be structurally designed to accommodate HVAC and mechanical within the buildings to minimize noise impacts to adjacent uses and public areas. Cooling equipment would be located on elevated levels in or on top of proposed structures. Noise associated with this system, and with air tempering equipment and ventilation shafts would be designed to minimize audible noise at street level. The HVAC and mechanical systems would utilize noise reduction devices to minimize noise. Retail operations at the FSTC would be similar to those existing and would not substantially change existing noise conditions. In conclusion, the FSTC would not result in any significant adverse noise impacts from stationary sources. Vibration and Ground-Borne Noise This alternative would not result in any changes to the existing subway alignments and profiles, in the type of trains using the track (i.e., suspension and wheel conditions would remain the same) and track structure. HVAC and mechanical equipment would be placed within buildings that would be designed to withstand vibratory impacts to the structures. Therefore, this alternative is not anticipated to result in a change in vibration levels at adjacent sensitive receptors, and there would not be any vibration and ground-borne noise impacts associated with the operation of Alternative 9. ALTERNATIVE 10

Under Alternative 10, the FSTC would be constructed as described in Chapter 4: Construction Methods and Activities and would be fully operational in 2025. Operation of the FSTC under this alternative would be similar to Alternative 9 and would not have any adverse noise and vibration impacts. 13.8 SUMMARY OF ADVERSE IMPACTS AND MITIGATION

MEASURES As described in the preceding sections, Alternatives 9 and 10 would create noise and vibration impacts during construction, as analyzed for 2005/2006, the peak construction period with the greatest potential for noise and vibration impacts. Mobile Sources Compared to 2003 existing conditions, Alternatives 9 and 10 would result in decreases or no change in traffic at two (2) of the receptor locations due to street closures for activities proposed under the FSTC. Additional traffic would be generated at the eight (8) other locations, seven (7) of which would result in an imperceptible increase of less than two (2) dBA during the AM peak traffic hour. The Century 21 Department Store - Cortlandt Street entrance (Site 4) would experience a Passenger Car Equivalent (PCE) (traffic volume) increase of almost 400 percent resulting in a substantial increase of 6.8 dBAs during the AM peak hour. Using a three (3) dBA increase as the discernible threshold, there would be adverse airborne noise impacts from mobile sources at Site 4 during the AM peak hour. Compared to pre-September 11 conditions, the FSTC would result in decreases in traffic at four (4) of the receptor locations, two (2) of which are due to street closures for activities proposed under the FSTC. Additional traffic would be generated at the five (5) other locations, all of which would result in an imperceptible increase of up to 1.6 dBA during the AM peak traffic hour. Using a three (3) dBA increase as the discernible threshold, there would be no adverse airborne noise impacts from mobile sources at any of the nine (9) locations during the AM peak hour.



Stationary Sources For Alternatives 9 and 10, peak one (1)-hour Leq, eight (8)-hour Leq, and 30-day Ldn for each month in the peak construction period were calculated at each of nine (9) receptor sites. Peak-hour noise levels would exceed FTA criteria of 90 dBA at Sites 3, 6, 8 and 9. The eight (8)-hour noise levels would exceed FTA criteria of 80 dBA (for residences and churches) and 85 dBA (office/commercial) at eight (8) of the nine (9) sites (see Table 13-9). When compared to 2003 levels, the 30-day Ldn levels would exceed FTA criteria at Sites 3, 6, 8 and 9 (see Table 13-10). It should be noted that at some locations, existing ambient noise levels are already above those specified in FTA impact criteria for construction. Consequently, mitigating construction noise to within FTA impact criteria levels would not be possible because the construction noise would be masked by the ambient noise levels. Vibration Under Alternatives 9 and 10, construction vibration at all nine (9) receptor sites during the 2005/2006 peak construction period would be less than 0.5 inch/sec. This is the threshold identified by NYCDOB’s Technical PPN # 10/88 to avoid potential damage to historic structures and structures specifically designated by the Commissioner of the NYCDOB. Five (5) locations with historical buildings, including two (2) which were included in the nine (9) locations, were also analyzed for vibration levels during the peak construction period. Four (4) of the five (5) historical buildings (Sites B, C, D and E) would experience maximum vibration levels above the FTA criteria of 0.20 for fragile historic buildings during the cut-off wall construction using either slurry wall or secant pile wall methods. These buildings include the AT&T Building at 195 Broadway (Site B), the East River Savings Bank on Church Street (Site C), the Bennett Building at 140 Fulton Street (Site D) and the Corbin Building at 192 Broadway (Site E). It is noted that the vibration levels associated with secant pile wall construction (using augur drill operations) would be substantially lower than those of slurry walls (with clam shell dropping operations). Various mitigation strategies were considered to limit the potential impact of noise and vibration. These strategies include source control, pathway control, and noise/vibration control at receptors. Noise reductions for each of these strategies were evaluated. Based on the extent of design and construction information that is available for the project during preparation of the Draft EIS (DEIS), mitigation of noise and vibration impacts from construction activities, excluding vehicular traffic and truck routing, was assessed either in a quantitative or qualitative manner. The following section discusses possible mitigation measures to reduce noise and vibration impacts. 13.8.1 AIRBORNE NOISE MITIGATION DURING CONSTRUCTION

The FSTC is located within a dense metropolitan area in close proximity to sensitive uses. This limits opportunities for developing feasible, cost-effective mitigation. Despite these constraints, NYCT is committed to developing mitigation measures that would reduce and, where practicable, eliminate significant impacts due to construction in accordance with FTA criteria. Currently, three (3) categories of noise control approaches are being explored: design considerations and project layout; sequence of operations; and alternative construction methods. A CEPP will be developed prior to construction and implemented throughout the construction of the FSTC. The CEPP would reflect the most recent designs and construction plans and would be updated continuously as the project schedule and activities evolve during construction. Many of the noise impacts occur in combination with the noise emissions of other Lower Manhattan Recovery Projects, particularly the construction of the Permanent WTC PATH Terminal and the WTC Memorial and Redevelopment Plan. NYCT has been and will continue to coordinate with sponsors of other Lower Manhattan Recovery



Projects in the development and implementation of noise mitigation measures to maximize the effectiveness of noise mitigation measures. An overview of potential elements of the CEPP is presented in the following paragraphs. An example of provisions to reduce noise emissions in a NYCT construction contract for a typical project in New York City is presented in Figure 13-4. EMISSION LIMITS AND PERFORMANCE STANDARDS

Construction of the FSTC would be limited between 7 AM and 6 PM, Monday through Saturday, as practicable. Noise from construction equipment is regulated by EPA noise emission standards which mandate that certain classifications of construction equipment, e.g. air compressors, pavement breakers, and heavy trucks, meet specified noise emission standards. NYCT would ensure that this regulation would be carefully followed. In addition, construction noise performance standards may be established by NYCT for locations of sensitive receptors adjacent to the FSTC. Such standards would be included with contract documents that will be met by all contractors during construction. Performance standards may include construction noise level thresholds for daytime, evening and nighttime hours at sensitive land uses at and/or adjacent to the FSTC. These threshold criteria would include hourly Leq and L10 during three (3) time periods, and may also include eight (8)-hour Leq and 30-day Ldn levels, consistent with FTA guidelines for construction noise. Specific restrictions to construction schedules may also be included to minimize potential interference with noise-sensitive uses, such as religious services at St. Paul’s Chapel. DESIGNATED TRUCK ROUTES

In general, because the project area has relatively high airborne noise levels due to existing traffic volumes, the increase in noise levels caused by delivery trucks and workers traveling to and from the construction sites would not be perceptible. However, localized increases in noise levels would be expected in the immediate vicinity of the FSTC near a few defined delivery truck routes and streets such as Broadway and Church Street. Since all truck trips would be restricted to the designated truck routes, it is anticipated that noise impacts associated with construction related traffic would be limited to the receptor sites adjacent to the designated truck routes such as Broadway and Church Street. NOISE MONITORING

Prior to construction, ambient noise measurements will be conducted at noise-sensitive locations, in addition to the noise measurements conducted during the environmental review process. After construction begins, representative 24-hour noise monitoring stations may be established; these stations will provide NYCT with the ability to monitor its contractors to ensure that the performance standards established by NYCT are met. Throughout construction, all contractors working on the FSTC may be required to meet the performance standards, procedures and conditions specified in the CEPP. DESIGN CONSIDERATIONS AND PROJECT LAYOUT

Design considerations and project layout approaches include such measures as constructing temporary noise barriers, placing construction equipment farther from noise-sensitive receptors, and constructing walled enclosures/sheds around especially noisy activities such as pavement breaking. There are several mitigation measures that have the potential to significantly reduce project impacts:

Example of Noise Reduction Specification

Included in a Construction Contract for a Typical NYCT Project

Measure additional sound levels for noise due to construction at the street line of the structure adjacent to

and along the area of the Contractor's operations and plant. Sound levels measured at the street line

shall not exceed the following:

Residential structures:

75 dBA: Daily, except Saturday and Sunday, 7:00 a.m. to 11:00 p.m.

60 dBA: At all other times.

Business-Commercial structures:

Daily, including Saturday and Sunday, all hours, a maximum of 85 dBA, unless otherwise

permitted by the Engineer.

Factory-Commercial structures:

Daily, including Saturday and Sunday, all hours, a maximum of 90 dBA.

Provide equipment and sound-deadening devices and take such noise abatement measures necessary

to comply with the requirements of the Contract, consisting of, for example, the following:

Shields or other physical barriers to restrict the transmission of noise.

Soundproof housings or enclosures for noise producing machinery.

Use of electrically operated hoists and compressor plants, unless otherwise permitted by

the Engineer.

Silencers on air intakes of equipment.

Maximum sized intake and exhaust mufflers on internal combustion engines.

Gears on machinery designed to reduce noise to a minimum.

Line hoppers and storage bins with sound deadening material.

The prohibition of the use of air or gasoline driven saws, unless otherwise permitted by

the Engineer.

Conducting the operation of dumping rock or other materials and carrying it away in trucks so

that noise is kept to a minimum.

Routing of construction equipment and vehicles carrying rock, concrete or other materials

over streets that will cause the least disturbance to residents in the vicinity of the work.


Example of Noise Reduction SpecificationIncluded in a Construction Contract

for a Typical NYCT Project

Figure 13-4

,.



• The use of acoustic barriers and walled enclosures around certain construction activities. For example, noise tents/enclosures could be used around workers using jackhammers. A temporary noise barrier 20-feet in height could be installed along the fence line/property line (at least partially) of the FSTC site to reduce the noise levels. In addition, temporary barriers e.g. wood panels on top of Jersey barriers could also be positioned adjacent to and moved along slurry wall and other construction operations, etc.;

• The installation of silencers on jackhammers, air compressors, generators, light plants and cranes to reduce noise levels;

• The use of electrically operated equipment, rather than combustion powered equipment, wherever possible;

• The use of soil lining inside aluminum carrying cases to reduce rock impact noise during truck load/unloading operations;

• The use of drive-through street-level truck enclosures for truck loading and unloading; • The use of sheds/enclosures at concrete pump sites during concrete truck unloading; and, • The placement of most loading/unloading inside the excavated areas and away from areas at

street-level, if possible. Overall, the implementation of such measures would reduce the number of adverse airborne noise impacts, but is unlikely to eliminate all of them. Even with these measures, construction operations would create adverse airborne noise impacts at locations adjacent to the FSTC. SEQUENCE OF OPERATIONS

Mitigation measures also include use of construction sequencing to reduce noise impacts. This can be achieved by either combining noisy operations to occur in the same time period, reducing impact duration, or by sequencing activities over a longer period, reducing impact intensity. NYCT would explore which construction operations can be limited to daytime operations only, without significantly affecting schedule and costs. At this time, NYCT is committed to restricting the timing of most surface activity related to cut-and-cover construction, such as building slurry walls, pile driving, and surface excavation. Such activities would not occur during the late evening and early morning hours (10 PM to 7 AM) unless these activities were enclosed or adequately distant from sensitive land uses, such as residences. However, it is possible that some activities could occur at night, though these would not include high noise producing activities. One general exception to the policy of avoiding overnight activities would involve utility work. Because utility work requires the complete closure of the roadway and shutting off utility service for several hours, utility work is normally undertaken at night. Some cut-and-cover construction would be needed, and noisy equipment, such as jackhammers, would at times be required. Where practicable, work would occur during the day. Moreover, late evening construction would occur during a limited number of evenings over the course of a year, which is the expected length of utility relocation work at a site. The feasibility of limiting other types of construction operations to daytime periods is also being examined by NYCT. It should be noted that even without construction of the FSTC, street reconstruction would occur as part of New York City Department of Transportation’s (NYCDOT) Street Reconstruction Program. ALTERNATIVE CONSTRUCTION METHODS

Alternative construction methods, using special low noise emission level equipment, and selecting and specifying quieter demolition methods would also be included in the CEPP. While impact pile driving is currently not anticipated, if such needs were to arise, alternative methods would be considered. The use of alternative construction methods would reduce the need for particularly annoying and disturbing operations such as the use of backup horns. Backup alarms are high-pitched signals that are designed to attract attention for workers who may be in the path of vehicles moving in reverse gear.



While effective, backup horns tend to produce noise that is generally annoying and disturbing to nearby residents, particularly late at night. Alternatives could include the use of infrared lighting and/or flagmen, provided it is approved by Occupational Safety and Health Administration (OSHA). In addition, NYCT would explore opportunities to use alternative, quieter construction techniques, and specially quieted equipment would be specified wherever feasible, economic and effective. The use of prefabricated or customized building components and materials could also help reduce the noise associated with cutting and assembling such components close to sensitive receptors. Sound Proofing of Residential Homes Noise levels at upper-story residential or commercial buildings may be difficult to mitigate with the noise barrier or other measures. Sound proofing of residential homes and/or commercial offices by installation of acoustical windows may provide additional noise reduction for those sensitive properties located at close proximity to the on-going construction operations. NYCT may conduct further study to investigate the feasibility and cost-effectiveness of providing sound proofing as a mitigation measure. Community Liaison and Complaint Hotline NYCT will establish a noise complaint process to be able to log and respond to noise complaints from affected residences. The community liaison and complaint hotline will also be set up in order to open a dialog and involve affected residents. It should be noted, however, that especially for such complex construction as that proposed in Lower Manhattan, alternative construction methods and mitigation measures require evaluation of other factors, including impacts to schedule and project cost considerations. If alternative construction methods result in schedule conflicts or delays, overall construction duration and exposure to construction noise could be extended. Overall, the types of noise mitigation that would be implemented at or adjacent to the FSTC would vary depending on the type and extent of construction and its proximity to sensitive uses (such as residences). Consequently, noise mitigation measures cannot be applied on a “one size fits all” basis, but must instead be tailored to the specific situation at each location. For each construction site, the noise control plan would include an inventory of all equipment and its associated noise levels; prediction of construction noise levels (which take account of ambient noise levels, the types of construction activities, percent of time in operation, and the time of day in operation); establishment of distances between receptors and noise sources; and finally, a description of the various noise reduction measures that could be used to meet the construction noise limits that would be imposed on the contractors. A preliminary list of such measures is provided below in Table 13-17. This list will be refined during subsequent phases of engineering and the Final EIS (FEIS) and will form the basis for contract construction documents. SUMMARY OF AIRBORNE NOISE MITIGATION MEASURES DURING CONSTRUCTION

One of NYCT’s goals is to minimize noise levels during construction. However, due to the proximity to residential properties and the duration of many construction activities, significant noise impacts during construction would be unavoidable. Therefore, NYCT is committed to implementing measures to reduce significant noise impacts resulting from construction, and all of the measures described above will be considered for feasibility and practicability of implementation. Measures to reduce noise impacts will be incorporated into project construction specifications. In some, but not all cases, these and other measures could substantially reduce noise levels during construction.



Table 13-17 Overview of Noise and Vibration Impacts and Mitigation of Construction Activities for Various Components and Locations - Fulton Street Transit Center


Possible Locations Types of Activities Typical Equipment Utilized Typical Time of

Operation Duration

(Mos.) Airborne Noise Impact Vibration Impact

Typical Equipment Noise Emission

Levels (dBA) Mitigation Potential Noise Level

Reduction in dBA

Beneath the RW at Church Street

Grout Improvement Immediately beneath

the Tracks/ Underpinning

Subsurface Grout Drills, Grout Pumps

Late at Night or on Weekends to

Avoid Disturbing Subway Operation

6 Months NS: Majority of the activities will be underground and covered by road deck. NS NA None Required. NA

Mining/Tunneling Subsurface Tunnel Roadheader 10 hours Between 7:00 and 5:00 6 Months NS: Majority of the activities will be

underground and covered by road deck. NS NA None Required. NA

Spoil Removal Street-Level Crane, Trucks, Loader 10 hours Between 7:00 and 5:00 6 Months S NS 88 Lining truck carrying case with ¾ CY of soil

to reduce impact noise from rock. 5

Concrete Pours Subsurface Concrete Pump 10 hours Between 7:00 and 5:00 6 Months NS: Majority of the activities will be


Tunneling for Underpasses

Beneath the 45 Line at Broadway

Welding/Piling Subsurface Welding Machines 10 hours Between 7:00 and 5:00 6 Months NS: Majority of the activities will be


Concourse under Dey Street Slurry Wall

Street-Level: Approximately

5 feet from Building Faces

Slurry Plant/Mixing Plant, Desanding Plant, Crawler Crane with Clam Shell,

Forklift, Concrete Pump, Trucks, Loader

10 hours Between 7:00 and 5:00 12 Months S: Slurry wall will reduce noise and

vibration vs. pile driving.

S: Slurry wall will reduce noise and vibration vs. pile

driving.

93 10

Installation of Temporary Roadway

Surface Decking Street-Level Auger Drill Rigs 10 hours Between

7:00 and 5:00 1 Month S S 85

Pile driving could be avoided if different construction method was employed;

Alternative construction equipment such as hydro-mill instead of clam shell excavator

may be used to reduce vibration near historical buildings; Use temporary noise

sheds/curtains/enclosures. 10

Excavation/Subsurface Construction Subsurface Crane, Trucks, Hydraulic Excavator,

Dozer, Welding Machine 10 hours Between

7:00 and 5:00 4 Months NS: Majority of the activities will be underground and covered by road deck. NS NA None Required. NA

Cut-and-Cover

AC mezzanine at Fulton Street

Misc. Machinery Use Street-Level 10 hours Between 7:00 and 5:00 4 Months NS NS NA None Required. NA

Drilled Pile Driving Street-Level Auger Drill, Crane, Air Compressor 10 hours Between 7:00 and 5:00 1 Month S NS 85 10

Secant Pile Wall Street-Level Auger Drill, Crane, Air Compressor 10 hours Between 7:00 and 5:00 1 Month S NS 85 10

Steel Erection Street-Level and Above Crane, Highlift, Tractor Trailer 10 hours Between

7:00 and 5:00 1 Month S NS 88 5

Building Stabilization

Corbin Building at the Corner of Broadway and

John Street

Anchoring Street-Level and Above Highlift 10 hours Between

7:00 and 5:00 1 Month S NS 88

Work would not occur late night; Use of temporary noise sheds/curtains/

enclosures and/or other mitigation measures would be employed.

5

De-Construction to Street-Level Street-Level

Crawler Crane with Clam Shell, Grapple, Hoe Ram, Bulldozer, Crane,

Jackhammers, Concrete Saws, Loader, Truck, etc.

10 hours Between 7:00 and 5:00 3 Months S S 90 5

Slurry Wall Street-Level Slurry Plant/Mixing Plant, Desanding Plant, Crawler Crane with Clam Shell,

Forklift, Concrete Pump, Trucks, Loader

10 hours Between 7:00 and 5:00 4 Months S: Slurry wall will reduce noise and

vibration vs. pile driving.

S: Slurry wall will reduce noise and vibration vs. pile

driving.

93 10

Subsurface Excavation Subsurface Trucks, Hydraulic Excavator, Loader, Crane

10 hours Between 7:00 and 5:00 2 Months S NS 88 10

Entry Facility/ Dey Street

Access Building

Entry Facility: Broadway

between Fulton and John Streets/

189 Broadway

Foundation and Super-Structure Subsurface Cranes, Concrete Pump, Trucks,

Generators, Tractor Trailer, etc. 10 hours Between

7:00 and 5:00 24 Months S: Pile driving generates substantial noise and vibration.

S: Pile driving generates substantial noise and vibration.

88

Work would not occur late night; Fit jackhammers, air compressors,

generators, light plant and cranes with silencers; Use noise tents/sheds around

workers using jackhammers; Enclose crane; Fit crane with silencer; Line truck carrying case with ¾ CY of soil to reduce

impact noise from rock.

10

Utility Relocation

All Cut-and-Cover Excavation Sites

Pavement Breaking, Excavation of Spoils,

Reinstallation of Utilities

Street-Level Bulldozer, Crane, Pavement Breaker, Jackhammers, Concrete Saws, Grinders

10 hours Between 7:00 and 5:00 Various S: Work could occur during late night

hours to avoid severe traffic disruptions.

NS: If Using saws instead of pavement

breaker. 88

Fit jackhammers, air compressors, generators, light plant and crane with

silencers, Use noise tents/sheds around workers using jackhammers.

10

Spoil Removal by Truck or

Barge

Cut-and-Cover Sites, Staging Areas, Truck Routes and

Excavation Sites

Trucks Traveling to and from Sites, Loading and

Unloading Street-Level Trucks, Loader 10 hours Between

7:00 and 5:00 Various S: Significant noise impact where loading and unloading takes place; No significant

noise impact on road/driver network. NS 88

Work would not occur late night, Line truck carrying case with ¾ CY of soil to reduce

impact noise from rock. 5

FSTC Site/WTC site Street-Level

Slurry Plant/Mixing Plant, Desanding Plant, Crane, Forklift, Concrete Pump,

Trucks, Loader

10 hours Between 7:00 and 5:00 Various S NS 88 5

Staging Area Streets and Sidewalks

Slurry Plants, Loading/Unloading,

Storage Street-Level Concrete Pumps, Loader, Crane, etc. 10 hours Between

7:00 and 5:00 Various S NS 85

Work would not occur late night; Enclose the crane; Fit crane with silencer; Use

flagmen or manually adjustable alarms to reduce back-up alarm noise. 5

S- Significant for noise and/or vibration; NS- Not significant for noise and/or vibration Source: The Louis Berger Group, Inc. 2004.

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13.8.2 GROUND-BORNE NOISE AND VIBRATION MITIGATION DURING CONSTRUCTION

As described above, construction activities could result in vibration and ground-borne noise impacts due to construction equipment operation. NYCT would explore a variety of mitigation measures to minimize such impacts. SEQUENCE OF OPERATIONS

Alteration of the sequence of construction activities so that multiple operations producing high vibratory levels do not take place in the same time period, avoiding nighttime activities, etc., will be evaluated during ongoing engineering to aid in the reduction of potential impacts. ALTERNATIVE CONSTRUCTION METHODS

Different construction methods could also be used to mitigate vibration and ground-borne noise. These include such measures as avoiding impact pile driving and equipment with high vibratory levels in vibration-sensitive areas, using non-impact construction technology, instituting special control measures to reduce the transmission of high vibratory levels to vibration-sensitive areas, etc. As discussed previously, where feasible, these types of measures would be used. Project construction engineers are exploring alternative construction techniques and special low-impact equipment. A number of controls would be implemented with respect to mitigation of vibration during construction. A preconstruction survey of any structure or use (e.g., operation of vibration- sensitive equipment such as laser eye surgery tools) likely to be adversely affected by the construction activities would be performed and thresholds or limiting values would be established that take into account each structure’s or use’s ability to withstand the loads and displacements due to construction vibrations. NYCT, through its contractors, would also meet with medical facilities or other users of especially sensitive equipment prior to construction to survey them regarding their special needs and schedule activities appropriately. Detailed construction specifications that impose reasonable acceptance criteria would be included in construction contracts. A project-wide vibration monitoring program would also be developed and implemented to monitor and identify vibration levels from construction activities at nearby sensitive receptors. This program would be reflected in the CEPP. A complaint response procedure would be implemented to promptly address community concerns and implement additional control methods where necessary. In addition, in advance of certain activities that are likely to result in vibrations, NYCT and its contractors will conduct extensive outreach to those in the surrounding blocks that could be affected. Additionally, vibration control plans would be developed and best management practices to limit vibration would be employed in sensitive areas, depending on the construction method required. These plans and practices would include the following measures. To avoid architectural damage (e.g., cracked plaster) to extremely fragile buildings within 80 feet of the construction work, deep saw cuts would be made between areas of pavement breaking and the sidewalk areas in front of buildings. With this technique, ground-borne vibration levels should be below the impact criteria at the foundations of most buildings and no damage is anticipated. Additionally, where practical, concrete cutters would be used on pavement surfaces instead of pavement breakers.



SPECIAL PROVISIONS FOR HISTORIC STRUCTURES

In addition to the mitigation measures described above, NYCT would consult with appropriate agencies such as NYCDOB and refer, as guidance, to applicable guidance set forth by the SHPO and the LPC to protect historic resources from increased vibration levels associated with construction activities. At any construction locations where historic resources, and particularly older fragile buildings, are within an area of potential effect, NYCT, through its construction contractors, would implement special vibration protection measures. To avoid any potential adverse effects to historic resources, a Construction Environment Protection Plan(s) would be developed in consultation with the SHPO and implemented before commencement of any excavation or construction. The CEPP would consist of an overall plan(s) of protection and avoidance of structural and architectural damage for all the potentially affected historic resources. Implementation of these plans would avoid or minimize the potential for adverse effects to historic resources during construction. The CEPP would be based on the requirements laid out in the “NYCDOB Technical PPN # 10/88,” concerning procedures for avoidance of damage to historic structures from adjacent construction. The PPN defines an adjacent historic structure as being contiguous to or within a lateral distance of 90 feet from a lot under development or alteration. These measures, to be included as part of the construction protection program for historic resources under both Alternatives 9 and 10, would include the following:

• Inspect and report on current foundation and structural conditions of any historic resources; • Establish a vibration monitoring program to measure vertical and lateral movement and vibration

to the historic structures within 150 feet of construction activities. Details as to the frequency and duration of the vibration monitoring program would be determined as part of the project’s ongoing consultation process with the SHPO;

• Establish and monitor construction methods to limit vibrations to levels that would not cause structural damage to the historic structures, as determined by the condition survey; and,

• Issue “stop work” orders to the construction contractor, as required, to prevent damage to the structures, based on any vibration levels that exceed the design criteria in the lateral or vertical direction. Work would not begin again until the steps proposed to stabilize and/or prevent further damage to the designated buildings were approved.

SUMMARY OF VIBRATION AND GROUND-BORNE NOISE MITIGATION MEASURES DURING CONSTRUCTION

With implementation of the measures discussed above, vibration levels during construction would be reduced below the levels that would cause architectural or structural damage. However, vibration levels would still be at levels that are perceptible, and could cause annoyance to residents adjacent to locations where substantial construction operations are taking place (e.g., locations adjacent to where excavated material is being removed from construction site, and locations where cut-and-cover and/or mining operations take place). At most of these locations, this vibration would occur for a considerable period of time. As described above, NYCT would not permit many types of operations to occur between 10 PM and 7 AM as a method of mitigating such impacts. Moreover, throughout the construction period, NYCT would maintain an extensive outreach system to advise affected communities of construction impacts. NYCT’s outreach system has been employed on tens of past projects. NYCT would also implement a CEPP throughout construction to prevent noise and vibration impacts wherever possible.

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