appendix vibration analysis report - 'virginia avenue … · virginia avenue tunnel...

Appendix F Vibration Analysis Report

June 2013

VIRGINIA AVENUE TUNNEL RECONSTRUCTION PROJECT

WASHINGTON, DC

VIBRATION ANALYSIS REPORT

June 2013

Prepared by CLARK/PARSONS, JOINT VENTURE

100 M Street, SE, Suite 1200 Washington, DC 20003

Phone: 202-775-3300. Fax: 202-775-3420

i

TABLE OF CONTENTS

Table of Contents ..................................................................................................................... i

ACRONYMS AND ABBREVIATIONS .......................................................................................... iii

STANDARDS ........................................................................................................................... iv

EXECUTIVE SUMMARY ............................................................................................................. v

1 INTRODUCTION .................................................................................................................... 11.1 PurposeofVibrationStudy...................................................................................................................................11.2 ProjectDescription...................................................................................................................................................1

2 VIBRATION BACKGROUND .................................................................................................... 42.1 VibrationBackground.............................................................................................................................................4

3 IMPACT CRITERIA .................................................................................................................. 63.1 OperationVibrationImpactCriteria.................................................................................................................63.2 ConstructionImpactCriteria................................................................................................................................7

4 EXISTING SETTING................................................................................................................. 84.1 ExistingLandUse......................................................................................................................................................84.2 VibrationMeasurements.......................................................................................................................................9

5 IMPACT ASSESSMENT ......................................................................................................... 215.1 ConstructionVibration.........................................................................................................................................215.2 Post‐ConstructionOperationVibration.........................................................................................................23

6 MITIGATION ....................................................................................................................... 276.1 ConstructionVibrationMitigation...................................................................................................................276.2 Post‐ConstructionoperationVibrationMitigation...................................................................................28

APPENDIX A FIGURES ............................................................................................................ 29

ii

LIST OF TABLES

Table ES‐1. Impact Distances for Existing and Future Ground‐Born Vibration Train Pass

By in the Tunnel

Table ES‐2. Construction Equipment Vibration Impact Distances

Table 3‐1. Land Use Categories and Metrics for Rail Noise Impact Criteria

Table 3‐2. Ground‐Born Vibration Criteria for Special Buildings

Table 3 3. Construction Vibration Building Damage Criteria

Table 4 1. Existing Train Pass‐by Vibration Measurements

Table 4 2. Existing baseline Vibration Measurements

Table 4 3. Existing Nighttime Baseline and Train Pass‐by Vibration Measurements

Table 4 4. Soil Factor Derived from Existing Train Pass By Measurements at the East

Portal

Table 5‐1. Measured Vibrations Levels verses Calculated Vibrations for Building Sites

near the Tunnel

Table 5‐2. Impact Distances for existing and future Ground‐Born Vibration Train Pass

By

Table 5‐3. Highest Construction Equipment Vibration Levels

Table 5‐4. Ground‐Born Vibration Source Levels for Construction Equipment

Table 5‐5. Construction Equipment Vibration Impact Distances

LIST OF FIGURES

Figure 1‐1. Project Location Map

Figure 2 1. Typical Levels of Ground‐Borne Vibration

Figure 4 1. Existing Train Pass‐by Longitudinal Vibration Measurements

Figure 4 2. Existing Train Pass‐by Transverse Vibration Measurements

Figure 4 3. Existing Train Pass‐by Vertical Vibration Measurements

Figure 4 4. Existing Night Time Train Pass‐by Vertical Vibration Measurements

iii

ACRONYMS AND ABBREVIATIONS

CSX CSX Transportation, Inc.

DDOT District of Columbia Department of Transportation

FHWA Federal Highway Administration

FTA Federal Transit Administration

HVAC Heating, Ventilation, and Air Conditioning

Lmax Maximum level for a single vibration event

MTA Maryland Transit Administration

PPV Peak Particle Velocity

RMS Root Means Square

USDOT United States Department of Transportation

VAT Virginia Avenue Tunnel

VdB Vibration decibel

VRE Virginia Railway Express

iv

STANDARDS The following guidelines are utilized for the vibration impact and mitigation assessment:

FTA Noise and Vibration Impact Assessment, May 2006.

v

EXECUTIVE SUMMARY A study was conducted to assess potential vibration conditions during and after the expansion

of Virginia Avenue Tunnel (VAT) on the surrounding community. CSX intends to expand the

existing one track tunnel to two tracks and increase the tunnel minimum vertical clearance to 21

feet above top of rail. This study was conducted in accordance to the procedures outlined in the

Federal Transit Administration Noise and Vibration Impact Manual. Three proposed VAT

alignment alternatives were assessed for vibration impacts in both construction and post‐

construction phases. All three of the proposed alternatives run under Virginia Avenue, SE near

vibration sensitive land use areas and buildings along a 3,800 feet stretch of tunnel within

Washington, DC. Vibration measurements were conducted at three locations near the proposed

VAT expansion. Results of these measurements were used to determine vibration levels from

existing train pass bys and calculate vibration transferability characteristics of the soil which

could then be used for predicting the vibration levels from construction activities and post‐

construction train operations.

Vibration impacts were evaluated for human annoyance and building damage. The distance

between vibration sensitive receptors and the new track alignments were obtain from the

concept design files. The train source used for calculating impact distances was derived from

the measured vibration levels. Table ES‐1 shows impact distances from the edge of track for the

potential of projected building damage and human annoyance due to the existing and future

train operations, as well as during construction. As indicated in Table ES‐1, any structures

farther than 20 feet away from the edge of track would not have vibration building damage

impacts and human annoyance impacts would not occur at more than 36 feet away from the

edge of track even when there are two trains traveling through the tunnel or tunnels at the same

time. Vibration impacts are not anticipated due to future, post‐construction train operations

because the closest building to any of the project alignment alternatives is 44 feet from edge of

track.

The potential for vibration annoyance and building damage was also analyzed for major

vibration producing construction equipment that would be used on this project. Vibration levels

produced by construction equipment were obtained from the Federal Transit Administration

Noise and Vibration Impact Assessment Manual. These vibration levels were used to calculate

the distances at which vibration impacts would occur. As shown in Table ES‐2, mitigation

measures would need to be considered, if construction equipment were to operate near

residential or institutional buildings within these distances. Because detailed construction

activities and types of equipment that will be utilized for each phase are not available at this

time, overall vibration levels from each construction phase cannot be predicted. Once detailed

construction schedule for various phases of the construction is developed during the final

design, these predicted vibration levels need to be confirmed and expanded as needed.

vi

Table ES‐1. Impact Distances for Existing and Future Ground‐Born Vibration Train

Pass By in the Tunnel

Alternatives

Distance to Potential Vibration

Building Damage feet

Distance to Potential Vibration Human Annoyance

feet

Existing/ No Build 10 17

Alternative 2 (during construction) 10 17

Alternative 2 20 36

Alternative 3 20 36

Alternative 4 20 36

Table ES‐2. Construction Equipment Vibration Impact Distances

Equipment

Distance to Potential Vibration

Building Damage2 feet

Distance to Potential Vibration Human

Annoyance1 feet

Large bulldozer 21 38

Loaded trucks 20 35

Hoe Ram 21 38

Caisson drilling 21 38

Vibratory compactor/roller 33 59

Sheet Driver (Sonic) 30 53

Jackhammer 13 23

Notes: 1. This is the distance at which the PPV is 0.04 in/sec or less at the inside of the building structure. 2. This is the distance at which the peak particle velocity is 0.20 in/sec or less.

While ground‐borne vibrations are not expected to exceed FTA building damage and human

annoyance impact criteria for the train operations on proposed alignment alternatives,

construction activities such as earth moving with bulldozers, the use of vibratory compaction

rollers, and sheet piling would have the most likely potential to cause some human annoyance

impacts. There are cases where it may be necessary to use this type of equipment in close

proximity to residential buildings near vibration sensitive area; however, there are mitigation

measures that can be used to minimize human annoyance.

Vibration Analysis Report 1

1 INTRODUCTION

1.1 PURPOSE OF VIBRATION STUDY The purpose of this study is to assess future vibration conditions at vibration sensitive locations

along the Virginia Avenue Tunnel Project. The Virginia Avenue Tunnel Vibration Study is

divided into six sections. Section 1 presents the overall Virginia Avenue Tunnel project

description. Section 2 explains the general vibration terminology. Section 3 presents the

guidelines and criteria used to assess the impact of the proposed Virginia Avenue Tunnel

project. Section 4 presents the results of baseline vibration measurements. Section 5 analyzes the

future impacts of construction, operation, and supporting facilities. Section 6 discusses possible

mitigation measures that may be required to reduce the impact of the Virginia Avenue Tunnel

Project.

1.2 PROJECT DESCRIPTION CSX Transportation, Inc. (CSX) is proposing to reconstruct the Virginia Avenue Tunnel. The

tunnel is located in the Capitol Hill neighborhood of the District of Columbia beneath

eastbound Virginia Avenue SE from 2nd Street SE to 9th Street SE, Virginia Avenue Park and

the 11th Street Bridge right‐of‐way between 9th and 11th Streets SE, and is aligned on south

side of Interstate 695 (I‐695). The tunnel portals are located a short distance west of 2nd Street

SE and a short distance east of 11th Street SE. CSX also owns or has easements of the rail lines

immediately east and west of the tunnel. The tunnel and rail lines running through the District

are part of CSX’s eastern seaboard freight rail corridor, which connects Mid‐Atlantic and

Midwest states.

The CSX proposal includes the complete reconstruction of the tunnel, which was built over 100

years ago. In addition to its age, the tunnel is also a bottleneck to the freight rail network with

its single‐track configuration and with a vertical clearance that does not allow for double‐stack

intermodal container freight trains. The Project will transform the tunnel to a two‐track

configuration, matching the number of tracks immediately east and west of the tunnel, and

provide the minimum 21 feet of vertical clearance to allow double‐stack intermodal container

freight train operations. This will allow more efficient freight movement, especially in light of

expected increases in freight volume. Reconstructing the tunnel to allow double‐stack

intermodal container freight trains would require lowering the grade below the rail line’s New

Jersey Avenue SE Overpass to provide the 21‐foot minimum clearance.

The following alternatives are being considered for the Project:

Alternative 1 ‐ No Build: The No Build alternative, which is automatically carried

forward into the Draft EIS. The tunnel would not be rebuilt under this alternative.

However, the railroad would continue to operate trains through the tunnel and at some

point, emergency or unplanned major repairs or rehabilitation could be required to this

Virginia Avenue Tunnel Reconstruction Project


critical, aging infrastructure that might prove equally or even more disruptive to the

community than the Build Alternatives.

Alternative 2 ‐ Rebuilt Tunnel / Temporary Runaround Track: This alternative

involves rebuilding the existing Virginia Avenue Tunnel. It would be rebuilt with two

tracks and enough vertical clearance to accommodate double‐stack intermodal container

freight trains. It would be rebuilt in generally the same location, except aligned

approximately seven feet to the south of the existing tunnel center line. It would be

rebuilt using protected open trench construction methods. During construction, freight

trains would be temporarily routed through a protected open trench outside the existing

tunnel (runaround track). The runaround track would be aligned to the south of the

existing tunnel. It would be parallel to the existing tunnel and would be below street

level. Due to new columns associated with the rebuilt 11th Street Bridge, the runaround

track would slightly separate from the tunnel alignment on the east end starting just

west of Virginia Avenue Park. Safety measures such as securing fencing would be used

to prevent pedestrians and cyclists from accessing the runaround track.

Alternative 3 ‐ Two New Tunnels: This alternative involves replacing the existing

Virginia Avenue Tunnel with two new permanent tunnels constructed sequentially.

Each new tunnel would have a single track with enough vertical clearance to allow

double‐stack intermodal container freight trains. A new parallel south side tunnel would

be built first as trains continue operating in the existing Virginia Avenue Tunnel. After

the south side tunnel is completed, train operations would switch over to the new tunnel

and the existing Virginia Avenue Tunnel would be demolished and rebuilt. With the

exception of operating in a protected open trench for approximately 230 feet

immediately east of the 2nd Street portal (within the Virginia Avenue SE segment

between 2nd and 3rd Streets SE), trains would operate in enclosed tunnels throughout

construction under Alternative 3. Throughout most of the length, the two tunnels would

be separated by a center wall. This center wall would be the new centerline of the two

tunnels, and it would be aligned approximately 25 feet south of the existing tunnel

centerline, between 2nd and 9th Streets SE. Due to new columns associated with the

rebuilt 11th Street Bridge, the tunnels would be separated on the east end starting just

west of Virginia Avenue Park, resulting in two separate single‐track tunnels and

openings at the east portal.

Alternative 4 ‐ New Partitioned Tunnel / Online Rebuild: Alternative 4 would result in

a new tunnel with a center partition wall separating two permanent single tracks.

Similar to Alternative 3, the new partitioned tunnel would be partitioned and have

enough vertical clearance to allow double‐stack intermodal container freight trains. It

would be aligned approximately 17 feet south of the existing tunnel’s centerline. The

new partitioned tunnel would be built using protected open trench construction

methods. Safety measures such as secure fencing would be used to prevent pedestrians

and bikers from accessing the protected open trench. The rebuild would occur ‘online’

meaning that during the period of construction, the protected open trench would

accommodate both construction activities and train operations. Maintaining safe and



reliable temporary train operations is a more complicated endeavor under Alternative 4

than under the other two Build Alternatives because of the online rebuild approach.

Regardless of Build Alternative, the Project would extend the east portal by approximately 330

feet to a location northeast of the 12th Street and M Street T‐intersection.

The anticipated limits of work are estimated to be 1,500 feet south of the West Portal of the VAT

to 1,200 feet north of the East Portal of the VAT, a total of 6,500 feet. Figure 1‐1 shows the project

location.

Figure 1-1. Project Location Map

New Jersey Ave. SE Overpass


2 VIBRATION BACKGROUND

This section describes the basic concepts of vibration methodology used in this study. This

information will provide background for the assessment procedures described in the later

sections.

2.1 VIBRATION BACKGROUND Vibration is an oscillatory motion, which can be described in terms of displacement, velocity, or

acceleration. Displacement, in the case of a vibrating floor, is simply the distance that a point on

the floor moves away from its static position. The velocity represents the instantaneous speed of

the floor movement, and acceleration is the rate of change of the speed. The response of

humans, buildings, and equipment to vibration is normally described using velocity or

acceleration. In this report, velocity will be used in describing ground‐borne vibration.

Vibration amplitudes are usually expressed as either peak particle velocity (PPV) or the root

mean square (RMS) velocity. The PPV is defined as the maximum instantaneous peak of the

vibration signal in inches per second. The RMS of a signal is the average of the squared

amplitude of the signal in inches per second. Although PPV is appropriate for evaluating the

potential of building damage, it is not suitable for evaluating human response. Since it takes

some time for the human body to respond to vibration signals, RMS amplitude is more

appropriate to evaluate human response to vibration than PPV.

The Federal Transit Administration (FTA) a division of the U.S. Department of Transportation

(USDOT) uses the abbreviation “VdB” for vibration decibels (FTA, 2006) to reduce the potential

for confusion with sound decibel and the reference value to covert PPV and RMS into VdB is 1

micro‐inch per second. For sources such as trains, PPV VdB levels are higher than RMS levels

and conversion factor of 4 is applied to PPV measurements when determining the VdB RMS

level this conversion number is known as the crest factor.

Figure 2‐1 illustrates common vibration sources and the human and structural responses to

ground‐borne vibration. As shown in Figure 2‐1, the threshold of perception for human

response is approximately 65 VdB; however, human response to vibration is not usually

significant unless the vibration exceeds 70 VdB, unless it’s a concert hall or other fine arts

performance venues. Vibration tolerance limits for sensitive instruments such as MRI or

electron microscopes could be much lower than the human vibration perception threshold.



Source: FTA (2006)

Figure 2-1. Typical Levels of Ground-Borne Vibration


3 IMPACT CRITERIA

This section presents the guidelines, criteria, and regulations used to assess noise and vibration

impacts associated with the proposed project.

3.1 OPERATION VIBRATION IMPACT CRITERIA The District of Columbia Department of Transportation (DDOT) environmental regulations do

not address potential vibration impacts; therefore, the criteria in the FTA Transit Noise and

Vibration Impact Assessment (FTA, 2006) were used to evaluate vibration impacts from train

operations. The evaluation of vibration impacts can be divided into two categories: (1) human

annoyance and (2) building damage.

HUMAN ANNOYANCE CRITERIA Table 3‐1 presents the criteria for various land use categories as well as the frequency of events.

The criteria are related to ground‐borne vibration causing human annoyance or interfering with

the use of vibration sensitive equipment. The criteria for acceptable ground‐borne vibration are

expressed in terms of RMS velocity levels in VdB and are based on the maximum levels for a

single event (Lmax). PPV has been added to this table to make an easier comparison to the

measured data for this project.

Table 3‐1. Land Use Categories and Metrics for Rail Vibration Impact Criteria

Land Use Category

Ground‐Borne Vibration Impact Levels (dB re 1 micro‐inch/sec)

and PPV (in/sec)

Frequent1 Events Occasional Events2 Infrequent3 Events

Category 1: Buildings where vibration

would interfere with interior

operations.

65 VdB4 0.007

in/sec 65 VdB4

0.007

in/sec 65 VdB4

0.007

in/sec

Category 2: Residences and buildings

where people normally sleep. 72 VdB

0.016

in/sec 75 VdB

0.023

in/sec 80 VdB

0.040

in/sec

Category 3: Institutional land uses

with primarily daytime use. 75 VdB

0.023

in/sec 78 VdB

0.032

in/sec 83 VdB

0.056

in/sec

Source: FTA, 2006.

Notes:

1. “Frequent Events” is defined as more than 70 vibration events per day.

2. “Occasional Events” is defined as between 30 and 70 vibration events of the same source per day.

3. “Infrequent Events” is defined as fewer than 30 vibration events per day.

4. 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.



There are some buildings, such as concert or band halls, TV and recording studios, as well as

theaters that can be sensitive to vibration and noise but do not fit into any of the three

categories. Because of the sensitivity of these buildings, they usually warrant special attention.

Table 3‐2 gives criteria for acceptable levels of ground‐borne vibration for various types of

special buildings.

Table 3‐2. Ground‐Born Vibration Criteria for Special Buildings

Type of Building or Room

Ground‐Borne Vibration Impact Levels (dB re 1 micro‐

inch/sec) and PPV (in/sec)

Frequent1 Events Occasional or Infrequent

Events2

Concert or Band Halls, TV Studios,

Recording Studios 65 VdB 0.007 in/sec 65 VdB 0.007 in/sec

Auditoriums, Theaters 72 VdB 0.016 in/sec 80 VdB 0.040 in/sec

Source: FTA, 2006.

Notes:

1. “Frequent Events” is defined as more than 70 vibration events per day.

2. "Occasional or Infrequent Events" is defined as fewer than 70 vibration events per day.

BUILDING DAMAGE CRITERIA Normally, vibration resulting from a train pass by would not cause building damage. However,

the potential for damage to fragile historic buildings located very near to or within the right‐of‐

way can be a concern. The FTA provides a vibration damage threshold criterion of 0.50 in/sec

PPV for fragile buildings and 0.12 in/sec PPV for extremely fragile historic buildings, for typical

train operations (FTA, 2006). The FTA recommends these criteria be used as a damage threshold

for the fragile structures located near the right‐of‐way of a rail project.

3.2 CONSTRUCTION IMPACT CRITERIA Construction activities can result in varying degrees of ground vibration, depending on the

equipment and method employed. The vibration associated with this transit construction

project involves demolition, excavation, and shoring of a tunnel and there is the potential for

building damage and it needs to be assessed. The construction vibration is generally assessed in

terms of PPV. Table 3‐3 summarizes the construction vibration limits shown in FTA guidelines.

Table 3‐3. Construction Vibration Building Damage Criteria

Building Category PPV (in/sec)

I. Reinforced-concrete, steel, or timber (no plaster) 0.5

II. Engineered concrete and masonry (no plaster) 0.3

III. Non-engineered timber and masonry buildings 0.2

IV. Buildings extremely susceptible to vibration damage 0.12

Source: FTA, 2006.


4 EXISTING SETTING

4.1 EXISTING LAND USE The VAT Project alternatives use an alignment that runs under Virginia Avenue, SE near

vibration sensitive land use areas and buildings along a 3,800 feet stretch of tunnel within

Washington, DC. For the purpose of this study, vibration sensitive receptors were selected by

their proximity to the three build alternative alignments and by future and existing land use,

and are describe in the following paragraphs:

HISTORIC

The Project Area is located in proximity to various federal buildings and facilities; however,

these buildings are not in close vicinity of the tunnel. The St. Paul African Union Methodist

Church, located at 401 I Street SE is listed on the National Register of Historic Places. Another

historic site is the Marine Barracks, oldest active post in the U.S. Marine Corps, is located at 8th

and I Streets SE. The Marine Barracks was placed on the National Register of Historic Places by

the U.S. Department of the Interior in 1976.

RESIDENTIAL

Category 2 residential land uses dominant on the west side of Eleventh Street and the north side

of M Street. South of the Southeast/Southwest Freeway (I‐695) there is a large area of residential

development, and in the area surrounding (and including) the Marine Barracks. The closest

residential development to the tunnel are Capitol Quarter Townhouses and Capper Senior

Building, which are located on the blocks between Third and Fifth Streets, SE, south of Virginia

Avenue SE. The new enlisted men’s quarters within the grounds of the Marine Barracks are also

close to the tunnel.

INSTITUTIONAL

These are the Category 3 land uses and facilities occupied by schools, hospitals, religious

organizations and similar institutions with primarily daytime use. The project area contains

Tyler Elementary School, Eagle Academy (two locations). The project area also includes St. Paul

African Union Methodist Church. There are no hospitals or public libraries in the project area.

MARINE BAND PRACTICE HALL The Marine Band Practice Hall is located near 7th Street, SE and Virginia Avenue, SE. The

practice hall is considered as a Special Building land use.

COMMERCIAL

There are no commercial buildings that are classified as Category 1, 2, or 3 land uses or are

considered as Special Building land use.



4.2 VIBRATION MEASUREMENTS Vibration measurements were conducted to determine baseline vibration levels from existing

train pass bys, and to calculate vibration transferability characteristics of the soil for the purpose

of projecting expected vibration levels during construction and post‐construction train

operation phases. On May 22 to 23, 2012 vibration measurements from passing trains were

conducted at three separate sites. The first measurement site is just outside East Portal, east of

Eleventh Street. The other two sites were selected as measurement sites near to the two

vibration sensitive structures closest to the project, the Capitol Quarter Townhouses and the

Marine Building/Band Practice Hall.

Vibration levels attributed to passing trains were measured at outside locations for each of the

three sites, and also at one additional inside site within the Marine Band Practice Hall. The

vibration measurements were conducted using GeoSonic 3000EZ plus and 3000LC portable

seismographs. Vibration levels were measured on the vertical, transverse, and longitudinal

axes. The seismograph has an internal calibration sequence and was operated according to the

manufacturer’s specifications and recorded PPV vibrations (in inches per second). Vibration

measurements were conducted by Parsons staff.

At each measurement site, two probes were set up perpendicular to the tunnel. Measurements

close to the East Portal were at 19 and 74 feet from the edge of the track. These measurements

were the closest sites to the tracks where the strongest vibration signal can be measured and the

results can be used for calculating the soil vibration transferability characteristics.

Vibration probes at EYA Capitol Quarter townhouses were located in the grassy area between

Virginia Avenue, SE and side walk. The first probe was at 40 feet from the edge of track and the

second one at 73 feet which was the same distance as the closest building to the edge of track,

but still in public space.

The two outside measurement locations near Marine Building were located at 61 and 127 feet

distances from the edge of the track. The probe at 127 feet was next to the closest point of the

building to the track. The third probe was located inside a closet across the hallway from the

Band Practice Hall. This location was chosen instead of a location inside Band Practice Hall to

avoid interference from the vibration levels created by the activities in the Marine Band Practice

Hall. Figures 1 through 3 in Appendix A shows the measurement locations.

Vibration levels at each location were measured for at least five train pass by on May 22nd, 2012.

During each measurement, speed of the train was recorded near the east portal using a radar

gun and numbers of the locomotives as well as number of the cars were recorded for each train.

Three measurement probes were left overnight at the Marine Band Practice Hall location due to

the access issues. Four additional train pass by were also recorded by these three probes until

they were pickup on morning of May 23rd, 2012.

Baseline vibration levels without any trains present were also recorded at each measurement

site. The locations of the measurements are shown in Figures 1 through 3 in Appendix A and

the train pass by vibration measurements results are listed in Table 4‐1 for site locations along

with the time of the train pass by, the speed of the train, and the number of cars. Table 4‐2

contains the baseline vibration data collected just before and after each train pass by during the



day at each site. Table 4‐3 contains the baseline and train pass by vibration data collected

overnight at the Marine Band Practice Hall.

These measurements establish the basis to predict vibration levels at the study area using FTA

procedures and to determine the soil propagation characteristics that were used to assess

potential building damage and human annoyance impacts based on FTA procedures and

guidelines.

The soil vibration propagation characteristic was calculated by comparing the PPV at different

distances from the track. The East Portal Site was the most suitable location within the project

area to measure the train tunnel pass bys within 20 feet of the track which is crucial in order to

calculate the soil propagation characteristic. The vibration wave from the train pass by

dissipates as the wave transfers through the soil between two distances. This dissipation rate is

dependent on the local soil composition and is called the soil factor in this report. The soil

factors at the East Portal vibration measurement site were calculated using recorded vibration

levels at 30 second intervals for each train pass by event. These values were then averaged to

calculate the soil factor for the surrounding area of the project and are shown in Table 4‐4.

The vertical‐axis results were used for this analysis as recommended in the FTA manual (FTA,

2006) because the vertical vibration is usually transmitted more efficiently into building

foundations than transverse or longitudinal vibration. This can clearly be seen in Figures 4‐1

through 4‐3 for Site 7 and Site 6. The PPV measurements for all of the axes at Site 7, the site

closest to the train pass by, are comparable, where as longitudinal and transverse measurements

levels at Site 6 are much lower than the vertical measurement level which demonstrates that the

vertical waves are being transmitted more efficiently than the other waves from the train pass

by.

The overnight vibration measurements revealed that the building’s HVAC system had notable

affect on the vertical vibration measurements as shown in Figure 4‐4. Between 21:45 and 04:30

baseline measurements at Site 3 are much lower than baseline measurements outside this time

range when apparently HVAC system was off.



Table 4‐1. Existing Train Pass‐by Vibration Measurements

Site 7 Site 6 Site 5 Site 4 Site 3 Site 2 Site 1

19 ft from edge of track 74 ft from edge of track 61 ft from edge of track 127 ft from edge of track 147 ft from edge of track 40 ft from edge of track 73 ft from edge of track

Long. Trans. Vert. Long. Trans. Vert. Long. Trans. Vert. Long. Trans. Vert. Long. Trans. Vert. Long. Trans. Vert. Long. Trans. Vert.

11:44:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

11:44:30 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

11:45:00 0.088 0.053 0.083 0.018 0.020 0.050 0.013 0.010 0.013 0.005 0.005 0.005 0.005 0.005 0.013 0.008 0.008 0.013 0.010 0.008 0.010

11:45:30 0.053 0.040 0.048 0.013 0.013 0.025 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.008 0.005 0.010

11:46:00 0.038 0.035 0.043 0.010 0.010 0.023 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.005 0.005 0.008

11:46:30 0.050 0.030 0.048 0.013 0.013 0.023 0.008 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.005 0.005 0.008

11:47:00 0.075 0.038 0.065 0.013 0.013 0.030 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.008 0.005 0.008

11:47:30 0.038 0.030 0.050 0.010 0.010 0.023 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

11:48:00 0.048 0.028 0.068 0.010 0.013 0.028 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.005 0.005 0.008

11:48:30 0.053 0.033 0.053 0.010 0.013 0.030 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.008 0.008 0.005 0.008

11:49:00 0.038 0.033 0.055 0.008 0.010 0.020 0.003 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

11:49:30 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

11:50:00 0.005 0.005 0.008 0.005 0.005 0.008 0.008 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

12:39:00 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.018 0.005 0.005 0.005 0.005 0.005 0.008

12:39:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.018 0.005 0.005 0.005 0.005 0.005 0.008

12:40:00 0.053 0.050 0.065 0.018 0.018 0.030 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.005 0.015 0.005 0.008 0.013 0.008 0.008 0.010

12:40:30 0.043 0.033 0.050 0.013 0.013 0.028 0.008 0.008 0.010 0.005 0.005 0.008 0.005 0.005 0.015 0.008 0.008 0.015 0.008 0.005 0.013

12:41:00 0.038 0.028 0.058 0.010 0.010 0.023 0.008 0.008 0.010 0.008 0.005 0.008 0.005 0.005 0.013 0.008 0.008 0.013 0.008 0.008 0.010

12:41:30 0.040 0.023 0.075 0.018 0.013 0.028 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.008 0.005 0.013 0.008 0.005 0.010

12:42:00 0.055 0.035 0.058 0.010 0.013 0.023 0.008 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

12:42:30 0.015 0.020 0.015 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

12:43:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

12:43:30 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.003 0.005 0.005 0.005 0.005 0.008

ppv, (in/sec) ppv, (in/sec) ppv, (in/sec) ppv, (in/sec)

Near 3rd StreetNear East Portal Marine Band Practice Hall

Vibration

Source Time

ppv, (in/sec)

Train with

120 Cars

traveling at

19 mph

Train with 70

Cars traveling

at 12 mph

ppv, (in/sec) ppv, (in/sec)

Note:

Red text denotes that the measured train pass by data is greater than the baseline vibration levels



Table 4‐1. Existing Train Pass‐by Vibration Measurements (Cont.)




13:46:30 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:47:00 0.005 0.005 0.008 0.005 0.005 0.005 0.003 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

13:47:30 0.080 0.040 0.070 0.015 0.015 0.048 0.005 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:48:00 0.050 0.030 0.063 0.010 0.010 0.030 0.013 0.010 0.010 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

13:48:30 0.050 0.025 0.065 0.013 0.010 0.028 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

13:49:00 0.053 0.033 0.063 0.015 0.013 0.028 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:49:30 0.060 0.038 0.083 0.013 0.010 0.023 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:50:00 0.055 0.025 0.065 0.010 0.010 0.025 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:50:30 0.070 0.025 0.050 0.013 0.010 0.028 0.005 0.008 0.008 0.005 0.005 0.003 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

13:51:00 0.058 0.033 0.060 0.018 0.013 0.030 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.008 0.005 0.008

13:51:30 0.063 0.033 0.055 0.015 0.013 0.030 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.010 0.010 0.005 0.008

13:52:00 0.063 0.033 0.055 0.013 0.013 0.025 0.008 0.005 0.010 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

13:52:30 0.043 0.020 0.040 0.005 0.005 0.005 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.005 0.005 0.008

13:53:00 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.013 0.008 0.008 0.008 0.008 0.008 0.010

13:53:30 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.010 0.008 0.008

13:59:30 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.008 0.005 0.005 0.008

14:00:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.008 0.005 0.008

14:00:30 0.063 0.050 0.088 0.015 0.018 0.050 0.013 0.010 0.013 0.008 0.005 0.008 0.005 0.005 0.013 0.008 0.008 0.010 0.005 0.005 0.010

14:01:00 0.040 0.045 0.033 0.010 0.013 0.028 0.008 0.005 0.010 0.008 0.005 0.005 0.005 0.005 0.015 0.008 0.008 0.015 0.008 0.005 0.010

14:01:30 0.048 0.043 0.050 0.013 0.015 0.030 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.008 0.005 0.008

14:02:00 0.038 0.030 0.070 0.013 0.013 0.035 0.008 0.005 0.010 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

14:02:30 0.033 0.023 0.035 0.005 0.008 0.015 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

14:03:00 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.015 0.003 0.005 0.005 0.005 0.005 0.010

14:03:30 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.005

14:15:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

14:15:30 0.013 0.018 0.010 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.010 0.008 0.010

14:16:00 0.068 0.063 0.080 0.015 0.020 0.043 0.015 0.015 0.015 0.005 0.005 0.005 0.005 0.005 0.013 0.008 0.008 0.013 0.008 0.008 0.013

14:16:30 0.035 0.028 0.038 0.013 0.013 0.033 0.010 0.008 0.010 0.005 0.005 0.008 0.005 0.005 0.010 0.005 0.005 0.010 0.005 0.005 0.010

14:17:00 0.023 0.018 0.025 0.013 0.010 0.030 0.008 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.005 0.005 0.008

14:17:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.015 0.003 0.005 0.005 0.005 0.005 0.008

14:18:00 0.003 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

ppv, (in/sec) ppv, (in/sec) ppv, (in/sec) ppv, (in/sec)


Vibration

Source Time

Train with 28

Cars traveling

at 20 mph

ppv, (in/sec)

Train with

143 Cars

traveling at

14 mph

Train with 47

Cars traveling

at 20 mph


Note:

Red text denotes that the measured train pass by data is greater than the baseline vibration levels



Table 4‐2. Existing Baseline Vibration Measurements




11:42:00 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.003 0.005 0.005 0.005 0.005 0.010

11:42:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

11:43:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

11:43:30 0.005 0.005 0.008 0.005 0.005 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

11:44:00 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.010

11:44:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

11:49:30 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

11:50:00 0.005 0.005 0.008 0.005 0.005 0.008 0.008 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

11:50:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

11:51:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.005

11:51:30 0.005 0.008 0.008 0.005 0.005 0.008 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.005 0.005 0.008

11:52:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.003 0.005 0.005 0.008

12:37:00 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.010

12:37:30 0.005 0.005 0.008 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

12:38:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

12:38:30 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

12:39:00 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

12:39:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.018 0.005 0.005 0.005 0.005 0.005 0.008

12:42:30 0.015 0.020 0.015 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

12:43:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

12:43:30 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

12:44:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

12:44:30 0.005 0.005 0.005 0.005 0.008 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

12:45:00 0.005 0.008 0.005 0.005 0.005 0.008 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:44:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

13:45:00 0.005 0.008 0.008 0.005 0.005 0.005 0.013 0.010 0.010 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:45:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:46:00 0.005 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.008 0.008 0.005 0.005 0.008

13:46:30 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.005 0.005 0.008

13:47:00 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.008 0.005 0.008

13:53:00 0.005 0.005 0.008 0.005 0.005 0.005 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:53:30 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

13:54:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.005

13:54:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.005 0.005 0.003 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.010

13:55:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.018 0.005 0.005 0.005 0.005 0.005 0.010

13:55:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

Vibration

Source Time

ppv, (in/sec)

Baseline

vibration

level before

and after the

11:45 train

pass by event

Baseline

vibration

level before

and after the

12:40 train

pass by event

Baseline

vibration

level before

and after the

13:48 train

pass by event

ppv, (in/sec) ppv, (in/sec)ppv, (in/sec) ppv, (in/sec) ppv, (in/sec) ppv, (in/sec)




Table 4‐2. Existing Baseline Vibration Measurements (Cont)




13:57:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

13:58:00 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.020 0.005 0.005 0.005 0.005 0.005 0.008

13:58:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

13:59:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.008 0.008 0.005 0.005 0.008

13:59:30 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.008 0.005 0.005 0.008

14:00:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.008 0.008 0.005 0.008

14:03:00 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.008 0.005 0.008

14:03:30 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

14:04:00 0.005 0.005 0.008 0.005 0.005 0.008 0.003 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

14:04:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.010

14:05:00 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.005

14:05:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

14:13:00 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.003 0.005 0.005 0.005 0.005 0.008

14:13:30 0.005 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.010 0.003 0.005 0.005 0.005 0.005 0.008

14:14:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

14:14:30 0.005 0.008 0.005 0.005 0.005 0.008 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.010

14:15:00 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

14:15:30 0.013 0.018 0.010 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.010 0.008 0.010

14:17:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

14:18:00 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.015 0.005 0.005 0.005 0.005 0.005 0.008

14:18:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

14:19:00 0.005 0.008 0.008 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.010

14:19:30 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.003 0.005 0.005 0.005 0.005 0.008

14:20:00 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

Vibration

Source Time

Baseline

vibration

level before

and after the

14:16 train

pass by event

ppv, (in/sec)

Baseline

vibration

level before

and after the

14:00 train

pass by event

ppv, (in/sec) ppv, (in/sec)ppv, (in/sec) ppv, (in/sec) ppv, (in/sec) ppv, (in/sec)




Table 4‐3. Existing Nighttime Baseline and Train Pass‐by Vibration Measurements

Site 5 Site 4 Site 3

Long. Trans. Vert. Long. Trans. Vert. Long. Trans Vert.

22:22:00 0.008 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.018

22:22:30 0.015 0.010 0.010 0.008 0.005 0.008 0.005 0.003 0.010

22:23:00 0.015 0.015 0.015 0.008 0.005 0.008 0.005 0.005 0.010

22:23:30 0.008 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.010

22:24:00 0.010 0.008 0.013 0.005 0.005 0.005 0.005 0.005 0.008

22:24:30 0.010 0.005 0.013 0.005 0.005 0.005 0.005 0.005 0.008

22:25:00 0.008 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.008

22:25:30 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.008

22:26:00 0.008 0.008 0.008 0.005 0.005 0.005 0.005 0.005 0.008

22:26:30 0.008 0.008 0.008 0.005 0.005 0.003 0.003 0.005 0.008

22:27:00 0.005 0.003 0.005 0.005 0.005 0.005 0.005 0.005 0.008

22:27:30 0.003 0.003 0.003 0.005 0.005 0.003 0.005 0.005 0.008

00:15:30 0.003 0.003 0.003 0.005 0.005 0.003 0.005 0.005 0.008

00:16:00 0.003 0.003 0.005 0.005 0.005 0.003 0.005 0.005 0.008

00:16:30 0.010 0.008 0.010 0.005 0.005 0.003 0.005 0.005 0.008

00:17:00 0.008 0.010 0.010 0.005 0.005 0.003 0.005 0.005 0.010

00:17:30 0.008 0.008 0.008 0.005 0.005 0.003 0.005 0.005 0.010

00:18:00 0.010 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.010

00:18:30 0.005 0.003 0.003 0.005 0.005 0.005 0.005 0.003 0.008

00:19:00 0.003 0.003 0.005 0.005 0.005 0.005 0.003 0.005 0.008

00:19:30 0.003 0.003 0.005 0.008 0.005 0.005 0.005 0.005 0.008

02:21:30 0.003 0.003 0.005 0.005 0.005 0.003 0.005 0.005 0.008

02:22:00 0.003 0.003 0.005 0.005 0.005 0.003 0.005 0.005 0.008

02:22:30 0.015 0.013 0.013 0.005 0.005 0.005 0.005 0.005 0.010

02:23:00 0.008 0.005 0.010 0.005 0.005 0.003 0.005 0.005 0.010

02:23:30 0.010 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.008

02:24:00 0.008 0.005 0.008 0.005 0.005 0.005 0.005 0.005 0.010

02:24:30 0.008 0.005 0.010 0.005 0.005 0.008 0.005 0.005 0.010

02:25:00 0.008 0.005 0.010 0.005 0.005 0.005 0.005 0.005 0.008

02:25:30 0.008 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.013

02:26:00 0.008 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.013

02:26:30 0.010 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.018

02:27:00 0.008 0.008 0.013 0.008 0.005 0.008 0.005 0.005 0.020

02:27:30 0.008 0.005 0.010 0.005 0.005 0.008 0.005 0.005 0.020

02:28:00 0.008 0.005 0.008 0.008 0.005 0.008 0.005 0.005 0.008

02:28:30 0.003 0.003 0.005 0.008 0.005 0.008 0.005 0.005 0.008

03:50:30 0.003 0.003 0.003 0.005 0.005 0.003 0.005 0.005 0.008

03:51:00 0.005 0.005 0.005 0.005 0.005 0.003 0.005 0.005 0.008

03:51:30 0.010 0.010 0.013 0.005 0.005 0.003 0.005 0.005 0.013

03:52:00 0.010 0.013 0.013 0.005 0.005 0.003 0.005 0.005 0.015

03:52:30 0.008 0.008 0.010 0.005 0.005 0.005 0.005 0.005 0.018

03:53:00 0.005 0.005 0.010 0.005 0.005 0.008 0.005 0.005 0.015

03:53:30 0.010 0.008 0.010 0.008 0.005 0.008 0.005 0.005 0.015

03:54:00 0.010 0.008 0.013 0.005 0.005 0.008 0.005 0.005 0.013

03:54:30 0.010 0.008 0.010 0.005 0.005 0.008 0.005 0.005 0.015

03:55:00 0.003 0.003 0.003 0.005 0.005 0.008 0.005 0.005 0.010

03:55:30 0.003 0.003 0.003 0.005 0.005 0.008 0.005 0.005 0.008

Train

Time

Train,

Speed and

number of

cars

unknown

Train,

Speed and

number of

cars

unknown

Train,

Speed and

number of

cars

unknown

Train,

Speed and

number of

cars

unknown

Marine Band Practice Hall

ppv, (in/sec) ppv, (in/sec) ppv, (in/sec)

Vibration

Source

Note:

Red text denotes that the measured train pass by data is greater than the baseline vibration

levels



Figure 4-1. Existing Train Pass-by Longitudinal Vibration Measurements

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

Site 7

Site 6

Site 5

Site 4

Site 3

Site 2

Site 1

Long. Vibration

PPV( in/sec)

Time



Figure 4-2. Existing Train Pass-by Transverse Vibration Measurements

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

Site 7

Site 6

Site 5

Site 4

Site 3

Site 2

Site 1

Trans. Vibration

Time

PPV( in/sec)



Figure 4-3. Existing Train Pass-by Vertical Vibration Measurements

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

Site 7

Site 6

Site 5

Site 4

Site 3

Site 2

Site 1

Trans. Vibration

Time

PPV( in/sec)



0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

18:00:00

18:19:30

18:39:00

18:58:30

19:18:00

19:37:30

19:57:00

20:16:30

20:36:00

20:55:30

21:15:00

21:34:30

21:54:00

22:13:30

22:33:00

22:52:30

23:12:00

23:31:30

23:51:00

00:10:30

00:30:00

00:49:30

01:09:00

01:28:30

01:48:00

02:07:30

02:27:00

02:46:30

03:06:00

03:25:30

03:45:00

04:04:30

04:24:00

04:43:30

05:03:00

05:22:30

05:42:00

06:01:30

06:21:00

06:40:30

07:00:00

07:19:30

07:39:00

07:58:30

Site 3

Site 4

Site 5

Vert. Vibration

PPV( in/sec)

Time

Figure 4-4. Existing Night Time Train Pass-by Vertical Vibration Measurements



Table 4‐4. Soil Factor Derived from Existing Train Pass By Measurements

at the East Portal

RMS VdB1

PPV

(in/sec)

RMS

VdB1

PPV

(in/sec)

11:45:00 86 0.083 82 0.050 0.372762

11:45:30 82 0.048 76 0.025 0.479783

11:46:00 81 0.043 75 0.023 0.460204

11:46:30 82 0.048 75 0.023 0.54111

11:47:00 84 0.065 78 0.030 0.568678

11:47:30 82 0.050 75 0.023 0.571134

11:48:00 85 0.068 77 0.028 0.652608

11:48:30 82 0.053 78 0.030 0.418567

11:49:00 83 0.055 74 0.020 0.744029

12:40:00 84 0.065 78 0.030 0.568678

12:40:30 82 0.050 77 0.028 0.426454

12:41:00 83 0.058 75 0.023 0.680296

12:41:30 85 0.075 77 0.028 0.724672

12:42:00 83 0.058 75 0.023 0.680296

13:47:30 85 0.070 82 0.048 0.277499

13:48:00 84 0.063 78 0.030 0.545692

13:48:30 84 0.065 77 0.028 0.619422

13:49:00 84 0.063 77 0.028 0.596436

13:50:00 84 0.065 76 0.025 0.702775

13:50:30 82 0.050 77 0.028 0.426454

13:51:00 84 0.060 78 0.030 0.509807

13:51:30 83 0.055 78 0.030 0.445811

13:52:00 83 0.055 76 0.025 0.579907

14:00:30 87 0.088 82 0.050 0.415786

14:01:30 82 0.050 78 0.030 0.37571

14:02:00 85 0.070 79 0.035 0.509807

14:02:30 79 0.035 71 0.015 0.623184

14:16:00 86 0.080 81 0.043 0.456616

Avg. 84 0.060 77 0.030 0.522996

Soil

FactorTime Vert Vert.

Peak Measurements

Site 7 (Near) Site 6 (Far)

Note:

1 ‐ Levels in VdB (re: 10‐6 in/sec.)


5 IMPACT ASSESSMENT

Construction of the Virginia Avenue Tunnel could potentially cause vibration impacts on

nearby building from construction and operation activities. The impact assessment and results

are presented in this section.

Construction related vibration predictions are preliminary because detailed construction

activities for various phase are not available yet. Construction vibration levels will be

recalculated during the final design when more details about construction activities become

available. Train pass by vibration levels may also need to be finalized if there are changes to the

project design that could affect the vibration levels.

5.1 CONSTRUCTION VIBRATION Two types of potential construction vibration impacts were analyzed: (1) human annoyance and

(2) building damage. The potential for human annoyance occurs when construction vibration

rises significantly above the threshold of human perception for extended periods of time.

Building damage can be cosmetic or structural. As a general matter, fragile buildings such as

historical structures have a greater potential to be susceptible to damage from ground vibration

than buildings that are not particularly fragile.

Vibration levels produced by construction equipment were obtained from the FTA Transit Noise

and Vibration Impact Assessment (FTA, 2006). Based on the typical vibration levels listed in Table

5‐1, calculations were performed to determine the distances at which vibration impacts would

occur according to the criteria discussed in Section 3.2. Table 5‐2 shows the results of those

calculations. The distances shown in Table 5‐2 are the maximum distances at which short‐term

construction vibration impacts may occur. Mitigation measures would need to be considered if

construction equipment were to operate closer to residential or institutional buildings than the

distances shown in Table 5‐2. However, using the distance information in Table 5‐2 as well as

knowing that the closest building to the alignment edge of track is 44 feet, as shown in Figures 1

through 3 in Appendix A, and that the two strongest construction vibration sources (sheet

driver and vibratory compactor operations), there should be no structural vibration impacts due

to construction operations under any of the alternatives. But there still remains the potential for

human annoyance impacts due to construction operation.

Table 5‐3 shows predicted vibration levels at nearby sensitive receivers from some of the major

construction equipment items that would create high vibration levels. In accordance to the

results presented in Table 5‐3, it is anticipated that certain major vibration producing

construction activities would cause annoyance to the closest units of Capitol Quarter

Townhouses and Capper Senior Building as well as occupancies of other close by buildings.



Table 5‐1. Ground‐Born Vibration Source Levels for Construction Equipment

Equipment PPV at 25 feet (in/sec)

Large bulldozer 0.089

Loaded trucks 0.076

Hoe Ram 0.089

Caisson drilling 0.089

Vibratory compactor/roller 0.210

Sheet Driver (Sonic) 0.170

Jackhammer 0.035

Source: FTA, 2006

Table 5‐2. Construction Equipment Vibration Impact Distances

Equipment

Distance to Potential Vibration Building

Damage1 feet

Distance to Potential Vibration Human

Annoyance2 feet

Large bulldozer 21 38

Dump trucks 20 35

Hoe Ram 21 38

Caisson drilling 21 38

Vibratory compactor/roller 33 59

Sheet Driver (Sonic) 30 53

Jackhammer 13 23

Notes: 1. This is the distance at which the PPV is 0.20 inch/sec or less. 2. This is the distance at which the PPV is 0.04 inch/sec or less at the inside of the building structure.

Source: FTA



Table 5‐3. Highest Construction Equipment Vibration Levels

Equipment

PPV (in/sec)

Capitol Quarter Townhouses and Capper Senior

Building (closest units)

St. Paul African Union Methodist

Church


Large bulldozer 0.036 0.004 0.010

Dump trucks 0.031 0.003 0.008

Hoe Ram 0.036 0.004 0.010

Caisson drilling 0.024 0.003 0.008

Vibratory compactor/roller 0.086 0.008 0.023

Sheet Driver (Sonic) 0.045 0.006 0.015

Jackhammer 0.014 0.001 0.004

Note: PPV are for single equipment but if more than one equipment is operating at the same time, PPV would be higher.

Base on the preliminary calculations and available project information; there would not be

construction vibration related building damages (e.g., plaster cracks) from individual

equipment items because there would not be buildings within the distances identified in Table

5‐2. However, this distance can vary depending on the soil composition and underground

geological layer between vibration source and receiver. In addition, not all buildings respond

similarly to vibration generated by construction equipment. Preliminary predictions presented

in Table 5‐3 indicate that certain construction activities could cause annoyance at the nearby

buildings.

Because detailed construction activities and types of equipment that will be utilized for each

phase are not available at this time, overall vibration levels from each construction phase cannot

be predicted. Once detailed construction schedule for various phases of the construction is

developed during the final design, the predicted vibration levels need to be confirmed and

expanded as needed.

Vibration from the train pass‐bys in the trench during the construction period for Alternative 2

was also considered.

5.2 POST-CONSTRUCTION OPERATION VIBRATION Train operational vibration assessment was conducted using the FTA procedures and impact

criteria along with the measured data at nearby vibration sensitive sites within the project area.

The three final design Alternatives include using one tunnel with two tracks or using two

tunnels with one track in each tunnel.



Vibration levels associated with train pass bys were calculated using four parameters: the

distance between the receptor and the edge of track recorded vibration measurements as the

vibration source reference for the train, soil factor calculated from the train pass by

measurements, and an adjustment factor to account for the train passing through the tunnel.

The distance between vibration sensitive receptors and the new track alignments were obtain

from the concept design files. The measured vibration levels from Site 7, the closest site to the

tracks, were used as the train source for calculating impact distances for the existing/ no build,

temporary trench route for Alternative 2, and the three future build alternatives. In the case of

temporary trench alternative and the three future design concepts, the highest recorded

vibration level was used as the train source to ensure that future impacts distances were not

under predicted; furthermore, the train source was doubled to take in account that two trains

can use the new tunnel simultaneously.

The soil factor calculated in Section 4 was used as a parameter to adjust the rate that the

vibration wave would decline in strength as it propagates away from the train. Also, the

vibration waves generated by a train moving along at grade rail travel more effectively along

the ground surface than when a train is moving through a tunnel. Because vibration waves do

not propagated as effectively from tunnel to the surface, the calculated impact distances must

include a tunnel adjustment factor. Table 5‐4 shows this factor for various pass by and the

averaged value which was used for calculating impact distances.

After all four parameters were taken into account; the distances to vibration impact were

calculated. These impact distances for building damage and human annoyance due to the

existing and future alternatives are shown Table 5‐5. As indicated in Table 5‐5, any structures

greater than 20 feet away from the edge of track would not have significant operational

vibration impacts and human annoyance impacts would not occur at more than 36 feet away

from the edge of track even when there are two trains using one tunnel with two tracks or using

two tunnels with one track in each tunnel at the same time.

Using the distance information in Table 5‐5 and knowing the closest building to the alignment

edge of track is 44 feet as shown in Figures 1 through 3 in Appendix A; therefore, there should

be no vibration impacts due to train operations under any of the alternatives.



Site 5 Site 4 Site 2

61 ft from nearest track 127 ft from nearest track 40 ft from nearest track 73 ft from nearest track

Meas Calc. Diff. Meas Calc. Diff. Meas Calc. Diff. Meas Calc. Diff.

11:45:00 0.013 0.054 0.041 0.005 0.041 0.036 0.013 0.063 0.050 0.01 0.050 0.040

11:45:30 0.005 0.027 0.022 0.005 0.019 0.014 0.005 0.034 0.029 0.01 0.025 0.015

11:46:00 0.005 0.025 0.020 0.005 0.018 0.013 0.008 0.031 0.023 0.008 0.023 0.015

11:46:30 0.008 0.026 0.018 0.005 0.017 0.012 0.008 0.032 0.024 0.008 0.023 0.015

11:47:00 0.005 0.033 0.028 0.005 0.022 0.017 0.008 0.043 0.035 0.008 0.030 0.022

11:47:30 0.005 0.026 0.021 0.005 0.017 0.012 0.005 0.033 0.028 0.008 0.023 0.015

11:48:00 0.008 0.032 0.024 0.005 0.020 0.015 0.008 0.042 0.034 0.008 0.028 0.020

11:48:30 0.005 0.033 0.028 0.005 0.024 0.019 0.008 0.039 0.031 0.008 0.030 0.022

11:49:00 0.003 0.023 0.020 0.005 0.013 0.008 0.005 0.032 0.027 0.01 0.020 0.010

12:40:00 0.005 0.033 0.028 0.005 0.022 0.017 0.013 0.043 0.030 0.01 0.030 0.020

12:40:30 0.01 0.030 0.020 0.005 0.022 0.017 0.015 0.036 0.021 0.013 0.028 0.015

12:41:00 0.01 0.026 0.016 0.008 0.016 0.008 0.013 0.035 0.022 0.01 0.023 0.013

12:41:30 0.008 0.032 0.024 0.005 0.019 0.014 0.013 0.044 0.031 0.01 0.028 0.018

12:42:00 0.01 0.026 0.016 0.005 0.016 0.011 0.005 0.035 0.030 0.008 0.023 0.015

13:47:30 0.008 0.051 0.043 0.005 0.041 0.036 0.005 0.057 0.052 0.008 0.048 0.040

13:48:00 0.01 0.033 0.023 0.005 0.022 0.017 0.005 0.042 0.037 0.008 0.030 0.022

13:48:30 0.005 0.032 0.027 0.005 0.020 0.015 0.005 0.041 0.036 0.008 0.028 0.020

13:49:00 0.005 0.031 0.026 0.005 0.020 0.015 0.005 0.040 0.035 0.008 0.028 0.020

13:50:00 0.008 0.029 0.021 0.005 0.017 0.012 0.005 0.039 0.034 0.008 0.025 0.017

13:50:30 0.008 0.030 0.022 0.005 0.022 0.017 0.005 0.036 0.031 0.008 0.028 0.020

13:51:00 0.005 0.033 0.028 0.005 0.023 0.018 0.005 0.041 0.036 0.008 0.030 0.022

13:51:30 0.008 0.033 0.025 0.005 0.024 0.019 0.01 0.039 0.029 0.008 0.030 0.022

13:52:00 0.01 0.028 0.018 0.005 0.018 0.013 0.005 0.036 0.031 0.01 0.025 0.015

14:00:30 0.013 0.054 0.041 0.008 0.040 0.032 0.01 0.065 0.055 0.01 0.050 0.040

14:01:30 0.008 0.032 0.024 0.005 0.024 0.019 0.005 0.038 0.033 0.008 0.030 0.022

14:02:00 0.01 0.039 0.029 0.005 0.027 0.022 0.005 0.048 0.043 0.008 0.035 0.027

14:02:30 0.008 0.017 0.009 0.005 0.011 0.006 0.005 0.022 0.017 0.008 0.015 0.007

Train with 28

Cars traveling at

20 mph

14:16:00 0.015 0.047 0.032 0.005 0.034 0.029 0.013 0.057 0.044 0.013 0.043 0.030

0.008 0.033 0.025 0.005 0.022 0.017 0.008 0.041 0.033 0.009 0.030 0.021Average

Near 3rd Street



Site 1

Vibration Source Time

ppv, (in/sec)

Train with 120

Cars traveling at

19 mph

Train with 70

Cars traveling at

12 mph

Train with 143

Cars traveling at

14 mph

Train with 47

Cars traveling at

20 mph

ppv, (in/sec)

Table 5‐4. Measured Vibrations Levels verses Calculated Vibrations for Building Sites near the Tunnel



Table 5‐5. Impact Distances for existing and future Ground‐Born Vibration Train Pass By

Alternatives

Distance to Vibration Potential Building

Damage feet

Distance to Vibration Potential Human

Annoyance feet

Train At Grade

Train in Tunnel

Train At Grade

Train in Tunnel

Existing/ No Build 13 10 24 17

Alternative 2 (during construction when there is a Temporary Trench Route)

13 10 24 17

Alternative 2 23 20 41 36




6 MITIGATION

This section discusses the possible mitigation measures that can be implemented to either

reduce or mitigate the vibration impacts generated by the construction and operation of the

proposed project.

6.1 CONSTRUCTION VIBRATION MITIGATION It is possible that certain construction activities could cause intermittent localized concern from

vibration in the Project Area. Processes such as earth moving with bulldozers, the use of

vibratory compaction rollers, and sheet piling could cause some human annoyance impacts.

There are cases where it may be necessary to use this type of equipment in close proximity to

residential buildings.

A vibration monitoring and mitigation plan will be prepared by a qualified vibration engineer,

which would include vibration monitoring procedures at predetermined vibration sensitive

sites, revised calculation of vibration levels for various construction phases, and revised

mitigation measures based on the re‐calculations. No construction work or the operation of

vibration generating equipment at the construction site would start until DDOT has approved

the plan. The plan would be updated if there are any major changes to the planned construction

activities.

The following are some procedures that can be used to minimize the potential for annoyance

from construction vibration:

Provide to the owners of buildings that are close enough to a construction vibration

source that may cause vibration impacts the option of the pre‐construction survey for

documenting the pre‐construction condition of that structure;

Conduct vibration monitoring during vibration‐intensive activities;

Properly maintain all motorized equipment in a state of good repair to limit wear

induced vibration.

Where feasible, avoid the use of pile driving near residences, and instead use drilled

piles or the use of a sonic or vibratory pile driver, which cause lower vibration levels,

where the geological conditions permit their use;

When there is possibility of annoyance from construction activities such as the operation

of vibratory rollers, absent urgent and unexpected circumstances, conduct such activity

only during weekday daytime hours when many residents are away from their homes;

Develop a phasing plan so that high vibration generating activities do not occur within

the same time period, to the extent practicable;

Avoid routing heavily‐loaded trucks through densely concentrated residences, if

reasonably possible;

CSX Virginia Avenue Tunnel Clearance Improvement Project


Where feasible, use demolition methods that do not involve impact; and

Avoid the use of vibratory rollers and packers near sensitive areas, if possible.

A combination of the mitigation techniques for equipment vibration control as well as

administrative measures, when properly implemented, can be selected to provide the most

effective means to minimize the effects of construction activity. Application of the mitigation

measures will reduce the construction impacts; however, temporary increases in vibration

would likely occur at some locations. The extent of potential impacts cannot be determined

until detail construction workplans for each phase of the construction operations have been

developed.

6.2 POST-CONSTRUCTION OPERATION VIBRATION MITIGATION According to vibration impact analysis, ground‐borne vibrations are not expected to exceed

FTA criteria for the train operations under any of the Project “Buildʺ alternatives; therefore,

vibration mitigation is not necessary.

s

A FIGURES

appendix vibration analysis report - 'virginia avenue … · virginia avenue tunnel...

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