v i b r a t i o n a n d n o i s e l e v e l s

No.9g e o p i e r f o u n d a t i o n c o i n c

t e c h n i c a l b u l l e t i n

Construction vibration and noise levels are important when considering the effect of construction activities on

adjacent buildings, building additions and neighbors. This technical bulletin describes the results of vibration

and noise monitoring performed adjacent to Rammed Aggregate Pier® (RAP) activities using the Geopier®,

Impact®, and Rampact® systems. This information should be used when evaluating the feasibility of a RAP

solution at a particular site. For sites with increased vibration and noise sensitivity, a site-specific monitoring

program should be considered.

1 . c o n s t r u c t i o n v i b r a t i o n s

Many construction activities result in the transmission

of vibrations across the construction site. Vibration

levels depend on the types of construction activities

as well as the soil conditions at the site. The effect of

vibrations on adjacent buildings depends on the build-

ing’s construction (wood, masonry, steel, concrete),

building age, distance of the adjacent building from

the source of vibration, duration of vibration, vibration

frequency, vibration amplitude and soil conditions. In

general, low frequency (long period) motions result in

a greater likelihood of building damage compared to

high frequency (short period) motions. This is because

of the significant damping effect that occurs in soils

subjected to high frequency (short period) motions. In

contrast, soils subjected to low frequency (long period)

motions may amplify the vibrations.

In the United States, high frequency vibrations levels

less than two in/sec at the building location are gener-

ally considered to be acceptable (Wiss 1981). These

levels of vibrations are unlikely to lead to building dam-

age. Vibration levels between 0.5 in/sec and 2 in/sec,

are generally considered to be an annoyance but not

structurally damaging. Vibration levels of less than 0.5

in/sec are often not noticeable.

p a g e t w o

Rammed Aggregate Pier construction is described

in detail in the Geopier Reference Manual (Fox and

Cowell 1998). RAP installation using the Geopier

system is constructed by drilling out a volume of

compressible soil to create a cavity and then ramming

select aggregate into the cavity in thin lifts using the

patented beveled tamper. The Impact system and

Rampact system are each installed in caving soils

through the use of a hollow mandrel driven to the

design depth. Aggregate placed down the center of

the hollow mandrel fills the cavity and is compacted

in thin lifts as the mandrel is raised up and rammed

down to achieve compaction. The ramming action

during Rammed Aggregate Pier construction causes

the aggregate to compact vertically and to push

laterally against the matrix soil, thereby increasing

the horizontal stress in the matrix soil. Rammed

Aggregate Pier construction results in a very dense

aggregate pier with superior strength and stiffness.

During installation, the hammers that produce the

ramming action operate at ranges of 400 to 600

cycles per minute (7 to 10 cycles per second) for

the Geopier system and 2,000 to 2,400 cycles per

minute for Impact and Rampact systems. These high

frequency vibration levels are higher than most other

construction activities resulting in a large amount of

damping within the reinforced soils at the project site.

Conversely, pile driving typically produces vibrations

associated with low frequencies on the order of 60

cycles per minute (one cycle per second) and an

associated period of one second. The RAP vibration

levels are thus both lower in amplitude and higher in

frequency than pile driving activities, resulting in lower

vibrations measured at adjacent sites.

Vibration monitoring has been performed at a

number of Rammed Aggregate Pier project sites to

evaluate the amplitude and frequency of vibrations as

a function of distance from the energy source. The

following table contains a sample of the collected

data. The table includes a description of the soil

conditions, installation technique, distance ranges

from source, as well as the field vibration data for

each of the project sites.

2 . r a m m e d a g g r e g a t e p i e r ® c o n s t r u c t i o n

3 . v i b r a t i o n m o n i t o r i n g

p a g e t h r e e

Table 1.

Vibration Monitoring Results*

LOCATION SOIL DESCRIPTION

REINFORCEMENT SOLUTION

DISTANCE FROM SOURCE (ft)

PEAK PARTICLE VELOCITY (ips)

FREQUENCY (Hz)

MEMPHIS, TN MED. STIFF CLAYGEOPIER 1.7 - 2 .18 - 2.96 43 - 57

GEOPIER 5 - 10 .12 - .70 43 - 73

SOMERVILLE, MA MED. DENSE GRANULAR FILL GEOPIER 1.5 - 10 .50 - .65 30 - 85

SAN LUIS OBISPO, CA STIFF CLAY GEOPIER 7 - 15 .04 - .55 15 - 60

MINNEAPOLIS, MN LOOSE SAND GEOPIER 3 - 50 .07 - .90 27 - 57

MINNEAPOLIS, MN LOOSE SANDIMPACT 3 - 20 .56 - .99 21 - 47

IMPACT 30 - 100 .02 - .48 21 - 47

MANALAPAN, NJ MED. DENSE SILTY SAND

IMPACT 5 - 10 .57 - 3.19 37 - 64

IMPACT 25 - 50 .10 - .62 34 - 73

*Monitoring results are also plotted in Figures 2 and 3.

At one project site, the Baptist Memorial Hospital

Addition in Memphis, Tennessee, Geopier elements

were installed in close proximity to existing hospital

facilities. An accelerometer was used at the site

to measure both accelerations and peak particle

velocities (PPV) during the installation of the Geopier

system. The accelerometer was positioned at

distances ranging from 1.7 feet to 10 feet away from

the Geopier elements as the tamper head elevation

ranged from the ground surface to greater than 13 feet

below grade. The subsurface conditions consisted of

medium-stiff clay with groundwater below the bottoms

of the piers. The results of the accelerometer testing

are shown graphically in Figure 1.

Figure 1.

Peak Particle Velocity With Depth

For Different Energy Source Distances

Radial Distance From Source

0

2

4

6

8

10

12

14

16

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5Peak Particle Velocity (in/sec)

Depth below grade (ft)

1.7 ft2 ft5 ft10 ft

Peak Particle Velocity (in/sec)D

epth

Bel

ow G

rade

(ft)

The results of the vibration monitoring data (Figure

1) indicate that RAP construction vibration amplitudes

decrease with increasing depth below the ground

surface. The highest vibration amplitudes are observed

when the tamper is at the ground surface. Table 1 and

Figures 2 to 4 show the ranges of peak particle velocity

with distance from the source. The data indicates that

vibration amplitudes reduce with radial distance from

the energy source. This rapid dissipation of vibration

amplitudes is attributed to the high frequency

(low period) vibrations resulting from the hammers

used during RAP construction. For Geopier elements,

the peak particle velocities are generally less than two

in/sec at distances of two feet from the installation

location and less than 0.75 in/sec at distances of

five feet from the installation location. For Impact

and Rampact elements, the peak particle velocities

are less than two in/sec at distances on the order of

10 to 15 feet from the pier installation location and

less than 0.75 in/sec at distances of 20 to 25 feet

from the installation location. The higher amplitudes

observed for the Impact and Rampact installations

are likely attributed to the displacement installation

procedure and the densification of the granular soils

during installation. As shown, predrilling and other

construction methods are effective at reducing

vibrations of displacement installations. Figure 4

shows a comparison of Geopier vibration levels from

the site in San Luis Obispo, California compared

with other construction equipment. As indicated, the

measured vibration levels are comparable to those

induced by a jack hammer or a large bulldozer and are

considerably lower than pile driving operations.

4 . d i s c u s s i o n o f v i b r a t i o n r e s u l t s

p a g e f o u r

Figure 2.

Peak Particle Velocities For Geopier System

With Distance From Energy Source

Figure 3.

Peak Particle Velocities For Impact and Rampact Systems

With Distance From Energy Source

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1 10 100

Distance from Source (ft)

Peak Particle Velocity (in/sec)

Range of PPV - Memphis, TNRange of PPV - San Luis Obispo, CA

Maximum PPV values - Minneapolis, MNMaximum PPV values - Somerville, MA

Distance From Source (ft)

Peak

Par

ticl

e Ve

loci

ty (i

n/se

c)

Distance From Source (ft)

Max

imum

Pea

k Pa

rtic

le V

eloc

ity

(in/s

ec)

Impact RAP Vibration Data

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

1 10 100 1000

Distance from Source (ft)

Max

imum

Pea

k Pa

rtic

le V

eloc

ity (i

n/se

c)

Manalapan, NJMinneapolis, MNDedham, MASeattle, WABow, NHNorth Kingstown, RILynn, MAGrand Rapids, MI

Range of Vibration Data

Typical Design Threshold

p a g e f i v e

Peak

Vel

ocit

y (m

m/s

ec) (

25 m

m/s

ec =

1 in

/sec

)

Distance from Source (m) (1 m = 3.28 ft)

Figure 4.

Peak Particle Velocity With Distance

From Geopier Installation (Fiegel 2005)

Figure 5 shows the peak particle velocities caused by

Geopier installation plotted with vibration frequency

as measured at the San Luis Obispo, California project

site. The figure indicates that the high frequency

energy used during installations results in peak

particle velocities lower than the recognized standard

threshold for building damage.

p a g e s i x

5 . n o i s e l e v e l s

Although the data from Table 1 and Figures 1 through

5 may be used for most project sites, settlement-

Construction noise decibel levels were recorded

during the installation of the Geopier system

at the Baptist Memorial Hospital project.

Using a decibel meter, the noise levels were

recorded with increasing distance from the Geopier

sensitive sites should include a site-specific monitoring

program to evaluate vibration levels.

installation. At each distance, readings were

recorded for the noise level while the ramming

assembly was positioned at both the top and the

bottom of the cavity. The results of the measurements

are summarized in Table 2 and shown in Figure 6.

Vibration Frequency (Hz)

Figure 5.

Peak Particle Velocity With

Vibration Frequency (Fiegel 2005)

Peak

Vel

ocit

y (m

m/s

ec) (

25 m

m/s

ec =

1 in

/sec

)

p a g e s e v e n

DISTANCE FROM RAMMING ASSEMBLY

(ft)

DECIBEL LEVEL WITH TAMPER AT TOP

(dB)

DECIBEL LEVEL WITH TAMPER AT BOTTOM

(dB)

2 100 104

5 100 102

10 96 98

25 86 98

50 82 90

100 75 82

Table 2.

Summary Of Noise Levels

Figure 6.

Range Of Geopier System Noise

Levels With Distance From Source

80

85

90

95

100

105

110

115

120

1 10 100

Distance from Source (ft)

Decibels (dB)

Pile Driver (107 dB)

Distance from Source (ft)

Peak

Vel

ocit

y (m

m/s

ec) (

25 m

m/s

ec =

1 in

/sec

)

Jack Hammer (94 dB)

Air Compressor (87 dB)

p a g e e i g h t

The decibel level for the Geopier installation process

reduces significantly with distance from the ramming

assembly. The decibel levels drop from approximately

100 dB adjacent to the Geopier installation equipment

to approximately 75 to 80 dB at a distance of 50 to

100 feet. For comparison purposes, it should be noted

that interpersonal communication is on the order of 60

dB, heavy truck traffic is on the order of 85 dB and pile

driving operations are on the order of 105 dB.

Rammed Aggregate Pier installations induce

high frequency (low period) vibrations during the

construction process. Vibration levels for the Geopier

system are typically within acceptable levels at

distances between 2 and 5 feet from the installation

location, while vibration levels for displacement Impact

and Rampact systems are within tolerable levels at

distances between 10 and 20 feet from installation

locations. Alternative construction approaches such

as predrilling helps reduce the vibration levels in close

proximity to Impact and Rampact piers. Noise levels

for all Rammed Aggregate Pier systems are consistent

with construction-type activities.

5 . n o i s e l e v e l s

p a g e n i n e

a c k n o w l e d g e m e n t s

The authors are indebted to Peterson Contractors, Inc. for providing vibration results and JGI/Eastern, Inc., French and Parrello Associates, and American Engineering Testing, Inc. for providing vibration monitoring ser-vices.

r e f e r e n c e s

Fiegel, G. (2005). Measurement of Vibration and Noise During the Installation of Rammed Aggregate Piers - Preliminary Data Report Draft, Department of Civil and Environmental Engineering. California Polytechnic State University. San Luis Obispo, CA.

Fox, N.S. and Cowell, M.J. (1998). Geopier Foundation and Soil Reinforcement Manual, Geopier Foundation Company, Inc., Scottsdale, AZ.

Wiss, J.F. (1981). Construction Vibrations: State-of-the-Art. ASCE Journal of the Geotechnical Engineering Division, 107 (GT2), pp. 167-181.

a u t h o r s

Brendan T. FitzPatrick, Director of Engineering/Development - North America, Geopier Foundation Company, Inc.Kord J. Wissmann, Ph.D., P.E., President / Chief Engineer, Geopier Foundation Company, Inc.

© 2006 Geopier Foundation Company, Inc.

© 2006 Geopier Foundation Company, Inc.Geopier®, Rammed Aggregate Pier®, Impact® and Intermediate Foundation® are registered trademarks of Geopier Foundation Company. The Rammed Aggregate Pier systems are protected under U.S. Patent Nos. 6,425,713; 6,688,815; 6,988,855; 5,249,892; 7,226,246; 6,354,766; 7,004,684; 6,354,768; 7,326,004 and other patents pending. The information contained herein has been carefully compiled by Geopier Foundation Company and to the best of its knowledge accurately represents RAP product use in the applications, which are illustrated. Printed in the U.S.A.

Geopier Foundation Company, Inc.150 Fairview Road, Suite 335Mooresville, NC 28117

Telephone: (704) 799.3185 or (800) 371.7470Fax: (704) 799.3235

e-mail: info@geopier.comwww.geopier.com

02_2012

Geopier Foundation Company, Inc.

800.371.7470www.geopier.com