20190208 Ver 1_Blasting statement with specs_20190215

For the Southeast Regional Lift Station Project blasting and mechanical methods of rock
removal is anticipated. The duration of these operations will be determined upon rock location,
depth, and hardness. It is anticipated that the contractor will perform blasting along the pipe
corridor (where allowed) for the full length of the alignment. Areas where rock removal is
required but not allowed, mechanical methods will be used. Refer to the Hazen Specifications
02220 "TRENCHING, BACKFILLING, BLASTING AND COMPACTING FOR UTILITIES" for
general blasting requirements provided below.
SECTION 02220
TRENCHING. BACKFILLING. BLASTING AND COMPACTING FOR UTILITIES
PART 1 -- GENERAL
1.01 THE REQUIREMENT
A. Excavation, trenching, backfilling and compacting for all underground utilities, drainage
piping and all related appurtenances.
B. All land disturbing activities shall be conducted so as to absolutely minimize erosion and
off site sedimentation.
1.02 RELATED WORK SPECIFIED ELSEWHERE
A. Division 2 - Sitework
B. Division 15 — Mechanical
1.03 QUALITY ASSURANCE
A. Referenced Standards:
American Association of State Highway and Transportation Officials (AASHTO):
a. T99, The Moisture -Density Relations of Soils using a 5.5 LB Rammer and
a 12 IN Drop.
b. T180, Moisture -Density Relations of Soils Using a 10 LB Rammer and an
18 IN Drop.
2. American Society for Testing and Materials (ASTM):
a. C33, Concrete Aggregates.
b. D698, The Moisture -Density Relations of Soils Using a 5.5 LB Rammer and
a 12 IN Drop. D698 is "Standard Proctor."
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C. D1557, The Moisture -Density Relations of Soils Using a 10 LB Rammer
and an 18 IN Drop. D1557 is "Modified Proctor."
d. D2487, Classification of Soils for Engineering Purposes.
e. D4253, Maximum Index Density of Soils Using a Vibratory Table.
f. D4254, Minimum Index Density of Soils and Calculation of Relative
Density.
B. Qualifications: Owner may hire an independent soils laboratory to conduct in-place
moisture -density tests for backfilling to assure that all work complies with this
Specification.
1.04 DEFINITIONS
A. Excavation: All excavation above subgrade of trench will be unclassified except solid rock
as defined below.
B. Rock: Solid, homogeneous material which cannot be removed without systematic drilling
and blasting. Material having a standard penetration resistance as determined by ASTM
D1586 greater than 100 blows per foot is defined as "rock."
C. Subgrade: Surface of the bottom of the trench after completing excavation of the trench
as required by Drawings.
D. Undercut Excavation: Unsuitable material below subgrade.
1.05 SUBMITTALS
A. See Section 01300 -Submittals.
B. Submit test reports and fully document each with specific location or stationing
information, date, and other pertinent information.
C. Submit respective pipe or conduit manufacturer's data regarding methods of installation
and general recommendations.
D. Submit sieve analysis reports on all granular materials.
E. Trench Safety Plan and/or trench shoring drawings including current certification of trench
shields if employed.
F. Dewatering procedures.
G. List of disposal sites for rock, excess materials and unsuitable materials and all required
permits for use of those sites.
H. If Contractor intends to perform blasting on this Project, then a blasting plan shall be
submitted per the requirements of Section 01300 and Subpart 3.07 herein.
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1.06 PROJECT CONDITIONS
A. Avoid overloading or surcharge a sufficient distance back from edge of excavation to
prevent slides or caving. Maintain and trim excavated materials in such manner to be as
little inconvenience as possible to public and adjoining property owners.
B. Provide full access to public and private premises and fire hydrants, at street crossings,
sidewalks and other points as designated by Owner to prevent serious interruption of
travel.
C. Protect and maintain bench marks, monuments or other established points and reference
points and if disturbed or destroyed, replace items to full satisfaction of Owner and
controlling agency.
D. Verify location of existing underground utilities.
E. Take necessary precautions to protect existing utilities from damage due to any
construction activity. Repair damages to utility items at own expense. Assess no cost to
Owner, Engineer, or auxiliary party for any damages.
PART 2 — PRODUCTS
2.01 BACKFILL
A. Select Backfill shall contain no man-made or organic materials and shall be free of rocks,
clods, or other materials larger than 2 -inches in nominal diameter. Materials from on-site
excavations may be used for select backfill provided they meet the specified requirements.
IF SUFFICIENT ON-SITE SELECT BACKFILL MATERIAL IS NOT AVAILABLE, THE
CONTRACTOR SHALL SECURE ACCEPTABLE MATERIALS FROM AN OFF-SITE
BORROW AREA AT NO ADDITIONAL COST TO THE OWNER, unless there is a specific
payment item for offsite select backfill material. Off-site borrow material shall be approved
by the Engineer before any material is transported to the work area.
B. Common backfill materials shall be free of all organic materials and shall not contain any
rocks larger than 6 inches in diameter. Materials from on-site excavations may be used
for common backfill provided they meet the specified requirements. IF SUFFICIENT ON-
SITE COMMON BACKFILL MATERIAL IS NOT AVAILABLE, THE CONTRACTOR
SHALL SECURE ACCEPTABLE MATERIALS FROM AN OFF-SITE BORROW AREA AT
NO ADDITIONAL COST TO THE OWNER, unless there is a specific payment item for
offsite common backfill material. Off-site borrow material shall be approved by the
Engineer before any material is transported to the work area.
2.02 BEDDING
A. Bedding material shall be NCDOT #67 stone.
2.03 CONCRETE
A. Concrete for encasement, cradles, caps and collars will be Class B in accordance with
NCDOT requirements.
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2.04 TOPSOIL
A. Topsoil shall be fertile, natural soil, free from large stones, roots sticks and weeds with a
neutral pH. It shall contain no mixture of refuse or any material toxic to plant growth.
Topsoil from off-site sources shall also have a minimum of 80% passing No. 4 sieve, a
maximum of 80% passing a No. 200 sieve, minimum of 5% organic content and a pH
between 6 and 7.
PART 3 — EXECUTION
3.01 GENERAL
A. Perform work in conformance with applicable State and Federal safety regulations
including, but not limited, to the following:
North Carolina Safety and Health Standards for the Construction Industry (29CFR
1926 Subpart P).
2. NC OSHA Industry Guide No. 14, Excavations.
3. NC OSHA Industry Guide No. 20, Crane Safety.
B. Provide barriers, warning lights, and other protective devices at excavations as necessary
for safety of workers and the public.
C. Provide traffic control in accordance with Section 02960 — Traffic Control.
D. Provide sloping of bank, shoring, sheeting, or other means of maintaining the stability of
the trench in accordance with the requirements of the Associated Contractor's Manual of
Accident Prevention OSHA, Part 1926.P.
E. In trench depths of 22 feet or greater, provide certification sealed by Structural Engineer
certifying that trench box, sheeting and shoring meets OSHA requirements.
3.02 TEST BORING TO DETERMINE ROCK PROFILE
A. Contractor shall contract with a 3rd party geotechnical engineering firm to perform test
borings along the centerline of the pipeline. The Contractor shall submit information
including a resume showing a minimum of 10 years experience on similar local projects
(within 50 miles), listing of local clients and current rate schedule for the proposed 3rd
party geotechnical firm to the Engineer for approval. Geotechnologies, Inc., Raleigh, NC,
performed the preliminary geotechnical report that is included in the Contact Documents.
Contractor may use Geotechnologies or another local firm with similar experience.
B. Upon completion of clearing operations and before any pipeline excavation, the
Contractor will coordinate with the geotechnical firm to test bore the centerline of the
pipeline alignment every 50' on centerline to determine the top elevation of solid rock as
defined above.
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C. Borings will be terminated a minimum of 12 inches below subgrade if no rock is
encountered.
D. Geotechnical firm will profile the top of rock and quantify the rock based on width and
subgrade dimensions as listed in Section 00410 - Bid. For purposes of quantifying the
rock 12" below subgrade will be used as top of rock elevation if no rock was encountered
to the point of termination.
E. Geotechnical firm shall prepare and submit a certified report of their findings to the
Contractor, Engineer and Owner. Report must be submitted to Engineer prior to
excavation.
3.03 EXCAVATION
A. Stripping of Topsoil
1. Topsoil shall be provided in all lawns, landscaped areas, cultivated fields and
pastures on the project. Contractor has the option to strip and stockpile existing
topsoil prior to trenching operations for subsequent reuse if it meets the definition
of topsoil in subpart 2.04 herein. Topsoil shall be kept separated from other
excavated materials and shall be piled free of roots and other undesirable materials.
Topsoil shall be protected with silt fencing for erosion control.
2. Topsoil replacement shall be in accordance with Section 02910 — Final Grading and
Landscaping.
B. Remove soil, rock, clay, silt, gravel, hard pan, loose shale, and loose stone as required
for complete and satisfactory installation of utility. The unit price bid for pipe will include
all excavation and trenching to subgrade, dewatering and backfilling with the exception of
granular bedding material for trench stabilization.
C. Excavation
Excavate trenches by open cut method to depth specified and/or shown on Drawings
and necessary to accommodate work.
2. Open trenches:
a. No more than 100 LF of trench shall be open at any one time.
b. Field adjust limitations as weather conditions dictate.
C. No trenches shall be left open overnight.
3. Observe following trenching criteria:
a. Excavate width to accommodate free working space.
b. Maximum trench width at top of pipe may not exceed the limits shown on
the Drawings.
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C. Cut trench walls vertically from bottom of trench to 1 foot above top of pipe,
conduit, or utility service.
d. All excavation and placement of backfill shall be carried out in the dry. See
Dewatering section below.
e. Brace and sheet trenches in full compliance with OSHA requirements and
all applicable codes and as required to protect existing roadways and
utilities. See Shoring and Sheeting section below.
D. All suitable material removed in the excavation shall be used as far as practicable in the
formation of embankments, subgrades, and shoulders, and at such other places as may
be indicated on the Drawings or indicated by the Engineer. No excavation shall be wasted
on site except as may be permitted by the Engineer. Refer to the drawings for specific
location and placement of suitable excavated materials in the formation of embankments,
backfill, and structural and roadway foundations. THE ENGINEER WILL DESIGNATE
MATERIALS THAT ARE UNSUITABLE. The Contractor shall furnish off-site disposal
areas for the excess and unsuitable material. Where suitable materials containing
excessive moisture are encountered above grade in cuts, the Contractor shall construct
above grade ditch drains prior to the excavation of the cut material when in the opinion of
the Engineer such measures are necessary to provide proper construction.
E. All excavations shall be made in the dry and in such a manner and to such widths as will
give ample room for properly constructing and inspecting the structures and/or piping they
are to contain and for such excavation support, pumping and drainage as may be required.
Excavation shall be made in accordance with the grades and details shown on the
Drawings and as specified herein.
F. Rock Excavation
Remove rock and dispose of in accordance with subpart 3.07 herein. Rock excavation
shall be carried 6 inches below the invert of the pipe. Pipe shall then be bedded
as shown on the Drawings and trenches brought back to grade with suitable
materials, properly compacted.
2. When the use of explosives is necessary for the prosecution of the work, then it shall
be in accordance with subpart 3.07 herein.
3. Payment for solid rock excavation will be as listed in the Pay Item Description in
Section 00410 — Proposal.
G. Dewatering
The Contractor shall furnish, install and operate all necessary machinery,
appliances and equipment to keep excavations free from water during
construction, and shall dewater and dispose of the water so as not to cause injury
to public or private property, or to cause a nuisance or a menace to the public. The
Contractor shall control surface runoff so as to prevent entry or collection of water
in excavations. The dewatering systems shall be installed and operated so that the
ground water level outside the excavation is not reduced to the extent that would
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damage or endanger adjacent structures or property. The release of groundwater
to its static level shall be performed in such a manner as to maintain the
undisturbed state of the natural foundation soils, prevent disturbance of compacted
fill or backfill and prevent flotation or movement of any structures, pipelines and
sewers.
2. Procedures for dewatering proposed by the Contractor shall be submitted to the
Engineer for review prior to any earthwork operations.
3. All water removed by dewatering operations shall be disposed of in accordance
with the North Carolina Sedimentation Pollution Control Act.
4. The dewatering system shall be of sufficient size and capacity as required to
control groundwater or seepage to permit proper excavation operations,
embankment construction and reconstruction, subgrade preparation, and to allow
pipe or structure to be placed in a dry condition. The system shall include a sump
system or other equipment, appurtenances and other related earthwork necessary
for the required control of water. The Contractor shall drawdown groundwater to at
least 3 feet below the bottom of excavations (subgrade) at all times in order to
maintain a dry and undisturbed condition.
5. The Contractor shall be solely responsible for proper design, installation, proper
operation, maintenance, and any failure of any component of the dewatering
system.
6. The Contractor shall be responsible for repairing, without cost to the Owner, any
damage to work in place and the excavation, including damage to the bottom due
to heave and including removal of material and pumping out of the excavated area.
The Contractor shall be responsible for damages to any other area or structure
caused by his failure to maintain and operate the dewatering system proposed and
installed by the Contractor.
7. The Contractor shall take all the steps that he considers necessary to familiarize
himself with the surface and subsurface site conditions, and shall obtain the data
that is required to analyze the water and soil environment at the site and to assure
that the materials used for the dewatering systems will not erode, deteriorate, or
clog to the extent that the dewatering systems will not perform properly during the
period of dewatering. Copies of logs of borings and laboratory test results used in
design will be made available to the Contractor. This data is furnished for
information only, and it is expressly understood that the Owner and Engineer will
not be held responsible for any interpretations or conclusions drawn therefrom by
the Contractor.
8. Cost of dewatering is to be included in the price of the pipe and structures in the
original bid.
H. Shoring and Shielding
1. The Contractor shall comply with OSHA trenching and excavation regulations as
revised in Subpart P of Part 1926 in the Federal Register. Shoring and/or shielding
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systems shall be used as specified in Subpart P to prevent caving of trench banks
and to provide a safe excavation.
2. The Contractor will be responsible for excavation safety and shall designate his
"competent person" (as defined in Subpart P) for the determination of proper
shielding/shoring systems.
Subgrade Stabilization via Additional Excavation and Stabilization Stone
Under this Section, the Contractor shall do all additional excavation specifically
requested by the Engineer when the subgrade materials cannot meet
compaction requirements for pipe or structure bedding. In this case, the
Contractor shall furnish all labor, equipment and materials for the placement and
compaction of additional crushed stone bedding as herein specified or as
directed by the Engineer.
2. Backfill for additional excavation shall be crushed stone bedding as described in
Pau Item Number 18 as described in Section 00410. Any and all work done
under this Section shall be at the direction of the Engineer. No payment will be
made for excavation beyond that described in the Pay Item Description. Any
excavation not authorized by the Engineer will be at the Contractor's expense.
3. Observe the following requirements when unstable trench bottom materials are
encountered.
a. Notify Owner/Engineer immediately when unstable materials are
encountered.
Remove unsuitable material to the width defined on the Drawings and the
depth as directed by the Engineer and dispose of the material off site.
C. Replace unsuitable material with bedding material unless otherwise
directed by the Engineer.
d. Coordinate measurement of undercut with Engineer listing Plan station and
limits.
4. Remove unstable trench bottom caused by Contractor failure to dewater, rainfall,
or Contractor operations at no additional cost to Owner.
J. Foundation for Pipelaying
Provide a continuous and uniform subgrade and bedding in the trench for all pipe in
accordance with trench cross-section indicated on the Drawings.
3.04 BACKFILLING
A. Compacted Select Backfill
1. Furnish where indicated on the Drawings, specified for trench embedment conditions,
and for backfill to a minimum of 12 inches above top of pipe.
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Comply with the following:
Place backfill in lifts not exceeding 6 inches (loose thickness).
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b. Stones/rock other than crushed bedding, shall not come in contact with or
be within 6 inches of pipe. Backfill that is more than 6 inches above top of
pipe may contain rocks measuring not exceeding 6 inches in any
dimension.
C. Hand place, shovel slice, and pneumatically tamp all select backfill.
d. Ensure all spaces beneath pipe are filled and compacted.
e. Compact each lift to specified requirements.
B. Common Trench Backfill
Perform in accordance with the following:
a. Place backfill in lift thicknesses capable of being compacted to densities
specified below in Compaction section.
b. Observe specific pipe manufacturer's recommendations regarding
backfilling and compaction.
C. Avoid displacing joints and appurtenances or causing any horizontal or
vertical misalignment, separation, or distortion.
C. Water flushing or flooding for consolidation is not permitted.
3.05 COMPACTION
A. General
Place and assure backfill and fill materials achieve an equal or higher degree of
compaction than undisturbed materials adjacent to the work.
2. In no case shall degree of compaction below "Minimum Compactions" specified be
accepted.
B. Compaction Requirements: Unless noted otherwise on the Drawings or more stringently
by other sections of these Specifications, comply with following trench compaction criteria:
Material Classifications
Crushed Stone Bedding
Select Backfill
Backfill
Backfill (Top 12 inches)
Aggregate Base Course (ABC)
Backfill Around Structures
AASHTO-T99 Density
95% Standard Proctor
95% Standard Proctor
90% Standard Proctor
98% Standard Proctor
100% Standard Proctor
95% Standard Proctor
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C. All backfill materials placed under State, City, County or Town roads (paved or unpaved),
streets and driveways shall be compacted to 95% of the Standard Proctor AASHTO-T99
density for the full length.
D. The Engineer may require compaction tests by an approved testing lab in order to verify
that the required compaction densities are being achieved. Such tests, where required
by the Engineer, will be provided by the Owner at his expense.
E. When excavations are within State, City, County or Town roads, density tests shall be
performed every 100-200 feet of trench length and every 24 inches of fill placed. Density
tests for aggregate base course material (ABC) shall be performed every 500 feet of
trench length. Density tests at other locations shall be at the discretion of the Engineer.
The Contractor shall allow adequate time for such tests to be performed.
3.06 FIELD QUALITY CONTROL
A. Testing
Perform in-place moisture -density tests per Section 01400 - Quality Control as
directed by the Engineer.
2. Costs of "Passing" tests will be paid by Owner.
3. In the event of failing tests perform additional tests as directed until compaction meets
or exceeds requirements.
4. Cost associated with "Failing" tests shall be paid by Contractor.
5. Reference to Engineer in this section will imply Soils Engineer when employed by
Owner and directed by Engineer to undertake necessary inspections and/or
testing.
6. Assure Engineer has immediate access for testing of all soils related work.
7. Ensure excavations are safe for testing personnel.
3.07 USE OF EXPLOSIVES
A. Blasting is allowable for the removal of rock, as defined herein unless specifically
prohibited by the Owner, Engineer or the Owner of an existing utility within the proximity
of the proposed blasting site. The Contractor shall review the Contract Documents and
Encroachment Agreements for areas where blasting is prohibited or restricted.
B. Blasting Submittals
1. In accordance with the procedures and requirements set forth in Section 01300 -
Submittals, the Contractor shall submit the following at least 30 working days prior to
beginning any blasting operations:
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a. Names, addresses, telephone numbers, and qualifications of the blasting
subcontractor(s) and explosives supplier(s) that will be used, including the
designated Blaster -In -Charge.
b. Copies of Training Certificates for the designated Blaster -In -Charge, blasting
foreman and any other key personnel that will be responsible for the work, showing
that they have received specialized training in the proper handling of explosives.
c. A Blasting Plan, indicating the methods, materials and equipment to be used. The
Blasting Plan should indicate the types of explosives to be used, drilling patterns,
and a general layout and schedule for executing the work in accordance with state
regulations.
d. A ground vibration and air blast monitoring plan, indicating structures that will be
monitored, monitoring equipment that will be used, and personnel that will perform
the monitoring. Contractor shall photograph structures to be monitored prior to
blasting.
e. Copies of pre -construction condition inspection and documentation of adjacent
structures on-site and off-site performed by the Contractor.
f. Planned location of all shots labeled by station number based on the results of the
third party geotechnical firm's rock profile detailed in subpart 3.02 herein.
g. Typical blasting setup for each blast indicating the number, diameter, and depth of
blast holes to be detonated in the round, and a plan showing the drill hole pattern,
spacing and distance to the free face; depth of overburden; total weight of
explosives in the round and the types of explosives to be used; loading diagram
showing the location of explosives, primers, and initiators; and location, depth, and
type of stemming to be used in each hole; initiation sequence, including delay timer
and delay system, total weight of explosive to be detonated on each delay, and a
list of the timing of the delays.
h. Log indicating the names and addresses of all properties have received advanced
written notification as required by this section.
Log of all properties where preblast surveys are planned.
j. Map indicating the locations of all planned seismic monitoring positions, distances
from the blast round, and seismograph types to be used to monitor vibrations and
air blast overpressures.
k. Type and amount of blasting mats and/or depth of soil cover to be used over the
top surface of the shot.
I. Any other information required by applicable state and federal regulations.
2. Within 24 hours after each blast round, Contractor shall submit a blasting report to the
Engineer with the information listed in subpart 3.07-G herein.
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C. Obtain required permits for blasting (e.g., from Town of Apex Fire Department or Wake
County Fire Marshall's Office) a minimum of 24 hours prior to blasting.
D. Store, handle, and use explosives in accordance with local, state, and federal laws and
regulations, or in the absence of such, in accordance with the provisions of the "Manual
of Accident Prevention and Construction" of the Associated General Contractors of
America, Inc. Federal regulations include, but are not limited to, Title 27, Chapter 11. Part
555 of the Code of Federal Regulations (CFR) and OSHA Standards — Part 1926, Subpart
U.
E. Provide written notification to all property owners within 1,500 feet of any blasting a
minimum of 30 days prior to blasting.
F. Provide verbal notification to all property owners within 500 feet of any blasting on the day
of the scheduled blast.
G. Take all necessary precautions to protect life and property, including the use of an
approved blasting mat where there exists the danger of throwing rock or overburden. Keep
the explosive materials that are on the job site in specially constructed boxes provided
with locks. Failure to comply with this specification shall be grounds for suspension of
blasting operations until full compliance is made. No blasting shall be allowed unless a
galvanometer is employed to check cap circuits. Where blasting takes place within 500
feet of a utility, structure, or property which could be damaged by vibration, concussion or
falling rock, keep a blasting log containing the following information for each and every
shot.
Date of shot
2. Time of shot
3. Crew supervisor
4. Number and depth of holes
5. Approximate depth of overburden
6. Amount and type of explosive used in each hole
7. Type of caps used (instant or delay)
8. The weather
9. Seismograph instrument and readings
H. Use explosives in such a way to minimize vibration to existing utilities and structures.
Provide only experienced personnel for blasting in accordance with accepted practices.
J. Contractor is responsible for safety of life and damage to property resulting from the use
of explosives. The Owner and Engineer shall be made aware of all blasting activities prior
to their occurrence.
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K. Contractor shall provide the services of an independent geotechnical testing firm
experienced in preblast assessment, crack monitoring and monitoring vibrations resulting
from blasting operations. The firm selected shall be evaluated by the Engineer and Owner
for approval as the official independent blast monitoring geotechnical firm.
L. The geotechnical testing firm shall perform the following testing/monitoring as related to
blasting operations:
Pre -Construction Condition Assessment
a. Prior to beginning construction, the geotechnical testing firm shall perform
a pre -construction condition assessment to document the conditions of all
buildings and other sensitive structures within 300 feet of the proposed
blasting area. The assessment shall be performed on all adjacent
properties and any other properties as directed by the Engineer or Owner.
The assessment should include video and photographic documentation of
all exteriors including building foundations, and installation of crack
monitors on existing cracks that might expand due to construction
vibrations. Provide all documentation described above to the Owner and
Engineer prior to construction.
2. Crack Monitoring
a. Prior to construction the geotechnical testing firm shall install crack
monitors on existing cracks that might expand due to construction
vibrations. Monitors shall be placed on buildings and other sensitive
structures within 300 feet of the proposed blasting area unless otherwise
directed by the Engineer.
During construction, the geotechnical testing firm shall perform periodic
readings, of sufficient frequency, of the crack monitors that were installed
prior to construction to assess/monitor the effects of the blasting
operations. Provide readings to the Engineer and Owner within 48 hours of
taking the reading. If crack monitor readings confirm that vibrations are not
contributing to crack width, crack monitors may be read once per week.
More frequent readings may be required by Owner or Engineer if
construction activities could result in greater earthborn vibrations. Testing
firm shall notify the Contractor, Engineer and Owner immediately if
monitoring indicates that construction operations have contributed to crack
widening. Contractor shall submit a plan for review that proposes alternate
construction methods to address the vibration problems and minimize
further damage.
3. Vibration Monitoring During Construction
a. The geotechnical testing firm shall monitor vibrations at no less than four
locations during all blasting activities. The locations shall be selected by
the geotechnical testing firm based on the location of construction activities
and their relative position to nearby structures. Prior to construction, a plan
showing the proposed monitoring locations shall be submitted to the
Engineer and Owner for approval. Adjustments may be made to the
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locations upon approval. The sensitivity range of the seismograph shall be
selected such that the recording is initiated below the maximum allowable
particle velocity of 1 in/sec and extends above the highest expected
intensity. Specific activities of the vibration source (i.e., blasting) shall be
indexed in time to allow correlation with the arrivals on the vibration.
The maximum allowable particle velocity is 1 in/sec. The testing firm shall
notify the Engineer and Owner immediately if monitors indicate that the
vibrations are above the criteria established. Activities causing the
vibrations shall be suspended until a revised construction plan has been
developed by the testing firm to alleviate the problem. The problem shall
be resolved by the Contractor at no additional cost to the Owner.
The vibration monitors shall consist of digital seismographs that display the
particle velocities and associated frequencies plotted against the criteria
established for this project. Each seismograph shall contain geophones
with response capability in three mutually perpendicular axes or
components; one vertical and two horizontal (radial and transverse).
The frequency response of the geophones shall be linear from at least 4 Hz
to more than 200 Hz. The sensitivity shall range from less than 0.02 in/sec
to more than 5.0 in/sec. The BlastMate III by Instantel is one type of
seismograph that is suitable for this project.
C. Vibration monitors shall be field calibrated by the testing firm before each
recording period. The transducer shall be positioned with the longitudinal
axis toward the vibration source. Transducers must be adequately coupled
with the ground. Operation and calibration of all equipment shall be per
manufacturer's recommendations. Vibration records shall be collected in
waveform plot or strip chart plot. The peak vector sum of the particle
velocity in longitudinal, transverse, and vertical planes shall be shown
along with the respective dominant or principle frequencies. The highest
recorded particle velocity (i.e., the vector sum of the three orthogonal
directions), when indexed to a particle vibration event, shall be reported as
the peak particle velocity. The recorded peak particle velocity shall be
compared to criteria appropriate for the subject of concern.
d. The Engineer and Owner shall be notified immediately of any complaint
received by the Contractor or geotechnical testing firm. The geotechnical
testing firm shall immediately review those construction activities inducing
the vibration and prepare a report documenting all relevant data such as
the time and date of the complaint, a description of the construction
activities, data from the monitoring instruments for the subject time/date,
complaint information (including photographs, if possible) of the alleged
damage. The firm shall submit for review a detailed plan for repair and
revised construction plan to address the vibration problems to minimize
further damage and complaints. The Contractor shall be responsible for
any and all necessary repairs at no additional cost to the Owner.
e. The testing firm shall provide monthly reports containing the results of the
crack monitors and vibration monitors during those activities that generate
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earthborn vibrations, including but not limited blasting operations. The
reports shall document that the firm has provided the work described
herein.
M. Submit monitoring reports in accordance with Section 01300 —Submittals.
N. The Owner reserves the right to require the removal of rock by other means if blasting
operations result in possible hazardous conditions.
O. Vibrations shall be monitored utilizing a seismograph capable of providing a record of
particle velocity and frequency along three mutually perpendicular axes utilizing internal
calibration. Measured peak particle velocity of ground motion at the monitored structure
shall not exceed the values shown in the following graph:
10
0.19 inch/sec
0.1
UNACCEPTABLE
ZONE
0.5 inch/sec
2.0 inch/sec
ACCEPTABLE
LIMITS
2.5 10 40 100
Frequency (Hertz)
3.08 REMOVAL OF EXCESS AND UNSUITABLE MATERIALS
A. The Contractor shall remove and dispose of off-site all excess and unsuitable materials at
no additional cost to the Owner.
B. All excess and unsuitable materials shall be disposed of in locations and under conditions
that comply with federal, state and local laws and regulations.
C. If the disposal site is located on private property, the submittal shall also include written
permission from the owner of record.
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D. The Contractor shall obtain an off-site disposal area prior to beginning demolition or
excavation operations.
E. All excess and unsuitable materials shall be hauled in trucks of sufficient capacity and tight
construction to prevent spillage. Trucks shall be covered to prevent the propagation of
dust.
F. When all excess and unsuitable material disposal operations are completed, the
Contractor shall leave the disposal sites in a condition acceptable to the Owner(s) of the
disposal site(s).
- END OF SECTION -
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