31_09_13.00_08_-_Amendment_0009.pdf

East Branch Dam, Dam Safety Modification, Cutoff Wall

SECTION TABLE OF CONTENTS

DIVISION 31 - EARTHWORK

SECTION 31 09 13.00 08

INSTRUMENTATION AND MONITORING

PART 1 GENERAL

1.1 SCOPE

1.2 MEASUREMENT AND PAYMENT

1.3 REFERENCES

1.4 SYSTEM DESCRIPTION

1.4.1 Existing Instrumentation

1.4.1.1 Automated Data Acquisition System (ADAS)

1.4.2 Additional Instrumentation for Installation

1.4.2.1 Piezometer

1.4.2.2 Inclinometer

1.4.2.3 Weir

1.4.3 Decommissioning Instrumentation

1.5 SUBMITTALS

1.6 PROJECT SITE CONDITIONS

1.6.1 Environmental Requirements

1.6.2 Field Considerations

1.7 SEQUENCING AND SCHEDULING

1.8 INSTALLATION PLANS

1.9 PERMITS, CERTIFICATIONS, AND LICENSES

1.10 JOINT INSTRUMENTATION MONITORING PLAN

PART 2 PRODUCTS

2.1 PIEZOMETERS

2.1.1 Sand Fill

2.1.2 Bentonite Pellets

2.1.3 Concrete

2.1.4 Polyvinyl Chloride Pipe

2.1.5 Porous Filter Tip

2.1.6 Grout For Piezometer Installation and Decommissioning

2.1.7 Vibrating Wire Pressure Transducers

2.1.7.1 Vibrating Wire Pressure Transducers Tests

2.2 INCLINOMETERS

2.2.1 Inclinometer Casing

2.2.2 Grout

2.2.2.1 Decommissioning Inclinometers

2.2.2.2 Embankment Inclinometers

2.2.2.3 Cutoff Wall Inclinometers

2.2.3 Concrete

2.2.4 Spiral Inclinometer Sensor

2.2.5 Inclinometer Probe

2.2.6 In-place inclinometers

2.3 ADAS EQUIPMENT

2.4 WEIR PLATES

2.4.1 Steel Plate

2.4.2 Weir Gauges

PART 3 EXECUTION

SECTION 31 09 13.00 08 Page 1

W911WN-13-R-0002 REVISED BY AMENDMENT 0009

3.1 GENERAL

3.2 PIEZOMETER REQUIREMENTS

3.3 INCLINOMETER REQUIREMENTS

3.3.1 Installation

3.3.2 Initial Spiral Survey

3.3.3 Manual Survey

3.3.4 In-Place Inclinometer Sensors

3.4 WEIR

3.5 RECORDS

3.6 MONITORING DURING CONSTRUCTION

3.6.1 General Instrumentation

3.6.2 Piezometers

3.6.3 Inclinometers

3.6.4 Weirs

3.6.5 Alignment and Settlement Surveys

3.7 FINAL CREST CONFIGURATION

3.7.1 Final Instrumentation Configuration Plan

3.8 OTHER REQUIREMENTS

-- End of Section Table of Contents --

SECTION 31 09 13.00 08 Page 2

SECTION 31 09 13.00 08

INSTRUMENTATION AND MONITORING

PART 1 GENERAL

1.1 SCOPE

The work covered by this section consists of furnishing all plant;

equipment; labor; and materials required for installing new piezometers, inclinometers, and weirs; reading existing instruments that include piezometers, weirs, etc. in addition to the newly installed instrumentation; monitoring reservoir level, outflow level, and outflow water quality and; maintaining an existing automated data collection system that reads piezometer transducers and in-place inclinometers at the dam and installing any additional automation equipment necessary to collect and post all recorded data and pool elevation to a secure FTP (file transfer protocol) (sFTP) site established as required by Section 31 09 14 DATA MANAGEMENT SYSTEM. This work also includes the decommissioning of select instruments.

1.2 MEASUREMENT AND PAYMENT

Measurement and payment for the work covered under this section will be made as specified in Section 01 22 00.00 10 MEASUREMENT AND PAYMENT.

1.3 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)

ANSI/NCSL Z540-1 (1994) Calibration Laboratories and Measuring and Test Equipment - General Requirements

ASTM INTERNATIONAL (ASTM)

ASTM C33/C33M (2013) Standard Specification for Concrete Aggregates

ASTM A240/A240M (2012) Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications

ASTM C1107/C1107M (2011) Standard Specification for Packaged Dry, Hydraulic-Cement Grout (Nonshrink)

ASTM D1785 (2012) Standard Specification for Poly(Vinyl Chloride) (PVC), Plastic Pipe, Schedules 40, 80, and 120

ASTM D6391 (2011) Field Measurement of Hydraulic Conductivity Using Borehole Infiltration

SECTION 31 09 13.00 08 Page 3

U.S. ARMY CORPS OF ENGINEERS (USACE)

EM 1110-2-1908 (1995) Instrumentation of Embankment Dams and Levees

1.4 SYSTEM DESCRIPTION

The purpose of the work specified herein is to monitor the existing instrumentation system at the dam (including manual and automated piezometers, inclinometers, water level gauges, water quality sensor, and weirs) as well as install new piezometers, inclinometers, and weirs that will supplement the existing Automated Data Acquisition System (ADAS) in monitoring for the East Branch project. These instruments will be used to monitor performance of the dam prior to, during and following construction of the cutoff wall. Monitoring shall be incorporated into the Data Management System as specified in Section 31 09 14 DATA MANAGEMENT SYSTEMS as well as the Joint Instrumentation Monitoring Plan (JIMP) included in Volume 3 - Attachments to Specifications.

1.4.1 Existing Instrumentation

There are currently ninety six open standpipe piezometers located in the embankment, foundation, and abutments. Forty six piezometers are automated with vibrating wire pressure transducers linked to a data logger programmed to capture readings at 15 minute intervals. Fourteen piezometers are read manually on a consistent basis. Twenty two piezometers are designated "Stand-by" which are to be read manually as required. Two vibrating wire pressure transducers installed at the site are to solely measure the changes in barometric pressure. The automated piezometers and barometers, along with the manual and stand-by piezometers shall be monitored and reported as specified in the Joint Instrumentation Monitoring Plan (JIMP) included in Volume 3 - Attachments to Specifications.

A total of eight weirs are installed at various locations downstream of the dam's centerline. Two weirs are automated by United States Geologic Survey (USGS) using transducers that capture readings at 15 minute intervals and are uploaded to their website. The data is available on the website for a period of one month (30 days). One automated weir is located at the exit of the conduit that runs beneath the right wall of the concrete spillway.

The second is located within the pump house adjacent to the upper pond at the toe of the dam. All weirs are read manually. This includes the two USGS automated weirs which are read manually in addition to being automated.

Two inclinometers are currently installed in the area of the grout void on the right abutment. One is located 30 feet downstream of the baseline and the other is located 11 feet upstream of the baseline. These are currently read manually on a quarterly basis.

Two gauges are located on site and installed by USGS. One gauge is located within the outflow that currently measures water level and water temperature on 15 minute intervals. The other is located off of the intake tower in the reservoir and measures water level and temperature on 15 minute intervals. USGS installed a water quality device near the location of the gauge in the outflow to measure specific conductivity, turbidity, pH, and dissolved oxygen on 15 minute intervals. All data is captured by a sensor, collected by a Data Control Panel (DCP), sent to satellites, uploaded to the USGS website, and downloaded manually. After a period of

SECTION 31 09 13.00 08 Page 4

30 days, the data is removed from the USGS website. Water temperature and downstream flow quality shall be monitored during construction as specified in Section 01 57 20.00 10 ENVIRONMENTAL PROTECTION and the Joint Instrumentation Monitoring Plan (JIMP) (included in Volume 3 - Attachments to Specifications).

Alignment and settlement deformations of the embankment crest is monitored by five alignment/settlement pins along the downstream edge of the crest road. The pins are referenced to two secondary control points located at either end of the Dam Crest Road on the right and left abutments. A primary control point is located on a pillar at the land end of the service bridge to the intake tower and serves at the datum control for the project. The secondary control points and alignment/settlement pins shall be maintained during construction through post construction and surveyed monthly. If the Contractor damages any of the monuments and pins, they must be replaced permanently regardless of the stage of construction at which the damage occurred. A submittal and plan must be provided to the Government and approved by the Contracting Officer before these instruments are damaged.

The locations of all existing instrumentation are shown on the contract drawings except that of the USGS gauges located at the intake tower and outflow area. The Contractor shall ensure the operation and protection of all instrumentation during the construction contract. Any accidental damage to the instrumentation and corresponding equipment is required to be reported to the Contracting Officer within 24-hours of the incident. It is the financial responsibility of the Contractor to replace the instrumentation and/or equipment unless noted for decommissioning in the drawings.

1.4.1.1 Automated Data Acquisition System (ADAS)

An Automated Data Acquisition System (ADAS) is configured to monitor automated instruments throughout the duration of the contract. The system collects data from 36 existing automated piezometers and 2 automated barometers while incorporating data from other instruments automated and maintained by USGS including 2 weirs, 1 reservoir gage, 1 outflow gage, 1 water quality sensor, and 1 precipitation gage. Manual instruments, designated as manual or stand-by in the drawings, are physically entered in the ADAS. A couple of automated instruments are required to be read manually in addition to their automatic readings mentioned below.

Construction monitoring cameras at various locations across the site have been incorporated into the system as well.

The system automatically reads and stores instrumentation data and cameras images at a preset time interval and reading frequency which is currently every 15 minutes. It has the capability to modify reading frequency when increased or decreased monitoring is needed, such as during a high risk event. All instruments are automatically scanned for threshold exceedance and the system is configured to trigger alarms based on any of the following types of conditions: static threshold exceedance, rate of change, and time delay with multiple values verification. All thresholds and alarm conditions are user configurable and readily adjustable.

Instrumentation data and camera images collected from the field are transferred to a primary local host computer with second backup. The data is converted from the raw form to the appropriate engineering units. Once converted the data from each instrument is compared to a range of threshold levels. Different threshold levels results in different system responses.

SECTION 31 09 13.00 08 Page 5

System responses include text or e-mail notifications to different groups of individuals as well as audible and visual alarming at the site.

Data and images from the system are populated at a secure website, accessible by the Government, and data is provided in both tabular and graphic format. Short term plots (30 day) as well as all history plots are required for each instrument. Every image is archived for the history of the project. Internet service is provided for 3 years at which point the Contractor becomes responsible for providing internet service.

1.4.2 Additional Instrumentation for Installation

Additional instrumentation shall be installed prior to, during, and post construction. Instrumentation to be installed includes open standpipe piezometers with vibrating-wire pressure transducers, inclinometer casings, in-place inclinometers, v-notch weirs, and any other equipment necessary to incorporate the instruments into the existing Automated Data Acquisition System (ADAS) for monitoring at East Branch Dam. An ADAS Equipment document presenting the equipment used in the existing system is provided in Volume 3 - Attachments to Specifications. All new automated instruments shall obtain readings at frequencies provided below starting on the hour.

Transferring of the existing ADAS as well as responsibilities, maintenance, and additions to the existing ADAS shall be achieved in accordance with and as specified in Section 31 09 14 DATA MANAGEMENT SYSTEM. Drilling and soil and rock sampling incidental to installation of the instrumentation, specifically piezometers and inclinometers, shall be performed in accordance with Section 02 32 00 SUBSURFACE DRILLING, SAMPLING, AND TESTING.

1.4.2.1 Piezometer

Thirteen piezometers are required to be installed in accordance with this specification. Each piezometer installed shall be an open standpipe fitted with a vibrating wire pressure transducer placed within the PVC riser.

Installation of the automated piezometer shall be performed in a manner that permits removal and replacement of the vibrating wire sensor or removal of the sensor and manual reading of the open standpipe piezometer.

All equipment necessary to link the piezometer to the existing ADAS shall be included and installed. Locations of the piezometers are provided in the drawings. Installation shall be achieved as specified below.

1.4.2.2 Inclinometer

The eleven inclinometers required for installation under this contract shall be installed in accordance with this specification. Three sets of inclinometers shall be installed along the dam: one set at approximate Station 8+50 on the right abutment, another set at approximate Station 11+90 in the valley, and the final set at approximate Station 18+90. A set consist of three inclinometers: one 15-foot downstream of the baseline, one within the cutoff wall, and one 30-foot upstream of the baseline. The downstream inclinometer at Station 8+50 already exists, located at Station 8+15 requiring only two inclinometer installations to complete that set.

The three remaining inclinometers shall be installed at the following locations: one at Station 8+25 30-feet downstream of the baseline, another at Station 12+00 30-feet upstream of the baseline, and the final within the cutoff wall at Station 1+00B past the turning point at the left abutment.

Nine inclinometers will be surveyed manually. The remaining two of the eleven inclinometers installed are required to be set up with in-place inclinometer sensors positioned every ten feet along the entire depth of the casing. All inclinometer casings will have an initial spiral survey

SECTION 31 09 13.00 08 Page 6 performed a week after installation and prior to any installation of in-place sensors and automation equipment, if required. All inclinometer casing will also have a manual survey preformed after the spiral survey regardless of any future in-place sensors or lack thereof. Frequencies of manual surveys on the non-automated inclinometers are provided below.

Locations of the inclinometers are provided in the drawings. Installation shall be achieved as specified below.

1.4.2.3 Weir

Two weirs shall be installed under this contract: both located above the exit of the outlet tunnel, downstream of the right abutment. The first will replace an existing weir that will be decommissioned prior to construction of the inclined drains. The replacement will continue to capture the drainage of the hillside above it. The second weir shall be placed at the outlet of the inclined drains which will capture and monitor the volume and clarity of water exiting from the drains. Installation of both weirs shall be constructed as a part of this contract as described in Section 33 26 00.00 08 INCLINED DRAINS. Installation shall occur after the inclined drains and collection basin have been constructed. Locations of the weirs are provided in the drawings. Installation shall be achieved as specified below

1.4.3 Decommissioning Instrumentation

Fourteen of the piezometers and one existing inclinometer shall be decommissioned prior to construction of the work platform. Weir #8a, located within the footprint of the inclined drain collection basin, shall be decommissioned with the demolition of the existing concrete slab. The location of these instruments and relevant details associated with the instruments are shown on the contract drawings.

1.5 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-01 Preconstruction Submittals

Joint Instrumentation Monitoring Plan (JIMP); G, DG

The JIMP shall be submitted within 120 days of issuance of Notice to Proceed and shall be reviewed and updated every 6 months, prior to each major feature of work, and at the Contracting Officer's discretion.

Piezometer Installation Plan; G, DG

Submit at least thirty days prior to installation. The Contractor shall submit his plan for installing piezometers to the Contracting Officer for approval as specified in paragraph INSTALLATION PLANS. No work shall be performed until this plan has been approved and no deviation from the approved plan will be permitted without prior approval by the Contracting Officer.

SECTION 31 09 13.00 08 Page 7

Inclinometer Installation Plan; G, DG

Submit at least thirty days prior to installation. The Contractor shall submit his plan for installing inclinometers to the Contracting Officer for approval as specified in paragraph INSTALLATION PLANS. No work shall be performed until this plan has been approved and no deviation from the approved plan will be permitted without prior approval by the Contracting Officer.

Final Instrumentation Configuration Plan; G, DG

Submit at least thirty days prior to demolition of the work platform. The Contractor shall submit his plan for moving instrumentation, equipment and enclosures to the Contracting Officer for approval as specified below. No work shall be performed until this plan has been approved and no deviation from the approved plan will be permitted without prior approval by the Contracting Officer.

SD-02 Shop Drawings

Piezometers; G, DG Inclinometers; G, DG Weir; G, DG

The Contractor shall submit details and drawings showing how the instrumentation system works for each type of instrument listed.

SD-03 Product Data

Sand Fill; G, DG Bentonite Pellets; G, DG Concrete; G, DG Polyvinyl Chloride Pipe; G, DG Porous Filter Tip; G, DG Vibrating Wire Pressure Transducers; G, DG Inclinometer Casing; G, DG In-place inclinometers; G, DG ADAS Equipment; G, DG Spiral Inclinometer Sensor; G, DG Inclinometer Probe; G, DG Weir Gauges; G, DG Weir Plate; G, DG

All product data shall be submitted for approval by the Government 60 days prior to installation or use.

SD-05 Design Data

Grout Mix Design; G, DG

SD-06 Test Reports

Piezometer Installation Detail; G, DG Transducer Installation Form; G, DG Transducer Installation Detail; G, DG Inclinometer Installation Detail; G, DG In-place Inclinometer Installation Form; G, DG In-place Inclinometer Installation Detail; G, DG

SECTION 31 09 13.00 08 Page 8

Vibrating Wire Pressure Transducers Tests; G, DG

Example forms and details are provided in Volume 3 - Attachments to Specifications.

SD-07 Certificates

Vibrating Wire Pressure Transducers; G, DG In-place inclinometers; G, DG

Permits, Certifications, and Licenses; G, DG

The Contractor shall submit copies of all required permits, certifications and licenses required prior to starting work.

SD-08 Manufacturer's Instructions

Vibrating Wire Pressure Transducers; G, DG In-place inclinometers; G, DG Spiral Inclinometer Sensor; G, DG Inclinometer Probe; G, DG ADAS Equipment; G, DG

SD-10 Operation and Maintenance Data

Vibrating Wire Pressure Transducers; G, DG In-place inclinometers; G, DG

The manual provided with the instruments shall be provided to the Government upon the approved completion of installation and testing of each instrument.

ADAS Equipment; G, DG

SD-11 Closeout Submittals

Piezometer Installation Report; G, DG Inclinometer Installation Report; G, DG

Submit no later than two weeks after successful installation.

Detailed records of installation including, but not limited to, procedures, equipment, and materials; quality control processes;

and adverse conditions encountered. A list of the important information at each instrument such as ID/serial number(s), depth, elevation, initial readings or surveys, installation forms, tests, lengths of cables, factory calibration sheets, and figures shall be included. The report, shall be submitted for review after successful installation of the piezometers and inclinometers in their respective reports.

1.6 PROJECT SITE CONDITIONS

1.6.1 Environmental Requirements

The Contractor shall comply with Section 01 57 20.00 10 ENVIRONMENTAL

PROTECTION.

SECTION 31 09 13.00 08 Page 9

1.6.2 Field Considerations

Locations for the piezometers, inclinometers, and weirs are established by the Government and shall not change unless requested by or approved by the Government. Access to the locations of the instrumentation shall in no way damage the embankment, existing instrumentation, or other project features. Any damage done by the Contractor to the embankment, existing instrumentation, or other project features while accessing piezometer locations shall be repaired by the Contractor to the original conditions or better at no additional expense to the Government. Since no separate payment will be made for access construction, all costs associated with this shall be included in the cost of Piezometer Installation. Any damage to the instrumentation and corresponding equipment is required to be reported to the Contracting Officer within 24 hours of the incident.

1.7 SEQUENCING AND SCHEDULING

Sequencing and scheduling of installation and decommissioning of instrumentation are critical. Piezometers, inclinometers, and weirs shall be installed or decommissioned as specified herein. Piezometers downstream of the centerline of the dam shall be installed prior to foundation grouting and construction of the cutoff wall. All piezometers installed shall be incorporated into the ADAS immediately after all equipment has been installed and connected to the ADAS. To establish adequate baseline data, the vibrating wire piezometers shall be installed a minimum of 30 days prior to the installation of any grouting or cutoff wall construction within (100) feet of the vibrating wire piezometer location.

Decommissioning of piezometers and inclinometer shall occur prior to grouting and construction of the cutoff wall.

Inclinometers upstream of the baseline shall be installed after the work platform and prior to grouting or construction of the cutoff wall.

Inclinometers downstream of the baseline shall be installed prior to the work platform, grouting and cutoff wall. They shall be incorporated into the ADAS immediately after all equipment has been installed and connected to the ADAS. The inclinometers to be installed in the cutoff wall shall be installed after the cutoff wall elements in which they are being placed and the associated verification drilling have been completed and accepted by the Contracting Officer.

Both weirs shall be installed after installation of inclined drains and concrete slab.

1.8 INSTALLATION PLANS

The Contractor shall prepare the following plans for installing the various items covered by this Section and submit them to the Contracting Officer for approval prior to commencing the installation:

a. Piezometer Installation Plan - a plan for installing piezometers, including procedures and methods for installing the piezometer assembly (porous filter tip and riser pipe); sand beneath, around, and above the porous filter tip; the bentonite seal; grout above the seal; four inch lockable protective steel cover labeled with piezometer numbering and lock; the vibrating wire pressure transducer; power supply; and the equipment necessary for automation. The plan shall include, but not be limited to, the proposed method of drilling and sampling soil and rock, including a description of the equipment and sampling tools that will

SECTION 31 09 13.00 08 Page 10 be used and all other relevant information required for the Exploratory Drilling and Testing Plan as described in Section 02 32 00 SUBSURFACE DRILLING, SAMPLING, AND TESTING; a listing of any subcontractors to include a description of how the subcontractors will be used; and a description of all methods and procedures that will be utilized to ensure a safe operation, and protect the embankment and the environment. This submittal shall also include a statement of the prior experience, in the type of work described in these specifications, of the person or persons designated to perform the work specified herein.

b. Inclinometer Installation Plan - a plan for installing inclinometers which shall include, but not be limited to, the proposed method of drilling and sampling soil and rock, including a description of the equipment and sampling tools that will be used and all other relevant information required for the Exploratory Drilling and Testing Plan as described in Section 02 32 00 SUBSURFACE DRILLING, SAMPLING, AND TESTING; sequence of installation; method and procedures for maintaining verticality of bore holes; procedures that will be used to prevent any damage to surrounding instruments; methods and procedures for grouting the annular space between the bore hole and the inclinometer casing; composition of grout mix; protection for the top of the casing to prevent damage to the inclinometer during cutoff wall construction; methods and procedures for cleaning the inclinometer casing after it has been grouted in place; method and procedure for installing and securing the in-place vertical inclinometer sensors, if required; and all related equipment necessary for automation. The submittal shall include, but not be limited to, the manufacturer of the proposed system; and the manufacturer's recommendation for installation, monitoring, and troubleshooting procedures.

1.9 PERMITS, CERTIFICATIONS, AND LICENSES

The Contractor shall be responsible for obtaining all permits, certifications and licenses required of him by Federal, State, and local law for the execution of this work prior to starting work.

1.10 JOINT INSTRUMENTATION MONITORING PLAN

The Joint Instrumentation Monitoring Plan (JIMP) (included in Volume 3 - Attachments to Specifications) shall be the governing document for all monitoring frequencies and instrument thresholds. The JIMP will also outline appropriate follow up reporting of incidents relating to the exceedance of instrument thresholds that, at the direction of the Contracting Officer, may result in a work stoppage in the interest of Dam Safety. It shall be the responsibility of the Contractor to make sure that any submitted data management plan complies with the stipulations outlined in the JIMP.

PART 2 PRODUCTS

2.1 PIEZOMETERS

2.1.1 Sand Fill

The filter material to be placed around the piezometer shall be washed, clean, silica sand composed of hard, tough, and durable particles free from any coating. The sand shall contain no detrimental impurities, no soft, friable, thin, or elongated particles, and shall be graded within the

SECTION 31 09 13.00 08 Page 11 following requirementsfor fine aggregate per ASTM C33/C33M within the gradation shown below:

Sieve No. % Passing by Weight 4 10095-100 6 63-95 8 44-7780-100 10 35-70 1416 20-5050-85 20 3-26 30 0-1525-60 40 0-8 50 0-45-30 100 0-50-10 200 0-20-3

2.1.2 Bentonite Pellets

Bentonite pellets approximately 3/8-inch in diameter shall be used for forming the required bentonite seals. The bentonite shall be comprised of a minimum purity of 90 percent sodium montmorillonite clay with moisture content no more than 10 percent with minimum dry bulk density of 75 pounds per cubic foot.

2.1.3 Concrete

Concrete for anchoring the steel flush mounted covers and riser pipes shall conformed to Section 03 30 53 MISCELLANEOUS CAST-IN-PLACE CONCRETE.

2.1.4 Polyvinyl Chloride Pipe

All Polyvinyl Chloride (PVC) pipe shall conform to the requirements of ASTM D1785 as shown on the requirements in the drawings. Each pipe shall be free from contamination by dirt, mud, oil, or any other substance which in the Contracting Officer's opinion may contribute to the reduced performance of the instrument. The riser pipe shall be 1 inch PVC Schedule 80 threaded pipe, manufactured or supplied by Piezometer Research and Development Corporation, 33 MaGee Avenue, Stamford Connecticut, or their equal. Glue for use during the assembly of the piezometer and pipe shall be as recommended by the manufacturer.

2.1.5 Porous Filter Tip

The porous filter tip shall be at least 12-inches in length made from fused aluminum oxide with 68 micron pores. Each porous tip shall be free from contamination by dirt, mud, oil, or any other substance which in the Contracting Officer's opinion may contribute to the reduced performance of the instrument. Porous tips with any oil or mud smears will be considered unsatisfactory for installation and shall be replaced at the Contractor's expense. Instruments, which have been contaminated, shall be destroyed and replaced by the Contractor at his expense. Each tube shall be immersed in water for not less than 24 hours before installation. The porous tips shall be Stock No. 125-24P, manufactured by Piezometer Research and Development Corporation, 33 MaGee Avenue, Stamford Connecticut, or their approved equal.

2.1.6 Grout For Piezometer Installation and Decommissioning

Piezometers to be decommissioned shall be backfilled and sealed permanently

SECTION 31 09 13.00 08 Page 12 with a cement grout meeting the requirements described in Section 31 32 23.13 08 PERMANENT FOUNDATION DRILLING AND GROUTING, Paragraph Grout Mixes or as otherwise approved by the Contracting Officer.

2.1.7 Vibrating Wire Pressure Transducers

The vibrating wire pressure transducers shall be Geokon Model 4500 or equivalent. The vibrating wire pressure transducers shall be rated for pressures of 100psi or greater, resolution of <= (less than or equal to) 0.05% F.S., and a thermal zero shift of <= 0.05% F.S./OC or comparable encased and sealed in all stainless steel. Each instrument shall be equipped with an integral gas discharge tube, varistor, plasma surge arrestor or comparable, for lightning damage protection, and thermistor inside the housing with accuracy of ±0.1 degrees Fahrenheit. The existing open standpipe piezometers to be instrumented and their corresponding locations and standpipe riser diameter are presented in the drawings. A warranty shall be included covering the transducers to be free of defects in materials and workmanship under normal use and service for no less than 1 year.

The transducers shall be ordered with sufficient cable length to place the transducer at the proper depth, connect to the equipment enclosure, and provide an additional two-foot spare cable inside the enclosure after connection to the radio transmitter or datalogger. The depth to the tip of the open standpipe piezometer shall be verified by the Contractor in the field. Approximate values are provided in the drawings. No splices will be allowed on any transducer cable. The cable shall be a high quality twisted pair type with three twists per foot of cable. The cable shall have shielding that is 360 degrees around the wire with integral shield drain wire or equivalent to Geokon Blue PVC cable typically installed with the Geokon Model 4500 vibrating wire pressure transducers (or equivalent).

Each cable shall be labeled with the identifying name of piezometer (as stated in Table 1) and the transducer serial number. The cables used in the system from the pressure transducers to data loggers are to be labeled with identifying name of piezometer and serial number of the vibrating wire pressure transducer with material that can withstand the elements. The label should be created and affixed in a manner that is protected from the elements and will last the life of the pressure transducer. The labels shall be located at the vibrating wire sensor, on the cable between the top of the riser and the protective cap of the open standpipe, and on the cable at the connection with the datalogger within the protective housing.

The vibrating wire pressure transducers selected to be installed in the open standpipe piezometers are contingent upon review and approval by the Government. The make, model, specifications, factory calibration sheets, data sheets and specific installation procedures shall be provided as stated in paragraph SUBMITTALS.

The Contractor shall also procure all other necessary materials and equipment to properly install, maintain, and monitor these devices and incorporate them into the ADAS.

2.1.7.1 Vibrating Wire Pressure Transducers Tests

Each vibrating wire pressure transducer shall undergo a pre-acceptance test to verify that it operates correctly prior to the Government taking possession of the instruments. If any are found to malfunction, the Contractor shall return it to the manufacturer for a replacement which will undergo the pre-acceptance testing prior to Government acceptance of the

SECTION 31 09 13.00 08 Page 13 equipment. This will repeat until the required amount of replacement instruments have been accepted and supplied to the Government.

2.2 INCLINOMETERS

2.2.1 Inclinometer Casing

The inclinometer casing shall be ABS plastic inclinometer casing manufactured by Slope Indicator Corporation, or approved equal. Casing shall have a minimum outside diameter of 2.75 inches (70 millimeters) in ten (10) foot long casing sections. The casing shall have snap connections and O-ring seals which is available in the Quick Connect (QC) or Shear-Wire casing. Final selection of the casing shall be based on the inclinometer manufacturer's recommendations. Casing shall have high quality flat surface grooves to permit free passage of the probe through curves in the casing without the wheel of the probe coming out of the groove. Each casing section shall be free from contamination by dirt, mud, oil, or any other substance which may contribute to the reduced performance of the instrument. Additional unacceptable substances are at the discretion of the Contracting Officer.

2.2.2 Grout

The Contractor shall submit the grout mix design for backfilling around the annulus between the inclinometer casing and cutoff wall. The design shall be submitted 60 days prior to installation. This submittal shall be completed in accordance with Section 01 33 16.00 08 CONTRACTOR SUBMITTALS

REQUIRING ENGINEERING AFTER AWARD.

2.2.2.1 Decommissioning Inclinometers

Cement grout for decommissioning of existing inclinometers meet the requirements described in Section 31 32 23.13 08 PERMANENT FOUNDATION DRILLING AND GROUTING, Paragraph Grout Mixes.

2.2.2.2 Embankment Inclinometers

The grout to be placed in the annulus between the inclinometers casing and soil and/or rock shall have an approximate cement-water-bentonite ratio of 1:2.5:0.3 or as recommended by the manufacturer. Water and cement shall be mixed first, then bentonite. The exact amount of bentonite to add is dependent upon the water, temperature, and agitation. The mixture should have the consistency of pancake batter.

2.2.2.3 Cutoff Wall Inclinometers

The grout that fills the annulus between the inclinometer casing and cutoff wall concrete shall be prepackaged grout that conforms to the requirements within ASTM C1107/C1107M. A submittal shall be provided to the Government identifying the mixture and shall only be implemented upon Government approval.

2.2.3 Concrete

Concrete for anchoring the steel flush mounted covers and riser pipes shall be conform to the requirements of Section 03 30 53 MISCELLANEOUS

CAST-IN-PLACE CONCRETE.

SECTION 31 09 13.00 08 Page 14

2.2.4 Spiral Inclinometer Sensor

The spiral sensor covers a system of equipment that enables surveying of the inclinometer casing. The main component spiral sensor shall be a stainless steel and aluminum English model manufactured by Durham Geo Slope Indicator with 5-foot wheel base equipped with a rotary potentiometer or equivalent. The range shall be plus or minus 3 degrees of rotation over its gauge length and a maximum rotation of plus or minus 4 degrees over its gauge length. The spiral sensor accuracy shall be plus or minus 10 arc minutes of gauge length.

The remaining equipment in the system includes the control cable, pulley, cable reel, readout box, sensor carrying case, indicator, data reduction software DigiPro and DMM, and tools and accessories for operation. All of the remaining equipment shall be manufactured by Durham Geo Slope Indicator or approved equivalent. The control cable shall contain steel core, Dacron torsion braid, and a santoprene cable jacket. The length shall be long enough to perform a survey for the deepest inclinometer over its entire depth and graduated with yellow 2-foot rubber marks and red 10-foot rubber marks. All marks are required to be molded onto the cable jacket. The pulley shall be the large model with a carbon-fiber clamp. The cable reel shall be the slip-ring reel type which allows the readout to remain connected while the reel is operated. The jumper cable to connect the real to the readout shall also be included. The readout box shall be Slope Indicator's Digitilt DataMate II or approved equivalent.

All inclinometer devices and accessories must be on the jobsite and certified fully by the factory representative prior to installation of the first inclinometer. Applicable instruction manuals published by the inclinometer manufacturer shall be considered part of these specifications and shall be used for procedures and calibration.

2.2.5 Inclinometer Probe

The inclinometer probe covers a system of equipment that enables manual surveying of the inclinometer casing. The main component is the inclinometer probe which shall be a Durham Geo Slope Indicator Digitilt English-Unit model or equivalent that includes a carrying case. The probe shall be wheeled, 1 inch in diameter, 30 inches long, and stainless steel that houses two force-balanced servo-accelerometers: one to measure tilt in the plane parallel to the inclinometer wheels and the other to measure tilt in the plane perpendicular to the wheels. The range shall be plus or minus 35 degrees from vertical with a resolution of 0.0012 inch over 24 inches.

The accuracy shall be plus or minus 0.01 inch per reading and plus or minus

0.3 inch per 50 readings.

The remaining equipment in the system includes the control cable, pulley, cable reel, and readout box which shall be procured at the same time as the inclinometer probe. All of the remaining equipment shall be manufactured by Durham Geo Slope Indicator or approved equivalent. The control cable shall contain steel core, Dacron torsion braid, and a santoprene cable jacket. The length shall be long enough to perform a survey for the deepest inclinometer over its entire depth and graduated with yellow 2-foot rubber marks and red 10-foot rubber marks. All marks are required to be molded onto the cable jacket. The pulley shall be the large model with a carbon-fiber clamp. The cable reel shall be the slip-ring reel type which allows the readout to remain connected while the reel is operated. The jumper cable to connect the real to the readout shall also be included.

The readout box shall be Slope Indicator's Digitilt DataMate II or approved

SECTION 31 09 13.00 08 Page 15 equivalent.

All inclinometer devices and accessories must be on the jobsite and certified fully by the factory representative prior to installation of the first inclinometer. All equipment mentioned in the Spiral Inclinometer Sensor, except for the sensor carrying case can be used with the inclinometer probe. Applicable instruction manuals published by the inclinometer manufacturer shall be considered part of these specifications and shall be used for procedures and calibration.

2.2.6 In-place inclinometers

The in-place inclinometer system includes casing, wheeled sensors and gauge tubes, top suspension kit, jumper cable and data reduction software all to be manufactured by Durham Geo Slope Indicator or equivalent. The inclinometer sensors shall be vertical in-place biaxial sensors housed in stainless steel, 1.25-inches (32mm) in diameter, waterproof to 300psi (2Mpa) and equipped with a thermistor. Repeatability within the inclinometer sensor shall be ±22 arc seconds (0.1mm/m) and fit to read 2.75-inch (70mm) diameter casing. The sensor for inclination readings shall be calibrated rated by MEMS (Micro Electro-Mechanical Systems). The required amount of sensors per inclinometer location is provided in the drawings.

The in-place inclinometer system shall consist of one top suspension kit supporting and securing a series of sensors connected with gauge tubes.

The gauge length consists of one sensor plus guage tube and shall be 10-feet. The amount of sensors and gauge tubing is dependent upon the as provided in the drawings and specified below.

All inclinometer devices and accessories must be on the jobsite and certified fully by the factory representative prior to installation of the first inclinometer. All ADAS monitoring equipment shall be new, compliant with the existing ADAS, and maintained in complete, fully functional operating conditions throughout the duration of the contract and shall become the property of the Government at the conclusion of the contract.

Applicable instruction manuals published by the inclinometer manufacturer shall be considered part of these specifications and shall be used for detail installation procedures, calibration, and monitoring.

2.3 ADAS EQUIPMENT

The remaining equipment within the Automated Data Acquisition System (ADAS) includes items such as power supply, radio transmitters , multiplexers, interfaces, and dataloggers . An ADAS Equipment document specifying the equipment used in the existing system is provided in Volume 3 - Attachments to Specifications. All equipment purchased by the Contractor to connect the new automated instrumentation to the existing ADAS shall be compliant or equal to those provided in the list.

2.4 WEIR PLATES

2.4.1 Steel Plate

The steel weir plates for the two v-notch weirs shall be 1/4 inch stainless steel conforming to ASTM A240/A240M, UNS S30400 and manufactured to dimensions provided in the drawings.

SECTION 31 09 13.00 08 Page 16

2.4.2 Weir Gauges

The gauges for the two weirs shall be USGS Style A made of rugged iron and finished with a special porcelain enamel to insure easy reading and resistance to rust or discoloration. Both shall be accurately graduated with grommeted holes for fastening to the structure.

PART 3 EXECUTION

3.1 GENERAL

The Joint Instrumentation Monitoring Plan (JIMP) (Volume 3 - Attachments to Specifications) shall be the governing document for all monitoring frequencies and instrument thresholds.

3.2 PIEZOMETER REQUIREMENTS

The Contractor shall install 13 open standpipe piezometers with vibrating wire pressure transducers set within the risers. To establish adequate baseline data, the vibrating wire piezometers shall be installed and successfully capture data as required by this specification, a minimum of 30 consecutive days of piezometer readings prior to the installation of any grouting or cutoff wall construction within 100 feet of the vibrating wire piezometer location. The open standpipe piezometers shall be installed at the locations with the filter tip set and sensing zone in the appropriate in situ materials to the depths indicated in the drawings. The vibrating wire pressure transducers shall be installed within the open standpipe riser 14 inches above the tip of the filter. Piezometer depth and transducer position may be adjusted in the field at the Contracting Officer's discretion based on actual observed field conditions.

Each piezometer listed in the drawings as new shall contain a vibrating wire piezometer transducer to monitor pressures in either the embankment, foundation soils or near top of rock, depending on tip elevation. The Contractor shall procure all other necessary material and equipment to properly install, maintain, and monitor these devices. Each transducer's cable shall be labeled for identification at a readout terminal installed to protect the cable and connecting points from damage. The vibrating wire piezometer installation shall be in accordance with the diagram included in the drawings.

Drilling and soil and rock sampling incidental to installation of the piezometers shall be performed in accordance with Section 02 32 00 SUBSURFACE DRILLING, SAMPLING, AND TESTING. The Contractor shall remove all drill casing incrementally during piezometer installation. Casing should be left in the borehole and removed in sections during completion of the installation to avoid premature collapse and potential loss of the borehole. EM 1110-2-1908, (Included in Volume 3 - Attachments to Specifications) Chapter 6 sections 6-7 gives further guidance that will be required during this installation.

Open standpipe piezometers with a porous filter tip shall be installed at all locations. The sensing zone will be a tremied sand filter capped with a five foot bentonite seal to isolate the pore water. Lengths of each filter zone are provided in the drawings. Sand shall be tremied in place, tamping no more than every 2-ft and finally the top of the sand until the appropriate elevation or length of influence zone has been achieved.

After placement of the open standpipe, porousfilter tip and sand filter

SECTION 31 09 13.00 08 Page 17 sensing zone, the placement of bentonite in saturated zones shall be poured slowly to fill the annular space, tamping every foot until the required 5-ft layer is in place, checking the depth to verify constructed seal thickness. After the bentonite has been placed to the proper elevations, a sufficient amount of water to allow the bentonite to hydrate shall be added. In unsaturated zones, the bentonite pellets shall be poured in 2 inch lifts, and then hydrated with water until the required 5-ft layer is in place, checking the depth to verify constructed seal thickness. If sonic drilling is used for embankment instrumentation, it is permissible to "vibrate" the bentonite and/or sand to achieve proper compaction. Staged Tremie method of placing grout backfill shall be required as described in Section 02 32 00 SUBSURFACE DRILLING, SAMPLING, AND TESTING. The Contractor shall complete the PIEZOMETER INSTALLATION DETAIL for each piezometer and submit the form to the Contracting Officer within 48 hours after the piezometer has been installed. Drilling methods and information shall be as per Section 02 32 00 SUBSURFACE DRILLING, SAMPLING, AND TESTING. The bore holes and installation records shall be input into gINT as described in Sections 02 32 00 SUBSURFACE DRILLING, SAMPLING, AND TESTING and 31 09 14 DATA MANAGEMENT SYSTEM.

Piezometers placed within the work platform shall be installed with a removable flush-mount steel cover to protect from damage and surface water intrusion. A conduit for transducer cable shall be placed beneath the work platform, connecting the PVC riser to an equipment enclosure box to house the electronic equipment necessary for incorporating in to the existing ADAS. All enclosure boxes for piezometers within the work platform shall be located beyond the upstream edge of the work platform but in no case be closer than 5 feet to the edge of the new crest road alignment.

Piezometers outside of the work platform shall be installed with a 4-inch diameter steel external casing over the portion of the piezometer above the existing ground surface to protect the riser pipe from damage and water intrusion and locking cap with a label identifying the number of the piezometer. The external casing shall be embedded to at least 3.5 feet to prevent frost heave. The protective covering over each piezometer shall be visibly marked with the piezometer number in bold alpha-numeric characters as so designated in these specifications. The enclosure boxes for piezometers within the embankment shall be placed 3 feet away, but no more than 10 feet, from the piezometer riser pipe and casing. Cable and conduit can be buried in trenches between piezometers and equipment enclosures as long as the Government approves the location and following is met: 1) The depth of the trench shall be between 1- to 2-feet deep and backfilled with the excavated embankment material. 2) The backfill shall be moist (not dry or wet) during placement and compacted in 4-inch lifts using hand-plate compactor. 3) Compaction is achieved up to and closely around the conduit to avoid loose zones. 4) Backfill is brought up to the original ground surface (prior to excavation) in the required lift heights. 5) The trenched area is seeded after compaction and equipment enclosure. Locations of equipment enclosures relative to the baseline are provided in the drawings.

Final location may be adjusted in the field at the Contracting Officer's discretion.

Field falling head tests shall be performed on all open standpipe piezometers a week after installation. The testing shall be performed in accordance to ASTM D6391 and prior to installation of the vibrating wire pressure transducers and acceptance of the piezometer.

Each vibrating wire sensor shall be calibrated and saturated for a minimum of 24 hours prior to installation in the hole. All other manufacturer recommendations shall be followed to ensure the vibrating wire sensors once

SECTION 31 09 13.00 08 Page 18 installed function as designed. During installation, each sensor shall be kept saturated until within two (2) minutes of installation in the riser pipe and hole. This is to minimize air bubbles and their impact on the sensors.

The vibrating wire pressure transducers shall be placed and installed 14 inches above the tip of the open standpipe, no larger than 0.75-inch (19mm) in diameter, rated for pressures of 100 psi or greater, labeled with the identifying number of the piezometer and transducer serial number…