503DRILLED SHAFTS

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5-53SECTIO N 503 – DRILLE D SHAFTS

503.0 1 DESCRIPTION . This work shall consist of mobilizing and furnishing all materials, equipment, labor, and services necessary to construct drilled shafts in accordance with these provisions, the Plans, 503.0 2 MATERIALS . Materials shall meet the requirements of the following subsections: Mortar, Type IV ................................ ................................ ................................ ......... 707.0 1(e) Bar Reinforcement ................................ ................................ ................................ .....713.01 Steel Casing for Drilled Shafts ................................ ................................ .................. 730.03 Water ................................ ................................ ................................ .......................... 745.01 Concrete shall conform to the requirements of Section 541 for Concrete, Class SCC, with the exceptions that the maximum aggregate size shall be 1/2 inch , the 56 day surface resistivity test is not required , and an anti -washout admixture shall not be used f or underwater concrete . Additionally, concrete shall have a blocking assessment of “ No Visible Blocking” during a period equal to the anticipated pour period plus 2 hours, as determined in accordance with ASTM C1621 . Temporary steel pipe piles shall be smooth walled structural steel. Centralizers for bar reinforcement shall be constructed of a non -corrosive material that is compatible with and as durable as the shaft concrete. Water shall have a pH conforming to the slurry requirements listed herein.

gel characteristics to transport excavated material to a suitable screening system. The slurry percentage and specific gravity used to make the suspension shall be sufficient to maintain the stability of the excavation and allow proper concrete placement. The acceptable ranges of values for mineral slurry are specified in Table 503.02A .

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5-54TABLE 503.02A – RANGE OF VALUES FOR MINERAL SLURRY AT 68ºF

Property Test Requirement Density (lb s/ft3) Mud weight (density) ( API RP 13B -1, Section 1 ) 64.3 – 72.0 1 Viscosity (sec ./quart) Marsh funnel and cup ( API RP 13B -1, Section 2.2 ) 28 – 50 pH Glass electrode, pH meter, or pH paper 8.0 – 11.0 Sand content immediately prior to placing concrete Sand content test ( API RP 13B-1, Section 5 ) 4.0% max. 1 Unit weights stated are exclusive of weighting agents that may be proposed by the Contractor with the agreement of the slurry manufacturer’s representative and the Agency. Mineral slurry shall be de -sanded so that the sand content does not exceed 4% (by volume) measured 1 foot from bottom of shaft prior to concrete placement. All referenced tests shall be conducted by the Contrac tor with results presented to the Engineer. All necessary equipment and materials shall be provided by the Contractor.

the excavation and to transport e xcavated material to a suitable screening system. Polymer slurry (vinyl (dry) or natural polymers) shall be made from partially hydrolyzed polyacrylamide polymer

Slurry properties at the time of mixing and at the time of concreting shall be in conformance with the written recommendations of the manufacturer. The use of a blended mineral -polymer slurry is not permitted. The acceptable ranges of values for polymer sl urry are specified in Table 503.02B .

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5-55TABLE 503.02B – RANGE OF VALUES FOR POLYMER SLURRY AT 68 ºF

Property Test Requirement Density (lb s/ft3) Mud weight (density) ( API RP 13B -1, Section 1 ) 64 max. 1 Viscosity (sec ./quart) Marsh funnel and cup ( API RP 13B -1, Section 2.2 ) 32 – 135 pH Glass electrode, pH meter or pH paper 8.0 – 11.5 Sand content immediately prior to placing concrete Sand content test (API RP 13B-1, Section 5 ) 1.0% max. 1 Unit weights stated are exclusive of weighting agents that may be proposed by the Contractor with the agreement of the slurry manufacturer’s representative and the Agency. Polymer slurry shall be de -sanded so that the sand content is less than 1% (by volume) prior to concrete placement. All referenced tests shall be conducted by the Contractor with results presented to the Engineer. All necessary equipment and materials shall be provided by the Contractor. 503.0 3 PREQUALIFICATION .

work has successfully installed drilled shafts of similar diameter, length, and difficulty as shown on the Plans, and a minimum of one project requiring similar on -site topographical and geotechnical conditions to those described in the Plans.

construction of drilled shaft foundations of similar size (diameter and depth) and difficulty to those shown on the Plans, and in similar geotechnical conditions to those described in the Contract. The work experience shall be direct supervisory responsibility for the on -site drilled shaft construction operations. Project management level positions indirectly supervising on -site drilled shaft construction operations will not be considered acceptable for this experience requirement.

shafts with similar diameters and lengths, and in similar conditions.

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5-56Details describing the equipment and methods used, difficulties encountered and how they were

overcome, and the results of any testing performed, shall be included. For each project cited, the name and telephone number of someone who can be contacted as a reference shall be included.

integrity testing firm, and the names of the personnel who will conduct nondestructive QA testing and analysis of the drilled shafts. The testing firm and the testing personnel shall meet the following minimum quali fications:

shaft projects in the last two years.

a minimum of two ye ars of experience in drilled shaft nondestructive testing and interpretation.

methods the Contractor has selected for nondestructive testing of drilled shafts.

professional engineer . The Contractor shall submit this information to the Engineer for review, evaluation, and approval prior to submitting detailed information as req uired under Subsection 503.04 . The Engineer will render a decision within 7 calendar days after receipt of the submission. The Contractor or subcontractor will not be permitted to install drilled shafts without this approval. The Engineer may suspend the d rilled shaft construction if the Contractor substitutes unapproved field personnel without prior approval by the Engineer. The Contractor shall be fully liable for the additional costs resulting from the suspension of work and no adjustments in Contract time resulting from such suspension of work will be allowed. 503.0 4 SUBMITTALS . All approvals are subject to satisfactory field performance. Approval of a submittal does not relieve the Contractor or its subcontractor of their responsibilities to satisfactorily complete the work detailed in the Contract. If the approved submittal procedures do not produce satisfactory field performance, the Contractor will be responsible for submitting revised procedures. No further drilled shaf t work will be allowed until the revised procedures have been approved.

503 5-57 (a) Drilled Shaft Installation Plan . The Contractor shalls ubmit a drilled shaft installation plan that documents the proposed procedures and equipment for installing drilled shafts. The submittal shall include, but not be limited to, the following information:

equipment suitability to the anticipated site and subsurface conditions, including a project history of the drilling equipment demonstrating the successful use of the equipment on shafts of equal or greater size in similar subsurface conditions. A list describing the type of equipment to be used, including drill rigs, cranes, drilling tools, casing installation equipment, final cleaning equipment, de -sanding equipment, slurry pumps, bailing buckets, tanks, sampling equipment, tremies or concrete pumps, and any other equipment necessary for drilled shaft installation shall also be included.

drawings shall include the sequence for each shaft, the overall construction sequence, areas that are planned to be used for staging, and detailed drawin gs of all over -water equipment for drilled shaft installation including containment measures to prevent drilling spoils from entering the water.

installation and temporary casing installation and removal shall be provided. This shall include casing dimensions, material, and splice details. Welding procedures shall be submitted in accordance with Subsection 506.10 for permanent casing splices.

removal of sediment from the shaft bottom, and procedures for control, removal, and disposal of spoils. This shall include details of proposed methods to clean the shaft after initial excavation an d details of proposed methods to check shaft bottom cleanliness.

caving, bottom heave, etc., using temporary casing, slurry, or other means) during excavation and concrete placement. The details shall include a review of method suitability to the anticipated site and subsurface geotechnical conditions.

and grabs.

503 5-58 (7) Verification methods of final shaft dimensions and verticality. Include details of proposed corrective measures to be implemented as necessary.

inspection program shall be thorough enough to assure the Engineer that each drilled shaft meets the requirements of these provisions.

steel reinforcement cage including bar count, bend schedule, dimensions, splices, and bracing.

cage in the drilled shaft.

methods and sequence of steel reinforcement cage erection, the temporary support, and the

equipment to be used for erection. The erection plan shall identify specific lifting points on

the cage and demonstrate that all of the erection equipment has adequate capacity for the

work to be performed.

in accordance with Subsection 503.02.

batching, delivery to the site, how concrete acceptance samples will be collected, quality

control testing, proposed location for concrete acceptance testing, proposed operational

procedures for concrete pump, initial tremie pipe insertion, raising tremie pipe during

concrete placement, reinsertion of a tremie pipe if required, method to accurately monitor

the volume of concrete being placed at all times during the placement, removal of waste

concrete, and provisions to prepare the completed shaft top at its final shaft top elevation.

shaft diameter, or between the shaft casing and surrounding soil, where permanent casing

is specified.

representative assigned to the project.

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slurry manufacturer’s technical representative in the proper use of the slurry. The

submittal shall include a signed training certification letter from the slurry

manufacturer for each individual, including the date of the training.

detailed mix design (including all additives and their specific purpose in the slurry

mix), and a narrative describing its suitability to the anticipated subsurface

geotechnical conditions, shall also be provided for the proposed slurry.

performed, test methods to be used, and minimum or maximum property

requirements which must be met to ensure that the slurry functions as intended,

considering the anticipated subsurface conditions and shaft construction methods,

in accordance with the slurry manufacturer’s recommendations and these

specifications.

of taking a slurry sample at a specific depth, without being contaminated by slurry

from another depth.

loss or loss of slurry stabilization properties.

The Agency will review the submittal for compliance with the requirements of the Contract. If the

drawings or procedures have misinterpreted the Plans or specifications, the submittal will be

returned as rejected. The submittal shall not be marked as approved or approved as noted until all

of the required information has been received and reviewed.

Once a complete submittal has been received, the Agency shall be allowed 21 calendar days for

the initial review period and 14 calendar days for the review of each subsequent resubmittal.

The Contractor will not be permitted to install drilled shafts until the drilled shaft installation plan

has been marked as approved or approved as noted by the Agency. The Contractor or fabricator

shall assume all risk for materials ordered or work performed prior to written notification by the

Agency. After the drilled shaft installation plan has been marked approved or approved as noted,

no changes shall be made without the written approval of the Agency.

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Engineer within 1 working day after a drilled shaft is installed. The submittal shall include the

following information:

where required.

drilled shafts, and before removing the drilled shaft installation equipment from the site, the

Contractor shall provide the Engineer with a plan showing the as-installed location of all drilled

shafts installed to the tolerances specified in the Contract.

503.05CONSTRUCTION TOLERANCES. In-place tolerances for drilled shafts shall be as follows:

3 inches for shafts supporting a single column less than 5 feet in diameter and otherwise by no

more than 6 inches.

for shafts that are not socketed in rock. This tolerance applies for the total length of shaft.

the Plans.

inches from the projection elevation shown in the Plans.

Drilled shaft excavations and completed shafts not constructed within the required tolerances are

unacceptable. The Contractor shall submit written correction procedures to the Engineer for approval prior

to correcting the deficiencies. The Contractor is responsible for correcting all unacceptable shaft

excavations and completed shafts to the satisfaction of the Engineer at no cost to the Agency and without

extension of the Contract completion date.

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503.06DRILLED SHAFT PRE-CONSTRUCTION MEETING. A drilled shaft pre-construction

meeting shall be held after the approval of the drilled shaft installation plan, but prior to commencing

construction of the drilled shafts. The purpose of the meeting will be to review all aspects of the drilled

shaft construction and testing and to facilitate coordination between all parties involved.

Individuals attending the meeting representing the Agency shall include the Engineer, the Project

Manager, the design engineer, the Structural Concrete Engineer, and the Geotechnical Engineering

Manager.

Individuals attending the meeting representing the Contractor and subcontractor shall include the project

superintendent and all foremen in charge of excavating the shaft, placing casing and slurry, placing

reinforcing steel, and placing the concrete. A representative from the concrete producer shall also attend

the meeting. If slurry is to be used, the slurry manufacturer shall be available by phone for technical

assistance during this meeting. All parties shall be notified a minimum of 7 calendar days in advance of

the meeting date.

If the Contractor proposes a significant revision of the approved shaft installation narrative, as determined

by the Engineer, an additional conference shall be held before any additional shaft construction operations

are performed.

503.07CONSTRUCTION REQUIREMENTS

casing shall be watertight and clean prior to being placed in the excavation and shall be installed

or removed without disturbing the surrounding soil. Casings shall have inside diameters not less

than the indicated shaft sizes and not more than 6 inches greater than the indicated shaft sizes.

Permanent casing shall be of ample strength to resist damage and deformation from transportation

and handling, installation stresses, and all pressures and forces acting on the casing. It is the

Contractor’s responsibility to determine the final wall thickness necessary to meet these

requirements. No appurtenances, reinforcement, or holes shall be added to the casings without

approval of the Engineer.

Temporary casing shall be of ample strength to resist damage and deformation from transportation

and handling, installation and extraction stresses, and all pressures and forces acting on the casing.

The casing shall be capable of being removed without deforming and causing damage to the

completed shaft, and without disturbing the surrounding soil.

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drilled shaft is poured immediately after drilling is complete, the shaft is inspected and

accepted by the Engineer, and reinforcing steel placed and accepted.

that the Contractor can achieve the required bottom of hole cleanliness to the satisfaction

of the Engineer.

any drilled shaft. A stable shaft excavation shall be maintained at all times.

through whatever materials are encountered, to the dimensions and elevations shown in the Plans

or otherwise required by the Contract. The Contractor shall extend the drilled shaft base elevations

when the Engineer determines that the material encountered during the excavation is unsuitable or

differs from that anticipated in the design of the drilled shaft. The Contractor’s methods and

equipment shall be suitable for the intended purpose and materials encountered.

Pre-excavation, using appropriate sediment and turbidity controls when in or near waters of the

state, may be needed to advance past shallow obstructions before installing casing.

including, but not limited to, logs, boulders encountered outside the strata identified on the boring

logs, and man-made objects that in the judgment of the Engineer cannot be removed using

conventional tools such as conventional augers, drilling buckets, or underreaming tools or reverse

circulation drilling (if this is used as the primary drilling method). Reasonable effort shall include

operating approved equipment at maximum power, torque, and down thrust for a period of at least

15 minutes with minimal forward movement. Surface and subsurface obstructions at drilled shaft

locations shall be removed by the Contractor. Drilling tools that are lost in the excavation shall not

be considered obstructions and shall be promptly removed by the Contractor without

compensation.

When suspected obstructions are encountered, the Contractor shall notify the Engineer and

recommend a course of action to advance the drill hole in an expedient manner. The Engineer will

determine if an obstruction has been encountered.

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excavation. Slurry cannot be made from native materials, or material from the excavation. The

level of slurry shall be maintained at a height sufficient to prevent caving of the hole. The slurry

head shall remain above the piezometric head of the groundwater at all times during installation

and cleaning out.

The slurry shall be pre-mixed, and adequate time for hydration shall be allowed prior to

introduction into the shaft excavation. Adequate slurry tanks shall be provided when specified or

when required by the Engineer. Mixing of the slurry shall not occur in the hole for the drilled shaft.

Slurry pits will not be allowed without written permission from the Engineer.

Adequate de-sanding equipment shall be provided where required for slurry operations.

Appropriate steps shall be taken to prevent slurry from setting up in the shaft excavation, such as

agitation, circulation, and adjusting the properties of the slurry. Bentonitic slurry shall not sit

unagitated for more than 4 hours.

If the unagitated bentonitic slurry is in the hole for more than 4 hours, or if caking develops, the

sides shall be scraped to remove the filter cake before proceeding with the excavation.

The properties of the pre-mixed slurry shall be checked as slurry is introduced and periodically

thereafter. Control tests shall be performed on the slurry to determine density, viscosity, and pH

before and during shaft excavation to establish a consistent working pattern.

Immediately prior to placing shaft concrete, slurry samples shall be taken from the bottom and 10

feet from the bottom of the drilled shaft excavation using an approved slurry sampling tool. Any

heavily contaminated slurry and spoil that has accumulated at the bottom of the shaft shall be

removed. The slurry shall be within the specification requirements immediately before concrete

placement.

If slurry is used, the slurry manufacturer’s technical representative shall:

adjust the slurry mix to the specific site conditions.

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lengths shall be as shown on the Plans. The top of rock socket elevation shown on the Plans has

been estimated based on test borings and survey. The actual top of rock socket may vary in the

field based on observations made by the Geotechnical Engineering Manager during drilling. The

rock socket shall begin beneath any weathered or highly fractured rock encountered.

alignment of each shaft excavation (moving drilling equipment against the sidewalls, weighted

tapes, or other means approved by the Engineer). Electronic measuring equipment may be used

but is not required. The Contractor shall determine the dimensions and alignment under the

direction of the Engineer. The Contractor shall measure the final shaft depth after cleaning. Unless

otherwise stated in the Plans, a minimum of 50% of the base of each shaft shall have less than 1

inch of sediment. Debris at any place on the base of the shaft shall not exceed 2 inches.

be installed at every intersection between vertical and horizontal (or spiral) reinforcing.

Centralizers shall be installed at the bottom and along the axial length of the steel reinforcing at

sufficient spacing to maintain proper concrete cover. The longitudinal spacing shall not exceed 10

feet. A minimum of four centralizers shall be placed at each longitudinal spacing and shall be

spaced no greater than 4 feet and equally spaced around the shaft circumference.

drilled shaft excavation by the Contractor and inspection by the Engineer. Concrete placement

shall continue in one operation to the top of the shaft, or as shown in the Plans.

Concrete shall be placed underwater by use of a concrete pump or tremie. A tremie shall have a

hopper at the top that empties into a tube at least 10 inches in diameter constructed of heavy-gauge

steel pipe with watertight joints. If a pump is used, a watertight tube with a minimum diameter of

4 inches constructed of heavy-gauge steel pipe with watertight joints shall be used.

Throughout the underwater concrete placement operation, the discharge end of the tube shall

remain submerged in the concrete at least 5 feet until the work is completed, resulting in a

seamless, uniform shaft. If at any time during the concrete pour the end of the tube is removed

from the fluid concrete and discharges above the rising concrete level, a measurement will be made

to determine the elevation and the shaft will be considered defective. The Contractor shall take

appropriate and immediate action to correct the deficiency.

The Contractor’s construction operations in the vicinity of a drilled shaft excavation with freshly

placed concrete and curing concrete are subject to the following restrictions:

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a drilled shaft within 72 hours after the conclusion of placing concrete.

calendar days after completing concrete placement operations, the Contractor shall not

place and advance a casing, or perform drilling, within four shaft diameters of the centerline

of the shaft.

removed by one of the following methods:

shaft top level and allowed to cure in place for removal later.

dewatered prior to initial concrete set, and waste concrete removed in the dry by

methods approved by the Engineer. The Contractor shall submit calculations

demonstrating that the concrete in the shaft at the time of dewatering provides a

minimum factor of safety against uplift of 1.25.

final concrete is placed. Waste concrete shall be allowed to evenly overflow the full

top circumference of the casing and may not channel or bleed off by notches or

holes cut in the casing top. Any fresh concrete in the casing at a level above the

Plan shaft top level after ejecting all waste concrete may be dipped or pumped out

to the Plan shaft top elevation while still plastic by methods and equipment

approved by the Engineer, or allowed to cure in place for removal later. If fresh

concrete will be removed to the Plan shaft top elevation while still plastic, the

Contractor shall submit calculations demonstrating that the concrete in the shaft at

the time of fresh concrete removal provides a minimum factor of safety against

uplift of 1.25.

Waste concrete shall be considered to be the top 24 inches of initial concrete placed, plus

the height of any additional volume of waste concrete deposited in the shaft where concrete

placement was halted and restarted, plus any additional amount necessary to produce full

strength, non-segregated concrete at the Plan shaft top level.

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average unconfined compressive strength of 2,500 psi or, in lieu of concrete strength

testing, beginning 7 calendar days after completion of concrete placement. Final top

preparation steps shall consist of:

methods.

concrete without any signs of segregation or contamination.

Engineer to verify that concrete has full design strength.

full-strength, non-segregated concrete.

by the Engineer. The Contractor may submit a request to the Engineer to leave some or all

temporary casing in place. The Agency reserves the right to reject any and all proposals.

503.08RECORDS. The Contractor shall keep a record, independent of that which may be kept by the

Engineer, of all pertinent data relative to the installation of the drilled shaft. This record shall be available

for the Engineer’s inspection until the completion of the project, and a copy shall be transmitted to the

Engineer within 3 calendar days of the completion of each shaft. For each shaft, this record shall include:

elevation of each soil or rock material encountered during shaft excavation, and any obstruction

encountered.

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placed (actual) and a plot of depth versus volume.

503.09INTEGRITY TESTING. Drilled shaft integrity testing and analysis shall be conducted on all

completed drilled shafts. The testing and analysis shall be performed by an integrity testing firm retained

by the Contractor. The final test report shall be stamped and signed by a professional engineer and

submitted to the Engineer for approval. When not otherwise specified in the Contract, the Contractor shall

perform integrity testing in accordance with one of the following methods:

the condition of the concrete within drilled shafts. The test shall meet ASTM D6760 requirements

as modified herein.

The Contractor shall install access tubes for CSL testing in the drilled shafts to permit access for

the CSL test probes. One tube per 1.0 foot of shaft diameter, rounding up to the nearest whole

number of tubes, (e.g. 8 tubes for an 8 foot diameter shaft) shall be installed.

Access tubes for CSL testing shall be steel pipes with a minimum wall thickness of 0.145 inches

and an inside diameter of at least 1-1/2 inches. The access tubes shall have a round, regular inside

diameter free of defects and obstructions, including all pipe joints, in order to permit the free,

unobstructed passage of 1.3 inch maximum diameter source and receiver probes used for the CSL

tests. The Contractor shall securely attach the access tubes to the interior of the reinforcement cage

for the shaft. The access tubes shall be equally spaced around the shaft, inside the spiral or hoop

reinforcement and midway between adjacent vertical reinforcement. The access tubes shall be

placed 2 inches clear of the vertical reinforcement. If these minimums cannot be met due to close

spacing of the vertical reinforcement, then the access tubes shall be bundled with the vertical

reinforcement.

The access tubes shall be installed in straight alignment and as near to parallel to the vertical axis

of the reinforcement cage as possible. The tubes shall be secured, such that the tubes stay in

position during reinforcement cage and concrete placement. The tubes shall extend from 6 inches

above the shaft bottoms to a minimum of 2 feet above the top of the shaft. The tubes shall not be

allowed to rest on the bottom of the drilled shaft excavation.

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The access tubes shall be watertight and free from corrosion with clean internal and external faces

to ensure a good bond between the concrete and the access tubes. The access tubes shall be fitted

with watertight caps on the bottom and the top. Splice joints in the access tubes, if required to

achieve full-length access tubes, shall be watertight. The Contractor shall clear the access tubes of

all debris and extraneous materials prior to installing the access tubes. The access tubes shall be

full of clean water prior to concrete placement. The caps shall be sealed to prevent debris from

entering the pipes after the water is placed.

Testing shall be performed after the shaft concrete has cured for a minimum of 72 hours.

Additional curing time prior to testing may be required if the shaft concrete contains admixtures,

such as set retarding admixture or water reducing admixture. The additional curing time prior to

testing required under these circumstances shall not be grounds for additional compensation or an

extension of time. All CSL testing shall be completed within 7 calendar days of concrete

placement.

After placing the shaft concrete and before beginning CSL testing of a shaft, the Contractor shall

inspect the access tubes. Each access tube that the test probe cannot pass through shall be replaced,

at the Contractor’s expense, with a 2 inch diameter hole cored through the concrete for the entire

length of the shaft. Unless directed otherwise by the Engineer, cored holes shall be located

approximately 6 inches inside the reinforcement and shall not damage the shaft reinforcement.

Descriptions of inclusions and voids in cored holes shall be logged and a copy of the log shall be

submitted to the Engineer.

Any anomalies indicated by longer pulse arrival times and significantly lower energy signals shall

be reported to the Engineer and further tests shall be conducted as required to evaluate the extent

of possible defects. A written report shall be submitted within 5 working days of the completion

of testing. The CSL testing and analysis results shall be presented to the Engineer in a report

according to ASTM D6760 requirements. A CSL log for each tube pair tested shall be presented

with any defect zones identified on the logs. When required, 3D tomographic analysis shall be

performed using all offset data, and color coded 3D tomographic images shall be included in the

report.

Findings from cored holes shall be preserved, identified as to location, and made available for

inspection by the Engineer.

Care shall be exercised in the removal of caps or plugs from the pipes after installation so as not

to apply excess torque, hammering, or other stresses which could break the bond between the tubes

and the concrete.

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Upon completion of CSL testing and acceptance of the shaft by the Engineer, all water shall be

removed from the access tubes and any cored holes. The access tubes and cored holes shall be

filled using grout tubes that extend to the bottom of the access tube or cored hole or into the grout

already placed. The grout used to fill access tubes and cored holes shall have strength properties

equivalent to or better than those of the drilled shaft concrete and be approved by the Engineer.

The access tubes and cored holes in a particular shaft shall not be filled with grout until all testing

is completed and the shaft has been accepted by the Engineer.

cement to assess the quality of the drilled shaft. The test shall meet ASTM D7949, Method B

requirements as modified herein.

TIP equipment shall include a computer-based TIP data acquisition system that automatically

collects data at user defined time intervals to monitor and download temperature versus time after

casting. Wires shall be furnished with built-in sensors as recommended by the drilled shaft

integrity testing firm.

Drilled shafts with TIP testing shall have the number of wires equal to the greater of 4 or the

nearest whole integer value, rounded up, of the diameter of the drilled shaft measured in feet.

Thermal wire cables shall be installed evenly in each drilled shaft by the integrity testing firm.

The thermal wire cables shall be aligned with the longitudinal reinforcement of the drilled shaft

and wire slack shall be minimized. The thermal wire cables shall be tied to the longitudinal

reinforcement at maximum 3-foot intervals.

Thermal wire cables shall be connected to a thermal access port (TAP) prior to concrete placement.

The position and serial number of each thermal wire cable in the drilled shaft shall be recorded.

TIP data collection shall begin immediately prior to the start of concrete placement and extend a

minimum duration of 30 hours, or as recommended by the integrity testing firm and accepted by

the Engineer The timing interval and duration may be revised by the integrity testing firm or the

Engineer as the project conditions require.

Potential local anomalies shall be reported immediately to the Engineer, as indicated by locally

low temperatures relative to the average temperature at that depth, or by average temperatures

significantly lower than the average temperatures at other depths.

A written report shall be submitted within 5 working days of the completion of testing. The TIP

testing and analysis results shall be presented to the Engineer in a report according to ASTM D7949

requirements. The following information shall also be provided:

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shaft adjustments made per the manufacturer’s recommendations, so that temperature plots

are adjusted for end effects.

average at any depth from the overall average over the entire length.

the estimated radius and shape of each shaft along its depth, as calculated comparing the

temperature at each depth to the overall average temperature.

anomalies, including a characterization and evaluation of the anomaly.

The Contractor shall not commence concrete operations in subsequent shaft excavations until the integrity

test report has been submitted for the previously completed shaft and the Engineer has given approval.

This requirement may be waived at the discretion of the Engineer.

503.10ACCEPTANCE OF DRILLED SHAFTS. The Engineer will determine final acceptance of each

shaft and will provide a response to the Contractor within 7 calendar days after receipt of the final integrity

test report.

Unacceptable drilled shafts are drilled shafts that are rejected by the Engineer due to damage, failure to

advance through obstructions, mis-location, misalignment, failure to install the drilled shaft to the proper

bearing stratum, or the results of the shaft integrity testing indicate defects. Rejection of a shaft based on

the shaft integrity testing shall require conclusive evidence that a defect exists in the shaft. If the shaft

integrity test results are complex or inconclusive, the Engineer may require additional testing to confirm

the location of the defect.

For all shafts determined to be unacceptable, the Contractor shall submit a remedial action plan to the

Engineer for approval. If the remedial action plan requires any modifications to the dimensions of the

shafts detailed in the Plans, they shall be supported by calculations and working drawings. All remedial

correction procedures and designs shall be stamped and signed by a professional engineer and submitted

to the Engineer for approval. The Contractor shall not begin repair operations until receiving the

Engineer’s approval of the remedial action plan.

If the Engineer determines that the concrete placed is structurally inadequate, that shaft will be rejected.

The placement of concrete shall be suspended until the Contractor submits to the Engineer written changes

to the methods of shaft construction needed to prevent future structurally inadequate shafts and receives

the Engineer’s written approval of the submittal.

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At the Engineer’s direction, a core hole (standard NX size rock core) shall be drilled in any questionable

quality shaft (as determined from shaft integrity testing and analysis or by observation of the Engineer) to

explore the shaft condition.

Prior to beginning coring, the Contractor shall submit to the Engineer the method and equipment used to

drill and remove cores from shaft concrete. The Engineer shall issue written approval before the coring

work can be started. The coring method and equipment shall provide for complete core recovery and shall

minimize abrasion and erosion of the core.

If a defect is confirmed, the Contractor shall pay for all coring costs. If no defect is encountered, the

Agency will pay for all coring costs as extra work and, if the shaft construction is on the critical path of

the Contractor’s schedule, compensation for the delay will be granted by an appropriate time extension.

Materials and work necessary, including engineering analysis and redesign, to effect corrections for shaft

defects shall be furnished to the Engineer’s satisfaction at no additional cost to the Agency.

503.11METHOD OF MEASUREMENT. The quantities of Drilled Shaft in Earth and Drilled Shaft in

Rock of the size specified to be measured for payment will be the number of linear feet of drilled shaft

placed in the complete and accepted work (except where measurement is made for Drilled Shaft

Obstruction Drilling and Removal as specified below) measured to the nearest 0.1 foot from the Plan top

of concrete shaft elevation to the bottom of shaft. Measurement will be taken at the cross-sectional center

of the shaft.

The quantity of Drilled Shaft Obstruction Drilling and Removal to be measured for payment will be the

number of linear feet performed in the complete and accepted work, over the depth range in which

obstructions are encountered, measured to the nearest 0.1 feet as determined by the Engineer. No

measurement for Drilled Shaft in Earth or Drilled Shaft in Rock will be made within the limits of Drilled

Shaft Obstruction Drilling and Removal.

The quantity of Mobilization of Drilled Shaft Equipment to be measured for payment will be on a lump

sum basis in the complete and accepted work.

503.12BASIS OF PAYMENT. The accepted quantities of Drilled Shaft in Earth and Drilled Shaft in

Rock will be paid for at the Contract unit per price linear foot. Payment will be full compensation for

excavation, dewatering, temporary or permanent casing, slurry, concrete, reinforcing steel, integrity

testing, and grouting CSL tubes, and for furnishing all labor, tools, equipment, and incidentals necessary

to complete the work.

503

The accepted quantity of Drilled Shaft Obstruction Drilling and Removal will be paid for at the Contract

unit price per linear foot. Payment will be full compensation for performing the work of overcoming

encountered obstructions and for furnishing all materials, labor, tools, equipment, and incidentals

necessary to complete the work.

The accepted quantity of Mobilization of Drilled Shaft Equipment will be paid for at the Contract lump

sum price. Payment will be full compensation for mobilization, remobilization, and demobilization of

drilled shaft equipment from the project including the erecting, dismantling, and all incidental tasks

necessary to complete the work, and the furnishing of all supervision, equipment, labor, tools, and

incidentals necessary to complete the work.

Partial payments for Mobilization of Drilled Shaft Equipment will be made as follows:

sum price will be paid.

complete and the equipment has been removed from the site.

Costs associated with providing all submittals required as part of the work, and any necessary

modifications thereto, will be considered incidental to the Contract items in this section.

Payment will be made under:

Pay Item Pay Unit

00 Drilled Shaft in Earth ................................................................................Linear Foot

503.1500 Drilled Shaft in Rock ................................................................................Linear Foot

503.2000 Drilled Shaft Obstruction Drilling and Removal ......................................Linear Foot

503.2500 Mobilization of Drilled Shaft Equipment .................................................Lump Sum

504

5-73SECTIO N 504 – FURNISHIN G EQUIPMEN T FOR DRIVIN G PILING

504.0 1 DESCRIPTION . This work shall consist of furnishing the equipment required to drive piles. 504.0 2 EQUIPMENT .

Form from the Engineer. The Contractor shall complete this form in its entirety and shall submit copies to the geotechnical consultant employed by the Contractor when load tests ar e required, and to the Engineer so that a wave equation analysis may be performed. At least 14 calendar days prior to the beginning of any pile driving, the Contractor shall furnish , for the Engineer’s acceptance, specifications and applicable information to verify the capacity and capability of the proposed pile driving hammer. No test piles or production piles shall be driven prior to this acceptance. During the pile driving operations, no changes to the accepted equipment will be permitted wi thout the Engineer’s permission.

drive the type and length of pile specified to the maximum ultimate pile capacity or nominal axial pile resistance shown on the Plans. Each hammer shall be equipped with an anvil or clamp suitable for transmitting the driving force to the pile. The valve mechanism and the other parts of the air or diesel hammer shall be mainta ined in first class condition to ensure that the length of stroke for a single -acting hammer and the design number of blows per minute for a double -acting hammer will be obtained. The drive head shall be axially aligned with the hammer and pile and shall be guided by leads and not be free -swinging. It shall fit around the pile head in such a manner as to prevent transfer of torsional forces during driving while maintaining proper alignment of the hammer and pile. The pile driving equipment shall not induce a compressive stress greater than 90% of the yield stress of the pile material. In addition, the pile driving equipment shall be capable of driving the pile to the required ultimate capacity at a blow count of between 3 blows and 15 blows per inch a s indicated by the wave equation analysis program (WEAP).

position and alignment will be as specified and as shown on the Plans. The selection of leads or form of bracing shall be adequate to align and restrain the piling during placement. If the leads or bracing are not adequate to place the piling to within the specified tolerance, the Contractor shall modify the leads or system of bracing until it obtains results acceptable t o the Engineer.