96M03/29/06

S565-96M.doc

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  Use on projects as appropriate.

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**Section 565 - DRILLED SHAFTS**

**Construction Requirements**

[Delete Subsections 565.08, 09, and 10 and substitute the
following:]{.underline}

**565.08 Integrity Testing.** Perform integrity testing on drilled
shafts using the nondestructive crosshole sonic logging (CSL) method for
concrete drilled shafts to verify the structural integrity of the
drilled shafts. Use test procedure FLH 521-01, Standard Method for
Determining Pulse Velocity Through Concrete in Drilled Shafts.

**(a) Personnel requirements for CSL.** Field-testing and interpretation
of the recorded measurements shall be performed by an engineer with at
least two years of experience with drilled shaft CSL testing and data
interpretation. Provide personnel resumes of job experience and
appropriate documentations including names, addresses, and telephone
numbers of organizations that will verify the information. Approval of
CSL testing personnel is required before drilled shaft work begins.
Allow three weeks for the Government to approve/disapprove CSL personnel
proposed to perform testing. Provide labor support as required to
adequately perform the required tests.

**(b) Equipment requirements for CSL.** Provide portable CSL testing
equipment meeting FLH T-521 and the following:

> **(1)** An ultrasonic source probe and one or more receiver probe
> capable of producing records of signal amplitude and energy through
> concrete (multi-receiver systems are preferred for rapid and accurate
> data collection). Probes shall be able to descend freely through a
> 52.5 mm inside diameter steel, water-filled access tube. Probes shall
> have a cable length sufficient to test the full depth of all drilled
> shafts.
>
> **(2)** A suitable measurement device to accurately and continuously
> record probe depths during testing.
>
> **(3)** A triggering system that synchronizes the ultrasonic pulse
> with the receiver.
>
> **(4)** A microprocessor based data acquisition and recording system
> with the capability of displaying and monitoring individual records in
> real time. The system shall have the capability to amplify/filter data
> and print ultrasonic logs on site.
>
> **(5)** An independent stable 110V, 60Hz, AC power supply if needed.

**(c) CSL test requirements.** Perform integrity tests on **all**
production-drilled shafts as directed by the CO in accordance with
FLH-521-01, Standard Method for Determining Pulse Velocity Through
Concrete in Drilled Shafts. Shafts shall be tested after 2 days and
within 45 days of concrete placement. Prior to testing the Contractor
will provide CSL personnel with information on drilled shaft bottom and
tip elevations, concrete placement dates, tube lengths and surveyed tube
positions.

**(d) CSL access tube preparation.** Provide and install standard weight
steel tubes (ASA

B36.10, 52.5 mm I.D.) for each drilled shaft as shown on the plans. Use
pipes that have a round, regular internal diameter, free of defects or
obstructions, including any at pipe joints, to permit the free,
unobstructed passage of source and receiver probes. Use tubes that are
watertight and free from corrosion with clean internal and external
faces to ensure probes passage and good bond between the concrete and
tubes. Do not use duct tape or similar materials to seal joints. Do not
use stiffening devices such as mandrels in the access tubes during
concrete placement.

Fit the tubes with a watertight shoe on the bottom and a removable cap
on the top. All access tube joint shall be watertight. Secure tubes
firmly to the interior of the reinforcement cage. Install the tubes in a
regular, symmetric pattern as shown in Table 565-1 such that each tube
is spaced the maximum possible distance from each adjacent tube. Tubes
shall be as near to parallel as possible. The tubes shall be installed
150 mm above the shaft bottoms, at least 1 m above the shaft tops, and
at least 0.6 m above the ground surface. Do not bend or damage the tubes
during reinforcement installation operations.

Fill the tubes with clean water within 4 hours of concrete placement and
cap the tube tops. Do not apply excess torque, hammering or other stress
the tube at any time that could affect tube-concrete bond. If tubes are
not acceptable for testing for reasons such as: (1) tube plumbness (2)
tube does not retain water (3) tube-concrete debonding (4) tube
obstructions, provide replacement access tubes by core drilling or
propose an alternative test method approved by the CO. After integrity
testing, inspection and data analysis are completed and accepted by the
CO, fill access tubes with approved neat cement slurry or grout from the
bottom using a tremie.

**Table 565-1**

**Drilled shaft access tube placement and CSL test Schematic**

**(e) CSL results and reporting.** Preliminary results shall be provided
to the CO for each shaft tested on site prior to CSL personnel leaving
the site. A detailed CSL report and all test data in ASCII format with a
header (identifying shaft tested, tube coordinates, and each data
column) shall be submitted to the CO on a compact disk within 5 days of
test completion.

Allow 5 days for the CO to conduct a review of the data prior to any
further construction on the tested shaft. The Government may request
additional time for independent review and analysis of the data.

The CSL Report shall include but not be limited to the following:

> **(1)** Project identification and dates of testing
>
> **(2)** Table and a schematic showing shafts tested with
> identification of tube coordinates and collar elevation
>
> **(3)** Names of personnel that performed the tests/interpretation and
> their affiliation
>
> **(4)** Equipment used
>
> **(5)** Data logs
>
> **(6)** Interpretation, analysis, and results

Data logs shall include XY plots of (FAT), amplitude, and velocity
versus depth. Process CSL data to construct easy to understand 2D/3D (2D
cross-sections between tubes and 3D volumetric images for the entire
shaft). The cross-sections shall be color-coded tomographic images
indicating velocity variations along the shaft. Location and geometry of
defect/unconsolidated zones shall be identified in 3-D color images with
detailed discussion. The results shall correlated to the following
Concrete Condition Rating Criteria (CCRC) based on percent (%) decrease
in velocity value as shown in Table 565-2.

**Table 565-2**

Concrete Condition Rating Criteria (CCRC)

+------------+-----------+-------------+------------------------------+
| **CCRC     | **Rating  | **Velocity  | **Indicative Results**       |
| Rating**   | Symbol**  | Reduction** |                              |
+------------+-----------+-------------+------------------------------+
| Good       | G         | 0 to 10%    | Acceptable concrete          |
+------------+-----------+-------------+------------------------------+
| Qu         | Q         | 10 % to 25  | Minor concrete contamination |
| estionable |           | %           | or intrusion. Questionable   |
|            |           |             | quality concrete.            |
+------------+-----------+-------------+------------------------------+
| Poor       | P/D       | 25 %        | Defects exist, possible      |
|            |           |             | water slurry contamination,  |
|            |           |             | soil intrusion, and or       |
|            |           |             |                              |
|            |           |             | poor quality concrete.       |
+------------+-----------+-------------+------------------------------+
| Water      | W         | V= 1,450    | Water intrusion, or water    |
|            |           | m/s         | filled gravel intrusion with |
|            |           |             | few or no fines present.     |
|            |           | to 1,525    |                              |
|            |           | m/s         |                              |
+------------+-----------+-------------+------------------------------+
| No signal  | NS        | No signal   | Soil intrusion or other      |
|            |           | received    | severe defect absorbed the   |
|            |           |             | signal, tube debonding if    |
|            |           |             | near top.                    |
+------------+-----------+-------------+------------------------------+

Three 150mm by 300mm concrete cylinders shall be prepared for testing
from the same concrete mix used in the drilled shaft. Pulse velocity
(PV) testing shall be performed along the diametric axis of the
cylinders in accordance with ASTM C 597, Standard Test Method for Pulse
Velocity Through Concrete. PV tests shall be conducted on the same date
that the CSL testing is being conducted in the drilled shafts.
Deviations from these values shall be used for determining the concrete
Condition Rating Criteria.

**(f) Correction of Defects.** If drilled shaft integrity testing
indicates the presence defects or unconsolidated concrete zones or if
the CO determines that construction defects may have occurred; core
drilling shall be performed to further investigate. In such a case a
minimum of two cores shall be drilled to intercept the imaged defect
zones and sample cores shall be obtained from these suspect areas.

If a shaft is determined to have defects, submit a plan for remedial
action to the CO for approval. Modifications to the drilled shaft or
load transfer mechanisms required by the remedial action shall be
designed and stamped by a registered professional engineer. Include
drawings stamped by a registered engineer for all foundation elements
affected. Do not begin remedial action work until the CO has approved
the remedial action plan. Furnish materials and work necessary to
correct defective drilled shafts.

**565.09 Acceptance.** Material for mineral slurry will be evaluated
under Subsections 106.02 and 106.03.

Construction of drilled shafts will be evaluated under Subsections
106.02 and 106.04.

Concrete will be evaluated under Section 552. Concrete, tremie placed or
pumped, will be sampled at point of discharge into the tremie or
concrete pump hopper.

Reinforcing steel will be evaluated under Section 554.

**Measurement**

**565.10** Measure drilled shafts by the meter from the plan top
elevation to the approved tip. Do not measure portions of shafts
extending deeper than approved.

Do not measure concrete or reinforcing steel for payment.

Measure trial drilled shafts, determined to be satisfactory, by the
meter from the approved tip elevation to the ground surface at the
center of the shaft.

Measure drilled shaft bells by the each.

**Payment**

**565.11** The accepted quantities, measured as provided above, will be
paid at the contract price per unit of measurement for the pay items
listed below that are shown in the bid schedule. Payment will be full
compensation for the work prescribed in this section. See Subsection
109.05.

All costs associated with core drilling and/or alternative testing shall
be borne by the Contractor. If a defect is confirmed, the Contractor
shall bear all costs involved with the shaft coring and defect
remediation. If no defects exist, the Government will bear all coring
and grouting costs.

Payment for the three cylinders to determine Pulse Velocity values will
not be paid for directly but will be considered subsidiary to the work
prescribed in this section.

Payment will be made under:

**Pay Item Pay Unit**

56501 Drilled shafts Meter

56502 Trial drilled shaft Each

56503 Bell Each

56504 Crosshole sonic logging Each

56505 Coring/pressure grouting Meter