Amend_0002_Attach_B-_Auger_Cast_Piling.PDF

Project Number HDR Client Name Issue Date Project Name - Deliverable Type

AUGER CAST PILING

31 63 16 - 1 ARCHITECTURE MASTER

SECTION 31 63 16

AUGER CAST PILING

PART 1 - GENERAL

1.1 SUMMARY

A. Furnish labor, materials, tools, equipment, and services for Auger Cast Piling, as indicated, in accordance with provisions of Contract Documents.

B. Subsoil information:

1. Additional test borings and other exploratory operations may be made, provided such operations are acceptable to Architect.

C. Definitions:

1. Pile: Cast-in-place pile made by rotating a continuous helical flight hollow shaft auger into subsoil and injecting concrete under sufficient pressure as auger is withdrawn to ensure a continuous column of concrete of minimum diameter(s) and design load(s) indicated.

2. Geotech: Geotechnical Engineer or Representative of Foundation Consultant employed by Owner to inspect foundation work.

D. Completely coordinate with work of other trades.

1.2 QUALITY ASSURANCE

A. Qualified Pile Installers:

1. Longfellow Foundations, Inc.

2. L G Barcus and Sons.

3. Other installers desiring approval comply with Section 00 26 00.

B. Pile Testing:

1. Conduct _______ load tests.

2. Install test piles in locations and to elevations directed by Geotech.

3. Contractor design test pile arrangement and furnish apparatus necessary to safely test load pile to twice design load.

4. Load test arrangement and apparatus must be acceptable to Geotech.

5. Geotech establishes test load criteria for test piles.

6. After concrete has reached its 28 day strength, test load pile in accordance with ASTM-

D1143, “Standard Test Method for Piles Under Static Axial Compressive Load.”

a. Standard loading procedure

b. Cyclic loading

c. Loading in excess of standard test

d. Constant time interval loading

e. Constant rate of penetration method for individual piles

f. Quick load test method for individual piles

g. Constant settlement increment loading method for individual piles

7. Allowable settlement: Not more than 3/4 IN after removal of load

8. Allowable settlement: Not more than ______ after removal of load

9. Hydraulic jack and pressure gauge must have been recently calibrated.

10. Provide digital gauge readings on uplift pile and rest pile. Contractor to verify readings.

11. In event of failure to attain test load, repeat load test with new test pile as directed by

Geotech. Installation of additional test piles will be paid for as set forth in Section 1.4. The additional pile test shall be performed without additional cost to the Owner.

12. Installation, equipment and procedures for test program identical to those planned for remainder of piles.

AUGER CAST PILING

31 63 16 - 2 ARCHITECTURE MASTER

13. Test piles may remain in completed structure provided they meet requirements of permanent piles.

C. Concrete Testing:

1. Concrete cylinder tests.

2. Take three 75 MM 3 IN diameter x 150 MM 6 IN high test cylinders each morning and afternoon for each drilling rig operating.

3. Record piles represented by each batch of test cylinders.

4. Cylinder molds: Type which will retain mortar expansion yet permit escape of water and air.

5. Test 1 cylinder at 7 days and 2 cylinders at 28 days.

6. Test in accordance with ASTM-C39.

D. Tolerances:

1. Location: 75 MM 3 IN from location indicated for center of gravity of each single pile or pile group; 25 MM 1 IN from location indicated perpendicular to a wall and 125 MM 5 IN from location indicated parallel to wall.

2. Alignment:

a. Maintain plumb or verticality to within 1 in 120 from vertical.

3. Cut-off:

a. Cut off elevation; 25 MM 1 IN above and 75 MM 3 IN below design elevation.

E. Inspections:

1. All piles shall be continuously inspected by the Geotech.

2. The Geotech shall be present during all pile installations.

1.3 SUBMITTALS

A. Project Information:

1. Names of 3 past successful installations under similar conditions.

2. Record of pile installation to Architect and Geotech. Submit prior to pouring cap. Include the following information:

a. Location.

b. Number.

c. Date drilled.

d. Length (tip to cut-off) and tip elevation.

e. Quantity of concrete pumped into each pile.

f. Cylinder strength of concrete.

g. Unusual conditions encountered.

h. Test reports.

3. Grout Mix Design.

1.4 CONTRACT PRICE ADJUSTMENT

A. Contractor bid on total lineal footage of production pile indicated for base bid.

B. Cost of pile load tests including test and uplift pile in base bid.

C. Base bid will be adjusted in amount (add or deduct) determined by multiplying difference between Base Bid Length indicated and total length of production pile installed by appropriate unit price on proposal form.

D. Total length of Production Piles:

1. Accumulated length of production piles from tip to cut-off.

2. Do not include rejected piles.

3. Include discontinued piles and additional piles required due to obstructions and additional pile load tests.

AUGER CAST PILING

31 63 16 - 3 ARCHITECTURE MASTER

PART 2 - PRODUCTS

2.1 MATERIALS

A. Concrete:

1. Adequacy for purpose is Contractor’s responsibility.

2. Minimum strength: 27.5 MPa 4000 PSI at 28 days, 75 x 159 MM 3 x 6 IN cylinders.

3. Consistency (Corp of Engineer’s Specification CRD C-79): Not less than 21 seconds.

4. Cement: Portland cement conforming to ASTM-C150. Cement used shall correspond to that upon which selection of concrete proportions was based.

5. Sand: ASTM-C33. Obtain from a source approved by the State Highway Department for use in concrete for State Bridges.

6. Water: Potable: Demonstrate by testing that water does not contain deleterious amounts of chloride.

7. Admixtures: Comply with applicable ASTM standards.

B. Reinforcing: ASTM A615, Grade-60.

C. Reinforcing:

1. Dywidag bars, ___ mm ___ IN diameter (fy=1000 MPa 150 KSI).

PART 3 - EXECUTION

3.1 MIXING AND PUMPING OF GROUT

A. Use only adequate mixing and pumping equipment in preparation and handling of concrete.

1. Provide accurate (recently calibrated) concrete pressure gauge in clear view of equipment operator.

2. Use screen between mixer and pump, or between mixer and agitator.

3. Remove soil, rust, or other foreign material from mixing drums, stirring mechanisms, and other portions of equipment in contact with concrete.

4. Provide an operating stroke counter to continuously record volume of grout pumped.

Calibrate the pump on site by pumping a known volume of grout exceeding 50 gallons.

B. Accurately measure materials by weight as they are fed to mixer.

C. Mix not less than one minute.

1. If agitated continuously, concrete may be held in mixer or agitator for period not exceeding

2 HRS at temperatures below 21 DEGC 70 DEGF and for period not exceeding 1-1/2 HR at higher temperatures.

2. Recirculate concrete through pump or through mixer drum or agitator and pump if there is lapse in operation.

D. Monitor installation of Auger cast Piles using a Pile Installation Recorder:

1. The recorder shall record appropriate information during both the auguring phase and the grouting phase of the installation to assure a minimum grout volume is pumped per unit depth increment. It shall print the results immediately upon completion of each pile. The PIR-A (available from Pile Dynamics, Inc., 4535 Renaissance Parkway, Cleveland OH 44128; phone: 216-831-6131; fax: 216-831-0916; shall be deemed acceptable installation recording equipment. Equipment shall have the following minimum components.

a. The recorder shall include a display unit capable of numerically and/or graphically displaying the information from all sensors, and be able to print results on-site in English units, and store information on a memory card. Unit shall have an easy-to-use touch-screen interface and shall provide immediate feedback to the rig operator, particularly during the critical grouting phase to assure minimum grout volume per depth increment.

b. A Depth Sensor shall track the movement of a cable attached to the drill top to measure auger top (and thus auger tip) location at all times during installation. Depth shall be set to zero when the auger tip is touching the ground surface. The maximum pile depth (from ground elevation) shall be recorded.

AUGER CAST PILING

31 63 16 - 4 ARCHITECTURE MASTER

c. A Magnetic Flow Meter (MFM) shall be installed in the grout line to measure grout volume pumped within an accuracy of +/- 2 PCT.

d. The Field Printer shall record a hard copy of results for each pile including incremental auguring times, incremental grout volumes, and summary grout volumes. Printed results shall be provided to the Engineer or Inspector immediately following completion of each pile installed.

e. The Grout Pressure Sensor monitors and records grout line pressure. Although not used to evaluate incremental volume, this sensor can also count pump strokes. The MFM total volume and total pump strokes allows computation of volume per pump stroke to evaluate consistency of grout pump performance and alert the field crew if pump maintenance is needed.

f. The Torque Pressure Sensor monitors crane torque during auguring. Keeping this pressure below but near the maximum pressure allowed by the crane will reduce stalling the crane and improve overall drilling and production efficiency.

2. The auger tip depth and drilling rate (FT/MIN) shall be displayed during drilling. The depth increment of 2 FT for grouting shall be selected so that a minimum of 5 or more strokes are required per increment. The MFM and Depth Sensor information are sufficient to determine volume pumped per unit depth increment (which shall be displayed to the crane operator graphically as a bar chart with the minimum grout ratio clearly displayed as a guide). The printout shall be inspected prior to moving the rig, and if the grout pumped falls below the specified allowable minimum grout ratio for any depth increment, the pile shall be reaugured to 5 FT past the defect and regrouted while the grout is still fluid. The specified minimum grout ratio of 115 PCT may be adjusted by the Engineer based on observed grout return depths and PIR-A grout installation records.

3. The Pile Installation Recorder shall be operational prior to installation of the piles, and shall be maintained during the installation of all production piles unless otherwise directed by the Engineer. In the unlikely event that the unit is not fully operative, the Contractor shall notify and work with the manufacturer to rectify the situation. In a brief interim duration as directed by the Engineer, the Inspector shall manually record incremental volume until the unit is fully operative.

4. The recorder does not replace the Inspector but rather assists the Inspector during the critical grouting phase by accurately monitoring grout pumped versus depth. The Inspector shall still observe and record arrival times of grout trucks, obtain grout samples, pile location versus planned location, grout return depth, reinforcement bar placement, excavation and other unusual activities or installation information as directed by the Engineer. The Inspector shall collect printouts for each pile installed and transmit them to the Engineer daily.

3.2 PILE INSTALLATION

A. Install piles such that required penetration into Bearing Stratum defined in Soils Report is achieved.

B. Select and use installation methods suitable to soil profile which will produce continuous column of concrete of minimum diameter indicated, free of voids and foreign material. A head of at least 15 FT of grout shall be maintained above the injection point.

C. Extend piles to elevation indicated or established by Geotech.

D. Accomplish drilling with plug in lower end of auger.

E. Coordinate rate of concrete injection and rate of auger withdrawal from soil so as to maintain sufficient positive pressure at bottom of auger flight.

1. Jerky removal of auger flight will be sufficient basis for requesting that pile or piles in question are test loaded.

2. Use at least 4 part line for withdrawing auger.

AUGER CAST PILING

31 63 16 - 5 ARCHITECTURE MASTER

F. Should obstruction, including but not limited to boulders, cobbles, rubble fill, or timbers, be encountered which prevent placing pile to depth required, or causes pile to drift from required location, remove obstruction where possible.

1. When it is impossible or impracticable to remove obstruction and when so directed by

Architect/Geotech, complete short pile.

2. Install additional adjacent pile as directed by Architect/Engineer.

3. Pile refusal shall be defined as no advancement in drilling for 3 minutes.

G. Place reinforcing with spacers to prevent contact with soil.

H. Extend “Dywidag” bars full length of uplift piling.

1. Place through auger or use spacers to locate bar at pile center.

2. Splice, if required, by mechanical means capable of developing at least 125 PCT of yield strength of bar.

3. Install steel plates and nuts at top of bars.

3.3 CUTOFF

A. Cut off piles at elevations indicated.

1. Remove fresh concrete from top of pile no sooner than 3 HR after pile installation.

2. Or cut off down to final cutoff point at any time after initial set has occurred.

3. Top of piles after cutoff shall be level and with full diameter cross-section.

B. Clean and straighten exposed reinforcement.

3.4 REJECTION OF PILES

A. Replace rejected piles.

B. Piles may be rejected for:

1. Being installed outside specified tolerances.

2. Being broken, damaged or collapsed.

3. Failing to develop specified resistance.

4. Failure to meet specifications.

C. Subject to approval of Architect, take one of following remedial steps:

1. Cut off and abandon rejected pile.

2. Install additional pile or piles at locations designated by Architect.

D. Redesign of pile caps caused by rejected piles will be at Contractor’s expense.

END OF SECTION