Chrysler LLC Construction Standards

12/17/04

SECTION 02466 - DRILLED PIERS

PART 1 - GENERAL

1.1  SUMMARY

  1. This Section includes cast-in-place concrete drilled piers.

1.2  UNIT PRICES

  1. Basis of Bids: Base bids on indicated number of drilled piers; design length from top elevation to bottom of shaft; and diameter of shaft.
  2. Basis for Payment: Payment for drilled piers will be made on actual net volume of drilled piers in place and approved. The actual length and shaft diameter may vary to coincide with elevations where satisfactory bearing strata are encountered, and with actual bearing value of bearing strata determined by an independent testing and inspecting agency. Adjustments will be made on net variation of total quantities, based on design dimensions for shafts.
  3. No additional compensation will be made for excavation, concrete fill, reinforcement, casings, or other costs due to unauthorized over excavation.
  4. No payment will be made for rejected work.
  5. Unit prices include labor, materials, tools, equipment, and incidentals required for excavation, trimming, shoring, casings, dewatering, reinforcement, concrete fill, and other items for a complete drilled-pier installation.

1.3  SUBMITTALS

  1. Product Data: For each type of product specified. Include reinforcement and admixtures.
  2. Shop Drawings: For concrete reinforcement detailing fabricating, bending, and placing.
  3. Design Mixes: For each class of concrete. Include revised mix proportions when characteristics of materials, project conditions, weather, test results, or other circumstances warrant adjustments.
  4. Laboratory Test Reports: For evaluation of concrete materials and mix design test.
  5. Qualification Data: For firms and persons specified in "Quality Assurance" Article to demonstrate their capabilities and experience. Include lists of completed projects with project names and addresses, names and addresses of architects and owners, and other information specified.
  6. Record drawings at Project closeout according to Division1 Section "Contract Closeout."

1.4  QUALITY ASSURANCE

  1. Installer Qualifications: Engage an experienced installer who has specialized in installing drilled piers similar to those required for this Project.
  2. Drilled-Pier Standard: Comply with provisions of ACI336.1, "Specification for the Construction of Drilled Piers," unless modified in this Section.
  3. The slurry displacement method of installation will not be permitted.
  4. Survey Work: Engage an experienced surveyor to perform surveys, layouts, and measurements for drilled piers. Lay out each drilled pier to lines and levels required before excavation and record actual measurements of each drilled pier's location, shaft diameter, bottom and top elevations, deviations from specified tolerances, and other specified data.
  5. Record and maintain information pertinent to each drilled pier and cooperate with testing and inspecting agency to provide data for required reports.

1.5  PROJECT CONDITIONS

  1. Existing Utilities: Locate existing underground utilities before excavating drilled piers. If utilities are to remain in place, provide protection from damage during drilled-pier operations.
  2. Should uncharted or incorrectly charted piping or other utilities be encountered during excavation, consult Architect/Engineer immediately for directions as to procedure. Cooperate with Owner and utility companies in keeping services and facilities in operation. Repair damaged utilities to satisfaction of utility owner.
  3. Site Information: A geotechnical report accompanies the Contract Documents, and the recommendations of the geotechnical engineer expressed therein shall be requirements. Neither the Owner nor the Architect/Engineer will be responsible for interpretations or conclusions drawn from the geotechnical data presented in the report. Make additional test borings and conduct other exploratory operations as necessary.
  4. The geotechnical report attached is from the North Plant. Borings for the South Plant have been ordered and the resulting report will be distributed when it becomes available.

PART 2 - PRODUCTS

2.1  REINFORCING MATERIALS

  1. Reinforcing Bars: ASTMA615, Grade60, deformed.
  2. Joint Dowel Bars: Plain steel bars, ASTMA615 Grade60. Cut bars true to length with ends square and free of burrs.

2.2  CONCRETE MATERIALS

  1. Portland Cement: ASTMC150, TypeI or II.
  2. Fly Ash: ASTMC618, TypeC or F, with maximum loss of ignition (LOI) of 6 percent.
  3. Aggregates: ASTMC33, 3/4-inch maximum aggregate size.
  4. Water: Potable, complying with ASTMC94 requirements.
  5. Admixtures: Provide admixtures certified by manufacturer to be compatible with other admixtures and to contain not more than 0.1 percent chloride ions by mass of portland cement or cementitious material.
  6. High-Range, Water-Reducing Admixture: ASTMC494, TypeF.
  7. Air-Entraining Admixture: ASTMC260.

2.3  ANCHOR RODS

  1. Anchor Bolts: ASTMA36, straight, threaded; complete with steel setting template.
  2. Nuts: ASTMA563 heavyhex carbon steel.
  3. Plate Washers: ASTMA36 carbon steel.
  4. Washers: ASTMF436 hardened carbon steel.
  5. Finish: Plain.

2.4  TEMPORARY CASINGS

  1. Steel Pipe Casings: ASTM A 283, Grade C; or ASTM A 36 carbon steel plate, with vertical joints full-penetration welded according to AWS D1.1.
  2. Paper, or Fiber Tube Forms: Products that will produce surfaces with gradual or abrupt irregularities not exceeding specified formwork surface class. Provide units with sufficient wall thickness to resist plastic concrete loads without detrimental deformation.
  3. Use: Shafts that extend above grade.
  4. Product: Sonotube or comparable product acceptable to the Architect.

2.5  CONCRETE MIX

  1. Prepare design mixes, according to ACI301, for concrete by either laboratory trial batch or field experience method. For trial batch method, use a qualified independent testing and inspecting agency for preparing and reporting proposed mix designs.
  2. Do not use Owner's independent testing and inspecting agency.
  3. Limit use of fly ash to not exceed 25 percent of weight of portland cement.
  4. Proportion mixes according to ACI211.1 and ACI301 to provide normal-weight concrete with the following properties:
  5. Compressive Strength (28 Day): 3000 psi.
  6. Maximum Water-Cement Ratio at Point of Placement: 0.62.
  7. Slump Limit: Capable of maintaining a slump of 4 inches for 2 hours after placement and as follows:
  8. 5 inches, plus or minus 1 inch.
  9. Concrete-mix design adjustments may be proposed when characteristics of materials, project conditions, weather, test results, or other circumstances warrant.

2.6  CONCRETE MIXING

  1. Ready-Mixed Concrete: Comply with requirements and with ASTMC94. Do not add water after mixing.
  2. When air temperature is between 85 and 90degF, reduce mixing and delivery time from 1-1/2 hours to 75 minutes; when air temperature is above 90degF, reduce mixing and delivery time to 60 minutes.

PART 3 - EXECUTION

3.1  PREPARATION

  1. Protect structures, utilities, sidewalks, pavements, and other facilities from damage caused by settlement, lateral movement, vibration, and other hazards created by drilled-pier operations.

3.2  EXCAVATION

  1. Classified Excavation: Excavation is classified and includes excavation to bearing elevations. Excavation will be classified as standard excavation, special excavation, and obstruction removal, as follows:
  2. Standard excavation includes excavation accomplished with conventional augers fitted with soil or rock teeth, drilling buckets, and under-reaming equipment attached to drilling equipment of size, power, torque, and down thrust necessary for the work.
  3. Special excavation includes excavation that requires special equipment or procedures above or below indicated depth of drilled piers where drilled-pier excavation equipment used in standard excavation, operating at maximum power, torque, and down thrust, cannot advance the shaft.
  4. Special excavation requires use of special rock augers, core barrels, air tools, blasting, or other methods of hand excavation.
  5. Earth seams, rock fragments, and voids included in rock excavation area will be considered rock for full volume of shaft from initial contact with rock.
  6. Obstructions: Removal of unanticipated boulders, concrete, masonry, or other unforeseen obstructions that cannot be removed by conventional augers fitted with soil or rock teeth, drilling buckets, or under-reaming tools attached to drilling equipment of size, power, torque, and down thrust necessary for the work, will be paid according to Contract provisions for changes in the Work.
  7. Dewatering: Prevent surface and ground water from entering excavated shafts. Dewater excavated shafts before concreting. Conduct water to site drainage facilities.
  8. Excavate shafts for drilled piers to indicated elevations.
  9. Excavate bottom of drilled piers to level plane.
  10. Remove loose material and water from bottom of excavation.
  11. Notify and allow testing and inspecting agency to test and inspect bottom of excavation. If unsuitable bearing stratum is encountered, make adjustments to drilled piers as determined by Architect/Engineer.
  12. Do not excavate shafts deeper than elevations indicated, unless approved by Architect/Engineer.
  13. Additional excavation will be paid according to Contract provisions for changes in the Work.
  14. Excavate shafts for closely spaced drilled piers and those occurring in fragile or sand strata, only after adjacent drilled piers are filled with concrete and allowed to set.
  15. Temporary Casings: Install watertight steel casings of sufficient length and thickness to prevent water seepage into shaft; to withstand compressive, displacement, and withdrawal stresses; and to maintain stability of shaft walls.
  16. Temporary casings may be left in place or may be withdrawn during concrete placement at Contractor's option.
  17. Tolerances: Construct drilled piers to remain within the following tolerances:
  18. Maximum Variation from Location: Not more than the lesser of 4.2 percent of pier diameter or 3 inches from design center location.
  19. Out-of-Plumb: Not more than 12.5 percent of pier diameter, or not more than 1.5 percent of pier length, whichever is less.
  20. Concrete Cutoff Elevation: Plus 1 inch, minus 3 inches.
  21. Bottom Area of Pier: Not less than 96 percent of pier area required.
  22. Shaft Diameter: Not less than 98 percent or more than 110 percent of shaft diameter indicated.
  23. If location or out-of-plumb tolerances are exceeded, provide corrective construction. Submit design and construction proposals to Architect/Engineer for review before proceeding.
  24. Inspection: Each drilled pier must be inspected and tested before placing concrete.
  25. Provide and maintain facilities with equipment required for testing and inspecting excavations. Cooperate with testing and inspecting personnel to expedite the Work.
  26. Notify Architect/Engineer and testing agency at least 6 hours before excavations are ready for tests and inspection.

3.3  REINFORCEMENT

  1. Comply with recommendations of CRSI's "Manual of Standard Practice" for fabricating, placing, and supporting reinforcement.
  2. Clean reinforcement of loose rust and mill scale, earth, and other materials that reduce or destroy bond with concrete.
  3. Fabricate and install reinforcing cages symmetrically about axis of shafts in a single unit.
  4. Accurately position, support, and secure reinforcement against displacement during concreting. Maintain minimum cover to reinforcement.
  5. Use templates to set anchor bolts, leveling plates, and other accessories to be set in concrete. Provide blocking and holding devices to maintain required position during final concrete placement.
  6. Protect exposed ends of extended reinforcement, dowels, or anchor bolts from mechanical damage and exposure to weather.

3.4  CONCRETE PLACEMENT

  1. Place concrete in a continuous operation and without segregation immediately after inspection and approval of the shaft by an independent testing and inspecting agency.
  2. Place concrete by means of bottom discharge bucket, flexible drop chute, elephant-trunk hopper, or tremie. Use chutes or tremies for placing concrete, or pump concrete into place.
  3. Free fall method is acceptable providing steps are used to direct and maintain concrete pour vertically down the center of the shaft.
  4. Place concrete in a dry shaft, unless placement underwater or by slurry displacement is approved by Architect/Engineer.
  5. Place concrete in slurry-filled shafts or underwater by tremie method or pumping. Control placement operations to ensure tremie is embedded no less than 60 inches into concrete, and the flow of tremied concrete is continuous from bottom to top of drilled pier.
  6. Other methods of depositing concrete may be used, if approved by Architect/Engineer.
  7. Coordinate withdrawal of temporary casings with concrete placement operations to maintain a head of concrete no less than 60 inches above casing bottom.
  8. Screed concrete at cutoff elevation level and apply a scoured, rough finish. Where cutoff elevation is above the ground elevation, form top section above grade and extend shaft to required elevation.
  9. Set anchor bolts by means of a steel template in the top of shafts that do not receive a future concrete cap. Position bolts at correct elevations, complying with Architect acceptable templates.
  10. Protect concrete work, according to ACI301, from physical damage or reduced strength that could be caused by frost, freezing, or low temperatures.
  11. Do not use frozen materials or materials containing ice or snow. Do not place concrete on frozen subgrade or on subgrade containing frozen materials.
  12. Do not use calcium chloride, salt, or other mineral-containing antifreeze agents or chemical accelerators.
  13. When hot-weather conditions exist that would seriously impair quality and strength of concrete, place concrete according to ACI301 to maintain delivered temperature of concrete without exceeding 90degF.
  14. Place concrete immediately on delivery. Keep exposed concrete surfaces and formed shaft extensions moist by fog sprays, wet burlap, or other effective means for a minimum of 7 days.
  15. Remove paper, or fiber tube forms on shafts that extend above grade.

3.5  FIELD QUALITY CONTROL

  1. Testing Agency: Owner will provide testing and inspecting agencies to sample materials, perform tests, and submit test reports during excavation and concrete placement for drilled piers.
  2. A drilled pier report shall be prepared for each drilled pier as follows:
  3. Actual top and bottom elevations.
  4. Description of soil materials.
  5. Description, location, and dimensions of obstructions.
  6. Final top centerline location.
  7. Variation of shaft from plumb.
  8. Shaft excavating method.
  9. Design and tested bearing capacity of bottom.
  10. Levelness of bottom and adequacy of cleanout.
  11. Ground-water conditions and water-infiltration rate, depth, and pumping.
  12. Description, diameter, and top and bottom elevations of temporary or permanent casings.
  13. Description of soil or water movement, sidewall stability, loss of ground, and means of control.
  14. Shaft dimensions and variations from original design.
  15. Date and time of starting and completing excavation.
  16. Inspection report.
  17. Position of reinforcing steel.
  18. Concrete placing method, including elevation of consolidation and delays.
  19. Elevation of concrete during removal of casings.
  20. Remarks, unusual conditions encountered, and deviations from requirements.
  21. Concrete testing results.
  22. Soil Testing: Bottom elevations, bearing capacities, and lengths of drilled piers indicated have been estimated from available soil data. Actual elevations and drilled-pier lengths, and bearing capacities will be determined by a qualified independent testing and inspecting agency on excavation. Final evaluations and approval of data will be determined by Architect/Engineer.
  23. Concrete: Sampling and testing of concrete for quality control will include the following:
  24. Sampling Fresh Concrete: ASTMC172, except modified for slump to comply with ASTMC94.
  25. Slump: ASTMC143; 1 test at point of placement for each compressive-strength test, but no less than 1 test for each concrete load.
  26. Air Content: ASTMC231, pressure method; 1 test for each compressive-strength test.
  27. Concrete Temperature: ASTMC1064; 1 test hourly when air temperature is 40degF and below and when 80degF and above, and 1 test for each set of compressive-strength specimens.
  28. Compression Test Specimens: ASTMC31; 1 set of 4 standard cylinders for each compressive-strength test, unless otherwise directed. Mold and store cylinders for laboratory-cured test specimens, unless field-cured test specimens are required.
  29. Compressive-Strength Tests: ASTMC39; 1 set for each drilled pier, but not more than 1 set for each truck load. One specimen will be tested at 7 days, 2 specimens will be tested at 28 days, and 1 specimen will be retained in reserve for later testing if required.
  30. When frequency of testing will provide fewer than 5 strength tests for a given class of concrete, testing will be conducted from at least 5 randomly selected batches or from each batch if fewer than 5 are used.
  31. When strength of field-cured cylinders is less than 85 percent of companion laboratory-cured cylinders, evaluate current operations and provide corrective procedures for protecting and curing the in-place concrete.
  32. Strength level of concrete will be considered satisfactory if averages of sets of 3 consecutive strength test results equal or exceed specified compressive strength and no individual strength test result falls below specified compressive strength by more than 500 psi.
  33. Test results will be reported in writing to Architect/Engineer, concrete manufacturer, and Contractor within 24 hours of testing. Reports of compressive-strength tests will contain Project identification name and number, date of concrete placement, name of concrete testing and inspecting agency, concrete type and class, location of concrete batch in drilled pier, design compressive strength at 28 days, concrete mix proportions and materials, compressive breaking strength, and type of break for both 7- and 28-day tests.
  34. Nondestructive Testing: Impact hammer, sonoscope, or other nondestructive device may be permitted but shall not be used as the sole basis for acceptance or rejection.
  35. Additional Tests: Testing and inspecting agency will make additional tests of concrete when test results indicate concrete strengths or other requirements have not been met.

3.6  DISPOSAL OF MATERIALS