SECTION 02371

DRILLED CONCRETE PIERS (CAISSONS)

PART 1 GENERAL

SECTION INCLUDES

Machine drilled shaft [placement of shaft liner] [and][.] [belling the base.] [shear ring.]

Placing concrete[.] [and reinforcement.]

RELATED WORK

Section [_____] - Information Available To Bidders: Subsurface Investigation Report.

Section [01400 - Quality Control] [01410 - Testing Laboratory Services]: Testing laboratory services.

Section 02222 - Excavation: Excavation to working level.

[Section 02356 - Pile Load Tests: Requirements for pier load tests.]

Section [______-____________]: [Caps] [and][.] [grade beams.]

Section 03200 - Concrete Reinforcement: Requirements for concrete reinforcement.

Section 03300 - Cast-In-Place Concrete: Requirements for concrete.

REFERENCES

AASHTO M36 - Corrugated Metal Culvert Pipe.

ACI 336.1 - Construction of End Bearing Drilled Piers.

ASTM A252 - Welded and Seamless Steel Pipe Piles.

UNIT PRICES

Design Pile Quantity: Determined by quantity of piles indicated in the Contract Documents.

Design Pile Length: Based on the length from point to cut-off elevation [of [____] ft ([____] m).] [as indicated.] Test Piles: [5] [____] ft ([1.5] [____] m) longer than design length piles.

Contract Pile Quantity: Determined by quantity of piles identified in the Project Record Documents.

Actual Pile Length: Determined by length of piles identified in Project Record Documents.

Adjustments in Contract Price will be made due to changes in number and length of piles, based on unit prices established in the Agreement as follows:

Contract Pile Quantity, and [_______________.]

Contract unit price per unit length including test piles, multiplied by the actual pile length. Base measurement on total linear measurement of piling from point to cut-off elevation, except for test piles calculated at [5] [____] ft ([1.5] [____] m) longer.

Determination of Unit Measurements: [Identified by site measurements and verified by the Architect/Engineer.] [________________.]

QUALIFICATIONS

Installer: Company specializing in performing the work of this Section with minimum [__________] years [documented] experience.

Design and select pier under direct supervision of a Professional Structural Engineer experienced in design of this work and licensed [at the place where the Project is located.] [in the State of [____________].]

PRE-INSTALLATION CONFERENCE

Convene [one] [_____] week prior to commencing work of this Section, under provisions of Section [01039.] [________.]

FIELD MEASUREMENTS

Verify that field measurements and survey benchmarks are as indicated on Drawings.

PART 2 PRODUCTS

MATERIALS

Shaft Liner:	ASTM A252, Grade [T1] [T1a] [T1b]; single length steel pipe, with [plain] [lapped] ends, of diameter and wall thickness indicated.

****** [OR] ******

Shaft Liner:	AASHTO M36, [____] inch ([____] mm) thick [corrugated] steel tube; of diameters [and weight per lineal foot (meter)] indicated. [Weld standard lengths to form required lengths.]

Concrete Materials and Mix: Specified in Section [03300] [________] using Type [____] cement, maximum [____] aggregate size, [____] psi ([____] MPa) 28 day strength, [____] inch ([____] mm) slump.

[Reinforcement: Specified in Section [03200] [________] [spiral wound].]

Equipment:	Appropriate to dewater excavated shaft.

PART 3 EXECUTION

EXAMINATION

Verify site conditions under provisions of Section [01039.] [________.]

Verify that site conditions will support equipment for performing pier and ramming operations[.] [and testing.]

PREPARATION

Use placement method which will not cause damage to nearby structures.

Notify adjacent and affected land owners and building occupants [with [____] days] notice before proceeding with the Work.

Protect structures near the Work, from damage.

INSTALLATION

[Construct piers in accordance with ACI 336.1.]

****** [OR] ******

Drill concentric and vertical pier shafts [and belled bases] [shear rings] to diameters and depths indicated.

[Place steel liners immediately after drilling. Set firmly in place.]

Clean shaft and bottom of loose material. Maintain shafts free of water.

Allow inspection of shaft [and liner] prior to placement of [reinforcement and] concrete.

[Place reinforcing steel in accordance with Section [03200] [________].]

Place concrete in accordance with Section [03300] [________] with equipment designed for vertical placement of concrete.

[Progressively raise shaft liner. Do not permit top of pile to deform to a mushroom shape.]

[Extend reinforcement] [Provide dowels] for connection of [caps.] [grade beams.]

TOLERANCES

Maximum Variation From Vertical: 1 in [48.] [____.]

Top Elevation: Maximum [4] [____] inches ([100] [____] mm) from elevation indicated.

FIELD QUALITY CONTROL

Field inspection will be performed under provisions of Section [01400.] [01410.] [________.]

Perform load tests to requirements of Section [02356.] [________.]

Test Piles: Same diameter and type as specified for other piling, placed in same manner.

Accepted test piles may [not] be used in the Work.

Accurately record the following:

Sizes, lengths, and locations of piers[.] [and footing groups.]

Sequence of placement.

Final base and top elevations.

Deviation from indicated locations.

UNACCEPTABLE PIERS

Unacceptable Piers: Piers that fail, are placed out of position, are below elevations, or are damaged.

Provide additional piers or replace footings failing to conform to specified requirements.

END OF SECTION