2405.01 DESCRIPTION.
Foundations and substructures shall consist of the bases or supports upon which the superstructure rests. They may consist of abutments and piers with or without piling or drilled shafts. The various types shall be constructed in conformance with the contract documents and with requirements of this section and various sections applying to the type of construction designated. The provisions of Sections 2401, 2402, 2403, 2404, 2408, 2414 and 2501 shall apply in addition to provisions of this section.

The requirements of this section shall not apply to culverts.

When the contract includes an item for Excavate and Dewater, the footings for piers shall be constructed in the dry using either steel sheet pile cofferdams and tremie concrete seal courses or other means of maintaining a dry excavation, as may be developed by the Contractor and approved by the Engineer. Water must not seep through the bottom of the excavation during placement of the footing concrete. Unbalanced water pressure must not be acting on the bottom of the footing during curing of the footing concrete.

Approval of the Contractor's recommended procedure shall not relieve the Contractor from responsibility to place the footing and pier concrete in the dry. The Engineer reserves the right to require the Contractor to provide cofferdams and tremie concrete seal courses if, during construction, the Engineer determines that the excavation cannot be satisfactorily dewatered by the Contractor's recommended procedure.

2405.02 CONSTRUCTION OF COFFERDAMS.
In construction of foundations and substructures, the cofferdams used shall be constructed in a manner capable of satisfactorily resisting earth and water pressure without appreciable displacement.

If submittal for review is designated in the contract documents or requested by the Engineer, the Contractor shall furnish details to show that the cofferdams will meet the requirements herein. The cofferdam plans, including the computations and drawings, shall be submitted in accordance with Article 1105.03. Work shall not be started prior to the receipt by the Contractor of the agreed upon plans. However, this review shall not relieve the Contractor of responsibility for satisfactory results and safety of the workers on the project.

Cofferdams shall be of steel sheeting of such length that it may be driven to a depth which will prevent unstable material from flowing into the excavation, and it shall form a safe and adequate cofferdam. Cofferdams shall be strongly braced, but bracing shall be placed so it will not be encased in the concrete of the structure, except as provided in the following paragraph and approved by the Engineer.

If the bracing is at elevations so that it will not be exposed in the finished structure, the bracing shall be cut off flush with the surface of the concrete. If the bracing is at elevations so that it will be exposed in the finished structure, the bracing shall be recessed and cut off at least 4 inches (100 mm) inside the face of the concrete. Pockets shall be formed around the bracing. These pockets shall then be neatly filled with concrete after the bracing is cut off. Small openings may be left in diaphragm walls and other thin sections to provide for cofferdam bracing, provided these openings are not located to interfere with the structural integrity of the structure and are located in places where they can be filled later in a satisfactory manner. Cofferdam bracing shall not be placed to bear against heavy concrete sections less than 3 calendar days old. In the case of thin sections or unfavorable weather conditions, this time may be increased at the discretion of the Engineer.

A clear space of at least 18 inches (0.5 m) shall be provided on all sides between the footing and the cofferdam. In no case, except for seal courses, shall the cofferdam be used as a form for the concrete footing. An independent form shall be built for the footing. The sheeting of the cofferdam shall be of such a type and shall be driven to prevent as nearly as possible the entrance of water through the walls of the cofferdam. Pumps of sufficient capacity shall be provided to keep the excavation free from water in accordance with Article 2403.15, until the concrete has reached initial set.

All excavated areas in and around cofferdams shall, after the foundation is in place, be backfilled to the original ground surface or streambed with materials meeting the provisions for the appropriate required regulatory permits. If additional material has been added adjacent to the pier sites, this material shall be removed to the ground line or streambed.

2405.03 SEAL COURSES.
If material encountered at the designed elevation of the bottom of the footing is so porous that water enters at a rate that it is impractical to lower the water level to this elevation by pumping, or if the material cannot be prevented from flowing into the excavation by driving sheeting to reasonable depths, the Engineer may require the Contractor to seal the cofferdam with concrete. The seal course shall be placed below the elevation of the bottom of the footing in the manner prescribed in Article 2403.15 and the cost of this work will be paid for in accordance with Article 1109.03.

After placement of the seal course, the cofferdam shall not be dewatered until test beams show a flexural strength of not less than 500 psi (3.5 MPa).

2405.04 FOOTINGS.
Footings shall be constructed as shown in the contract documents or as ordered in writing by the Engineer. Footings resting upon solid rock shall be anchored by extending the footing at least 6 inches (150 mm) into the solid rock, but adjustment in quantities will not be made for extending the dimensions horizontally beyond the neat lines shown in the contract documents. All loose boulders and fragments of rock shall be removed before the footing is placed.

Concrete shall not be placed in a footing until the Engineer has inspected and approved the depth of excavation and integrity of the foundation materials and has given the Contractor permission to proceed.

2405.05 CLASS OF CONCRETE.
All foundations and substructures shall be constructed of Class C structural concrete unless otherwise specified in the contract documents. Concrete in seal courses shall be Class X structural concrete (not air entrained) mixed with sufficient water to provide a satisfactory mix having a slump of not more than 8 inches (200 mm).

2405.06 PLACING CONCRETE.
The provisions of Section 2403 shall apply to all concrete placed in foundations and substructures. In reinforced concrete substructures, reinforcement extending into footings shall be securely fastened in position and shall be inspected by the Engineer before any concrete is placed. Suitable wood or metal forms shall be used to enclose all footing concrete, except for extension into rock as provided in Article 2405.04.

2405.07 CONSTRUCTION JOINTS.
In general, each footing shall be constructed as a monolith. If construction joints are required, they shall be made as specified in Article 2403.13.

2405.08 ICE BREAKERS.
Ice breakers shall be set true to alignment and with correct batter. The anchorage shall be in place before concrete is placed. The ice breaker shall be considered as a part of the substructure.

2405.09 ANCHOR BOLTS FOR BRIDGE BEARINGS AND FOUNDATIONS.

Anchor bolts shall meet the requirements of ASTM F 1554, Grade 36, and be full-length galvanized. Anchor bolts shall be Unified Coarse Thread Series and have Class 2A tolerance. The end of each anchor bolt intended to project from the concrete shall be color coded in blue to identify the grade. Washers shall be galvanized and shall meet the requirements of ASTM F 436. Nuts shall meet the requirements of ASTM A 563, DH, be heavy hex, and be galvanized. Nuts may be over-tapped in accordance with the allowance requirements of ASTM A 563. Galvanizing shall meet the requirements of ASTM A 153, Class C; or ASTM B 695, Class 50.

A. For Bridge Bearings.
Unless otherwise specified in the contract documents, anchor bolts to be embedded in concrete substructures shall be set in drilled holes. Anchor bolts shall be set prior to the time the concrete is placed, when specified in the contract documents.

1. Anchor Bolts Set in Drilled Holes.
Anchor bolts for bridge bearings shall be accurately set perpendicular to the plane of the bridge seat in clean, dry holes. The locations of anchor bolts in relation to slotted holes in expansion shoes shall be varied to compensate for the temperature of the structure. The nuts on anchor bolts at the expansion bearings of spans shall be adjusted to permit movement of the span with changes in temperature. Anchor bolts shall be set with a hydraulic cement or polymer grout.

When a hydraulic cement grout is used, it shall meet the requirements of Materials I.M. 491.13. The diameter of the hole shall be 1/2 inch (13 mm) larger than the bolt diameter, and the annular space shall be slightly overfilled with grout.

When polymer grout is used, it shall meet requirements of Materials I.M. 491.11. The diameter of the hole shall be 1/8 inch (3 mm) larger than the bolt diameter, and the annular space shall be filled with the grout in accordance with the manufacturer's recommendations and limitations, as approved by the Engineer.

2. Preset Anchor Bolts.
When the contract documents specify, anchor bolts for bridge bearings shall be set prior to placing concrete. The bolts shall be held firmly in a rigid template which spans the concrete with sufficient clearance to permit proper finishing of the surface of the concrete. Welding on anchor bolts will not be allowed. The Contractor shall obtain a template from the manufacturer/ fabricator for proper placement of the anchor bolts. The template shall remain in place until the concrete has hardened. Anchor bolts shall be set accurately at points specified in the contract documents and be plumb within 1/4 inch (6 mm) per 12 inches (300 mm).

B. For Foundations.
Welding on anchor bolts will not be allowed. The bolts shall be held firmly in a rigid template which spans the concrete with sufficient clearance to permit proper finishing of the surface of the concrete. The Contractor shall obtain a template from the manufacturer/fabricator for proper placement of the anchor bolts. The template shall remain in place until the concrete has hardened. Anchor bolts shall be set accurately at points specified in the contract documents and be plumb within 1/4 inch (6 mm) per 12 inches (300 mm).

2405.10 FINISH.
Surfaces of concrete foundations and substructures shall be finished as provided in Article 2403.21.

2405.11 PLACING SUPERSTRUCTURE.
The provisions of Article 2403.19 shall apply to the placing of superstructures on piers and abutments.

2405.12 RECONSTRUCTION OF SUBSTRUCTURES.
When the work involves reconstruction of an existing substructure, the Contractor shall submit detailed plans for supporting the superstructure in accordance with Article 1105.03.

The superstructure shall be securely shored or guyed at all times while it is raised off the substructure to prevent overturning or slipping from the temporary supports.

2405.13 PILE SUBSTRUCTURES.
When designated in the contract documents, the substructure will be constructed by driving piling for abutments and piers. All piles shall be driven in conformance with requirements of Section 2501. Earth approaches shall be supported laterally by sheet piling or by backing planks resting against the abutment piling. Wood, steel, and concrete construction in connection with pile substructures shall conform to requirements of Sections 2403, 2407, 2408, or 2409.

2405.14 METHOD OF MEASUREMENT AND BASIS OF PAYMENT.
For the quantities involved in foundations and substructures, the quantity will be measured and the Contractor will be paid as provided in the following sections:

Excavation for Structures. Section 2402 shall apply.
Structural Concrete. Section 2403 shall apply.
Reinforcement. Section 2404 shall apply.
Precast and Prestressed Concrete. Section 2407 shall apply.
Structural Steel. Section 2408 shall apply.
Timber and Lumber. Section 2409 shall apply.
Piles. Section 2501 shall apply.

These payments shall be full compensation for furnishing all materials, equipment, and labor and for performance of all work necessary to complete the substructure in conformance with the contract documents.

When the contract documents do not provide a separate price for Class X concrete, payment for this concrete when ordered by the Engineer will be as extra work. The quantity paid for shall be limited to that concrete placed within 18 inches (0.5 m) of the footing, as shown in the contract documents.

When the contract includes an item for Excavate and Dewater, payment will be made at the contract lump sum price each for Excavate and Dewater. This payment will be full compensation for all Class 20 and Class 21 excavation, cofferdams and tremie concrete seals, if used, costs of other procedures required to dewater the excavations, pumping, bailing and drainage, and all materials, work, labor, and equipment required to place the footings and piers in the dry, including the cost of furnishing design computations and drawings. Additional compensation will not be allowed for any delays resulting from compliance with the above requirements.