Immediately after completion of the concrete pour, the metal conduit shall be blown out with compressed oil free air to the extent necessary to break up and remove any mortar in the conduit before it hardens. Approximately 24 hours after the concrete pour, the metal conduits shall be flushed out with water and then blown out with compressed oil free air. Prior to placing forms for roadway slabs of box girder structures, the Contractor shall demonstrate to the satisfaction of the Engineer that all ducts are unobstructed and if the prestressing reinforcement has been placed, that the steel is free and unbonded in the duct. After the tendons have been stressed to the required tension, each conduit encasing the prestressing steel shall be blown out with compressed oil free air. The conduit shall then be completely filled from the low end with grout under pressure. Grout shall be pumped through the duct and continuously wasted at the outlet until no visible slugs of water or air are ejected and the efflux time of ejected grout is not less than 11 seconds. All vents and openings shall then be closed and the grouting pressure at the injection end shall be raised to a minimum of 100 psi (689 kPa) and held for a minimum of 10 seconds. If aluminum powder is used to expand the grout, it shall be added as follows: From 2 to 4 grams of the unpolished variety (about 1 to 2 teaspoons) shall be added for each sack of cement used in the grout. The exact amount of aluminum powder will be designated by the Engineer. The dosage per batch of mortar shall be carefully weighed. A number of weighings may be made in the laboratory and doses placed in glass vials for convenient use in the mix. The aluminum powder shall be blended with pumicite or other inert powder in the proportion of 1 part powder to 50 parts pumicite (or other inert powder) by weight. The blend shall be thoroughly mixed with the cement and sand before water is added to the batch to prevent the blend from floating in the water. The amount of the blend used should vary from 41⁄2 ounces (0.128 kg) per sack of cement for concrete having a temperature of 70° F. (21 t°c) to 7 ounces (0.198 kg) for a temperature of 40° F. (4 t°c). After all ingredients are added, the batch shall be mixed for 3 minutes. Batches of grout shall be placed within 45 minutes after mixing. 553.20 Unbonded Steel. Where the steel is not to be bonded to the concrete, it shall be carefully protected against corrosion by a coating of tar or other waterproofing material, in addition to any galvanizing which may be specified in addition to the requirements of ASTM A 416 (AASHTO M 203) and ASTM A 421 (AASHTO M 204). 553.21 Handling. Extreme care shall be exercised in handling and moving precast prestressed concrete members. Precast girders and slabs shall be transported in an upright position and the points of support and directions of the reactions with respect to the member shall be approximately the same during transportation and storage as when the member is in its final position. If the Contractor deems it expedient to transport or store precast units in other than this position, it shall be done at his own risk after notifying the Engineer of his intention to do so. Care shall be taken during storage, hoisting, and handling of the precast units to prevent cracking or damage. Units damaged by improper storage or handling shall be replaced by the Contractor at his expense. 553.22 Placing. Precast prestressed concrete piling shall be placed in accordance with the requirements for precast concrete piling in Section 551. Other precast prestressed structural members shall be placed in the structure in conformity with the plans and special provisions governing the particular type of structure to be built. Method of Measurement 553.23 Structural Members. The quantity to be measured for payment will be the actual number of precast prestressed concrete structural members, except piling, of the several types and sizes, installed in place, completed and accepted. Each member will include the concrete, reinforcement and prestressing steel, enclosures for prestressing steel, anchorages, plates, nuts, and other such material contained within or attached to the unit. Piling will be measured as provided in Section 551. Lump-sum measurement will be in accordance with subsection 109.01. 553.24 Other Items. The quantities of other contract items which enter into the completed and accepted structure will be measured for payment in the manner prescribed for the several items involved. Basis of Payment 553.25 Structural Members. The quantity, determined as provided above, will be paid for at the contract price per unit of measurement or lump sum for the pay items listed below and shown in the bid schedule, which price and payment will be full compensation for the work prescribed in this section except prestressed concrete piling, which will be paid for as provided for in Section 551. 553.26 Other Items. The quantities of other contract items which enter into the completed and accepted structure will be paid for at the contract unit prices for the several pay items as prescribed for the items involved. Pay item 553(1) Prestressed structural concrete mem- 553(2) Prestressed concrete Pay unit Each. Lump sum. Section 554.-REINFORCING STEEL Description 554.01 This work shall consist of furnishing and placing reinforcing steel in accordance with these specifications and in reasonably close conformity with the plans. Materials 554.02 Materials. Reinforcing steel shall meet the requirements of subsection 709.01. Construction Requirements 554.03 Order Lists. Before ordering material, all order lists and bending diagrams shall be furnished by the Contractor for the approval of the Engineer, and no materials shall be ordered until such lists and bending diagrams have been approved. Approval of order lists and bending diagrams will in no way relieve the Contractor of his responsibility for ascertaining accuracy of such lists and diagrams. Revision of materials furnished in accordance with such lists and diagrams to meet compliance with design drawings shall be at the expense of the Contractor. 554.04 Protection of Materials. Reinforcing steel shall be protected at all times from damage by storing on blocking, racks, or platforms. Prior to placing concrete, reinforcing steel which is to be embedded, shall be free from heavy rust, dirt, mud, loose scale, paint, oil, or any other foreign substance. 554.05 Bending. All reinforcing bars requiring bending shall be bent cold and shall be bent in accordance with American Concrete Institute procedures unless otherwise detailed. Bars partially embedded in concrete shall not be bent except as shown on the plans or otherwise permitted. Qualified men shall be employed for cutting and bending, and proper appliances shall be provided for such work. 554.06 Placing and Fastening. In bridge decks, reinforcing shall be fastened at alternate intersections unless this results in ties being more than 12 inches (0.305 m) apart in which case each intersection shall be tied. The supports for reinforcing steel shall not be spaced more than 4 feet (1.22 m) apart transversely or longitudinally. The placement of deck reinforcing steel shall not deviate more than ± 1/4-inch (6.35 mm) in the vertical direction, from the position shown on the plans. Concrete shall not be placed in any member until the reinforcement placement has been approved. Splicing, except where shown on the plans, will not be permitted without the approval of the Engineer. Lap lengths shall be as shown on the plans Welding of reinforcing steel will not be permitted unless shown on the plans or authorized in writing by the Engineer. All welds shall conform to the requirements of AASHTO Standard Specifications for Highway Bridges. Metal supports which extend to the surface shall not be used. Placing bars on layers of fresh concrete as the work progresses and adjusting bars during the placing of concrete will not be permitted. Main reinforcement bars carrying determinate stresses shall be spliced only where shown on the plans or on approved shop drawings. The minimum spacing center-to-center of parallel bars shall be 21⁄2 times the diameter of the bar, but in no case shall the clear distance between the bars be less than 11⁄2 times the maximum size of the coarse aggregate. Bundle bars shall be tied together at not more than 6-foot (1.83 m) centers. All reinforcement shall have a clear coverage of 2 inches (51 mm) except as shown on the plans or specified herein. Method of Measurement 554.07 The quantity of reinforcing steel to be paid for on this contract shall be the quantity shown on the bid schedule, unless changes in design are made which affect this quantity, in which case the quantity in the bid schedule will be adjusted by the amount of the change for purposes of payment. If the bid schedule provides for a lump sum payment, no measurement for payment will be made. No measurement or payment will be made for splices added by the Contractor for his convenience. Whenever there are no bid schedule items provided for reinforcing steel, costs will be considered as incidental to other bid schedule items. Basis of Payment 554.08 The accepted quantities of reinforcing steel, determined as provided above, will be paid for at the contract price per pound or lump sum price, complete in place. No allowance will be made for clips, wire, or other material used for fastening reinforcement in place. Payment will be made under: Pay item 554(1) Reinforcing steel. 554(2) Reinforcing steel.. Pay unit Section 555.-STEEL STRUCTURES Description 555.01 This work shall consist of steel structures and the steel structure portions of composite structures, constructed in reasonably close conformity with the lines, grades, and dimensions shown on the plans or established by the Engineer. The work will include the furnishing, fabricating, erecting, and painting of structural metals called for in the special provisions or shown on the plans. Structural metals will include structural, rivet, welding, special, and alloy steels, metallic electrodes, steel forgings and castings, and iron castings. This work will also include any incidental metal construction not otherwise provided for, all in accordance with these specifications, plans and special provisions. Materials 555.02 Materials shall meet the requirements of the following sub 555.03 Shop Inspection. The contractor shall give the Engineer ample notice of the beginning of work at the mill or in the shop, so that |