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. (8-97) (FA 4-11-97) (REV 4-9-97)

SECTION 450

PRESTRESSED CONSTRUCTION

Index:

450-1 Description

450-2 Pretensioned Precast Prestressed Concrete

450-2.1 General

450-2.2 Quality Control/Quality Assurance Program

450-2.2.1 General

450-2.2.2 Definitions

450-2.2.3 Contractor's Quality Control

450-2.2.4 Department's Quality Assurance

450-2.2.5 Independent Assurance

450-2.3 Prestressed Plant

450-2.3.1 General

450-2.3.2 Approval

450-2.3.3 Plant Staff Organization and Qualifications

450-2.3.4 Measuring and Testing Equipment

450-2.4 Disapproval of Precast Prestressed Concrete Plants

450-2.4.1 Department's Conditional Status

450-2.4.2 Debarment

450-2.4.3 Contract Time Extensions and Claims

450-2.5 Materials

450-2.5.1 Concrete

450-2.5.2 Prestressing Steel

450-2.5.3 Strand Chucks and Splice Chucks

450-2.5.4 Reinforcing Steel

450-2.5.5 Accessories

450-2.5.6 Miscellaneous Materials

450-2.5.7 Material Acceptance and Testing

450-2.6 Construction

450-2.6.1 Shop Drawings

450-2.6.2 Inspection

450-2.6.2.1 General

450-2.6.2.2 Preplacement Operations

450-2.6.2.3 Concrete Operations

450-2.6.2.4 Postplacement Operations

450-2.6.2.5 Noncomplying Prestressed Members

450-2.6.2.6 Member Certification

450-2.6.3 Forms

450-2.6.3.1 Materials

450-2.6.3.2 Supports

450-2.6.3.3 Alignment

450-2.6.3.4 End Header Locations

450-2.6.3.5 Surface Conditions

450-2.6.3.6 Form Ties

450-2.6.3.7 Corners, Angles and Joints

450-2.6.3.8 Form Release Materials

450-2.6.4 Protection and Placement of Prestressing Steel

450-2.6.4.1 Protection of Prestressing Steel

450-2.6.4.2 Placing Prestressing Steel

450-2.6.4.3 Cleanliness of Prestressing Steel

450-2.6.4.4 Debonded Strands

450-2.6.5 Stressing Equipment

450-2.6.6 Stressing Operations

450-2.6.6.1 General

450-2.6.6.2 Single Straight Strand Stressing

450-2.6.6.3 Multiple Straight Strand Stressing

450-2.6.6.4 Draped Strand Stressing

450-2.6.6.5 Wire Breakage

450-2.6.6.6 Strand Chucks and Splice Chucks

450-2.6.6.7 Position of Prestressing Steel

450-2.6.7 Reinforcing Steel

450-2.6.8 Placing Other Embedded Material

450-2.6.8.1 Posttensioning Anchorages

450-2.6.8.2 Inserts and Lifting Devices

450-2.6.8.3 Bearing Assemblies

450-2.6.8.4 Void Forms

450-2.6.9 Concrete Operations

450-2.6.9.1 Temperature Restrictions

450-2.6.9.2 Placing Concrete

450-2.6.9.3 Vibration of Concrete

450-2.6.9.4 Inspection of Posttensioning Ducts

450-2.6.9.5 Finishing

450-2.6.9.6 Curing

450-2.6.10 Form Removal

450-2.6.11 Detensioning

450-2.6.11.1 General

450-2.6.11.2 Method of Stress Transfer

450-2.6.11.3 Trimming Strands

450-2.6.12 Noncomplying Prestressed Members

450-2.6.12.1 General

450-2.6.12.2 Surface Deficiencies

450-2.6.12.3 Cracks

450-2.6.12.4 Repair Methods and Materials

450-2.6.12.5 Submittal of Proposal to Accept or Sructural Deficiencies

450-2.6.12.6 Repairs Prior to Approval

450-2.7 Dimensional Tolerances

450-2.7.1 General

450-2.7.2 Tolerances

450-2.8 Handling and Storage

450-2.8.1 Handling

450-2.8.2 Storage

450-2.9 Shipping

450-2.10 Erection

450-2.11 Documentation

450-2.12 Measurement and Payment

450-2.12.1 General

450-2.12.2 Prestressed Piling (All Piling)

450-2.12.3 Prestressed Beams

450-2.12.4 Prestressed Slab Units

450-2.13 Method of Payment

 

SECTION 450

PRESTRESSED CONSTRUCTION

450-1 Description.

The work specified in this Section consists of fabricating, storing, transporting, and erecting precast prestressed concrete members prestressed by the pretensioning method. The requirements of Section 346, Section 400, Section 415, Section B460, and Division III, together with other applicable sections of the specifications covering specific construction items, shall also apply, except as modified herein.

450-2 Pretensioned Precast Prestressed Concrete.

450-2.1 General: Pretensioned precast prestressed concrete members are members prestressed by the pretensioning method. In this method, steel components are stressed and anchored; the concrete for the member is then cast and cured, and finally the stress in the steel components is released from the anchorages to the concrete through bond, after the concrete has attained its specified release strength. When members are prestressed by a combination of pretensioning and posttensioning, the applicable requirements of this Section shall apply to all the activities related to the fabrication of such members.

450-2.2 Quality Control/Quality Assurance Program:

450-2.2.1 General: The quality control/quality assurance program for precast prestressed concrete members is composed of the quality control activities performed by the Contractor and the quality assurance activities performed by the Department.

The Contractor is assigned the responsibility for controlling the quality of fabrication of precast prestressed concrete members in accordance with the requirements described herein, under the monitoring of the Department. The Contractor shall have a quality control plan (QCP) acceptable to and approved by the Engineer prior to commencement of any work.

450-2.2.2 Definitions: The quality control/quality assurance program is defined by the following:

Quality Control (QC): The activities performed by the Contractor to ensure that materials, methods, techniques, personnel, procedures and processes utilized during fabrication of precast prestressed concrete members are within the required limits.

Quality Assurance (QA): The activities performed by the Engineer to assure that the quality and acceptability of the precast prestressed concrete members are in accordance with this Section and the contract.

Independent Assurance (IA): The activities performed by the Engineer, the Federal Highway Administration, or any other local or State agency, who do not normally have direct responsibility for quality assurance. IA sampling and testing and IA procedures are normally used to determine reliability of QC and QA sampling and testing, and to evaluate fulfillment of QC and QA activities.

450-2.2.3 Contractor's Quality Control: The Contractor shall develop and implement a QCP with the objective of verifying that all materials and workmanship incorporated into the precast prestressed concrete members conform with the level of quality required by this Section. The Contractor's QCP shall also verify that the fabrication processes are controlled to assure that the finished member conforms to the physical characteristics and dimensions called for by the plans and this Section. The QCP shall be in sufficient detail to enable the Department to determine the adequacy of the plan. The plan shall also include a management statement of dedication to quality and to the QCP. The plan shall contain a schedule of frequencies of the sampling, testing, inspection, and documentation that the Contractor shall perform. As a minimum, the QCP shall address items listed below. The plan shall be submitted in writing to, and approved by, the Engineer prior to beginning fabrication. Modifications to the QCP shall be submitted for approval in the same manner.

A QCP will be approved by the Engineer for each project. Approval of the QCP will be extended on a project by project basis upon written request from the Contractor for all continuing work at a specific prestressed concrete plant, provided the materials, methods, techniques, procedures, processes and personnel qualifications utilized during fabrication of precast prestressed concrete members remain the same.

QCP General Format:

(1) General Information

Company Name, Address and Location

Plant Number, Address and Location (if different from above)

Plant Organizational Chart

Plant Personnel and Experience

General Manager

Production Manager

Plant Engineer

Quality Control Manager

Quality Control Inspectors and Technicians

Stressing Foreman / Yard Superintendent

Statement of Management Commitment to Quality Control

Department Approval of Plant

(2) Materials

Description of Testing Facilities to be Utilized for Materials Testing

Site Plan Detailing Material Storage and Handling Facilities

Sampling and Testing Frequencies of the Following Materials:

Concrete (In accordance with 450-2.5.7)

Miscellaneous Materials

Procedure for verifying steel products received are represented by certified test reports and that the material meets specification requirements.

(3) Inspection

Responsibility for Inspection Operations

Inspection of Pre-placement Operations

Control of Dimensions and Tolerances

Stressing Bed and Formwork

Positioning of Embedded Items

Size and Position of Reinforcing Steel and Welded Wire Fabric

Size, Position, and Condition of Prestressing Steel and/or Posttensioning Ducts

Stressing Operations

Inspection of Concrete Operations

Proportioning and Mixing of Concrete

Handling, Placing, and Consolidation of Concrete

Concrete Finishing

Concrete Curing

Inspection of Postplacement Operations

Detensioning and Stripping of Forms

Dimensional and Alignment Tolerances

Handling, Storage, Transportation

Member Identification

Repairs

Resolution of Non-Complying Issues

Concrete Sealing

(4) Procedures

Proposed Method of Duct Support

Temperature Changes

Procedure for adjusting stressing force for temperature differential

Procedure for heating, covering, insulating or housing concrete work during cold weather after casting and prior to detensioning

Procedure for protection of exposed strands between stressing headers or anchorages

Proposed location of thermocouples

Detensioning Procedures

Non-complying Members

Procedure for identification, evaluation and disposition of deficiencies

Repair methods and materials

QCP Review/Revision

Procedure to periodically address and correct repetitive noncompliance issues

(5) Acceptance and Certification of Members

Producers Stamp Configuration

Certification Statement

(6) Documentation

Material Acceptance

Pre-placement Inspection

Stressing

Placement Operation

Postplacement Inspection

Deficiencies

Repairs

450-2.2.4 Department's Quality Assurance: The Department will perform inspections, sampling, and testing to assure the quality and acceptability of the materials, methods, techniques, procedures and processes being utilized by the Contractor in the fabrication of precast prestressed concrete members. For this purpose, the Engineer will perform periodic assurance inspections, sampling and testing during, but not limited to, any of the following stages of fabrication:

(a) Prior to Tensioning

(b) During Tensioning

(c) Prior to Concrete Placement

(d) During Concrete Placement and Curing

(e) Prior to Detensioning

(f) During Detensioning

(g) After Detensioning

(h) Storage

(i) Prior to Shipment

The Department's Quality Assurance Program is reflected in the Department's Manual for Quality Assurance of Precast Prestressed Concrete Members.

450-2.2.5 Independent Assurance: In addition to quality assurance inspection, sampling and testing, the Department may perform independent assurance inspection, sampling and testing to provide independent monitoring of the fabrication process and the QC and QA activities. Independent assurance activities may be performed during, but not limited to, the stages of fabrication of precast prestressed members identified in 450-2.2.4. Results of the independent assurance inspections, sampling and testing will not constitute a basis for determining the acceptability of precast prestressed concrete members but will assist in the evaluation of the Contractor's quality control.

450-2.3 Prestressed Plant:

450-2.3.1 General: Initial Acceptance of a precast prestressed concrete plant will require approval of a QCP in accordance with 450-2.2.3 and compliance with 450-2.3.2, 450-2.3.3 and 450-2.3.4 below. A plant that fails to comply with these requirements will not be acceptable to produce precast prestressed concrete members for Department projects. A plant is defined as an independent operating facility capable of performing all the operations necessary to fabricate precast prestressed concrete members.

450-2.3.2 Approval: The precast prestressed concrete plant shall be approved prior to producing precast prestressed concrete members for Department projects. The Contractor shall make a written application with the Department for approval of the prestressed concrete plant. Application shall be made with the Department's District Materials Office for the District in which the plant is located. For out-of-state prestressed concrete plants, the Contractor shall submit the application to the District Materials Office for the District in which the construction project is located.

The approval status of any prestressed concrete plant may be a provisional approval reflecting only passing an initial inspection by the Department or a complete approval.

The approval process is intended to evaluate the plant's capability for fabricating quality members in accordance with established standards through a series of inspections, which include an initial in-depth inspection and subsequent unannounced spot inspections of the plant.

A plant will be approved by the Department for each project. Approval of the plant will be extended on a project-by-project basis upon written request from the Contractor for continuing work provided the plant has produced members for Department projects within 1 year prior to the request.

450-2.3.3 Plant Staff Organization and Qualifications: The plant's organization shall include, as a minimum, a full-time production manager and a full-time quality control manager at each plant. The plant shall have on staff a professional engineer registered in the state of Florida, or have on retainer a consultant engineer registered in the state of Florida. The plant engineer may serve as the quality control manager, unless the plant engineer has direct responsibilities for production. If the plant engineer has duties directly related to production, another registered professional engineer must be available for consultation by QC personnel relative to QC issues. The quality control manager shall report to the top management of the plant through a path independent of production.

The plant shall have sufficient qualified production personnel with prestressed concrete fabrication experience who are responsible for the complete fabrication process, storage and shipment of the members. The QCP shall include the work experience and qualifications of key plant production personnel and QC personnel such as the production manager, stressing foreman, yard supervisor, and quality control manager.

The quality control manager shall be a registered professional engineer or shall have at least 5 years of related experience and have a Prestressed Concrete Institute (PCI) Technician/Inspector Level II certification. A quality control inspector shall have, as a minimum, a PCI Technician/Inspector Level II certification. These requirements may be met by alternate experience and certification considered to be equivalent by the Engineer.

450-2.3.4 Measuring and Testing Equipment: The Contractor shall have a laboratory with the equipment necessary to perform required testing. All measuring and testing equipment shall conform to the applicable standards of the specifications. Measuring and testing equipment shall be on-site prior to its need and in working condition. The number of units shall be adequate to meet the production and testing schedule included in the QCP. Reserve equipment shall be available to replace equipment used in daily production in the event of breakdown. The reserve equipment shall be of the same type as the equipment being used.

450-2.4 Disapproval of Precast Prestressed Concrete Plants:

450-2.4.1 Department's Conditional Status: It will be the responsibility of the Contractor to take immediate and positive actions as applicable to resolve deficiencies in fabrication that result in failure to meet the contract requirements. A written explanation shall be submitted to the Engineer explaining how the Contractor proposes to resolve deficiencies noted by the Department. Any specification compliance deficiency detected prior to fabrication by the Contractor's QCP shall be corrected. Any deficiency detected after fabrication shall be resolved in accordance with 450-2.6.12. Failure to correct deficiencies in a timely manner or continued production of members with noted deficiencies will be justification for disapproval of the plant.

The Contractor shall have a procedure to periodically address repeating noncomplying issues with plant production personnel and require resolution of the issues through better production control. Such procedure shall be included in the QCP.

When a plant fails to maintain compliance with this Section and the contract, as evaluated by the Department, the plant may be placed in a conditional approval status for a period of time which will depend on the nature of the deficiency and the corrective action required. A plant may remain in a conditional approval status for a maximum period of 6 months. The plant will be removed from conditional approval status by the Department after the deficiencies are satisfactorily resolved. If the deficiencies are not resolved, the requirements of 450-2.4.2 shall apply. Approval of a plant that is in a conditional approval status will not be extended for a new project.

450-2.4.2 Debarment: Failure to maintain the Department's approval status will result in the debarment of the plant. Also, failure to take positive action to resolve deficiencies found by the Department's quality assurance activities will result in the debarment of the plant. Plants that have been debarred will not be allowed to fabricate any members for Department work. Members that have been fabricated prior to debarment of a precast prestressed concrete plant shall be subject to review by the Department for compliance with this Section and the contract, before shipment to the project site.

Debarment status will be removed by the Department upon satisfactory resolution of deficiencies that caused the debarment.

450-2.4.3 Contract Time Extensions and Claims: Contract time extension requests and claims for extra compensation will not be considered by the Department for the time and expense for the Contractor to resolve deficiencies or to retain another acceptable precast prestressed concrete producer when a plant is placed on a conditional or debarred status.

450-2.5 Materials:

450-2.5.1 Concrete: Concrete for all prestressed members shall be as specified in Section 346, as indicated on the plans or as modified by this Section or the specifications.

Concrete shall be produced in central mix plants approved in accordance with Section 346, unless otherwise permitted by this Section. Ready mix concrete produced in ready mix plants approved in accordance with Section 346 may be used if the following criteria are met:

Concrete shall be delivered to the placement site within a maximum of 20 minutes after the first addition of water to the mix.

When the concrete is produced in a central mix plant and malfunctions occur, concrete from any other local Department approved plant (either central mix or ready-mixed) may be used to complete any ongoing concrete placement of the entire bed line being cast without restrictions on delivery time as stated above. Concrete placement in other bed lines shall not resume until repairs to the central mix plant have been completed or approval to use another approved central mix plant or to continue using a ready mix plant has been obtained from the Department.

450-2.5.2 Prestressing Steel: Steel strands shall meet the requirements of 933-1. Strands from more than one source shall not be used in any individual prestressed element.

Steel bars shall meet the requirements of 933-2. Steel wires shall meet the requirements of 933-3.

The shipping package for prestressing steel shall be clearly marked stating that the package contains high-strength prestressing steel and indicating the care to be used in handling.

450-2.5.3 Strand Chucks and Splice Chucks: Strand chucks shall be capable of anchoring stressing loads positively and with a minimum of differential slippage. Strand chucks shall be designed for the size of strand used. Length of grips and configurations of serrations shall be such as to ensure against strand failure within the grips.

Splice chucks used to transmit the prestressing force from one partial length prestressing strand to another shall develop at least 90% of the minimum specified ultimate tensile strength of the prestressing steel.

450-2.5.4 Reinforcing Steel: Steel reinforcement shall conform to the requirements of 931-1.1, except as otherwise provided in the plans or this Section.

Welded deformed steel wire fabric for concrete reinforcement shall meet the requirements of 931-1.2.

450-2.5.5 Accessories: Bearing assemblies shall conform to the requirements of Section 962. Unless otherwise specified, bearing assemblies shall be coated in accordance with 962-7.

Inserts shall consist of miscellaneous items such as anchor bolts, threaded anchorages, conduits, pipes, wiring, built-in fixtures, and lifting devices. Inserts shall conform to the requirements shown on the plans or as approved by the Engineer. Aluminum inserts shall not be allowed.

Duct enclosures embedded in the concrete for prestressing steel shall meet the requirements of Section B460.

All sheathing (debonding material) shall be tubular non-slit, high-density polyethylene or polyprophylene with a minimum wall thickness of 0.025 inch, and having an inside diameter exceeding the maximum outside diameter of the pretensioning strand by 0.025 inch to 0.14 inch.

Silicone adhesive sealant used to seal sheathing tubes shall be a commercial adhesive sealant labeled as 100% silicone.

Void forms shall be of a type for which service adequacy has been demonstrated. Void forms shall have sufficient strength to provide stability during handling and placing and to withstand hydrostatic pressures and other forces imposed upon them during concrete placement. The form material shall be neutral with respect to the generation of products harmful to the physical and structural properties of the concrete. The Contractor shall retain responsibility for any detrimental effects resulting from the presence of the form material within the member. All voids shall be positively vented to the outside of the member.

Restraining devices for deflecting draped tendons shall be lubricated rollers with bronze bushings or roller bearings for hold-up points, and low-friction, free-turning rollers for hold-down points. The devices shall be of sufficient rigidity and have adequate support so that the position of the strand will remain unchanged under the induced load. The devices shall not induce friction to the tendons to the point of preventing attainment of the required jacking force and elongation.

The steel spirals for reinforcing in concrete piling may be manufactured from stock meeting the requirements of any grade of reinforcing steel, as shown in ASTM A 615, or hard-drawn wire.

450-2.5.6 Miscellaneous Materials: Membrane curing compound for curing concrete shall conform to the requirements of 925-2. Membrane curing compounds shall be compatible with coatings or other materials to be applied to the surfaces.

Epoxy resin compounds for application to Portland Cement Concrete shall conform to the requirements of Section 926.

Curing blankets shall be light colored polyethylene-coated blankets, quilted blankets of cotton, burlap, or other suitable water absorbent material (weighing not less than ten ounces per linear yard 40 inches wide), or insulated blankets.

Burlap shall conform to the requirements of 925-1.

Penetrant sealers used on concrete shall conform to the requirements of Section 413. The sealer shall be compatible with other materials to be applied to the concrete surface.

450-2.5.7 Material Acceptance and Testing:

(a) Concrete:

(1) Contractor Sampling and Testing: QC sampling and testing for concrete shall be the responsibility of the Contractor and shall be performed by the quality control inspectors. The sampling and testing of plastic concrete shall be performed after delivery to the casting site.

The water/cement ratio of concrete deliveries shall be verified for compliance with requirements. For each design mix, the concrete shall be sampled and tested for slump, air content, temperature and compressive strength, in accordance with the following, as a minimum for all concrete classes:

For Compressive Strength: Every 50 cubic yards or part thereof.

For Air Content, Slump and Temperature: Every 50 cubic yards or part there-of or at intervals not exceeding 1 hour.

The temperature, slump and air content of plastic concrete shall be checked on the initial load of each placement operation for verification of acceptance criteria.

If the initial concrete temperature is less than the maximum permitted placement temperature by more than 5 F, the concrete temperature shall be monitored and recorded at 1 hour time intervals for subsequent loads. During placement when concrete temperature is within 5 F of the maximum specified placement temperature every second load shall be checked for compliance.

The concrete placement operation shall not proceed until the concrete complies with specification requirements for plastic concrete. Noncomplying loads which cannot be adjusted to meet the specification requirements shall be rejected.

(2) Acceptance Sampling and Testing: Acceptance sampling and testing of concrete shall be the responsibility of the Department and shall be in accordance with Section 346.

(b) Reinforcing Steel and Welded Wire Fabric: All reinforcing steel and welded wire fabric shall be identified by LOTs. A LOT of reinforcing steel or welded wire fabric is a shipment of material that is from the same manufacturer and heat. A shipment of material is defined as a single vehicle load of material delivered to the plant. The Contractor shall obtain, and provide to the Department, a certified mill analysis and physical properties report showing compliance with 450-2.5.4 for each LOT of material received. The Contractor shall verify that the report represents the steel received and that the steel meets contract requirements.

Each shipment of reinforcing steel or welded wire fabric received by the Contractor shall be assigned a LOT number and shall be tagged in such a manner that each such LOT can be accurately identified at the plant or job site. The Contractor shall obtain records identifying assigned LOT numbers with the heat of the material represented. All unidentified reinforcing steel or welded wire fabric received at the plant or job site shall be rejected. Any material that cannot be positively identified prior to use shall be rejected.

Acceptance sampling and testing of reinforcing steel shall be the responsibility of the Department.

Acceptance sampling and testing of welded wire fabric shall also be the responsibility of the Department.

Members cast using material from a LOT that does not conform to the requirements shall be subject to evaluation in accordance with the applicable provisions of 450-2.6.12.1 and 450-2.6.12.5. The remainder of the material from the same LOT shall be rejected.

(c) Prestressing Steel for Pretensioning: All prestressing steel shall be identified by LOTs. A LOT of prestressing steel is a shipment of material that is the same size and production grade from the same manufacturer. A shipment of material is defined as a single vehicle load of material delivered to the plant. The Contractor shall obtain and provide to the Department for each LOT of material received, certified test values for specified material properties together with a representative load-elongation curve and the modulus of elasticity value based upon strand nominal area. Production tolerances applied in selection of the reported strand modulus shall also be provided and supported by records maintained by the strand manufacturer. The Contractor shall verify that documents provided represent the shipment and that the steel meets contract requirements.

Each shipment of prestressing steel received by the Contractor shall be assigned a LOT number and tagged in such a manner that each LOT can be accurately identified. The Contractor shall maintain complete records for each LOT identifying the material and its properties. All unidentified prestressing steel received at the plant or job site shall be rejected. Any materials that can not be positively identified prior to use shall be rejected.

Acceptance sampling and testing of prestressing steel shall be the responsibility of the Department. The Department shall select and obtain from the Contractor two 7 foot samples from each LOT of material received for testing. One of the samples shall be tested; the remaining sample, properly identified and tagged, shall be stored for future testing in the event of loss or failure of the first sample to meet minimum requirements. If the first sample fails to meet the requirements specified, the second sample shall be tested. If both samples fail to meet specified requirements, the heat or LOT of material shall be rejected and replaced with material meeting the requirements. If one sample fails and one sample meets the material requirements, additional tests may be performed by the Engineer to confirm material acceptability. Tests shall be performed to determine compliance with ASTM A 416.

Members cast using material from a LOT that does not conform to the requirements shall be subject to evaluation in accordance with the applicable provisions of 450-2.6.12.1 and 450-2.6.12.5. The remainder of the material from the same LOT shall be rejected.

(d) Strand Chucks and Splice Chucks: Acceptance of strand chucks and splice chucks shall be based on certified test results obtained by the Contractor showing compliance with 450-2.5.3.

(e) Steel Accessories: Acceptance of steel accessories shall be based on certified test results obtained by the Contractor. Accessory materials for prestressed concrete shall comply with the requirements of Section 933. Steel accessories which have not been pre-approved by the Department shall not be used until the Contractor obtains certified copies of pre-qualification tests which demonstrates satisfactory performance. Additional tests shall be performed by the Contractor when deemed necessary by the Engineer or when required by the plans.

(f) Ducts: The Contractor shall obtain material certifications for duct material certifying that the material meets contract requirements.

(g) Miscellaneous Materials: Acceptance of miscellaneous materials shall be based on certifications by the Contractor that the materials are adequate to function as intended. Miscellaneous materials which have not been pre-approved by the Department shall not be used until the Contractor obtains certified copies of pre-qualification tests which demonstrate satisfactory performance. Additional tests shall be performed by the Contractor when deemed necessary by the Engineer or when required by the plans.

450-2.6 Construction:

450-2.6.1 Shop Drawings: Plans for prestressed bridge members will designate the prestressing to be done by the pretensioning, posttensioning or combined methods. Plans for all precast prestressed concrete members will be detailed for at least one of these methods.

Information necessary to fabricate or erect precast prestressed concrete members that is not included in the plans furnished by the Department or this specification shall be furnished by the Contractor. Submission of shop drawings when required shall comply with 5-1 and any additional plan requirements.

When the design plans contain all the information necessary for fabrication of a pretensioned member, a formal shop drawing submittal is not required. Shop drawings will be required for members which are posttentioned or partially posttentioned. In order to fabricate precast pretensioned concrete members under this provision, all detailed and specified materials, dimensions, component types and sizes and methods of stressing and detensioning must be in strict accordance with the plans and this Section.

In lieu of formal shop drawings, one copy of the following shall be furnished to the Engineer for information only:

(a) A copy of the Framing Plan with member designations for all superstructure components

(b) Strand detensioning schedule

(c) Tensioning and elongation calculations

If the Contractor desires to use materials or methods that differ in any respect from those shown in the plans and described in this Section, he shall submit full plan details and specifications. In order for any alternate materials or methods to be considered, they will be required to comply fully with the intent of following:

(a) The provisions of these specifications

(b) The AASHTO Standard Specifications for Highway Bridges, edition with interims as referenced in plans

(c) The provisions of the Department's "Structures Design Guidelines"

(d) Design criteria and notes on the plans

(e) The recommendations of the material manufacturer

(f) Any materials change proposed by the Contractor and approved by the Engineer

The Engineer shall be the sole judge as to the adequacy and propriety of any variation of materials or methods, and the right is specifically reserved to the Engineer to reject at any time any alternate details or designs based upon the use of materials or methods which are not fully equivalent in all respects to those shown in the plans and described in this Section.

450-2.6.2 Inspection:

450-2.6.2.1 General: The Contractor shall be responsible for the QC inspections of all phases of work. The inspection frequency and depth shall be sufficient to assure that all materials and workmanship incorporated into the work conform to contract requirements and that the fabrication processes are controlled to assure that the finished product conforms to the physical characteristics and dimensions required by the contract. Responsibility for inspection operations shall be under the quality control manager. The quality control manager shall have an adequate number of quality control inspectors to assure review of all materials and fabrication processes. A review of the information obtained through QC inspections shall be discussed on a weekly basis with production personnel to identify fabrication areas that may need strengthening or modifying, or equipment that needs to be repaired or replaced.

Appendix VI in the Department's Manual for Quality Assurance for Precast Prestressed Concrete Members contains guidelines for inspecting precast prestressed concrete member fabrication. These guidelines may be used by the Contractor in developing the QCP inspection requirements.

450-2.6.2.2 Preplacement Operations: The quality control inspector shall routinely review the work operations performed to prepare a casting bed for concrete placement. Prior to concrete placement, the quality control inspector shall review the completed bed to verify all specification requirements have been met. The quality control inspector shall be notified far enough in advance of concrete placement to give the inspector sufficient time to make a review of the casting bed. Items in 450-2.6.3 through 450-2.6.8 shall be routinely inspected as the work is being performed and again prior to concrete placement.

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