512.05 Basis of Payment.
PRESTRESSED CONCRETE BRIDGE MEMBERS
513.01 Description.
This Section shall cover the furnishing and installation of prestressed concrete bridge members. The required details of the members and the required details for the installation of the members in the structure will be shown on the plans.
513.02 Materials.
a.ALDOT Procedure . Material requirements for the production of precast prestressed concrete bridge mem bers are given in this Section and also in ALDOT -367 "Production and Inspection of Precast Non -Prestressed and Prestressed Concrete".
b.Reinforcing Steel and Prestressing Steel . Reinforcing steel and prestressing steel shall meet the requirements given in SECTION 835. Reinforcing steel shall be Grade 60 {Grade 420}. Prestressing steel strands and bars shall be the type shown on the plans.
c.Concrete Mixture Requirements .
1.General . The prestressed concrete producer shall establish the proportion of m aterials following the guidelines given in ALDOT -170, "Method of Controlling Concrete Operations for Structural Portland Cement Concrete" and ALDOT -367, “Production and Inspection of Precast Non -Prestressed and Prestressed Concrete”. The prestressed concrete producer shall submit the proposed concrete mixture proportions to the Materials and Tests Engineer for approval following the guidelines given in ALDOT- 170. The distribution of the approved concrete mixture shall be in accordance with the requirements given in ALDOT -170 and ALDOT -367. Any changes of the materials and/or proportions of the approved concrete mixture, excluding chemical admixture dosage, shall require a concrete mixture re- submittal and approval. The 28 -day compressive strength for prestressed concrete bridge members shall be 5000 psi {35 MPa} or the 28 -day compressive strength shown on the plans.
2.Conventional Concrete Mixture Design Requirements . The mixture design shall be based on the following requirements: MIXTURE DESIGN CRITERIA ALL MEMBERS Minimum Cementitious Factor (Lbs/Yd3) {kg/m3} 550 {330} Maximum Water/Cementitious Material Ratio 0.45 Maximum Slump (prior to admixture) (in) {mm} 4.0 {100} The maximum allowable total air content is 6.0 % by volume. The concrete mixture design shall be based on a target total air content of 4.5 %. Chemical admixtures may be used to increase the slump of the concrete to a maximum of 9 inches {225 mm} if this is proposed in the concrete mixture design submittal and approved for incl usion in the mixture. The approved water -to-total cementitious material ratio shall not be exceeded in order to increase the slump.
3.Self -Consolidating Concrete Mixture Design Requirements . Self-consolidating concrete (SCC) for the production of prestressed concrete members (including piles) shall meet the additional requirements of this Item. SCC is utilized to fill the formwork and encapsulate the reinforcing steel without, or with only minimal, applied vibratory consolidation. The concrete producer s hall establish the SCC mixture proportion in accordance with the guidelines given in ALDOT 170 with the exception that the producer shall determine the SCC mixture proportion to meet the required design properties given in the following table.
512.05 Basis of Payment.
REQUIRED DES IGN PROPERTIES OF THE SCC MIXTURE Properties shall be measured from a minimum size batch of 3 cubic yards {2 cubic meters}. Property Requirement Compressive Strength at 28 days The compressive strength shall be 5,000 psi {35 MPa} or the compressive strength shown on the plans. Cementitious Materials Content Minimum 600 lb/yd3 {355 kg/m3} of concrete. Water/Cementitious Materials Ratio Maximum 0.40. Nominal Aggregate Size Maximum ¾ inches {20 millimeters}. Fine/Total Aggregate Ratio 0.45 to 0.55 by volume. Total Air Content Maximum 6.0 % by volume. The design of the mixture shall be based on a target total air content of 4.5 %. Temperature Freshly mixed concrete temperature as limited in ALDOT- 367. Drying Shrinkage Maximum of 0.04 % after 28 days of drying. Slump Flow1 Minimum 25 inches {635 millimeters} and maximum 29 inches {735 millimeters}. Passing Ability1 Difference between slump flow and J -Ring flow 3.0 inches {75 millimeters} or less. Stability1 VSI 1.0 or less. Robustness Slump flow 29 inches {735 millimeters} or less and VSI 1.0 or less. NOTE: 1. Test shall be completed within 10 minutes after completion of mixing. Chemical Admixtures for the production of SCC shall be selected from List II- 1 of the Department’s "Materials, Sources, and Devices with Special Acceptance Requirements" Manual. Refer to Subarticle 106.01(f) and ALDOT -355 concerning this list. Approved viscosity modifying admixtures (VMA) may be used as a part of the chemical admixtures if they are shown in the approved mixture design.
4.Cementitious Materials . The cementitious materials used in the prestressed concrete m ixture shall meet the requirements given in Sections 806 and 815. Fly ash, ground granulated blast furnace slag, and microsilica can be substituted for a portion of portland cement. Various options of maximum percent allowable mineral admixture substitut ions for portland cement are defined in the following table. MAXIMUM PERCENT OF ALLOWABLE MINERAL ADMIXTURE SUBSTITUTION FOR PORTLAND CEMENT (BY WEIGHT) Substitution Option Class C or Class F Fly Ash Ground Granulated Blast Furnace Slag Microsilica 1 30 % - - 2 - 50 % - 3 - - 10 % 4 20 % - 10 % 5 20 % 30 % -
5.Special Requirements for Piles constructed in Severe Exposure Conditions . Piles constructed in a marine environment, within 10 miles {16 kilometers} from coastline, completely or partially submerged in seawater, located within the tidal and splash zones, exposed to seawater spray, exposed to brackish water, or as shown on the plans shall meet the requirements of this Item.
512.05 Basis of P ayment.
Cement for piles shall be Type II and thus low in tricalcium aluminate content . If requested by the Contractor and approved by the Materials and Tests Engineer, Type I or Type III cement containing a maximum of 8 % tricalcium aluminate may be used. Concrete mixtures used in piles shall hav e a maximum permeability of 2,000 coulombs. The concrete for piles shall contain Class "F" fly ash and microsilica as components of the cementitious material. The required percentage of fly ash and microsilica by weight {mass} of the total cementitious material content shall be as follows: CEMENTITIOUS MATERIAL CONTENT IN PILES Cement (Type II) 70 % Fly Ash (Class “F”) 20 % Microsilica 10 % Total Cementitious Materials Content 100 %
513.03 Construction Requirements.
a.Manufacturer's Plant, Laboratory and Personnel Requirements . The concrete bridge member manufacturing plant shall be certified by the Precast/Prestressed Concrete Institute (PCI) Plant Certification Program. Certification of the production plants shall be Category B4 (Prestressed Deflected Strand Bridge Members). The manufacturer shall submit proof of the plant certification to the Materials and Tests Engineer prior to the start of production. The manufacturing plant shall hav e on site, at the time of manufacturing bridge components for ALDOT, at least one technician that is certified as an ALDOT Concrete Technician. This technician shall also be certified as PCI Level I/II. The manufacturer shall submit proof of this certifica tion to the Materials and Tests Engineer prior to the start of production and during production when required by the Engineer. The manufacturer's laboratory and laboratory personnel shall be qualified in accordance with the requirements given in ALDOT -405, "Certification and Qualification Program for Concrete Technicians and Concrete Laboratories".
b.Shop Drawings and Notification of Manufacturer . The Contractor shall submit shop drawings to the Bridge Engineer for approval prior to production. The comple te details of prestressed concrete members shall be submitted as Shop Drawings in accordance with the requirements given in Article 105.02. The submittal shall include the proposed tensioning and de -tensioning procedures. Within 30 days after the award of the contract, the Contractor shall notify the Materials and Tests Engineer in writing of the name and address of the manufacturer of the prestressed concrete bridge members. The notification shall include the manufacturer's proposed fabrication schedule.
c.Concrete Testing . Sampling and testing shall be done in accordance with the requirements of ALDOT -367. The Department’s inspector will determine the point of sampling and testing schedule for each line of production. Sampling and testing shall be performed as close as possible to the casting bed in the presence of a Department inspector.
1.Conventional Concrete Testing Requirements during Production. Conventional concrete shall be in compliance with the requirements given in the following table during production.
512.05 Basis of Payment.
REQUIRED PROPERTIES OF CONVENTIONAL CONCRETE MIXTURES DURING PRODUCTION Property Requirement Compressive Strength at 28 days The compressive strength shall be 5,000 psi {35 Mpa} or the compressive strength shown on the plans. Temperature Freshly mixed concrete temperature as limited in ALDOT- 367 Total Air Content Maximum 6.0 % by volume. Slump Maximum 9 inches if chemical admixtures are used.
2.SCC Testing Requirements during Production . SCC shall be in compliance with the requirements given in the following table during production. REQUIRED PROPERTIES OF THE SCC MIXTURE DURING PRODUCTION Property Requirement Compressive Strength at 28 days The compressive strength shall be 5,000 psi {35 MPa} or the compressive strength shown on the plans. Temperature Freshly mixed concrete temperature as limited in ALDOT- 367. Total Air Content Maximum 6.0 % by volume. Slump Flow Minimum 25 inches {635 millimeters} and maximum 29 inches {735 millimeters}. Stability VSI 1.0 or less, or Sieved fraction 7.5 % or less for gradation with ½” nominal aggregate size or smaller, or sieved fraction 15% or less for gradation with ¾” nominal aggregate size. 1 NOTE: 1. The sieve fraction is determined by the Sieve Stability Test in accordance with ALDOT -452.
d.Camber of Girders and Bridge Deck Spans . The theoretical camber of girders will be shown on the plans. The camber of girders shall be a minimum of ½ inch {13 mm} at the time of shipment. The camber of span sections shall be a minimum of ¼ inch {6 mm} at the time of shipment.
e.Surface Finish . All surfaces shall, except as noted below in this Subarticle, have a Class 1 surface finish in accordance with the requirements given in Section 501. The outside of all exterior girders shall have a Class 2 surface finish in accordance with the requirements given in Section 501 if a Class 3 is not shown to be required on the plans. The final Class 2 finish shall not be applied until after the completion of the construction of the bridge deck on the girders. A Class 2 surface shall be applied to the final exposed surface of concrete piles if shown to be required on the plans. Girder top surfaces shal l be intentionally roughened with transverse grooves that penetrate the concrete surface to a minimum depth of ¼ of an inch {6 mm} spaced at no more than ½ of an inch (13 mm) in the hardened concrete. Riding surfaces, cast integrally as part of the precast member, for example in bridge deck span sections, shall be finished with either a wood float finish or with a broom finish done with a broom with medium to stiff bristles. A broom finish shall be applied in a transverse direction and shall penetrate the surface approximately ⅛ of an inch. Surfaces of precast bridge deck span sections that will be bonded to an overlay shall be raked in a transverse direction to provide a roughened surface for the application of the overlay. The roughened surface shall ha ve a minimum of ¼ inch {6 mm} ridges raised in the hardened concrete.
512.05 Basis of Payment.
f.Handling, Storing, and Transporting Members . The Contractor shall be fully responsible for handling, storing and transporting prestressed concrete bridge members in a manner that wil l prevent damage to the members. Girders shall be handled and stored in an upright position. Lifting hooks or similar devices for lifting shall be placed at points close to each end of each member or at the locations shown on the plans. Devices shall be of sufficient strength and embedment to provide safe handling of the members. Blocking under units during storage and handling shall be placed to prevent damage. Piles shall be lifted, stored, transported, and placed in the pile driving leads in a manner tha t will eliminate the possibility of damaging bending stresses, cracking and spalling. Piles shall be lifted by means of a suitable bridle or sling attached to the pile at pickup points designated on the plans. Cracked piles will be rejected and shall be im mediately removed and replaced without additional compensation. All prestressed concrete bridge members except piles shall be held at the plant for a minimum of 4 days after casting. Piles shall be held at the plant for a minimum of 21 days after casting . All prestressed concrete bridge members shall not be transported until the minimum 28 -day compressive strength is obtained and verified by test cylinders.
g.Installation of Prestressed Concrete Members .
1.Damaged Members . Members that are damaged in any way shall be replaced or repaired without extra compensation.
2.Prestressed Concrete Girders . Prestressed girders shall be lifted by attachment at the lifting points shown on the shop drawings. Girders shall be supported a t the bearing points shown on the plans when they are put into the structure. The Contractor shall be fully responsible for the stability of the girders during construction. The Contractor shall submit working drawings in accordance with the requirements given in Article 105.02 for temporary bracing installed to provide stability for the girders.
3.Installation of Deck Span Members . Deck span members that will not be covered by an overlay shall be installed so that the difference in the top surface of adj acent members does not exceed 1/4 of an inch {6 mm}. Deck members shall be replaced without extra compensation if the difference in the surface is not within the allowable 1/4 of an inch {6 mm} difference. Members not meeting the installation tolerance may be installed in other locations in the structure if this results in an acceptable deck surface. Deck span members shall be bolted together as shown on the plans to provide snug tight fit. Beveled washers shall be provided if the flat washers, bolt heads a nd nuts are not in full bearing on each other after tightening. Snug tight is defined as the tightness that can be produced by one or two solid blows from an impact wrench or by full effort of a person using an ordinary 2 foot {610 mm} spud wrench. The thr eads of the bolts shall be burred to prevent removal after the members have been acceptably bolted together. At the completion of the bolting together of the members, the concrete keyway shall be filled with a 1:2:3 concrete mixture, by weight {mass}, of cement, fine aggregate, and coarse aggregate, respectively. The maximum size of the coarse aggregate shall be 3/8 of an inch {9.5 mm}, and the maximum amount of water allowed shall be 6 gallons per 100 pounds {1 liter per 2 kg} of cement. The keyways shall be filled in accordance with the following: • Standard mixing of the concrete shall be completed a minimum of 45 minutes in advance of placement; • The mixture shall be retempered by remixing the concrete without additional water just prior to placing; • The co ncrete mixture shall be placed in the keyway, tamped, and packed as necessary to insure complete filling of the joint; • The exposed surface of the newly placed concrete keyway shall be struck to the same elevation as the adjacent deck sections; • The surface shall be given a wood float finish. • The concrete keyway shall be cured as per Subarticle 501.03(j).
h.Placement of Cranes on Bridge Decks . Cranes shall not be placed on a bridge deck unless approved by the Engineer. The Contractor shall submit a placeme nt plan for review prior to placing a crane on a bridge deck. The placement plan shall be submitted in accordance with the requirements given in Section 510.
512.05 Basis of Payment.
513.04 Method of Measurement.
a.Item No. 513-A. Girders will be measured per each girder of eac h type and length.
b.Item No. 513-B. Each type of girder will be measured per linear foot of casting length shown on the approved shop drawings minus the length of elastic shortening and shrinkage. This will be the length recorded on the Shipping Notice (BMT -139) prepared by the Department's Plant Inspector. A copy of BMT- 139 shall be sent with the shipment of the girders.
c.Items 513-C and 513 -D. Concrete span sections will be measured per each type and size.
513.05 Basis of Payment.
a.Unit Price Coverage .
1.Items 513- A and 513- B. Concrete girders will be paid for at the contract unit price for each type of girder. This price shall be full compensation for furnishing all materials, accessories, tools and labor necessary to manufacture and install the girders. This price shall also be full compensation for premolded bituminous filler, for all items cast into the concrete including metal bearing plates and studs welded to these plates, and for obtaining a Class 2 surface finish on the outside of all exterior girders.
2.Items 513- C and 513- D. Concrete deck span sections will be paid for at the contract unit price for each type and size. This price shall be full compensation for furnishing all materials, accessories, tools and labor necessary to manufacture and install the span sections. This price shall also be full compensation for all items cast into the concrete, for the tie bolts, for expansion and bearing materials, for cover concrete over fittings, for grout and grouting, for placement of keyways, and for surface finishing. Other structural steel items and handrail will be covered under other items of work.
3.Partial Payment . Partial payments will be made in accordance with the following schedule: • Fabrication and delivery to approved stora ge site. (Approved storage sites and partial payment for stored materials are addressed in Article 109.07); • Erected and the required finish applied to girder units or the bolting up and casting o f Keyway on Deck Units - 100%. Partial payments for members t hat are unacceptable because of damage, improper installation or any other reason will be recovered by the Department on the next monthly estimate or final estimate, whichever is applicable.
b.Payment will be made under Item No .: 513-A * Pretension ed-prestressed Concrete Girders, Type ** (SPECIALTY ITEM) - per each 513-B Pretensioned -prestressed Concrete Girders, Type ** (SPECIALTY ITEM) - per linear foot {meter} 513-C Prestressed Concrete Interior Span Sections, ____ Wide by ____ Deep by ____ Long (SPECIALTY ITEM) - per each 513-D Prestressed Concrete Exterior Span Sections, ____ Wide by ____ Deep by ____ Long (SPECIALTY ITEM) - per each * Length ** Type I, II, III, etc.
515.02 Materials.
SECTION 515 WATERPROOFING AND DAMPPROOFING
515.01 Description.
a.General . This Section shall cover the work of furnishing and applying a waterproofing or dampproofing surface to concrete in accordance w ith the methods prescribed for the several classes of waterproofing or dampproofing described below, each to be applied where called for on the plans and in conformity with the requirements of these Specifications.
b.Methods . The following four classes of waterproofing and one of dampproofing are covered by these Specifications:
1.Class A Waterproofing . Prime coat, mop coat of hot asphalt, and 2 alternate layers of fabric and moppings of hot asphalt.
2.Class B Waterproofing . Prime coat, mop coat of hot asphalt, and 2 alternate layers of fabric and moppings of hot asphalt with a mortar protection course.
3.Class C Waterproofing. Prime coat, mop coat of hot asphalt, and 2 alternate layers of fabric and moppings of hot asphalt with an asphalt plank protection course.
4.Class D Waterproofing . Manufactured waterproofing products.
5.Dampproofing . Prime coat and 2 mop coats of hot asphalt.
515.02 Materials.
a.General . All materials shall conform to the provisions of Division 800 , Materials. Specific reference is made to the following: Section 802, Fine Aggregates. Section 805, Mineral Filler. Section 815, Cement.
b.Primer . Primer used with asphalt mop coats shall meet the requirements of ASTM D 41.
c.Mop Coat . Asphalt for mop coat shall meet the requirements of ASTM D 449, Type I, II, or III as designated by plan details; however, unless otherwise designated, Type II shall be used.
d.Water Proofing Fabrics . Waterproofing fabric shall be woven cotton fabric meeting requiremen ts of ASTM D 173.
e.Asphalt Plank . Asphalt plank shall be in accordance with requirements of ASTM D 517.
f.Class D Waterproofing Materials . All Class D Waterproofing materials furnished by the Contractor for use shall be listed on List II - 10, WATERPROOFING MATERIALS, of the Department's "Materials, Sources, and Devices With Special Acceptance Requirements" Manual. Refer to Subarticle 106.01(f) and ALDOT- 355 concerning this list.
Source: Alabama Standard Specifications for Highway Construction, 2022 Edition. Pages 378–383 of 934.