DIVISION 13 SPECIAL CONSTRUCTION SECTION WIREWOUND, CIRCULAR, PRESTRESSED CONCRETE WATER TANKS

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1 DIVISION 13 SPECIAL CONSTRUCTION SECTION WIREWOUND, CIRCULAR, PRESTRESSED CONCRETE WATER TANKS PART 1 GENERAL 1.01 SUMMARY A. Section Includes: 1. The Contractor shall furnish all labor, materials, tools, and equipment necessary for the design, fabrication, erection, and inspection of one (1) wirewound, circular, prestressed concrete water tank (and its foundation) with no architectural features. Include all items not shown or specified but required for proper installation and operation of the equipment. 2. Contractor shall provide tank and foundation design as required herein. B. Related Sections include, but are not limited to: 1. Section Summary of Project. 2. Section Contract Considerations. 3. Section Measurement and Payment. 4. Section Submittals. 5. Section Site Piping. 6. Section Disinfection of Water System. 7. Section Cast-In-Place Concrete. 8. Section Process Pipe and Fittings REFERENCE A. Reference Standards include, but are not limited to: 1. ACI Specification for Structural concrete for Buildings. 2. ACI Building Code Requirements for Reinforced Concrete. 3. ACI Code Requirements for Environmental Engineering Concrete Structures and Commentary. 4. ACI Seismic Design of Liquid Containing Concrete Structures and Commentary. 5. ACI 372R - Design and Construction of Circular Wirewound Wrapped Prestressed Concrete Structures. 6. ACI 506R - Guide to Shotcrete. 7. ASTM A185 - Standard Specification for Steel Welded Wire Reinforcement, Plain, for Concrete. 8. ASTM A416 - Standard Specification for Steel Strand, Uncoated Sevenwire for Prestressed Concrete. 9. ASTM A475 - Standard Specification for Zinc-Coated Steel Wire Strand. 10. ASTM A586 - Standard Specification for Zinc-Coated Parallel and Helical Steel Wire Structural Strand. 11. ASTM A615/A615M - Standard Specification for Deformed and Plain Carbon-Steel Bars for concrete Reinforcement. 12. ASTM A821 - Standard Specification for Steel Wire, Hard Drawn for Prestressing Concrete Tanks

2 1.03 SUBMITTALS 13. ASTM A1008/A1008M - Standard Specification for Steel, Sheet, cold- Rolled, Carbon, Structural, High-Strength Low-Alloy, High-Strength Low- Alloy with Improved Formability, Solution Hardened, and Bake Hardenable. 14. ASTM C31 - Standard Practice for Making and Curing Concrete Test Specimens in the Field. 15. ASTM C33 - Standard Specification for Concrete Aggregates. 16. ASTM C39 Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. 17. ASTM C618 - Type F Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete. 18. ASTM C920 - Specification for Elastomeric Joint Sealants. 19. ASTM C Standard Specification for Packaged Dry, Hydraulic- Cement Grout. 20. ASTM D Standard Specification for Flexible Cellular Materials Sponge or Expanded Rubber. 21. ASTM D Standard Test Method for Density and Unit Weight of Soil in Place by the Sand-Cone Method. 22. ASTM D Standard Specification for Preformed Sponge Rubber and Cork Expansion Joint Fillers for Concrete Paving ad Structural Construction. 23. ASTM D Classification System for Rubber Products in Automotive Applications. 24. ASCE Standard Minimum Design Loads for Buildings and Other Structures. 25. AWWA C652 - Standard for Disinfection of Water Storage Facilities. 26. AWWA D110 - Wirewound, Circular, Prestressed Concrete Water Tanks, Type III. 27. US Army Corps of Engineers Specification CRD-C-572, Specification for PVC Waterstop. 28. Occupational, Health, and Safety Administration (OSHA) 29. American Welding Society 30. Uniform Building Code with Rapid City Modifications. A. Shop Drawings and Product Data: Submit, in accordance with Section 01300, detailed specifications, drawings, and data covering all materials, parts, devices, equipment, and other accessories forming part of equipment for the complete operational system. 1. Structural design calculations and detailed construction drawings, sealed by a Professional Engineer experienced in the design of AWWA D110, Type III wire-wound, prestressed concrete tanks and registered in the state of North Dakota. For Record Purposes Only. 2. Technical data including manufacturer s information, specifications, fabrication drawings, and installation instructions. 3. Shop drawings for mild reinforcement, formwork, prestressing systems, piping, appurtenances, waterstops, etc

3 4. Mill certificates for mild reinforcing, prestressing steel, and any other steel components. a. Indicate ultimate and yield strength for all steel components. 5. Concrete and shotcrete design mixes and placement procedures. 6. Tank surface finishes, coating materials, and color options. 7. Safety program. B. Manufacturer s Instructions: Furnish under provisions of Section 01300, manufacturer s printed instruction for delivery, handling, storage, assembly, installation, startup, adjusting, operation, and finishing as appropriate. C. Manufacturer s Field Service Reports: Furnish, under provisions of Section 01400, reports covering start up, demonstration, and instructions. D. Operation and Maintenance Data: Submit in accordance with Section on all parts, devices, equipment, and other accessories forming the complete operational system. E. Certificates: 1. Manufacturer s certification of proper installation and satisfactory performance. 2. Affidavits of Compliance for building codes and OSHA standards. F. Warranty: Two (2) year warranty QUALIFICATIONS A. Bidders as the Prime Contractor MUST be a Tank Supplier and have successfully completed in its own name a minimum of twenty (20) projects of similar size and complexity as this Project within the last ten (10) years with a minimum of ten (10) of those projects having been in service for at least five (5) years adhering to AWWA D110 Standard Type 3. Experience in the construction of AWWA D110 Type 1, 2 or 4 tanks is not acceptable. B. See Instruction to Bidders for additional contractor qualification requirements DESIGN REQUIREMENTS A. Tank: 1. Design in accordance with AWWA D110, Standards for Wirewound Circular Prestressed Concrete Tanks, Type III: Precast Concrete with a Steel Diaphragm. B. Characteristics: 1. Storage capacity: 2 MG 2. IWall diameter (I.D): FT. 3. Depth of tank: 30.0 FT. 4. Dome rise: 1:10 5. Finished floor elevation: FT. 6. Overflow elevation: 2318 FT. 7. High water level: 29.5 FT (overflow)

4 8. Floor slope: 1% (high point at floor perimeter). 9. Footing/ floor thickness: Per tank designer and in accordance with AWWA D110. Minimum thickness shall be 6-inches. 10. Minimum wall thickness: Per tank designer and in accordance with AWWA D Minimum dome thickness (including roof joints): 4 inches (for both castin-place and precast domes). 12. Overflow design capacity: 5,000 gpm. 13. Tamper proof tank venting; pipe penetrations, access hatches, and layout and piping shall be as shown in the Contract Documents. 14. Provision for pipe and appurtenance supports shall be made as required. The tank Contractor shall design, furnish, and install pipe supports and brackets attached to the tank. All supports on the tank interior shall be as detailed on the drawings. C. Foundation 1. It shall be the sole responsibility of the tank contractor to design and construct the tank foundation. This shall include retaining a professional Geotechnical Engineer registered in the state of North Dakota to conduct a subsurface investigation of the site. This investigation shall include the preparation of a geotechnical report, documenting the test methods, confirming the appropriate foundation type, providing the tank foundation design criteria and defining the needed foundation preparation. 2. The Geotechnical Investigation shall be in accordance with ACI 327R, Appendix A. The design criteria information in the report shall include the following: a. Subgrade elevation b. Allowable bearing capacity c. Total foundation settlement d. Differential foundation settlement e. Shrinkage/swell potential of subgrade soils f. Potential for liquefaction g. Seismic site class h. Slope stability i. Approximate existing surface elevation at each boring 3. The Geotechnical Engineer shall also inspect the exposed subgrade surface conditions after excavation and during compaction of the subgrade to confirm that the subgrade soils and/or rock are suitable to support the tank loadings. The Contractor shall submit the Geotechnical report, documenting testing methods and inspection reports to the Engineer. 4. For bidding purposes only, the Contractor shall assume the following criteria: a. A 6 membrane foundation system. b. Subgrade elevation will be ft. c. A minimum allowable bearing capacity of 3,000 psf. d. Maximum total foundation settlement of 2, differential foundation settlement less than the tolerable amounts provided within ACI 372R, Appendix A. e. Shrinkage/swell potential of subgrade soils less than ½. f. Potential for liquefaction does not exist

5 g. Seismic site class D per ASCE 7. h. Foundation drainage system is not necessary. 5. If the results of the geotechnical investigation and related testing indicate additional borings, foundation design, type, and/or preparation work is necessary, it will be recommended to the Engineer and paid for as a changed condition. D. Tank Design 1. Horizontal prestressing shall be continuous. Discontinuous prestressing tendons will not be allowed. 2. Backfill Pressure: Earth loads shall be determined by rational methods of soil mechanics. Backfill loads shall not be used in the design of the tank to counteract hydraulic loads or to reduce the amount of required prestressing. 3. The tank walls shall be considered as a cylindrical shell with partial edge restraint. 4. The tank walls shall be reinforced vertically by deformed steel rods. The continuous mechanically bonded steel diaphragm can be taken as effective vertical reinforcing. 5. The prestressed tank walls shall be of precast construction. Shotcrete or cast-in-place concrete core walls are not permitted. 6. Tank analysis and design shall take into account all required openings and penetrations through tank elements. A stress plate shall be required at all above grade locations where prestress wires are displaced 12- inches or greater. The stress plate shall be designed to transfer stress across the opening. 7. No reduction in ring compression or tension in the wall will be taken due to restraint at the bottom. 8. Floor slab shall be designed as a membrane floor and shall be place monolithically. No construction joints will be allowed unless otherwise approved by the Engineer. Minimum ratio of floor reinforcement area to concrete area shall be 0.8 percent. Wall footings may be above or below floor grade, but shall be placed monolithically with the floor. E. Loadings 1. Unit weight of contained liquid: 62.4 pcf 2. Elevation of backfill: 4 ft. a. Refer to Appendix A for geotechnical information for existing onsite reservoir. Geotechnical information for the site for the proposed tank will be provided by addendum. 3. Snow live loading on dome roof: 30 psf plus snow drift loading per IBC Wind loading on tank wall during construction: ASCE Design for lowest mean temperature variations including greatest water, soil, and air temperature differentials around the tank. 6. Design for an additional live loads for normal operations and maintenance operations. At minimum, this shall include up to eight people, 2,000 pounds of equipment, and tripod point loads at dome penetrations. The tank designer shall provide the Owner (via Shop Drawings and Record Drawings) with the maximum dome roof loading criteria for operations and maintenance activities

6 F. Geotechnical (Refer to Appendix A): 1. Design foundation in accordance with geotechnical report in Appendix B (to be added by Addendum). G. Vent capacity requirements: 1. Maximum fill rate: 5,000 gpm. 2. Maximum draw down rate: 5,000 gpm. H. Seismic: 1. In accordance with local code requirements. 2. Site Class C in accordance with IBC I. Minimum Concrete Cover: 1. Top cover for membrane floors: 2 inches. 2. Bottom cover for membrane floors: 3 inches. 3. Reinforced concrete exposed to earth, weather, or liquid: 2 inches. 4. Pre-stressed concrete exposed to earth, water, ambient air, or liquid: 1-½ inches. 5. Minimum concrete or shotcrete over steel reinforcement shall be 1-½ inches. J. No anchor penetrations shall be allowed on tank walls STORAGE AND PROTECTION A. Store and protect in accordance with Section REGULATORY REQUIREMENTS A. All Products that may come into contact with water intended for use in a Public Water System shall meet American National Standards Institute (ANSI)/National Sanitation Foundation (NSF) International Standards 60 and 61, as appropriate. A Product will be considered as meeting these standards if so certified by NSF, the Underwriters Laboratories, or other organization accredited by ANSI to test and certify each Product WARRANTY A. The tank contractor shall supply a written warranty for the tank structure against any defective materials or workmanship for a period of two years from the date of tank acceptance. 1. If any materials or workmanship, including piping and appurtenances, prove to be defective within the two-year period, they shall be repaired or replaced by the tank contractor at no additional cost to the Owner. 2. In case of leakage, Contractor shall promptly repair the tank at its own expense. Allowable leakage is defined herein

7 PART 2 PRODUCTS 2.01 ACCEPTABLE TANK CONTRACTORS A. Natgun Corporation; Wakefield, Massachusetts. B. Preload Company; Hauppauge, New York MATERIALS A. General Requirements: 1. Design and all materials shall comply with AWWA D110. B. Concrete 1. Concrete shall conform to ACI 301. Cement shall be Portland cement Type I or Type II. 2. Admixtures, other than air-entraining and water reducing admixtures, will not be allowed unless approved by the Engineer. 3. Concrete floor, footing, pipe encasement and all other work shall have a minimum 28-day strength of 3,500 psi and shall not be air-entrained. The aggregate shall meet the requirements of ASTM C33. Course aggregate shall have 100 percent passing the 1 ½ inch sieve and be No Fibers shall be Microfiber by Grace, Fibermesh 150 by Propex, or equal. Fiber lengths shall be a maximum of ¾ inches. The amount of polypropylene fibers added to the concrete mix shall conform to the manufacturer s recommendations. 4. Concrete floor shall incorporate superplasticizer and water-reducing to its mixtures. 5. Concrete for wall and dome roof construction shall have a minimum 28- day strength of 4,000 psi. All wall and dome concrete shall be airentrained. 6. Concrete in direct contact with prestressed reinforcement shall not contain water-soluble chloride ions in excess of 0.06 percent of the weight of the cement in the mix. C. Shotcrete 1. Shotcrete materials shall meet the requirements of ACI 506. Cement shall be Portland cement Type I or Type II. 2. The wet mix process shall be used for shotcreting. 3. Shotcrete wire coat used for covering intermediate layers of prestressing wire shall consist of not more than three parts sand to one part Portland cement by weight; additional coats of shotcrete shall consist of not more than four parts sand to one part Portland cement by weight. Polypropylene fibers shall be included in the shotcrete used for the finish covercoat. Fibers shall be Fibercast 500 by Propex, or equal. Fiber length shall be 1/4 inches. The amount of the fibers added to the shotcrete used for the finish covercoat shall conform to the manufacturer s recommendations. Fly ash may be incorporated into the finish covercoat as long as it conforms to ASTM C618, Type F

8 4. Shotcrete for tank construction shall not contain water-soluble chloride ions in excess of 0.06 percent of the weight of the cement in the mix. 5. Shotcrete shall have a minimum strength of 4,500 psi at 28 days. D. Mortar Fill and Non-shrink Grout 1. Mortar fill and non-shrink grout shall have a minimum compressive strength of 4,000 psi at 28 days. 2. Mortar shall consist of not more than three parts sand to one part Portland cement by weight. 3. Mortar in direct contact with prestressed reinforcement shall not contain water-soluble chloride ions in excess of 0.06 percent of the weight of the cement in the mix. 4. Non-shrink grout shall be of the nonmetallic type meeting all requirements of ASTM C1107 grade A or C. E. Prestress Wire for Circumferential Wrapping 1. Steel for prestressing wire shall be cold drawn, high carbon wire meeting the requirements of ASTM A821, having a minimum ultimate tensile strength of 210,000 psi. 2. Splices and anchor clamps for prestressing wire shall be ferrous material compatible with the wire and shall develop the full strength of the wire. 3. Where the tank surface is exposed to earth, weather, or liquid and less than 1.5-inches of concrete cover is provided; wire shall be galvanized per ASTM A586 (Table 4 for Class A coating). F. Reinforcement 1. Reinforcing steel shall be new billet steel conforming to ASTM A615, Grade Welded wire fabric shall conform to ASTM A Reinforcing steel shall be free from loose rust, scale, contaminants, and accurately fabricated. 4. Reinforcing steel shall be accurately positioned and shall be secured in place with wire ties or suitable clips. Rebar chair supports may be either steel or plastic. 5. The tank designer shall use base restraint cables to resist earthquake loads in the design when required. Seismic base restraint cables shall be hot-dipped galvanized seven-wire A416 prior to galvanizing, and ASTM A475 after galvanizing. 6. Nonprestressed reinforcement shall conform to the requirements of ACI The circumferential rebar shall be continuous between adjacent precast wall panels spaced vertically at 24 minimum. G. Steel Diaphragm 1. Vertically ribbed steel sheets with adjacent and opposing channels that shall provide a mechanical bond to the concrete. 2. Conform to ASTM A Diaphragm steel thickness shall be a minimum of inches. 4. Diaphragm sheets shall be continuous for the full height of the tank

9 H. Elastomeric Materials 1. Waterstops shall be of polyvinyl chloride meeting the requirements of the Corps of Engineers Specification CRD-C Plastic waterstops shall have a minimum ultimate tensile strength of 2,000 psi and ultimate elongation of 350 percent, and shore hardness of 70 to 80 durometer. 3. Neoprene or natural rubber bearing pads shall consist of minimum ultimate tensile strength of 1,500 psi, a minimum elongation of 500 percent and a maximum compressive set of 50 percent, and shall comply with the requirements of ASTM D2000 and a hardness of 30 to 50 Durometer. a. Natural rubber bearing pads shall contain only virgin natural polyisoprene as the raw polymer and the physical properties shall comply with ASTM D20000 Lime Call Out M 4 AA 414 A1. 4. Sponge filler shall be closed-cell neoprene or rubber conforming to the requirements of ASTM D Polysulfide sealant shall meet the requirements of ASTM C920 and shall have permanent characteristics of bonding to metal surfaces, flexibility, and resistance to extrusion due to hydrostatic pressure. Air-cured sealants shall not be used ACCESSORIES A. Provide the following accessories as shown on the Drawings: 1. Inlet/outlet piping penetrations. 2. Overflow piping and weir. 3. Drain sump and piping penetrations. 4. Dome roof hatch: 42-inch minimum square aluminum hatch with lockable hinged cover and curb frame. Locate hatch as shown on Drawings. 5. Ladder as shown. 6. Dome roof vent(s): a. Fiberglass mesh with stainless steel skirt and a minimum 24-inch diameter opening. b. Frost free operation. PART 3 EXECUTION 3.01 EXAMINATION A. Verify that Site conditions are ready to receive work and field measurements are as shown on Drawings CONSTRUCTION A. Install in accordance with AWWA D110, manufacturer s instructions, and shop drawings. B. The tank shall be constructed to the dimensions shown on the approved shop drawings

10 C. Footing and Floor Slab 1. Prior to placement of the floor reinforcing, a six mil polyethylene moisture barrier shall be placed over the base material. Joints shall be overlapped a minimum of 6 inches. 2. Prior to placement of the floor concrete, all piping that penetrates the floor shall be set and encased in concrete. 3. The minimum amount of mild steel reinforcement in the floor shall be 0.8 percent of the concrete area in each of two perpendicular directions. 4. The floor slab shall be designed as a membrane floor and shall be placed monolithically with the footing. 5. No construction joints will be allowed unless approved by the engineer. 6. The vertical waterstop shall be placed and supported so that the bottom of the center bulb is at the elevation of the top of the footing. The waterstop shall be supported without puncturing any portion of the waterstop unless it manufactured with holes for tying. The waterstop shall be spliced in a manner which provides complete continuity as a water barrier, and each splice shall be successfully spark tested prior to encasement in concrete. 7. The floor shall be cured by flooding with water, and shall remain saturated for a minimum of 7 days. 8. The floor slab shall receive a trowel finish. D. Precast Core Wall 1. The core wall shall be constructed of precast panels and vertical joints filled with shotcrete, mortar, or cast-in-place concrete. 2. Bearing pads shall be located and held in their proper position prior to erection of wall panels. Nailing of pads shall not be permitted. 3. Sponge filler pads shall be properly secured. All voids around the bearing pads and the sponge shall be caulked with an approved nontoxic sealant to prevent mortar seepage. 4. Wall and dome panel beds shall be located around the periphery of the tank as required. The beds shall be constructed to provide finished panels with the proper curvature of the tank. 5. The precast wall shall be constructed with a continuous waterproof steel diaphragm embedded in the exterior of the precast panel. The steel diaphragm shall be full length without horizontal joints. 6. Precast panel shall be fabricated to the curvature of the tank radius. The tolerance in panel wall thickness shall be -0 to + ¼ inch. Concrete for each panel shall be placed in one continuous operation. 7. The precast panels shall be erected to the correct vertical and circumferential alignment. The edges of adjoining panels shall not vary inwardly or outwardly by more than 3/8-inch and shall be placed to the tank radius within ± 3/8-inch. 8. Vertical diaphragm joints shall be mechanically seamed except where located between wall panels, in which case joints shall be sealed with polysulfide or other suitable sealant. All vertical diaphragms shall not be permitted except by design. 9. Joints between precast wall panels shall be bridged with a 10 gauge steel plate edge sealed with polysulfide or polyurethane and filled with mortar as shown on the drawings. No through wall ties will be permitted

11 10. Precast panel shall be covered with polyethylene sheet for curing, when the panel has sufficiently firmed. 11. The interior of precast wall panels shall receive a light broom finish. E. Prestressing 1. Prestressing wire will be placed on the wall with a wire-winding machine capable of consistently producing a stress in the wire within a range of minus 7 percent to plus 7 percent of the stress required by the design. A written record of stress readings shall be maintained. 2. If applied stresses fall below the design stress in the steel, additional wire will be provided to bring the force on the corewall up to the required design force. If the stress in the steel is more than 7 percent over the required design stress, the wrapping operation should be discontinued, and satisfactory adjustment made to the stressing equipment before proceeding. 3. No circumferential movement of the wire along the tank wall will be permitted during or after stressing the wire. Stressing may be accomplished by drawing the wire through a die or by another process that results in uninterrupted elongation, thus assuring uniform stress throughout its length and over the periphery of the tank. 4. Each coil of prestressing wire shall be temporarily anchored at sufficient intervals to minimize the loss of prestress in case a wire breaks during wrapping. 5. Minimum clear space between prestressing wires is 5/16-inch or 1.5 wire diameters, whichever is greater. Any wires not meeting the spacing requirements shall be replaced. Prestressing shall be placed no closer than two inches from the top of the wall, edges of openings, or inserts, nor closer than three inches from the base of walls or floors where radial movement may occur. 6. The band of prestressing normally required over the height of an opening shall be displaced into circumferential bands immediately above and below the opening to maintain the required prestressing force. Bundling of wires shall be prohibited. 7. A stress plate shall be used at all permanent wall penetrations above grade that results in displacement of wire equal to or greater than 12- inches in height. The stress plate shall accommodate portion of the prestressing wires normally required for the height of the opening. The remaining prestress wires normally required shall be displaced into circumferential bands immediately above and below the penetration. The effect of banded prestressing shall be taken into account in the design. 8. Ends of Individual coils shall be joined by suitable steel splicing devices capable of developing the full strength of the wire. Limit splices. F. Shotcreting 1. All shotcrete shall be applied by ACI certified nozzlemen. Comply with weather limitations per AWWA D110 and ACI placement requirements. 2. The steel diaphragm shall be covered with a layer of shotcrete at least ½- inch thick prior to prestressing

12 3. Each prestress wire shall be protected by a shotcrete wire coat of a thickness not less than ¼-inch and each individual wire shall be encased in mortar. 4. The outer wire layer shall be protected by the wire coat plus two or more additional coats of shotcrete, totaling at least 1-inch in thickness over the outer layer of wire. 5. Dust efflorescence, oil, and other foreign material shall be removed from surface to be shotcreted. The nozzle distance from the prestressing shall be such that shotcrete does not build up or cover the front face of the wire until the spaces behind and between the prestressing elements are filled. 6. Vertical wires shall be installed under tension and spaced no more than 3-feet apart to establish uniform and coating thickness. Monofilament line (100 lb. test) or 18 or 20 gauge high tensile strength steel wire shall be used guide wires shall be removed after placement of the covercoat. 7. All exposed shotcrete coating shall be kept moist for at least seven days. Moist curing shall be started as soon as possible without damaging the shotcrete. Curing shall be by fog spraying or sprinkling. Curing may be interrupted for subsequent application of prestressing and shotcreting. 8. Contractor shall test wall for hollow spots and repair any defective areas. G. Dome Roof 1. The dome roof shall be constructed to proper spherical curvature. Construction joints shall be located and configured to maintain an adequate strength. 2. The cast-in-place dome or the dome forms shall be designed to resist all forces acting with respect to its sloped surface. 3. Dome forms shall not be removed until the concrete has attained sufficient strength, and until the full circumferential prestressing force has been applied to the dome ring. 4. The exterior dome surface shall receive a coat of membrane-forming curing compound immediately after completion of the final finishing operation. 5. The dome roof shall be fixed to the tank wall in accordance with Type A or Type B shown in Figure 2, AWWA D The exterior dome surface shall be given a light broom finish. 7. Provided cementitious based damp-proofing and coatings for dome roof as specified in Section H. Backfilling 1. Backfilling shall not begin until the tank is complete and has passes watertightness test. 2. Refer to Appendix A for additional backfilling requirements. Consult with geotechnical engineer. 3. Maximum loose lift: 8-inches (and compact as required). 4. Heavy mechanical equipment shall not be allowed near perimeter wall. Roller equipment with operating weights less than 4,000 lbs shall be used for compaction near perimeter walls

13 3.03 INSPECTION A. Place no foundation concrete until soil approved by geotechnical engineer. B. Test concrete per Section Specifications. C. Slump, air content and temperature testing shall be performed on each truck where cylinders are taken. D. All concrete testing shall be in accordance with ASTM C31 and C39, at the expense of the contractor, and shall be conducted by an independent testing agency approved by the Engineer. E. Testing of shotcrete shall be in accordance with ACI 506, except as specified herein. One test panel shall be made for each of the following operations: corewall, cover, wire cover, and covercoat. Test panels shall be made from the shotcrete as it is being placed, and shall, as nearly as possible, represent the material being applied. The method of making a test sample shall be as follows: A frame of wire fabric (one foot square, three inches in depth) shall be secured to a plywood panel and hung or placed in the location where shotcrete is being placed. This form shall be filled in layers simultaneously with the nearby application. After 24 hours, the fabric and plywood backup shall be removed and the sample slab placed in a safe location at the site. F. The sample slab shall be moist cured in a manner identical with the regular surface application. The sample slab shall be sent to the testing laboratory. Nine three inch cubes shall be cut from the sample slab and subjected to compression tests in accordance with current ASTM Standards. Three cubes shall be tested at the age of 7 days, three shall be tested at the age of 28 days, and three shall be retained as spares. Testing shall be by an independent testing laboratory, approved by the Engineer and at the Contractor s expense CLEANING, DISINFECTION, AND TESTING A. The tank construction shall be complete and ready to be placed into service prior to cleaning, disinfecting, and testing. All hatches and vents shall be in place. During testing the tank access shall be kept locked, except during measurement of the water level, and security systems, and procedures in place to prevent contamination of the stored water. B. The contractor shall notify the Engineer prior to disinfecting the tank. Disinfection shall be in accordance with AWWA C652 and local regulations. C. Prior to placing the tank in service, bacteriological tests shall be taken, and successful results received. Testing shall be by an independent testing laboratory acceptable to Engineer and at the expense of the Contractor. D. Watertightness testing shall be completed prior to placement of any backfill over the wall footing to facilitate observation of criteria for walls and wall-floor joints

14 E. Watertightness testing procedures shall be in accordance with AWWA D110 with the exception that the net liquid loss, for a period of 96 hours, shall not exceed a loss of 0.05 of 1 percent of the tank capacity. 1. The Owner will provide water for the initial test at no cost. END OF SECTION