prestressed concrete tanks brochure

®

Introduction The Crom Corporation has been buildingPRESTRESSED CONCRETE TANKS since 1953. Our chief purpose is to provide a turnkey design and construction service stressing good workmanship, structural integrity, pleasing appearance, greatest economy and watertightness. CROM® tanks are known for superb longevity and low maintenance costs. This publicationdescribes our company and its operations. The tanks featured to the right have been in service for several decades.

COVER PHOTOS:

The Crom Corporation • 250 SW 36th Terrace • Gainesville, FL 32607 • Telephone (352) 372-3436 • FAX (352) 372-6209 • www.cromcorp.com

City of Selma, AlabamaThree Digester Tanks50’ x 33’Consulting Engineers:Rader & AssociatesBuilt in 1967

City of Ocala, FloridaThree Digester Tanks45’ x 24’3”Two Trickling Filters120’ x 7’11”One Final Sedimentation Tank40’ x 8’8”Consulting Engineers:Russell & AxonBuilt in 1955

Department of Veteran AffairsGainesville, Florida; Malcolm RandallVA Hospital750,000-Gallon Water Storage Tank42’ x 72’4” with dome and 650 GPM aeratorConsulting Engineers:Polyengineering, Inc.

Metro Water & Sewer DepartmentNashville, Tennessee10,000,000-Gallon Equalization Tank195’ x 44’10” with domeConsulting Engineers:Brown & Caldwell

City of Fernandina Beach, Florida1,500,000-Gallon Elongated Aeration Tank221’ long x 84’ wide x 11’9” highConsulting Engineers:Owner is Engineer

City of Belleview, FloridaBelleview WWTPTwo 600,000-Gallon SBR Tanks72’ x 21’Consulting Engineers:Barnes, Ferland & Associates, lnc.

1

2

1

2

3

4

��

��

��

��

��

��

1 2

3 4 5

1

2

Loudoun County Sanitation AuthorityAshburn, Virginia; Broad Run WRFTwo 620,000-Gallon Anaerobic Digesters50’ x 63’11” with conical roofsConsulting Engineers:CH2M Hill

5

®

History of Prestressed Concrete Tanks Circular prestressed concrete tanks have been in various stagesof development and perfecting for decades. Early systems used in theUnited States called for the use of cast-in-place concrete in the corewall of the tank and steel rods with turnbuckles as the prestressingelements. Although theoretically this approach to circumferentiallyprestressed concrete tanks was sound, deficiencies in placement ofconcrete together with insufficient residual compression in the corewall brought about modifications and improvements. In the early 1930’s, the matter was fully understood when J.M. Crom, Sr. began the development of what was later to become the COMPOSITE system of tank wall construction, using a steel shell cylinder with shotcrete encasement for the core wall, and high strength wire for the prestressing elements. Successors to Mr. Crom have over the years improved andperfected the COMPOSITE system for tank wall construction. Theseimprovements have included the selection of better constructionmaterials, together with ever-improving design and constructionprocedures. Consideration was given to:

Ready-mixed concrete and pneumatically applied shotcrete in combination with a steel shell diaphragm.

Rods, cables and high-strength wires for purposesof prestressing.

Emulsion type sealants, polysulphides, polyurethanes, and epoxies for sealing the steel shell diaphragm.

Wall base joints using conventional waterstops; special bearing pad and waterstop combinations; and monolithic floor-wall joint connections.

Emerging from all of these was the development of the prestressedCOMPOSITE wall system:

The steel shell diaphragm was found to be the mostfoolproof means for making the core wall watertight.

Shotcrete with its high cement factor and low water/cementratio had greater corrosion inhibition, impermeability andstrength than conventional concrete.

High-strength wire could be used to more accuratelyapply prestressing forces and could be better protectedfrom corrosion and mechanical damage.

In the early 1950’s, J.M. Crom, Sr. and three associates, Ted Crom,Jack Crom, Jr., and Frank Bertie, established The Crom Corporation,with headquarters in Gainesville, Florida, for the prime purpose ofperfecting the design and construction techniques for tanks withcomposite walls. Since then, their successors have continued thetradition of excellence initiated by the company’s founders. The company has constructed in its own name and with its ownforces over 4,000 circular and elongated PRESTRESSED CONCRETE TANKS.

•

•

•

•

•

•

•

®

(Left)Steel Shell Diaphragm

(Middle)Shotcrete

(Right)High StrengthPrestressing Wires

City of Gainesville, FloridaThree 5,000,000-Gallon Reservoirs160’ x 33’3” each.Tanks Built in 1968 & 1972:Consulting Engineers:CH2M Hill(formerly Black, Crow& Eidsness, Inc.)Tank Built in 1992:Consulting Engineers:CDM Smith (formerly Camp Dresser & McKee, Inc.)

In the due course of time, the features in the composite wall design using diaphragm, shotcrete, and high strength wire were incorporated in American Water Works Association Standard D110 “Wire- and Strand-Wound, Circular, Prestressed Concrete Water Tanks” anddesignated as “Type II core wall: Shotcrete with a Steel Diaphragm.” For all practical purposes, as we continue our description of CROM® tanks in this publication, the terms “Prestressed Concrete Tanks with Composite Wall” and “AWWA D110 Tanks with Type II wall” are synonymous.

History ...continued

®

Prestressed ConcreteTank Design - AWWA D110 Type II Composite Wall:“Shotcrete with a Steel Diaphragm” The Crom Corporation has developed tank technology with thefinest attributes:

Guaranteed WatertightnessStructural IntegrityGreatest EconomyBest Appearance

WATERTIGHTNESS Watertightness of the AWWA D110 Prestressed ConcreteTank with Type II Composite wall is made possible by combinedperformance of a steel shell diaphragm, shotcrete encasement, and wire prestressing. The steel shell extends continuously the full height of the tankwall, thus precluding by positive means any through-wall leakage. The diaphragm has no horizontal joints. The vertical joints whichconnect the steel shell panels are sealed by epoxy injection afterthe diaphragm is encased inside and outside with shotcrete.The corrugations in the steel cylinder, running in a vertical direction, provide a mechanical bond between the diaphragm and the shotcrete encasement. Mild steel reinforcement is included to resist bending moments, shrinkage, and temperature stresses. Circumferentialprestressing assures permanent ring compression in the tankcore wall.

STRUCTURAL INTEGRITY The Crom Corporation designs its structures under thesupervision of professional engineers; trains and certifies its keyemployees; selects and uses the best available construction materials; and adheres rigidly to high standards of quality construction.

ECONOMY Economy is a natural by-product of the AWWA D110 Prestressed Concrete design with Type II Wall – lesser quantities of materials and labor are utilized than is possible under conventional reinforcedconcrete design. Of greater significance is the quality of permanence inherent inthe construction materials used. Shotcrete is a durable, impermeable, high-strength building material whose long life under minimummaintenance procedures is universally recognized. Under most operating conditions, interior surfaces of the tank donot require painting. This is a major cost benefit. Exposed exteriorsurfaces are usually painted for beautification.

APPEARANCE In AWWA D110 Prestressed Concrete Tanks with Type II Walls,the soft texture of the shotcrete finish assures lasting beauty with a minimum of care. The low silhouette dome roof, pleasing in line and shape, completes the structure’s architectural appeal.

••••

•

•

•

•

®

Prestressed Concrete TankAWWA D110 Type II Composite Wall Design:“Shotcrete with a Steel Diaphragm”

®

Method of CompanyOperations The Crom Corporation is a highly specialized constructioncompany that devotes its efforts to engineering design andcomplete construction of PRESTRESSED CONCRETE TANKS.Its design/build operations include:

Tank Design

Reliable Preliminary Cost Estimates

Strict Specifications

Complete Tank Construction

Expert Workmanship

Five-Year Guarantee

••••••

TANK DESIGN The Crom Corporation assists the client by submitting, uponrequest, preliminary designs for the prestressed concrete tanksrequired for the project. Close coordination with the client permits early and accurateengineering decisions regarding tank dimensions, piping, sumps,launders and other appurtenances, including accommodationsfor equipment. This service is provided without cost or obligation. It ensures awell coordinated project from early design to full construction stage.

RELIABLE PRELIMINARYCOST ESTIMATES

As part of its service, The Crom Corporation offers reliablecost estimates at preliminary stages of design. This allows theconsulting engineer and the owner to evaluate the economy of the PRESTRESSED CONCRETE design in comparison with competing construction techniques. Preliminary estimates provided by The Crom Corporationare accurate and reliable. Within the limits of given time, projectconditions, general economic conditions and scope of workenvisioned, The Crom Corporation will not exceed its earlyestimate when the project is brought to the point of bidding.

®

•

•

STRICT SPECIFICATIONS The Crom Corporation adheres to the highest standards ofprofessional engineering and construction. Tank structures aredesigned and built in accordance with applicable sections of:

ACI 372 Design and Construction of Circular Wire andStrand Wrapped Prestressed Concrete Structures, publishedby American Concrete Institute.

AWWA D110 Wire- and Strand-Wound Circular,Prestressed Concrete Water Tanks; Type II Wall: Shotcrete witha Steel Diaphragm, published by the American Water Works Association.

Design drawings and calculations prepared by The CromCorporation will carry the seal of one of the company’s full-timeregistered professional engineers. The installations shown in thispublication are typical of tanks built under these strict specifications.

New Hanover County Water & Sewer DistrictWilmington, North CarolinaTwo 1,000,000-Gallon Finished Water Storage Tanks100’ x 17’6” with domeConsulting Engineer:Arcadis

Town of Braselton, GeorgiaTwo 1,200,000-Gallon Sequential Batch Reactors92’1” x 24’600,000-Gallon Aerobic Digester65’3” x 24’6”Consulting Engineer:Engineering Management, Inc.

Florida Power & Light Company5,000,000-Gallon Reclaimed Water Tank120’ x 59’2” with domeConsulting Engineer:Mathews Consulting, Inc.

®

COMPLETE TANK CONSTRUCTION The Crom Corporation provides a complete tank constructionservice. The company prefers no division of responsibility with respectto the tank structure itself. As a consequence, tanks are built totallyby The Crom Corporation, including wall footings, floor slab, circular wall, dome roof, and other such appointments as are required for thestructure. By avoiding a division of responsibility, the consultingengineer and the owner can proceed with confidence that the tankwill be built expertly and the responsibility for its performance willbe clearly shouldered by The Crom Corporation.

The floor of the prestressed tank is a heavily reinforcedmembrane concrete slab. This view illustrates placement of floorconcrete, reinforced with mild steel bars: a strong foundation.

Steel shell diaphragm is erected on a system of formworkespecially designed for this purpose. Steel shell extends continuously the full height of the tank to insure watertightness. To avoid jointsealing problems, no horizontal splices are allowed in the diaphragm. Vertical joints in the steel shell are sealed watertight by epoxyinjection.

Exterior encasement of the steel shell is accomplished with shotcrete, which is pneumatically placed concrete. The core wall of the tank is built up to its full thickness by applying successive layers of shotcrete.

The wall formwork has been removed and the inside face ofthe diaphragm is now encased with shotcrete. To insure goodworkmanship, all shotcrete nozzlemen are certified by the American Concrete Institute.

Vertical reinforcing bars are placed to design requirements and will later be encased in shotcrete. Once this encasement is complete, the tank wall is ready for epoxy injection of the vertical joints in the encased diaphragm.

Dome roof construction is undertaken with the aid of a system of forms made to the accurate curvature of the dome shell. Ordinarily, the dome has a rise from springline to apex of 1/10th the diameter of the tank.

1

2

3

4

5

6

®

1 2

3 4

5 6

®

EXPERT WORKMANSHIP A hallmark of The Crom Corporation business style is the highstandard of quality workmanship required of its field crews. Thecompany over a period of many years has thoroughly trained fieldconstruction personnel totaling more than 500 people who havebecome experts in tank construction. Unlike work in other fields,construction of tanks for water service is critical in that leakagecannot be tolerated. By constant control of its field operations, The Crom Corporationis able to guarantee the highest quality of workmanship in terms ofwatertightness, appearance, and dimensional accuracy of its structures. Because the company specializes in one area of construction, thehigh risk often associated with tank construction is overcome. Inspection of tanks built as early as 1953 indicates that thesevessels have endured the test of time and arduous service.

Once the roof formwork is completed with an overlay ofsheathing, reinforcement is placed.

The free-span dome roof is constructed of cast-in-placeconcrete. This view shows dome concrete being placed by thepumpcrete method.

Both the core wall and the free-span dome roof are circumferentially prestressed using high-strength steel wirewrapped around the tank in a continuous helix. Wall prestressingis designed to carry the tank’s hydraulic load, while dome ringprestressing resists the horizontal forces of roof live and dead loads.

To avoid over-stressing or under-stressing of the tank, thetension in the wire is accurately measured to within 2% accuracyby the use of a direct-reading electronic digital stressometer.

In order to afford complete protection for the prestressingelements, a shotcrete covercoat is placed over the wire, permanentlybonding the wire to the tank wall. Whenever two or more layersof prestressing steel are required, a flash coat of shotcrete separatesthe layers. Once the cover coat has been finished, the tank isstructurally complete.

Final stage of construction involves the erection of accessories and painting of the exterior surfaces for decorative purposes.

7

8

9

10

11

12

®

7 8

9 10

11 12

®

FIVE-YEAR GUARANTEE

The Crom Corporation guarantees workmanship and materialson the structural portion of its tanks for a five year period. If leakageor other defects appear within the five year period, The CromCorporation promptly makes repairs at its own expense uponwritten notice by the owner that such defects have been found.The tanks illustrated on these pages, like all structures built byThe Crom Corporation, carry this 5-year guarantee. It is common knowledge among consulting engineers and ownersthat representatives of The Crom Corporation frequently inspecttank installations long after they have been built in an effort to verifythat both the owner and the consultant continue to be pleasedwith the project. The Crom Corporation is available on short notice anywherein its area of operations for consultations or inspections.

Georgia Department of Water ServicesYellow River Water Reclamation FacilityLilburn, GeorgiaTwo 20,000,000-Gallon Equalization Tanks260’ x 52’6” with domesConsulting Engineers:Jordan, Jones & GouldingCH2M HillPrecision Planning, Inc.

City of Harrisonburg, VirginiaTower Street Reservoir8,000,000-Gallon Water Storage Tank140’ x 70’ with domeConsulting Engineers:Wiley/Wilson

City of Whiteville, North CarolinaWhiteville WWTP856,000-Gallon Sludge StorageTank92’ x 20’152,000-Gallon Aerobic Digester38’ x 20’Consulting Engineers:Green Engineering, PLLC

®

Hillsborough County Board ofCounty CommissionersTampa, FloridaTwo 5,000,000-Gallon Water Storage Tanks160’ x 33’3” with domesConsulting Engineers:AECOM (Formerly Boyle Engineering Corporation)

City of St. Cloud, FloridaNortheast Water Repump Station750,000-Gallon Water StorageTank85’ x 17’8” with domeConsulting Engineers:Reiss Engineering

Gwinnett County Board of CommissionersLower Big Haynes CreekPump StationLoganville, Georgia4,000,000-Gallon WastewaterEqualization Tank125’ x 43’8” with domeConsulting Engineers:Gresham Smith and Partners

City of Jacksonville Beach, FloridaFour 1,430,000-Gallon Sequential Batch Reactors97' x 28'Consulting Engineers:Waitz & Moye, Inc.

®

Typical Installations Water supply systems, wastewater treatment plants, and industrialinstallations create corrosive environments with varying degrees ofseverity. These facilities derive great benefits from the permanent andmaintenance-free nature of PRESTRESSED CONCRETE TANKS . Over 4,000 tanks have been built by The Crom Corporationranging in capacity from 25,000 gallons to 21 million gallons. These tanks are employed in applications virtually without limit.

Loudoun CountySanitation AuthorityAshburn, VirginiaTwo 1,800,000-GallonPermeate Tanks65’6” x 70’3” with domeConsulting Engineers:CH2M Hill

Stafford County Departmentof Public UtilitiesAquia WWTP – Stafford, VirginiaTwo Aeration Reactors154’ x 18’6”Secondary Clarifier175’8” x 15’4”Consulting Engineers:Parsons

Marion County Utilities DepartmentStonecrest Subregional WWTPSummerfield, FloridaOne of Two 1,117,000-Gallon Wastewater Package Treatment Tanks110' x 16'6”Consulting Engineers:GAI Consultants, Inc.

®

Water Reservoirs PRESTRESSED CONCRETE RESERVOIRS are usually built withfree-span dome roofs of concrete construction. Accessories, including ventilator, hatch cover, liquid level indicator, and interior ladder, are of fiberglass construction. Exterior ladder is fabricated aluminum. These features insure freedom from maintenance problems. All accessories use stainless steel fasteners throughout. The typical projects illustrated here exemplify the functional beautyof reservoirs built by the CROM® system.

City of Cape Coral, Florida12,000,000-Gallon Water Storage Tank210’ x 46’3” with domeConsulting Engineers:MWH Americas

Notla Water AuthorityBlairsville, Georgia500,000-Gallon Clearwell73’ x 21’2” with domeConsulting Engineers:G. Ben Turnipseed Engineers, Inc.

South Walton Utility Co., Inc.Walton County, Florida2,000,000-Gallon Water Storage Tank85’ x 47’4” with domeConsulting Engineers:Baskerville-Donovan, Inc.

®

Water Tanks with Aerators Reinforced plastic, widely known as fiberglass, is ideally suitedfor applications in water, wastewater, and industrial plants, wherecorrosion is a serious consideration. One such application is theaeration of water for removal of hydrogen sulphide using a natural draft tray aerator. Since aeration and storage of water are often complementaryoperations, installations which combine fiberglass aerators and CROM® PRESTRESSED CONCRETE TANKS are both attractiveand efficient. Because of the release of hydrogen sulphide gases during theaeration process, the non-submerged interior concrete surfaces of these tanks may be subject to corrosive attack, and should beprotected. This is often accomplished by poly-lining or coating the concrete surfaces above the high water line, or by exhaust fans, or by submerging the free-board surfaces (wall and roof) so as to achieve a self-washing effect. Periodic inspections should be made to evaluate the condition of these tanks.

City of KissimmeeSouthwest WTP2,000,000-Gallon WaterStorage Tank100’ x 34’1” with domeand 12,000 GPM AeratorConsulting Engineers:Jacobs

Southlake Utilities, Inc.Clermont, Florida1,000,000-Gallon Self-WashingWater Storage Tank80’ x 26’7” with flat roof and5,000 GPM AeratorConsulting Engineers:Sambamurthi Munipalli, P.E.

®

City of Haines City, FloridaTwo 500,000-Gallon Water Storage Tanks60' x 23'8" with domes and 5,000 GPM AeratorsConsulting Engineers:Envisors Consulting, LLC

Jacksonville Electric AuthorityJacksonville, FloridaCecil Commerce Center2,000,000-Gallon Water Storage Tank138' x 19' with dome and 20,000 GPM AeratorConsulting Engineers:MWH Americas, Inc.

Dauphin Island Water & Sewer AuthorityDauphin Island, Alabama1,000,000-Gallon Water Storage Tank80'4” x 29’ with dome and1,900 GPM AeratorConsulting Engineers:ADL/Constantine Engineering

®

Tanks with Architectural Treatment Utility, low maintenance costs, watertightness, and beautyare all attributes of PRESTRESSED CONCRETE TANKS built byThe Crom Corporation. Because of their proximity to sensitive residential or downtown neighborhoods, some installations demand superlative appearance. In these situations, CROM® PRESTRESSED CONCRETE TANKS witharchitectural treatment are ideal.

James City Service AuthorityWilliamsburg, VirginiaTwo 500,000-Gallon Water Storage Tanks55' x 28'2" with domesConsulting Engineers:AES Consulting Engineers/NICE Engineering

City of Tuscaloosa, AlabamaJerry Plott WTP1,000,000-Gallon Clearwell Tank90' x 24'5-1/2” with domeConsulting Engineers:CH2M Hill

®

Broward County Board of County CommissionersMiramar, Florida1,500,000-Gallon Water Storage Tank90' x 32'2" with domeConsulting Engineers:Hazen and Sawyer

City of Miramar, FloridaWeston Pump Station3,000,000-Gallon Water Storage Tank110' x 42'3” with domeConsulting Engineers:Tetra Tech

Knoxville Utilities BoardKnoxville, TennesseeMark B. Whitaker WTPTwo 4,000,000-Gallon Clearwells135' x 38'3" with domeConsulting Engineers:Burns and McDonnell

City of Boca Raton, Florida5,000,000-Gallon Reclaimed WaterTank155’ x 35’6” with domeConsulting Engineers:Mathews Consulting, Inc.

®

Vessels required in wastewater treatment plants includeequalization tanks, sludge digesters, effluent storage tanks, clarifiers, aeration tanks, SBR tanks, and package treatment tanks. Each of these provides an ideal application for the PRESTRESSED CONCRETEdesign, which permits economical construction and freedom fromthe usual corrosion problems encountered in wastewater treatment facilities. Installations depicted on these pages are representative of the superior structures built by The Crom Corporation.

(Left)Town of Chatom, AlabamaTwo 175,000-Gallon Sequential Batch Reactors36' x 23'One 75,000-Gallon Equalization Tank33’ x 11’6”Consulting Engineers:ADL, Inc./ConstantineEngineering, Inc.

(Right)Manchester, TennesseeOne 95,000-Gallon SludgeThickener Tank34’ x 14’Two 650,000-Gallon Anaerobic Digesters68’ x 24’One 750,000-Gallon Clarifier Tank89’ x 16’ (not shown)Consulting Engineers:Griggs & Maloney, Inc.

Tanks forWastewater Treatment

Emerald Coast Utilities Authority(ECUA)Cantonment, FLOne 3,000,000-Gallon Influent Equalization Tank140' x 28’Four 1,500,000-Gallon Clarifiers125’ x 16’6”Two 1,500,000-Gallon Sludge Storage Tanks120’ x 20’Two 2,150,000-Gallon Effluent Equalization Tanks110’ x 28’2” with domesTwo 10,000,000-Gallon Reject Storage Tanks260’ x 27’2”One 4,700,000-Gallon Effluent Equalization Tank156’ x 32’10” with domeConsulting Engineers:Baskerville-Donovan, Inc.

®

Paulding County Board of CommissionersHiram, Georgia470,000-Gallon Sludge StorageTank64' x 19'6"Consulting Engineers:Arcadis

Metro Water ServicesNashville, TennesseeFive 2,800,000-Gallon Anaerobic Digesters108’ x 40’6”Four 440,000-Gallon DAFT Tanks65’ x 17’7”Consulting Engineers:Earth Tech/Black & Veatch

City of OttawaOntario, CanadaTwo 3,300,000-Gallon ModifiedEgg-Shaped Anaerobic Digesters82'1/4” x 117’9-3/8” with conical floor and conical roofConsulting Engineers:CH2M Hill

Utilities Board of the City of Muscle Schoals, Alabama85,000-Gallon Pre-Aeration Tank30’ x 18’Consulting Engineers:Garver, LLC

®

More and more communities are utilizing municipally treated wastewater in an effort to augment their water supply. The Crom Corporation built its first reuse water tank in 1976 for Pinellas County, Florida. Consultants have recognized the advantages of CROM® PRESTRESSED CONCRETE TANKS ever since. CROM® tanks can be partially or fully buried, or easily embellished witharchitectural treatments. Along with in-plant installations, reuse tanks can be built within residential areas, or on golf courses, or on agricultural lands: wherever the demand for irrigation water is the greatest. Typical of such installations are the tanks pictured here: watertight, attractive, and permanent.

Tanks for Reuse Water

Primland ResortMeadows of Dan, Virginia500,000-Gallon Reuse WaterTank75’ x 15’8” with flat roof(left-tank under construction; right-finished installation )Consulting Engineers:Draper Aden Associates, Inc.

Pinellas County UtilitiesLargo, Florida5,000,000-Gallon Reuse Water Storage Tank155’ x 35’6” with domeConsulting Engineers:Parsons Engineering Science, Inc.

Florida Power & Light CompanyWest Palm Beach, Florida3,000,000-Gallon Reclaimed Water Tank160' x 20’ with domeConsulting Engineers:Jordan, Jones & Goulding, Inc.

®

City of Tavares, Florida5,000,000-Gallon ReclaimedWater Tank160’ x 33’3” with domeConsulting Engineers:Malcolm Pirnie, Inc.

On Top of the WorldClearwater, Florida2,400,000-Gallon Reuse Water Storage Tank120’ x 28’6” with domeConsulting Engineers:Jones Edmunds & Associates, Inc.

City of Apalachicola, Florida750,000-Gallon Reuse Water Tank70’ x 26’1” with domeConsulting Engineers:Baskerville-Donovan, Inc.

City of Clearwater, Florida5,000,000-Gallon Reclaimed WaterTank140’ x 43’5” with domeConsulting Engineers:McKim & Creed Engineers, P.A.

®

Circular and ElongatedPrestressed ConcreteOxidation Tanks In 1978, The Crom Corporation was given the opportunity to design and build a pair of CIRCULAR tanks for the City of Deland, Florida, constructing a clarifier tank in the center of the vessel, and a dual oxidation channel along the outer ring. The tanks have been watertight and free from maintenance problems. All walls are of the Composite Design, equivalent to AWWA Standard D 110 Type II Wall System: “Shotcrete with a Steel Diaphragm.” By the mid 1980’s, Design Engineers became interested in ELONGATED aeration tanks with separate multiple clarifiers.CROM® engineers developed unique design and construction methods to accommodate the different aeration processes being specified. These ELONGATED tanks feature COMPOSITE walls per AWWA Standard D 110 Type II: “Shotcrete with a Steel Diaphragm,” together with linear and circumferential prestressing. Over the years CROM® ELONGATED PRESTRESSED CONCRETE TANKS have become noted for their outstanding concrete crack control, watertightness, appearance, longevity and very low maintenance requirements.

City of Alachua, FloridaOne 1,200,000-Gallon ElongatedOxidation Tank233'3" long x 51' wide x 14'6"wall heightOne 5,000,000-Gallon ReclaimedWater Tank150’ x 37’-10” with dome (not shown)Two 450,000-Gallon Clarifiers70’ x 15’8” (not shown)Consulting Engineers:Jones Edmunds & Associates, Inc.

City of DeLand, FloridaTwo Oxidation Tanks/ClarifiersOuter Wall 153’10” x 11'6”Inner Wall 75' x 14'Consulting Engineers:Jones Edmunds & Associates, Inc.(formerly Smith & Gillespie Engineers)

City of Daytona Beach, FloridaTwo-Train Elongated 5-Stage Treatment Basin538’8” long x 243' wide x 17’9” wall heightConsulting Engineers:McKim & Creed Engineers, P.A.

®

City of Plant City, FloridaThree 4,000,000-GallonElongated Aeration Basins262' long x 117' wide x 22'6" wall heightThree 1,500,000-GallonClarifier Tanks130' x 15'11”Consulting Engineers:Arcadis

(Left)City of Bunnell, Florida500,000-Gallon ElongatedOxidation Tank132' long x 36' wide x 14'10" wall height990,000 Reuse Water Tank80' x 26'4” (not shown)Consulting Engineers:Mittauer & Associates, Inc.

(Right)Town of Callahan, FloridaOne 820,000-Gallon ElongatedOxidation Tank206'3” long x 40'6” wide x 13'9"wall heightTwo 110,000-Gallon Clarifier Tanks35' x 15'8”One 170,000-Gallon Digester45’ x 15’ (not shown)Consulting Engineers:Mittauer & Associates, Inc.

City of Fort Payne, AlabamaOne 2,240,000-GallonElongated Oxidation Tank301'4” long x 144'8” wide x 14'6"wall heightTwo 745,557-Gallon Clarifier Tanks90' x 15'8”Consulting Engineers:Ladd Environmental Consultants, Inc.

®

Tanks for Industrial Applications The problem of maintenance is particularly severe in manyindustrial installations. The corrosive atmosphere in chemical plantsand paper mills requires great care in the selection of constructionmaterials and techniques that will not be susceptible to deterioration. PRESTRESSED CONCRETE vessels built with composite walls haveperformed well as mill water treatment tanks and reservoirs, chemicalprocessing basins, and pulp storage chests lined with tile or fiberglass. Industrial plants build effluent water treatment facilities to combatstream pollution. As part of these installations, effluent treatment tanks are ideally built by the CROM® system.

Chicken Processing PlantCentral Georgia3,000,000-Gallon Wastewater Treatment Tank175’ x 18’400,000-Gallon Wastewater Treatment Tank75’ x 17’2”500,000-Gallon Wastewater Treatment Tank75’ x 18’40,000-Gallon Wastewater Treatment Tank20’ x 18’Consulting Engineers:Chas. N. Clark Associates, Ltd.

Copper Recycling PlantSouth Carolina21,000,000-Gallon Stormwater Collection Tank378’2” x 26’Consulting Engineers:URS (formerly B.P. Barber & Associates) and Energaes Consulting; A Joint Venture

®

Citrus Processing PlantLeesburg, Florida1,400,000-Gallon Digester100' x 24'6"6,700,000-Gallon Wastewater Treatment Tank215'6" x 24'6" with concentricclarifier wall 74'9" x 24'6"Consulting Engineers:U.S. Filter

Nebraska Bioclean-Mead LLCMead, NebraskaTwo 4,000,000-Gallon Digesters131’ x 40’ with domesTwo 500,000-Gallon Effluent Tanks65’ x 20’6” with domesConsulting Engineers:Biothane Corporation

Central Alabama Chemical PlantOne Clarifier Tank25’ x 15’One Clarifier Tank40’ x 15’6”One Stormwater Tank65’ x 18’One Equalization Tank78’ x 20’Two Aeration Tanks65’ x 18’Consulting Engineers:Atkins

®

Devon Consolidated Data CenterOklahoma City, Oklahoma80,000-Gallon ChilledWater Storage Tank30’ x 15’ with domeConsulting Engineers:Franfurt-Short-BruzaAssociates, P.C.

Nielsen Media ResearchOldsmar, FloridaTwo 750,000-Gallon Chilled WaterStorage Tanks46’ x 60’ with domesConsulting Engineers:Alfonso Architects and Engineering Matrix

Tanks for ThermalEnergy Storage Thermal energy storage is a process whereby electric powercosts for cooling can be shifted from high demand to lowdemand periods. This is accomplished by producing and storing chilled water during times of low cost/low power demand andusing it later at the time of peak demand and high cost. PRESTRESSED CONCRETE TANKS built by The CromCorporation are particularly well suited for these applications.

PRESTRESSED CONCRETE is the ideal material for chilled water storage tank construction.

Tanks may be partially or completely buried withoutconcern for maintenance.

Aesthetically pleasing insulation systems may be addedeconomically.

The free-span concrete dome can be designed to support the loads of internal piping.

Interior surfaces do not require costly coatings ormaintenance.

•

•

•

•

•

®

Broward Community CollegeCentral CampusDavie, Florida750,000-Gallon Chilled WaterStorage Tank68’ x 27’6” with domeConsulting Engineers:Engineering Matrix

U.S. ArmyFort Jackson, South Carolina2,250,000-Gallon Chilled WaterStorage Tank98’ x 40’ with domeConsulting Engineers:U.S. Army Corps of EngineersSavannah District

(Left)Walgreen Company – Warehouse & Distribution CenterWilliamston, South Carolina1,610,000-Gallon Chilled WaterStorage Tank65’ x 65’ with domeConsulting Engineers:The Korte Company

(Right)Dupont Fabros ACC4 Data CenterAshburn, VirginiaTwo 500,000-Gallon Chilled WaterStorage Tanks40’ x 53’2” with domesConsulting Engineers:CCG Facilities Integration Inc.

St. Mary’s Hospital, Inc.West Palm Beach, Florida1,400,000-Gallon Chilled WaterStorage Tank69’ x 53’ with domeConsulting Engineers:Johnson, Levinson, Slider & Davila, Inc.

®

The Crom Corporation has a history extending in excess of a half century during which time the design and construction of high quality PRESTRESSED CONCRETE TANKS has been its chief goal andaspiration. CROM® has built more AWWA D110 tanks than any other copmany in the world. In addition to our standard Type II tanks, we are fully qualified and experienced in designing and building prestressed concrete tanks under Type III of AWWA Standard D110. This Type III designation states that the tank core wall shall consist of “precast concrete with a steel diaphragm”. The difference is that Type II uses shotcrete together with diaphragm, whereas Type III uses precast concrete together with diaphragm. As described earlier in this brochure, in the case of Type II, the steel diaphragm is vertically erected full circle on supporting form work, the mild reinforcing steel is placed, and shotcrete is applied to the desired thickness of the corewall. The Type III methodology involves precasting the tank wall panels and then lifting them into position. The photographs shown on the opposite page illustrate the Type III procedure.

Prestressed ConcreteWall Design - AWWA D110 Type III Tanks: “Precast Concrete with a Steel Diaphragm”

Type II or Type III tanks can be built with a self supported free-span concrete dome roof or a column supported concrete flat roof or an aluminum dome.

After the tank floor has been cast, panels of steel diaphragm are placed in preformed casting beds. Mild steel reinforcement is added per design.

Panels are cast in multiple layers to insure a consistent radius.

After the concrete is cured, the precast panels are tilted up.Vertical joints between panels are sealed, and shotcrete is applied to the steel diaphragm along the exterior of the wall.

High strength prestressing wire is placed to provide the desired wall compression, then shotcrete is applied to bond wires to the wall.

This Type III tank has a flat roof using cast in place reinforced concrete.

This view of the tank interior shows the vertical columns required to support the flat roof.

1

2

3

4

5

6

®

1 2

3 4

5 6

AWWA D 110 Type III Core Wall Construction

®

Prestressed Concrete Tanks with EmbeddedPoly-Liner Since 1953, The Crom Corporation has been designing andbuilding PRESTRESSED CONCRETE TANKS for water storageand wastewater treatment, all built using a concrete core wallwith an embedded steel diaphragm and single wire circumferentialprestressing. It is a proven design. The Crom Corporation hasover 4000 tanks presently in service. When a storage project contains aggressive materials, CROM®

offers a PRESTRESSED CONCRETE TANK with a permanentlyEMBEDDED POLY-LINER which provides protection againstcorrosive liquids and gases. The poly-liner eliminates the need for coating or re-coating the interior surfaces of the tank. The most common application is to cast a standard concrete dome over a thermal seamed HDPE liner. CROM® also has experience in designing and building PRESTRESSED CONCRETE TANKS where the entireinterior (floor, wall and dome) has an embedded poly-liner. Consulting Engineers may specify different liner materials (HDPE - High Density Polyethylene; LLDPE - Linear Low Density Polyethylene; PP - Polypropylene); depending on the application’s requirements.

COMPLETE TANK CONSTRUCTIONThe Crom Corporation provides the design and completeconstruction of the tank, including the poly-liner and all tankaccessories such as ladders, vents and overflows. There is nodivision of responsibility.

1. Wall casting bed with poly-liner.

2. Poly-liner in place on dome form.

3. Casting concrete on a poly-lined dome.

1 2

3

®

Prestressed Concrete Tankswith Embedded Poly-Liner

®

In the interest of diversification, and in response to the demands of the market, The Crom Corporation has designed and built some outstanding and unique structures. Pictured on these pages areseveral of these projects.

Unique Installations

Murfreesboro Water & Sewer DepartmentMurfreesboro, Tennessee2,000,000-Gallon Elevated Water Storage Tank169’ to Overflow113’4” to Dome Ring32’ OD PedestalConsulting Engineers:Smith Seckman Reid, Inc.

(Right)City of Boynton Beach, Florida1,500,000-Gallon Elevated Water Storage Tank-Night Time View155’ to Overflow117’4” to Dome Ring32’ OD PedestalConsulting Engineers:The Crom Corporation

(Left)Escambia County Utilities AuthorityPerdido Key, Florida500,000-Gallon Elevated Water Storage Tank46’ x 39’ with dome125’ to High Water LineConsulting Engineers:Barrett, Daffin & Figg

®

Department of Veteran AffairsOrlando, Florida2,000,000-Gallon Bomb Resistant Fire Protection/Potable Water Storage Tank70’ x 71’ with domeConsulting Engineers:Roger, Lovelock & Fritz/Ellerbe Becket

City of Baltimore, MarylandBlack River WWTPTwo 3,000,000-Gallon Egg-Shaped Digesters85’ x 139’Consulting Engineers:Black & Veatch, Inc.

Seacoast Utility AuthorityPalm Beach Gardens, Florida400,000-Gallon Accelator Tank60’1” x 19’6”Consulting Engineers:Reese, Macon & Associates

prestressed concrete tanks brochure

Documents