Jamie Howard, Regional Manager

A Discussion on NFPA 22 (Chapter 10)- Concrete Gravity Tanks and Suction Tanks

AWWA D110 Storage Tanks

Type I: cast-in-place concrete with vertical prestressed reinforcement

Type II: shotcrete with a steel diaphragm

Type III: precast concrete with a steel diaphragm

Type IV: cast-in-place concrete with a steel diaphragm

AWWA D110 Storage Tank Types

AWWA D110 Storage Tanks Benefits

* NFPA 22 COMPLIANT

* ARCHITECTURAL ENHANCEMENTS

* TANK SITING FLEXIBILITY

* NO OUT OF SERVICE TIME

* MAINTENANCE FREE

CAPACITIES

• Large: 40 MG • Small: 80,000 Gallons

• Large: 492 Feet • Small: 22 Feet

DIAMETERS

• Tall: 100 Feet • Short: 10 Feet

HEIGHT

• Basic • Aesthetic

ARCHITECTURAL TREATMENT

• Buried • At Grade

BACKFILL

QUESTIONS

• WHAT ARE A COUPLE STANDARDS THAT GOVERN DESIGN OF PRESTRESSED PRECAST CONCRETE TANKS?

• AWWA D110, ACI 350, AND ACI 372

• WHAT IS ONE DIFFERENCE BETWEEN A D110 TYPE I TANK AND A D110 TYPE III TANK?

• TYPE I DOESN’T INCLUDE A STEEL DIAPHRAGM SINCE IT HAS VERTICAL PRESTRESSING.

• Differentially Buried • Multi-Use

BACKFILL

• STEEL TANKS DO A GREAT JOB IF MAINTAINED PROPERLY

• TAKEN OUT OF SERVICE FOR REGULAR PAINTING CYCLES

• EVERY 15 YEARS

• REPLACE BOLTS/GASKETS, ETC.

• MULTIPLE TANKS SO ONE TANK CAN BE TAKEN OUT OF SERVICE FOR MAINTENANCE

• D110 TYPE III TANKS DO NOT NEED TO BE TAKEN OUT OF SERVICE FOR

REGULAR MAINTENANCE.

• REGULAR MAINTENANCE (IF DESIRED) INCLUDES POWER WASHING EXTERIOR

NO OUT OF SERVICE TIME/MAINTENANCE FREE(COST OF OWNERSHIP)

• CONCRETE IS CORROSION RESISTANT AND STRONG IN COMPRESSION

• STEEL IS WATERTIGHT AND STRONG IN TENSION

• D110 TYPE III USES THE STRENGTHS OF EACH MATERIAL

• WATERTIGHT

• CORROSION RESISTANT

WHY CHOOSE CONCRETE OR STEEL?

Precast Concrete Corewall

Embedded Steel Diaphragm

Multiple Layers of Wire Prestressing

Seismic Restraints

Flexible Floor-wall Connection

AWWA D110 DESIGN AND CONSTRUCTION FEATURES

•FLOOR

•WALL

•PRESTRESSING

•ROOF

•SITE PREPARATION

•FLOOR REINFORCING AND PRECAST PANELS

•FLOOR POUR

TYPE III WALL•PRECAST ONSITE

•STEEL DIAPHRAGM WITHIN WALL

•ONSITE WALL PRECASTING

ONSITE PRECASTING BENEFITS

• HORIZONTAL, GROUND-LEVEL CASTING ALLOWS FOR DETAILED INSPECTION BY ALL PARTIES INVOLVED

• NO PANEL TRANSPORT TO SITE REQUIRED

• CONCRETE QUALITY IS TESTED AND ASSURED BEFORE PANEL BECOMES PART OF TANK STRUCTURE

• THE WORK IS PERFORMED LOCALLY BY DN TANKS

• LOCAL LABOR, MATERIALS AND EQUIPMENT

•WALL ERECTION

•WALL ERECTION

•COVE

•CLOSURE SLOTS

PRESTRESSING

•SHOTCRETE BASE COATING

•MULTIPLE LAYERS OF WIRE WRAPPING

•SHOTCRETE COVERCOAT

•WIRE WINDING

210,000 PSI STRENGTH WIRE, PER ASTM A821

PRODUCES CORE-WALL COMPRESSION

• PRESTRESSING QUALITY CONTROL

•SHOTCRETING

QUESTIONS?

• WHAT FORCE IS APPLIED TO THE PRESTRESS WIRE?

• 140,000 PSI

• HOW IS THE PRESTRESS WIRE PROTECTED?

• BY THE ENCAPSULATION WITH THE SHOTCRETE

ROOF TYPES

•CONCRETE DOME

•PRECAST DOME ROOF

•CAST-IN-PLACE DOME ROOF

•FLAT SLAB-COLUMN SUPPORTED ROOF

LARGE TANK HEATER PACKAGE

CHROMALOX HEATING SYSTEM

HEATER CONTROL PANEL

ELECTRIC HEATER WITHIN TANK

ELECTRICAL CONDUIT TO TANK HEATER

TECHNICAL PROJECT SUPPORT

ENGINEERING DESIGN

• SPECIFICATIONS

• CAD DRAWINGS

• TANK RENDERING

• Geotechnical Report Review

• Equipment Supplier Coordination

• TANK BUDGET

• PROJECT SITE VISIT

• SITING OPTIONS

• Construction Layout

• Full Sitework Estimate

• Value Engineering

ESTIMATING & BUDGETING

• CONSTRUCTION SCHEDULING

• EQUIPMENT LEAD TIME

• Work Coordination

SCHEDULING & COORDINATION

QUESTONS?

• WHAT ARE SOME BENEFITS OF AWWA D110 TYPE III PRESTRESSEDPRECAST CONCRETE TANKS OVER STEEL

• NO NEED TO REPAINT OR MAINTAIN CATHODIC PROTECTION

• TANKS CAN BE BACKFILLED TO FIT THE SITE

• MANY OPTIONS FOR ARCHITECTURAL TREATMENTS

• LOWER ENERGY COSTS TO STAY ABOVE 42 DEGREES WITH THE WATER TEMPERATURE

Bakersfield, CA

Danville – Geisinger, PA

London Grove, PA

Raleigh, NC

Questions?