Design Considerations for Selection of Pipe Design Considerations for Selection of Pipe Material for Large Diameter CSO Force MainMaterial for Large Diameter CSO Force Main

Pacific Northwest Clean Water Association

2010 Conference

Presented By Presented By M. Patty Nelson, City of PortlandM. Patty Nelson, City of PortlandPhil Phil RoppoRoppo, Brown and Caldwell, Brown and CaldwellMark Mark HavekostHavekost, Jacobs Associates, Jacobs Associates

Presentation Overview

Project OverviewDesign RequirementsPipe Materials ConsideredPipe Material EvaluationSelectionProject UpdateQuestions

PROJECT OVERVIEW

Willamette River Combined Sewer Willamette River Combined Sewer Overflow (CSO) ProgramOverflow (CSO) Program

Portsmouth Force MainPortsmouth Force Main

Deliver 120 mgdFrom Swan Island CSO Pump Station to Existing Portsmouth TunnelMeet ASFO Deadline of December 2011

Segment 1 Segment 1 –– Swan Island AlignmentSwan Island Alignment Single 66 Inch Force MainSingle 66 Inch Force Main

3,000 linear feet 84-inch Microtunnel4 Microtunnel Shafts6,800 linear feet Open CutSteel Pipe with Polyurethane Liner

Segment 2 Segment 2 –– Bluff AlignmentBluff Alignment Single 66 Inch Force Main inside a 10 Foot TunnelSingle 66 Inch Force Main inside a 10 Foot Tunnel

200 linear feet - Open Cut6,000 linear feet - Deep Tunnel2 Tunnel ShaftsFiberglass Reinforced Pipe

Profile ConsiderationsProfile Considerations

Force Main: Sloped to Drain

Segment 1: Conflicting Utilities

Segment 2: Deep Connection

Design RequirementsDesign Requirements120 120 mgdmgd, peak 140 , peak 140 mgdmgd

Single 66Single 66--Inch DiameterInch Diameter

Corrosion ResistantCorrosion Resistant

Handle Hydraulic Transient ConditionsHandle Hydraulic Transient Conditions

Pipe Materials ConsideredPipe Materials Considered

Welded Steel Pipe (WSP) with polyurethane liningWelded Steel Pipe (WSP) with polyurethane lining

FiberFiber--Reinforced Polymer Pipe (FRPP)Reinforced Polymer Pipe (FRPP)

Ductile Iron (DIP) with PROTECTO 401 (ceramic Ductile Iron (DIP) with PROTECTO 401 (ceramic epoxy lining)epoxy lining)

Reinforced Concrete Cylinder Pipe (RCCP)Reinforced Concrete Cylinder Pipe (RCCP)

Pipe Material EliminatedPipe Material Eliminated

Ductile Iron (DIP) Ductile Iron (DIP) Insufficient Size Insufficient Size

Reinforced Concrete Cylinder Pipe (RCCP)Reinforced Concrete Cylinder Pipe (RCCP)Corrosion concerns with concrete liningCorrosion concerns with concrete lining

Pipe Materials EvaluatedPipe Materials EvaluatedFiberFiber--Reinforced Polymer Reinforced Polymer Pipe (FRPP) ASTM D3754Pipe (FRPP) ASTM D3754

20 20 –– 40 foot length40 foot length

Push on jointsPush on joints

225 to 300 lbs per linear foot225 to 300 lbs per linear foot

Pipe Materials EvaluatedPipe Materials EvaluatedWelded Steel Pipe (WSP) Welded Steel Pipe (WSP) AWWA C200 AWWA C200

Polyurethane liningPolyurethane lining

40 foot length40 foot length

DoubleDouble--welded lap jointswelded lap joints

600 lb per linear foot600 lb per linear foot

Evaluation CriteriaEvaluation Criteria

CostCost

ConstructabilityConstructability

Structural DesignStructural Design

DurabilityDurability

Maintenance Maintenance

Installation RiskInstallation Risk

Sewer OperationSewer Operation

Cost ConsiderationsCost Considerations

Direct CostsDirect CostsProduction RatesProduction RatesRestraint RequirementsRestraint RequirementsNumber Welds/JointsNumber Welds/JointsWeight/HandlingWeight/HandlingCorrosion Resistant CoatingCorrosion Resistant CoatingMaintenance Access for Lined PipeMaintenance Access for Lined Pipe

Cost ComparisonCost ComparisonSegment 1Segment 1 Segment 2Segment 2

WSPWSP 4.37 - 4.69 million

5.07 5.07 –– 5.11 5.11 millionmillion

FRPFRP 4.52 4.52 -- 5.79 5.79 millionmillion

3.75 – 4.78 million

Thrust Restraint Thrust Restraint Required Required –– Poor Poor soils soils

Maintenance AccessMaintenance Access Intermediate Intermediate ShaftShaft

Constructability ConsiderationsConstructability Considerations

Space requirement Space requirement -- ShoringShoringEase of Installation Ease of Installation -- HandlingHandlingLength Pipe Length Pipe -- # Joints# JointsRestraint RequirementRestraint RequirementWeight of PipeWeight of PipeBackfill RequirementsBackfill Requirements

Constructability ComparisonConstructability ComparisonSegment 1Segment 1 Segment 2Segment 2

WSPWSP Double Welded Lap Joints

Prep/Patch Lining at Joints

Shoring system for external joint welds

Single welded lap joint – Careful fit for welding

Prep/Patch Lining at Joints

FRPFRP Push-on JJoints

Careful attention required for backfill

External thrust restraint system

Push-on Joints

Specialized bracing for backfilling in tunnel

Structural Design ConsiderationsStructural Design Considerations

LoadingLoadingInternal PressuresInternal PressuresExternal PressuresExternal PressuresAbility to handle ground movementAbility to handle ground movement

Structural Design ComparisonStructural Design ComparisonBoth WSP and FRP were designed to handle:

Internal Pressure 45 psi operating, 63 psi peakFull VacuumInstallation LoadsBackfill Loads

Durability ConsiderationsDurability Considerations

Internal Corrosion ResistanceInternal Corrosion ResistanceExternal Corrosion ResistanceExternal Corrosion ResistanceAbrasion ResistanceAbrasion ResistanceFatigueFatigue

Durability ComparisonDurability ComparisonSegment 1 & 2Segment 1 & 2

WSPWSP Internal Corrosion: Lining External Corrosion: Tape WrapAbrasion: Polyurethane HighestFatigue: Resistant

FRPFRP Pipe material Corrosion Resistant Abrasion: High ResistanceFatigue: Designed using higher pressure class to extend pipe life

Maintenance ConsiderationsMaintenance Considerations

Access for Repairs & CleaningAccess for Repairs & Cleaning

Method of RepairsMethod of Repairs

Historical Maintenance IssuesHistorical Maintenance Issues

Maintenance ComparisonMaintenance ComparisonSegment 1Segment 1 Segment 2Segment 2

WSPWSP Shallow force main

Air/Vac Access Vaults

Lining repairs anticipated

Repairs sensitive to workmanship & environment

Deep force main

Requires Intermediate Shaft for Access

Lining repairs anticipated

Repairs sensitive to workmanship & environment

FRPFRP Shallow force main

Air/Vac Access Vaults

Repairs using fiberglass and resin laminations – controlled environment

Deep force main

Repairs using fiberglass and resin laminations – controlled environment

Installation Risk ConsiderationsInstallation Risk Considerations

Excessive loads due to:Excessive loads due to:Pipe floatation Pipe floatation High grouting pressuresHigh grouting pressures

Poor JointsPoor Joints

Damage from InstallationDamage from Installation

Installation Risk ComparisonInstallation Risk ComparisonSegment 1Segment 1 Segment 2Segment 2

WSPWSP Lining damage during installation

Double Joints Protect

Lining damage during installation

Pipe grouted within tunnel

FRPFRP Pipe damage during backfill

Joint Leakage

Pipe damage during backfill

Joint Leakage

Summary of Pipe ComparisonSegment 1 Segment 2

Pipe Cost WSP FRPP

Constructability Neutral FRPP

Structural Design Neutral Neutral

Durability FRPP FRPP

Maintenance Neutral FRPP

Installation Risk WSP WSP

System Operation ConsiderationsSystem Operation ConsiderationsLow PressureLow Pressure

Wet Weather Operation OnlyWet Weather Operation Only

Avoid Full VacuumAvoid Full Vacuum

Air/Vacuum Relief & AccessAir/Vacuum Relief & Access

Air/Vacuum Relief ValvesAir/Vacuum Relief Valves

Locations needed for Air/Vacuum ReliefLocations needed for Air/Vacuum Relief

Must vent to surfaceMust vent to surface

Hydraulic Transient Analysis to Determine LocationHydraulic Transient Analysis to Determine Location

Pipe Material Considerations in Pipe Material Considerations in Hydraulic Transient AnalysisHydraulic Transient Analysis

Different Pipe Materials = Different Wave SpeedsDifferent Pipe Materials = Different Wave Speeds

Wave Speed impacts Transient AnalysisWave Speed impacts Transient Analysis

FRP = Higher Wave Speed than SteelFRP = Higher Wave Speed than Steel

Reviewed combinations of pipe type Reviewed combinations of pipe type SegSeg 1 & 1 & SegSeg 22

Objective Avoid Full Vacuum ConditionObjective Avoid Full Vacuum Condition

Transient Analysis: Steel Vs FRPTransient Analysis: Steel Vs FRP

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Force Main STA (ft) PS Discharge ~ STA 10+00

Pres

sure

(psi

g)

P Steady-State (psig)

Pressure Max (psig)

Pressure Min (psig)

Vent-O-Mat Location

60% Design Profile

Steady-State Pressure

Maximum Pressure

Minimum Pressure

Flow Exiting Pump Station

Tunnel Section

Option 7A:Segment 1: Fiberglass Pipe (wave speed 1,400 ft/s)Segment 2: Fiberglass Pipe (wave speed 1,400 ft/s)Vent-O-Mat Locations: 7

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Force Main STA (ft) PS Discharge ~ STA 10+00

Pres

sure

(psi

g)

P Steady-State (psig)

Pressure Max (psig)

Pressure Min (psig)

Vent-O-Mat Location

60% Design Profile

Steady-State Pressure

Maximum Pressure

Minimum Pressure

Flow Exiting Pump Station

Tunnel Section

Option 6A:Segment 1: Steel PipeSegment 2: Fiberglass Pipe (wave speed 1,400 ft/s)Vent-O-Mat Locations: 7

Selection: Segment 1 Steel + Segment 2 FRP Selection: Segment 1 Steel + Segment 2 FRP

All FRP All FRP Steel + FRP Steel + FRP

Fear FactorFear FactorPoor Experience with Plastic PipePoor Experience with Plastic Pipe

Major FacilityMajor Facility

Single Force MainSingle Force Main

Tunnel Tunnel –– Limited AccessLimited Access

Case History FRP PipeOwner Project Application Size

(inches)Length (LF)

Pipe Installation Method

City of Charleston, South Carolina

Harbor Tunnel, Ashley River Tunnel (2006)Cooper River Tunnel (2007)

Pressurized Sewer Siphon

20 – 54 5,0009,50018,100

HOBAS Carrier Pipe in Tunnel

Jackman Penstock Replacement (1982, 2003, 2007)

Jackman Penstock Replacement (1982, 2003, 2007)

Hydropower penstock

84 3,900 FlowtiteHOBAS

Open Cut

City and County of Honolulu

Hart Street Force Main (2000)

Sewer Force Main

51 2,100 HOBAS Pipe Jacking

City of Abilene Buck Creek Force Main

Sewer Force Main

36 26,000 HOBAS Open Cut

Goochland County, Virginia

Goochland/Henrico Regional FM

Sewer Force Main

48 44,800 Flowtite Open Cut

THE DECISIONTHE DECISION

Segment 1 Pipe MaterialSegment 1 Pipe Material

10,000 LF10,000 LF

6666--Inch Steel AWWA Inch Steel AWWA C200C200

Polyurethane LinerPolyurethane Liner

Tape WrapTape Wrap

Segment 2 Pipe MaterialSegment 2 Pipe Material66 inch FRPP – HOBAS ASTM D3754

WHERE ARE WE NOW?WHERE ARE WE NOW?

Segment 1 Update

Segment 2 Deep TunnelSegment 2 Deep Tunnel

QUESTIONS?QUESTIONS?