Challenges in Design andChallenges in Design andConstruction of LDWM

Presented by:

Rafael Ortega, PEk d d &Lockwood, Andrews & Newnam, Inc.

fRafael Ortega, PEVice President

Lockwood, Andrews & Newnam, Inc.

Agenda

IntroductionIntroduction

Agenda

IntroductionIntroductionDesign IssuesDesign IssuesROW CROW CROW ConcernsROW ConcernsTechnical SpecificationsTechnical SpecificationsCritical Installation and ConstructabilityCritical Installation and Constructability

Design Issues

Urban EnvironmentUrban Environment

Anticipating issues ahead of timeAnticipating issues ahead of timeReducing unknownsReducing unknownsConstructabilityConstructabilityInnovative solutionsInnovative solutions–– How to do more with less fundingHow to do more with less funding

Goal of Urban ProjectGoal of Urban Project

Minimize impact to trafficMinimize impact to trafficAvoid disturbance to adjacent structuresAvoid disturbance to adjacent structuresReduce surface restorationReduce surface restorationLimited staging or work areaLimited staging or work areaAvoid utility conflictsAvoid utility conflicts–– Maintain servicesMaintain services–– Reduce outagesReduce outages–– Avoid relocationsAvoid relocations

Understanding “What it Takes”Understanding What it Takes

Project requirementsProject requirementsProject requirementsProject requirementsSite visits Site visits –– key to more key to more complete designscomplete designscomplete designscomplete designs

Subsurface Utility Engineering

Critical in an urban environmentCritical in an urban environment

Subsurface Utility Engineering

Increase contractors’ level of confidenceIncrease contractors’ level of confidence–– Design packageDesign packageg p gg p g–– BiddingBidding–– ConstructionConstruction

Geotech Investigation

Soil conditions vary along alignmentSoil conditions vary along alignment

Geotech Investigation

Soil conditions vary along alignmentSoil conditions vary along alignmentDetermine limits of soil variationsDetermine limits of soil variationsS b f diti i tS b f diti i tSubsurface conditions impact:Subsurface conditions impact:–– LongLong--term performance of pipelineterm performance of pipeline

SpecificationsSpecifications–– SpecificationsSpecifications–– Tunneling criteriaTunneling criteria–– Construction claimsConstruction claimsConstruction claimsConstruction claims

Traffic Control

Key to project acceptance by stake holdersKey to project acceptance by stake holders

Traffic Control

Key to project acceptance by stake holdersKey to project acceptance by stake holdersThe more detailed the less disruptionThe more detailed the less disruptionO ti i h iO ti i h iOptimize phasing:Optimize phasing:–– Minimize duration of impactsMinimize duration of impacts

Provide for progressive transitionsProvide for progressive transitions–– Provide for progressive transitionsProvide for progressive transitions

ROW Concerns

Main Alternatives

Greenspoint Mall IAH Airport

Main Alternatives

Greenspoint Mall IAH Airport

Greens Rd.Greens Rd.World HoustonWorld Houston

LauderLauder

4

Route Evaluation FactorsRoute Evaluation Factors

Limits of City jurisdictionLimits of City jurisdictionLimits of City jurisdictionLimits of City jurisdictionROW AcquisitionROW AcquisitionDi ti t N i hb h dDi ti t N i hb h dDistinct NeighborhoodsDistinct NeighborhoodsType of Construction EnvironmentType of Construction Environment

D lD l–– Development typeDevelopment type–– Contamination Contamination

Easement BreakdownEasement Breakdown

Easements Lauder Aldine Bender Greens

Residential 37 26 8

Commercial 28 51 14

Undeveloped Tracts 14 27 21

TOTAL 79 104 43

Estimated structures impacted 2 5 0

Public CoordinationPublic Coordination

BusinessesBusinessesBus routesBus routesSchool yearSchool yearEmergency accessEmergency accessSpecial event trafficSpecial event traffic

Technical Specifications

AWWA Standards

Minimum requirementsMinimum requirementsMinimum requirementsMinimum requirementsAlternatives w/in standardsAlternatives w/in standardsResponsibility ofResponsibility of specifierspecifier to address projectto address projectResponsibility of Responsibility of specifierspecifier to address project to address project issuesissues

Rigid vs. Flexibleg

Width of TrenchWidth of TrenchWidth of TrenchWidth of Trench–– Practical Space RequiredPractical Space Required–– Larger Pipe = Larger WidthLarger Pipe = Larger Width–– Larger Pipe = Larger WidthLarger Pipe = Larger Width

All Pipe Not Created EqualAll Pipe Not Created Equal

All Pipe Not Created Equalp q

Made to OrderMade to OrderM t i lM t i lMaterial Material PropertiesPropertiesless fo gi ingless fo gi ing–– less forgivingless forgivingDesign Design ConsiderationsConsiderationsConsiderationsConsiderations

Nonmetallic Materials

PVC FRP HDPEPVC FRP HDPEPVC, FRP, HDPEPVC, FRP, HDPESpeed of installationSpeed of installationAlt ti i t tAlt ti i t tAlternatives in stray current areasAlternatives in stray current areasSteel or DIP bends and outletsSteel or DIP bends and outlets

V l fi i d lV l fi i d l–– Valves, fittings, and outlets Valves, fittings, and outlets –– Vertical and horizontalVertical and horizontal

.

Fusing Operationg p

Pipe Comparison SummaryPipe Comparison Summary

Gasket

Pipe MaterialPipe

Design Joint TypeCorrosion Protection

Field Modifications

Allowed?Field Welding

Allowed?

Gasket Joint

Bonding Req’d?

D til I R/F G Y Y N YDuctile Iron R/F G Y Y N YSteel F G or W Y Y Y Y or NFRP F G or W N Y N N

HDPE FFused/

Flanged N Y Y NPCCP R G or W Y N Y Y or NBar Wrapped F G or W Y N Y Y or NBar Wrapped F G or W Y N Y Y or N

F = Flexible R = Rigid G = Gasket W = Welded Y = Yes N = No

Critical Installationand Constructabilityand Constructability

Challenges During ConstructionChallenges During Construction

Pipe material availabilityPipe material availabilityPrivate utility relocationsPrivate utility relocationsCompetition for contractor’s Competition for contractor’s resourcesresourcesC t ti h d tC t ti h d tConstruction phased to Construction phased to avoid impacting operationsavoid impacting operations

Construction IssuesConstruction Issues

Verify densities of pipe beddingVerify densities of pipe beddingVerify densities of pipe beddingVerify densities of pipe beddingLay pipe continuouslyLay pipe continuouslyD tD t t llt ll i t b kfilli t b kfillDo not remove Do not remove stullsstulls prior to backfillprior to backfillPerform internal inspections during constructionPerform internal inspections during construction

Bedding Requirementsg q

Pipe EmbedmentPipe EmbedmentPipe EmbedmentPipe Embedment–– Bottom shapingBottom shaping–– Compaction at haunchesCompaction at haunches–– Compaction at haunchesCompaction at haunches

Movement of trench supportMovement of trench supportUse of special embedment material (depth)Use of special embedment material (depth)Use of special embedment material (depth)Use of special embedment material (depth)Trench damsTrench dams

Backfill Critical

Effectiveness of compaction criticalEffectiveness of compaction criticalEffectiveness of compaction criticalEffectiveness of compaction critical–– Loading capabilityLoading capability–– Deflection affects coating and liningsDeflection affects coating and linings–– Deflection affects coating and liningsDeflection affects coating and linings

E’ = Modulus of SoilE’ = Modulus of Soil–– % Compaction% Compaction% Compaction% Compaction–– Type of SoilType of Soil–– Greatest Affect on Wall ThicknessGreatest Affect on Wall Thickness

Improper InstallationImproper Installation

Proper BackfillingProper Backfilling

Joint GroutJoint Grout

Mortar Lining Spigot

Ring

Closure Considerations

Butt StrapButt StrapButt StrapButt Strap–– Requires true alignmentRequires true alignment–– 12” wide w/ 4” minimum overlap required12” wide w/ 4” minimum overlap required12 wide w/ 4 minimum overlap required12 wide w/ 4 minimum overlap required–– Welding of Welding of prestressedprestressed wireswires

Grouting RequirementsGrouting Requirementsg qg q–– Wire meshWire mesh–– NonNon--shrink groutshrink grout–– Interior and exterior weldsInterior and exterior welds

Butt-StrapButt Strap

Cl PiCl Pi P l G t dP l G t dClosure PieceClosure Piece Poorly GroutedPoorly Grouted

Exterior Joint Grout

Diaper;Diaper;Diaper;Diaper;–– w/ w/ ethafoamethafoam backingbacking–– WidthWidth–– WidthWidth

InstallationInstallation–– Grout mix and testingGrout mix and testingGrout mix and testingGrout mix and testing–– Bottom joint recess (similar to bell form)Bottom joint recess (similar to bell form)–– Rod and set time requiredRod and set time requiredqq

Ungrouted Exterior JointUngrouted Exterior Joint

Annular Space Issuesp

Flotation of PipeFlotation of PipeFlotation of PipeFlotation of PipeGrouting MonitoringGrouting Monitoring

M it i kM it i k–– Monitoring keyMonitoring key–– Pressure and volumePressure and volume–– Potential exists w/ lowPotential exists w/ low--density groutdensity groutPotential exists w/ lowPotential exists w/ low density groutdensity grout

Grouting Pressure Problemsg

Testing of Line

Impacted by potential contamination fromImpacted by potential contamination from

Testing of Line

Impacted by potential contamination from Impacted by potential contamination from existing sectionexisting sectionWater discharge receptorsWater discharge receptorsWater discharge receptorsWater discharge receptors–– CapacityCapacity–– LocationsLocationsLocationsLocations

Schedule considerationsSchedule considerations–– Fill ratesFill ratesFill ratesFill rates–– Required interconnects Required interconnects –– temporary and permanenttemporary and permanent

Unavoidable Change OrdersUnavoidable Change Orders

Debris encountered in excavationsDebris encountered in excavationsDebris encountered in excavationsDebris encountered in excavationsLonger work durationLonger work durationU ti i t d iU ti i t d iUnanticipated servicesUnanticipated services–– ActiveActive

abandonedabandoned–– abandonedabandoned

Questions ?