Challenges in Design and
 Construction of LDWM




            Presented by:
          Rafael Ortega, PE
  Lockwood, Andre...
Rafael Ortega, PE
      f
          Vice President
Lockwood, Andrews & Newnam, Inc.
Agenda

Introduction
Design Issues
ROW Concerns
       C
Technical Specifications
Critical Installation and Constructabili...
Design Issues
Urban Environment

Anticipating issues ahead of time
Reducing unknowns
Constructability
Innovative solutions
– How to do m...
Goal of Urban Project

Minimize impact to traffic
Avoid disturbance to adjacent structures
Reduce surface restoration
Limi...
Understanding “What it Takes
               What Takes”

Project requirements
Site visits – key to more
complete designs
Subsurface Utility Engineering
Critical in an urban environment
Increase contractors’ level of confidence
– Design package...
Geotech Investigation

Soil conditions vary along alignment
Determine limits of soil variations
Subsurface conditions impa...
Traffic Control

Key to project acceptance by stake holders
The more detailed the less disruption
Optimize h i
O ti i phas...
ROW Concerns
Main Alternatives

Greenspoint Mall                             IAH Airport
                       Greens Rd.
            ...
Route Evaluation Factors

Limits of City jurisdiction
ROW Acquisition
Distinct Neighborhoods
Di ti t N i hb h d
Type of Co...
Easement Breakdown


                                         Aldine
          Easements             Lauder            Gre...
Public Coordination


Businesses
Bus routes
School year
Emergency access
Special event traffic
Technical Specifications
AWWA Standards

Minimum requirements
Alternatives w/in standards
Responsibility of specifier to address project
issues
Rigid vs. Flexible
             g

Width of Trench
– Practical Space Required
– Larger Pipe = Larger Width
All Pipe Not Cr...
All Pipe Not Created Equal
           p               q


 Made to Order
 Material
 Mt il
 Properties
– less fo gi ing
   ...
Nonmetallic Materials

PVC, FRP, HDPE
PVC FRP
Speed of installation
Alternatives in stray current areas
Alt    ti    it   ...
.
Fusing Operation
     gp
Pipe Comparison Summary
                                                                                       Gasket
    ...
Critical Installation
and Constructability
Challenges During Construction


Pipe material availability
Private utility relocations
Competition for contractor’s
resou...
Construction Issues

Verify densities of pipe bedding
Lay pipe continuously
Do t
D not remove stulls prior to backfill
   ...
Bedding Requirements
            g   q

Pipe Embedment
– Bottom shaping
– Compaction at haunches
Movement of trench suppor...
Backfill Critical

Effectiveness of compaction critical
– Loading capability
– Deflection affects coating and linings
E’ =...
Improper Installation
Proper Backfilling
Joint Grout




    Mortar
             Spigot
    Lining
              Ring
Closure Considerations

Butt Strap
– Requires true alignment
– 12 wide w/ 4” minimum overlap required
  12”         4
– We...
Butt Strap
            Butt-Strap

Closure Piece
Cl      Pi           Poorly Grouted
                     P l G td
Exterior Joint Grout

Diaper;
– w/ ethafoam backing
– Width
Installation
– Grout mix and testing
– Bottom joint recess (si...
Ungrouted Exterior Joint
Annular Space Issues
                 p

Flotation of Pipe
Grouting Monitoring
– M it i key
  Monitoring k
– Pressure and ...
Grouting Pressure Problems
       g
Testing of Line

Impacted by potential contamination from
existing section
Water discharge receptors
– Capacity
– Location...
Unavoidable Change Orders

Debris encountered in excavations
Longer work duration
Unanticipated services
U    ti i t d    ...
Questions ?
2009-02-17 Seminar - Challenges In The Design And Construction Of Large Diameter Water Transmission Lines
2009-02-17 Seminar - Challenges In The Design And Construction Of Large Diameter Water Transmission Lines
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2009-02-17 Seminar - Challenges In The Design And Construction Of Large Diameter Water Transmission Lines

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Rafael Ortega, PE at LAN, discusses design issues, ROW concerns, technical specifications, and critical installation and constructability of large diameter water transmission lines.

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2009-02-17 Seminar - Challenges In The Design And Construction Of Large Diameter Water Transmission Lines

  1. 1. Challenges in Design and Construction of LDWM Presented by: Rafael Ortega, PE Lockwood, Andrews & Newnam, Inc. k d d
  2. 2. Rafael Ortega, PE f Vice President Lockwood, Andrews & Newnam, Inc.
  3. 3. Agenda Introduction Design Issues ROW Concerns C Technical Specifications Critical Installation and Constructability
  4. 4. Design Issues
  5. 5. Urban Environment Anticipating issues ahead of time Reducing unknowns Constructability Innovative solutions – How to do more with less funding
  6. 6. Goal of Urban Project Minimize impact to traffic Avoid disturbance to adjacent structures Reduce surface restoration Limited staging or work area Avoid utility conflicts – Maintain services – Reduce outages – Avoid relocations
  7. 7. Understanding “What it Takes What Takes” Project requirements Site visits – key to more complete designs
  8. 8. Subsurface Utility Engineering Critical in an urban environment Increase contractors’ level of confidence – Design package gp g – Bidding – Construction
  9. 9. Geotech Investigation Soil conditions vary along alignment Determine limits of soil variations Subsurface conditions impact: Sb f diti i t – Long-term performance of pipeline Long- – Specifications – Tunneling criteria – Construction claims
  10. 10. Traffic Control Key to project acceptance by stake holders The more detailed the less disruption Optimize h i O ti i phasing: – Minimize duration of impacts – Provide for progressive transitions
  11. 11. ROW Concerns
  12. 12. Main Alternatives Greenspoint Mall IAH Airport Greens Rd. World Houston Lauder 4
  13. 13. Route Evaluation Factors Limits of City jurisdiction ROW Acquisition Distinct Neighborhoods Di ti t N i hb h d Type of Construction Environment –DDevelopment type l – Contamination
  14. 14. Easement Breakdown Aldine Easements Lauder Greens Bender Residential 37 26 8 Commercial 28 51 14 Undeveloped Tracts 14 27 21 TOTAL 79 104 43 Estimated structures impacted 2 5 0
  15. 15. Public Coordination Businesses Bus routes School year Emergency access Special event traffic
  16. 16. Technical Specifications
  17. 17. AWWA Standards Minimum requirements Alternatives w/in standards Responsibility of specifier to address project issues
  18. 18. Rigid vs. Flexible g Width of Trench – Practical Space Required – Larger Pipe = Larger Width All Pipe Not Created Equal
  19. 19. All Pipe Not Created Equal p q Made to Order Material Mt il Properties – less fo gi ing forgiving Design Considerations
  20. 20. Nonmetallic Materials PVC, FRP, HDPE PVC FRP Speed of installation Alternatives in stray current areas Alt ti it t Steel or DIP bends and outlets –V l Valves, fittings, and outlets fi i d l – Vertical and horizontal
  21. 21. .
  22. 22. Fusing Operation gp
  23. 23. Pipe Comparison Summary Gasket Field Joint Pipe Corrosion Modifications Field Welding Bonding Pipe Material Design Joint Type Protection Allowed? Allowed? Req’d? Ductile Iron D til I R/F G Y Y N Y Steel F G or W Y Y Y Y or N FRP F G or W N Y N N Fused/ HDPE F Flanged N Y Y N PCCP R G or W Y N Y Y or N Bar Wrapped F G or W Y N Y Y or N F = Flexible R = Rigid G = Gasket W = Welded Y = Yes N = No
  24. 24. Critical Installation and Constructability
  25. 25. Challenges During Construction Pipe material availability Private utility relocations Competition for contractor’s resources Construction phased to C t ti h dt avoid impacting operations
  26. 26. Construction Issues Verify densities of pipe bedding Lay pipe continuously Do t D not remove stulls prior to backfill t ll i t b kfill Perform internal inspections during construction
  27. 27. Bedding Requirements g q Pipe Embedment – Bottom shaping – Compaction at haunches Movement of trench support Use of special embedment material (depth) Trench dams
  28. 28. Backfill Critical Effectiveness of compaction critical – Loading capability – Deflection affects coating and linings E’ = Modulus of Soil – % Compaction – Type of Soil – Greatest Affect on Wall Thickness
  29. 29. Improper Installation
  30. 30. Proper Backfilling
  31. 31. Joint Grout Mortar Spigot Lining Ring
  32. 32. Closure Considerations Butt Strap – Requires true alignment – 12 wide w/ 4” minimum overlap required 12” 4 – Welding of prestressed wires Grouting Requirements gq – Wire mesh – Non-shrink grout Non- – Interior and exterior welds
  33. 33. Butt Strap Butt-Strap Closure Piece Cl Pi Poorly Grouted P l G td
  34. 34. Exterior Joint Grout Diaper; – w/ ethafoam backing – Width Installation – Grout mix and testing – Bottom joint recess (similar to bell form) – Rod and set time required q
  35. 35. Ungrouted Exterior Joint
  36. 36. Annular Space Issues p Flotation of Pipe Grouting Monitoring – M it i key Monitoring k – Pressure and volume – Potential exists w/ low-density grout low-
  37. 37. Grouting Pressure Problems g
  38. 38. Testing of Line Impacted by potential contamination from existing section Water discharge receptors – Capacity – Locations Schedule considerations – Fill rates – Required interconnects – temporary and permanent
  39. 39. Unavoidable Change Orders Debris encountered in excavations Longer work duration Unanticipated services U ti i t d i – Active – abandoned
  40. 40. Questions ?

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