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. Challenges in Design and Construction of LDWM Presented by: Rafael Ortega, PE Lockwood, Andrews & Newnam, Inc. k d d
- 2. Rafael Ortega, PE f Vice President Lockwood, Andrews & Newnam, Inc.
- 3. Agenda Introduction Design Issues ROW Concerns C Technical Specifications Critical Installation and Constructability
- 5. Urban Environment Anticipating issues ahead of time Reducing unknowns Constructability Innovative solutions – How to do more with less funding
- 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. Understanding “What it Takes What Takes” Project requirements Site visits – key to more complete designs
- 9. Subsurface Utility Engineering Critical in an urban environment Increase contractors’ level of confidence – Design package gp g – Bidding – Construction
- 10. 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
- 11. 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
- 12. ROW Concerns
- 13. Main Alternatives Greenspoint Mall IAH Airport Greens Rd. World Houston Lauder 4
- 14. 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
- 15. 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
- 16. Public Coordination Businesses Bus routes School year Emergency access Special event traffic
- 19. AWWA Standards Minimum requirements Alternatives w/in standards Responsibility of specifier to address project issues
- 20. Rigid vs. Flexible g Width of Trench – Practical Space Required – Larger Pipe = Larger Width All Pipe Not Created Equal
- 21. All Pipe Not Created Equal p q Made to Order Material Mt il Properties – less fo gi ing forgiving Design Considerations
- 22. 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
- 23. .
- 24. Fusing Operation gp
- 25. 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
- 27. 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
- 28. 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
- 29. Bedding Requirements g q Pipe Embedment – Bottom shaping – Compaction at haunches Movement of trench support Use of special embedment material (depth) Trench dams
- 30. 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
- 33. Joint Grout Mortar Spigot Lining Ring
- 34. 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
- 35. Butt Strap Butt-Strap Closure Piece Cl Pi Poorly Grouted P l G td
- 36. 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
- 38. 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-
- 40. Testing of Line Impacted by potential contamination from existing section Water discharge receptors – Capacity – Locations Schedule considerations – Fill rates – Required interconnects – temporary and permanent
- 41. Unavoidable Change Orders Debris encountered in excavations Longer work duration Unanticipated services U ti i t d i – Active – abandoned
- 42. Questions ?