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Design Considerations for a 96-inch Diameter Rehab/Replacement of a Wastewater Pipeline. Wayne Hunter, RPS September 27, 2013. TRA CRWS System. Features of TRA System 21 cities served Services since 1959 Five primary interceptor systems
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Design Considerations for a 96-inch Diameter Rehab/Replacement of a Wastewater Pipeline Wayne Hunter, RPS September 27, 2013
TRA CRWS System Features of TRA System • 21 cities served • Services since 1959 • Five primary interceptor systems • 210 miles of large diameter (up to 108-inch diameter) pipelines • Elm Fork System carrying 190 MGD in 2040
CAC-11 Conditions Precedent 1984 construction of 17,200 LF of 96-inch diameter RCP (EF Int. 1-A) to replace 1959 RCP 1999 corrosion assessment using corings 2003 failure in pipeline due to corrosion 2004 I/I Master Plan identified “CAC-11” and EF-1 2007 construction of parallel EF-1, 104-inch diameter Hobas FRP, for added capacity 2008 failure in 96-inch pipeline 2008 condition assessment of 96-inch diameter pipeline, basis for design of CAC-11
TRA Direction for CAC-11 • Rehab or replace 17,200 LF of 96 inch pipe CAC-11 • Utilize parallel 104-inch EF-1 for carrying flows during CAC-11 rehab or replacement • Minimize impacts to Irving surface uses in developed parks and golf course
CAC-11 Condition Assessment • Internal Condition determined to be variable loss of concrete
CAC-11 Condition Assessment Point locations of infiltration due to adjacent river hydraulic grade line
CAC-11 Condition Assessment Corrosion at top half of pipe sufficient to result in dropped gaskets for upper half of pipe
Rehab or Replacement Consideration Original 1984 RCP C-76 Standard Typical RCP Loss of Concrete Due to Deterioration Differences varied between original RCP and corrosion impacted RCP?
Replacement determined to be non viable due to proximity of close 30-inch Reuse pipeline Two rehabilitation options Viable Rehab or Replacement Conclusions * Smaller slipline diameter required due to curvilinear sewer
CAC-11 Rehabilitation Plan • 1. Tapped WERF study of Large Diameter Pipeline Rehab • Defined more problem free CIPP when using less than 1,000 foot length rehab sections • Defined other design features to be addressed • 2. Utilized TTC Center (LA) • Modeled deteriorated pipe using Finite Element Analysis • Validated SPR and CIPP design
Rehabilitation Plan Spiral-Wound Liner Design Detail Two Cured In-Place Pipe Design Details With Rehabilitation established, several other issues remained
CAC-11 Floodplain Considerations • Downstream of three reservoirs • Instream river gage upstream • Downstream affected by 2 rivers converging • 2007 Hurricane Rita – 6 month out of banks • 2012 wet winter, 6th wettest winter all time – 1-2day out of banks in two instances, but dry out time two weeks typical
CAC-11 Floodplain Considerations Quantitative Precipitation Forecast Notification Window 7 day Forecast Reservoir and River Stages Website developed to provide an interface to see each of the real-time event triggers.
CAC-11 Floodplain ConsiderationsRecent Event January 8-9, 2013
CAC-11 Construction Site Considerations • Focused area • City of Irving Trinity View Park (playing fields) • 6000 LF • Average condition rating=5 (1-5 highest) • Average consequence of failure=2.4 (1-3 highest) • Land use-Irving Parks, recreation • Average depth (8-15 ft)
CAC-11 Construction Site Considerations • Focused area • City of Irving Twin Wells golf course • 4000 LF • Average condition rating=5 (1-5 highest) • Average consequence of failure=2.3 (1-3 highest) • Land use- golf course • Average depth (10-15 ft)
CAC-11 Construction Site Considerations • Site constraints to reduce impacts to golf course • Screening • Three month window • Noise and odor limits
CAC-11 Bid Outcome Engineers estimate $19.5M Range of bids $16.5-30M Low bid $16.5M Reinforced CIPP Second low bid $16.7M SWL Third low bid $17.0M Reinforced CIPP Fourth low bid $17.3M Non-reinforced CIPP
CAC-11 Lessons Learned Typical required experience relates to length of job in multiples of requested experience CAC-11 17,300 LF equates to nine 1,800 LF projects
CAC-11 Lessons Learned • Issues relating to CIPP • Styrene toxicity • One known WWTP upset • Possible issue small system • Can specify $$$ no styrene • Temperature impacts from discharge • Controlled release is specified
Project Installation Update By July 2013, 100% of CIPP had been installed through eighteen insertions averaging 900 feet with blind overlap
Project Installation Update Access road construction prior to set up Driving range access had to be built across course and maintain playing conditions
Project Installation Update Noise barrier walls and a temporary bypass trail were constructed at critical locations in golf course and parks
Project Installation Update Existing manholes removed for install access pits Setup on-site wet-out and install CIPP
Project Installation Update Due to specified length limits on install lengths, CIPP had to be overlapped, installed from both directions up to 1200 ft.
Project Installation Update New T-Base manholes installed
Placement of steel in 4-inch loss of concrete: Upper 270 degrees Project Installation Update Road on geotextile crossing golf course to screened area
Project Installation Update • Restoration to be completed November 2013, five months ahead of schedule Three to four wet weather events to date, some overbank flows Forced demobilization not yet utilized by TRA due to detailed weather monitoring
Recognition for Project 1. June 18, 2013, TRA CAC-11 project recognized by National Hydrologic Warning Council for innovation, presented Operational Award of Excellence 2. In October 2013, Trenchless Technology will present TRA CAC-11 Project as 2013 Project of the Year Runner up