Pearl City Force Main Repair Uses Sliplining Installation Method

Transcription

1 Pearl City Force Main Repair Uses Sliplining Installation Method City and County of Honolulu, Hawaii Department of Design and Construction Wastewater Division Russell Takara, P.E. Kyle Kaneshiro, P.E.

2 Outline Project Background The Problem Rehabilitation Goals Rehabilitation Options Analysis and Recommendations Design Schedule Project Challenges Design Concept Construction Challenges Conclusion and Lessons Learned

3 Project Background Parallel dual FM system (Pearl City SPS Waipahu SPS) Built in 1970 s DI pipe 30 to 48 each spanning 11,500 feet Pearl City Sewage Pump Station Max Dry Weather = 27 MGD Peak Wet Weather = 47 MGD

4 WAIPAHU Waipahu SPS PEARL CITY WAIPAHU FM PEARL HARBOR MIDDLE LOCH Pearl City SPS

5 The Problem 4 breaks from 2006 to 2010 Apr Break FM Condition Assessment Jan Break July Break July Break Breaks all within 250 ft section Failure: external corrosion

6 Project Map 74 Bend Pearl City FM System 42 and 30 DIP Energy Corridor Wailana Flood Control Channel Waipahu SPS 60 Bend Honolulu Fire Dept. Maintenance Facility Urban Forestry Nursery Yard Jan Break April 2006 Break Ted Makalena Golf Course from Pearl City SPS July 2010 Breaks

7 Corrosion Factors Primary Causes Corrosive Soils Groundwater tidal changes Stray currents from nearby utility corridor Cathodic Protection not operational

8 Rehabilitation Goals Design service life: min. 10 year ~ Budget = 3 Million Minimal impact to flow capacity Maintain flow during construction Minimize ferrous material Address poor soil conditions

9 Rehabilitation Options Slip line Cured In Place Pipe (CIPP) Tight Fit Liner Shallow Bury Open Cut Replacement Horizontal Directional Drill Replacement

10 Analysis Criteria Capital Cost Service Life Maintenance Hydraulic Capacity Constructability

11 Recommendation Slip line w/ Fusible PVC Economical Service life > 10 Minimal maintenance Minimal disturbance Hydraulics: FPVC ID > HDPE ID Minimal hydraulic impact to FM system

12 Design Schedule Immediate repair Accelerated Design 3 months Prepare design to 80% completion

13 Project Challenges Complexity of FM system Two pump stations connected Complex valve system to control flow Construction sequencing critical Maintain flow capacity during construction Bypass connection to non existing access

14 Project Challenges Fragility and proximity of the two pipes Adjacent facilities and structures

15 Project Map 74 Bend Pearl City Force Main System 42 and 30 DIP Sewer Easement HFD Waipahu Maintenance Facility from Pearl City SPS Waipahu SPS 60 Bend Urban Forestry Nursery Yard Ted Makalena Golf Course

16 Project Challenges Exist. 74 and 60 bends Long lead times for materials (custom bends, connection fittings, etc.) Poor soil conditions Funding requirements

17 Design Concept Slip line in two pulls (per pipe) 74 Bend Slip line Phase I (1,000+/ feet) Slip line Phase II ( 240+/ feet ) Waipahu SPS HFD Waipahu Maintenance Facility 60 Bend Urban Forestry Nursery Ted Makalena Golf Course

18 Design Concept Utilize bend locations as slip line launch/termination points Alt.: Slip line or open cut last section 74 Bend Exit Pit Phase I & II Slip line Phase I (1,000+/ feet) Entry Pit Phase I Slip line Phase II ( 240+/ feet ) Entry Pit Phase II Waipahu SPS 60 Bend HFD Waipahu Maintenance Facility Ted Makalena Golf Course Urban Forestry Nursery

19 Design Concept Slip line Exist. 42 DI with 36 FPVC Exist. 30 DI with 24 FPVC 74 and 60 bends Investigate bends Replace with custom PVC bends Bypass System Alignment to allow access to Fire Department Maintenance Facility

20 Design Concept Bypass System Bypass during dry season: max dry weather flow (27 MGD) Use bypass to service daily flows Maintain one force main pipe on standby for peak flows 74 Bend Waipahu SPS 60 Bend HFD Waipahu Maintenance Facility Urban Forestry Nursery Bypass Alignment Ted Makalena Golf Course

21 Design Concept Grout annular pipe space Provide flexible expansion joint to accommodate soil conditions

22 Construction Challenges 74 and 60 bends composed of multiple fittings and ball joints (in good condition) Maintain bends; redesign connections Modify thrust blocks 74 Bend 60 Bend

23 Construction Challenges Deviations in existing FM alignment

24 Construction Challenges Deviations in existing FM alignment Underground electrical conduits in location of insertion pit

25 Construction Challenges Grouting annular space

26 Construction Challenges Receiving Pit Phase I & II Entry Pit Phase I Waipahu SPS HFD Waipahu Maintenance Facility Entry Pit Phase II Existing Generator Building Urban Forestry Nursery Ted Makalena Golf Course

27 Construction Challenges Existing generator building: difficult installation angle 24 FPVC 36 FPVC

28 Construction Challenges

29 Construction Challenges

30 Lessons Learned Condition Assessment of DIP Test pull slip line section Utilize pulling head and pressure gauge on winch Require comprehensive grouting plan

31 Conclusions Slip lining with FPVC was successful in restoring force mains Minimal hydraulic impacts to FM system Reduction of spill potential Restored service life of pipe section

32 Questions? Thank You Russell Takara, P.E. Kyle Kaneshiro, P.E. The City & County of Honolulu Department of Design and Construction Wastewater Division