CALLEGUAS MUNICIPAL WATER DISTRICT ENGINEERING & CONSTRUCTION COMMITTEE April 27, 2015

Transcription

1 CALLEGUAS MUNICIPAL WATER DISTRICT ENGINEERING & CONSTRUCTION COMMITTEE April 27, 2015 NOTICE AND CALL OF A MEETING OF THE CALLEGUAS ENGINEERING & CONSTRUCTION COMMITTEE An Engineering & Construction Committee Meeting of Calleguas Municipal Water District is hereby called and notice of said meeting is hereby given for 5:00 p.m. on Monday, April 27, 2015 at Calleguas Municipal Water District, 2100 Olsen Road, Thousand Oaks, California. The Calleguas Municipal Water District s Engineering & Construction Committee meeting is noticed as a meeting of the Board of Directors for the purpose of compliance with the Brown Act. Members of the Board who are not assigned to the Engineering & Construction Committee may attend only as observers and cannot participate as members of the Board, whether or not a quorum of the Board is present. In order to preserve the function of the committee as advisory to the Board, members of the Board who are not assigned to the Engineering & Construction Committee will not vote on matters before the Engineering & Construction Committee. A. CALL TO ORDER AND ROLL CALL Steve Blois, Chair Andres Santamaria, Committee Member B. PUBLIC COMMENTS A G E N D A Opportunity for members of the public to address the committee on matters within the committee s jurisdiction (as required by Government Code Section (a)). Please limit comments to three minutes. C. COMMITTEE ITEMS 1. Discussion regarding CCNB/CCSB Broken Back Prevention and Rehabilitation Preliminary Design Report 2. Discussion regarding the capital improvement program (CIP) schedule, staffing, and financing 3. Discussion regarding findings of the Santa Susana Tunnel inspection D. OTHER COMMITTEE ITEMS Page 1 of 2 Calleguas MWD Engineering & Construction Committee Agenda April 27, 2015

2 E. FUTURE AGENDA ITEMS F. ADJOURNMENT NOTE: At the discretion of the committee, all items appearing on this agenda, whether or not expressly listed for action, may be deliberated and may be subject to action by the committee. This committee reviews items and makes a recommendation for final action to the full Board of Directors. Final action will be taken by the Board of Directors. Agendas for the meeting of the Board of Directors may be obtained from the Clerk of the Board. This committee will not take any action that is binding on the Board, even when a quorum of the Board is present. Writings relating to open session agenda items distributed to Directors less than 72 hours prior to a meeting are available for public inspection at Calleguas Administrative Office Building. Requests for a disability related modification or accommodation, including auxiliary aids or services, in order to attend or participate in a meeting should be made to the Clerk of the Board in advance of the meeting to ensure availability of the requested service or accommodation. Page 2 of 2 Calleguas MWD Engineering & Construction Committee Agenda April 27, 2015

3 CCNB/CCSB Broken Back Prevention and Rehabilitation ENGINEERING & CONSTRUCTION COMMITTEE MEETING APRIL 27, 2015

4 Overview Broken Back Failures Potential Locations of Concern Potential Rehabilitation Approaches Prioritization of Sites Recommended Next Steps

5 Broken Back Failures Caused when PCCP experiences high stress at the transition from concrete encasement or steel casing to granular backfill. With the rigidity of the encasement/casing and relatively soft backfill outside, stress concentrates on the pipe at the transition point where the encasement/casing ends, tearing the pipe can. Potential for multiple failures during a seismic event.

6 Broken Back Failures Year Material Dia. Line Location Type of Failure 1997 PCCP 66 CCNB Madera and Royal Wire Breaks 2004 PCCP 48 Calleguas Conduit Fitzgerald and Appleton Broken Back 2005 PCCP 78 CCNB Madera and Strathearn Steel Liner/ Wire Breaks 2007 PCCP 51 Calleguas Conduit Railroad Tracks and Broken Back Yosemite 2007 PCCP 51 Calleguas Conduit Railroad Tracks West of Joint Stearns 2010 PCCP 78 CCNB Near West Portal Broken Back

7 Potential Locations of Concern 250 cfs 80 cfs Legend 78 CCNB 66 CCNB 51 Calleguas Conduit 48 Calleguas Conduit West Portal

8 Potential Locations of Concern Conditions meriting concern: PCCP is installed at the transition of concrete encasement or steel casing and granular backfill. AND The pipeline has not already been repaired as a result of a failure. Nearly 100 locations of potential concern were identified, most of which would need to be addressed at both ends of the encasement/casing.

9 Potential Rehabilitation Approaches 1. Installation of cement-sand slurry 2. Carbon fiber reinforcement 3. Steel liners

10 Installation of Cement-Sand Slurry Placement of cement-sand slurry at the transition area and approximately feet beyond would provide a more gradual transition from the end of the encasement/casing to the granular backfill. Although stiff, the lower strength of the cement-sand slurry would offer some flexibility as compared to the encasement/casing and reduce the stress on the pipe. This is how we construct new encasements and casings.

11 Installation of Sand-Cement Slurry

12 Installation of Sand-Cement Slurry Advantages: Least costly (approximately $250,000 per location for both ends). It is possible to perform the work without taking the pipeline out of service (although the pipe must be properly supported). Disadvantages: Ground movement (settlement or heave) that completely undermines the cement-sand slurry would negate the benefit of the slurry. Construction must be performed by open excavation often near obstructions that limit surface accessibility (such as near creeks/watercourses, within roads, and near railroad tracks) and in shallow groundwater conditions. Not feasible at all locations due to lack of surface accessibility.

13 Carbon Fiber Reinforcement Carbon fiber reinforcement involves the placement of layers of carbon fiber cloth saturated in epoxy longitudinally and transversely inside the pipe. Carbon fiber can be installed through manholes (exposed or buried). Calleguas has effectively used this approach to address wire breaks in PCCP.

14 Carbon Fiber Reinforcement

15 Carbon Fiber Reinforcement Provides for withstanding the existing external and internal forces on a pipe without assistance from the host pipe. Considers the pipe to be a cantilevered beam with the encasement/casing on the fixed end resisting a load (settlement or heave) 20 feet away that would cause a deflection of ½ inch or 1 inch (depending on pipe size). Assumes groundwater is present.

16 Carbon Fiber Reinforcement Although some agencies have concerns about delamination or the structural sufficiency of carbon fiber, Calleguas and P&I have investigated those issues and remain confident that it is an appropriate and reliable approach for this application.

17 Carbon Fiber Reinforcement Advantages: All work can be performed by entering through manholes (most of which are exposed at ground surface). In some locations, it is the only feasible approach due to lack of surface accessibility. Disadvantages: Highest cost (approximately $500,000 per location for both ends). Pipeline must be taken out of service to perform the work.

18 Steel Liners Steel liners can be installed, but access must be accomplished by excavating and removing a segment of PCCP. Similar to carbon fiber, the reinforcement would be placed through the transition area to provide increased resistance to stress generated by differential movement at the transition point. Because the steel cylinder is flexible, if the host PCCP fails, the steel cylinder will resist the added stress or deflect to relieve stress.

19 Steel Liners Advantages: Less costly than carbon fiber (approximately $400,000 per location for both ends). Some flexibility in location of excavations. Disadvantages: More costly than cement-sand slurry. Pipeline must be taken out of service to perform the work. Excavation is required and shallow groundwater may be an issue. Larger work area required than either cement-sand slurry or carbon fiber.

20 Selection of Preferred Rehabilitation Approach In order to use cement-sand slurry, there must be: Sufficient available surface accessibility for excavation at exact location. In order to use carbon fiber, there must be: Enough information to determine the location of the end of encasement/casing. Sufficient proximity to manholes for access and ventilation. Flat to moderate pipe slope between the access point and the rehabilitation location. In order to use steel liners, there must be: Enough information to determine the location of the end of encasement/casing. Sufficient available surface accessibility for excavation nearby.

21 Prioritization of Sites Do not address manhole encasements unless adjacent to a railroad track. Do not address CCSB unless adjacent to a railroad track. Prioritization for timing of the work: Longer encasements/casings have priority over shorter encasements/casings. Encasements constructed across soft bottom channels have priority over encasements installed for other reasons. Soft bottom crossings which have not had any hardscape improvements since construction have priority over those which have had a road constructed over, have had the channel armored, or have been realigned/improved (RCB). These priorities only apply to the phasing of slurry sites; phasing of steel liner and carbon fiber rehabilitation will ultimately be driven by shutdown schedules.

22 Prioritization of Sites Once these criteria have been applied, 25 priority sites remain with a total estimated cost of approximately $11 million: CCNB 15 Sites 5 carbon fiber reinforcement 10 cement-sand slurry CCSB 10 Sites 5 carbon fiber reinforcement 2 cement-sand slurry 3 steel liner Note: It is possible that some slurry sites could have to change methods if the City finds that the proposed traffic control poses an unacceptable burden on traveling public.

23 Recommended Next Steps Move forward with all three types of rehabilitation projects on parallel tracks. Cement-Sand Slurry: Initiate design for first phase of cement-slurry installation (3 highest priority sites). After completion of rehabilitation at first few sites, perform design for the remainder of sites (could be one or two more phases). Carbon Fiber and Steel Liner (together due to shutdown requirements): Initiate design for first phase of carbon fiber and steel liners based on which pipelines will be shut down in winter or (depending on staffing). In subsequent years, perform additional phases of fiber rehabilitation as CCNB/CCSB shutdowns allow.

24 Questions and Discussion

25 Calleguas Municipal Water District Capital Improvement Program Projected Schedule Current Staffing Level of Year of Project Uncertainty Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Completion Infrastructure Reliability, Rehabilitation, and Replacement CCNB/CCSB Blow Off Investigation/ Rehabilitation High NA Anode Well Replacement Low Broken Back Rehabilitation (Slurry, Ph1) Low Broken Back Rehabilitation (Slurry, Ph2) Low Broken Back Rehabilitation (Shutdown, Ph 1) Medium Broken Back Rehabilitation (Shutdown, Ph 2) Medium Broken Back Rehabilitation (Shutdown, Ph 3) Medium Broken Back Rehabilitation (Shutdown, Ph 4) Medium Broken Back Rehabilitation (Shutdown, Ph 5) Medium OSR and LPF Improvements Low Mesa Feeder Anchor Walls Low later Programmable Logic Controller (PLC) Replacement Low Emergency Repairs and Other Rehab/Replacement High NA Lake Bard and Wellfield Wellfield Standby Generators Low Miscellaneous Wellfield Improvements Low Sulfuric Acid Improvements Low Grandsen Pump Station, Phase 2 Low Wellfield Treatment Plant Low Conejo Pump Station Rehabilitation Medium Salinity Management Pipeline PHWA Discharge Station Low SMP Control Tank Low SMP 2B Low SMP 2D Low SMP 2E Medium SMP 3 Medium SMP 4 Medium SMP Discharge Stations High NA Emergency Pipe Procurement (PVC/HDPE) Low Interconnections LVMWD Interconnection Low Desalter Turn Ins High NA Low Water Quality Turn Ins High Hydro East Portal ARIG Low Springville ARIG Medium Miscellaneous Security Cameras (non LBWFP) Low later average Notes: Numbers are estimated hours per week. Total "available" project hours are 86 hrs/week with 3 PMs. Color code: blue preliminary design (4 hr/week default) green design (8 hr/week default) orange construction (12 hr/week default) purple post construction (2 hr/week default) red other

26 Calleguas Municipal Water District Capital Improvement Program Projected Schedule Additional Project Manager Level of Year of Project Uncertainty Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Completion Infrastructure Reliability, Rehabilitation, and Replacement CCNB/CCSB Blow Off Investigation/ Rehabilitation High NA Anode Well Replacement Low Broken Back Rehabilitation (Slurry, Ph1) Low Broken Back Rehabilitation (Slurry, Ph2) Low Broken Back Rehabilitation (Shutdown, Ph 1) Medium Broken Back Rehabilitation (Shutdown, Ph 2) Medium Broken Back Rehabilitation (Shutdown, Ph 3) Medium Broken Back Rehabilitation (Shutdown, Ph 4) Medium Broken Back Rehabilitation (Shutdown, Ph 5) Medium OSR and LPF Improvements Low Mesa Feeder Anchor Walls Low Programmable Logic Controller (PLC) Replacement Low Emergency Repairs and Other Rehab/Replacement High NA Lake Bard and Wellfield Wellfield Standby Generators Low Miscellaneous Wellfield Improvements Low Sulfuric Acid Improvements Low Grandsen Pump Station, Phase 2 Low Wellfield Treatment Plant Low Conejo Pump Station Rehabilitation Medium Salinity Management Pipeline PHWA Discharge Station Low SMP Control Tank Low SMP 2B Low SMP 2D Low SMP 2E Medium SMP 3 Medium SMP 4 Medium SMP Discharge Stations High NA Emergency Pipe Procurement (PVC/HDPE) Low Interconnections LVMWD Interconnection Low Desalter Turn Ins High NA Low Water Quality Turn Ins High Hydro East Portal ARIG Low Springville ARIG Medium Miscellaneous Security Cameras (non LBWFP) Low average Notes: Numbers are estimated hours per week. Total "available" project hours are 112 hrs/week with 4 PMs. Color code: blue preliminary design (4 hr/week default) green design (8 hr/week default) orange construction (12 hr/week default) purple post construction (2 hr/week default) red other

27 Available Resources with Current Staffing REB CCR FB KEM Eng Total Project Developers MoE Overhead Total MoE time for project related PM support and review, plus non project related, admin, and misc tasks. 2 Weekly estimate based on annual allowance for holidays (10 days), vacation (18 days), sick (12 days), and training (10 days). Available Resources with Additional PM REB CCR FB PM4 KEM Eng Total Project Developers MoE Overhead Total MoE time for project related PM support and review, plus non project related, admin, and misc tasks. 2 Weekly estimate based on annual allowance for holidays (10 days), vacation (18 days), sick (12 days), and training (10 days).

28 2015 PERLITER TUNNEL INSPECTION Engineering & Construction Committee Meeting April 27, 2015

29 Santa Susana Tunnel 7,260 feet of 96-inch Tunnel

30 Issues of Concern and Analysis Rusted beam Stalactites Cracks Visible rust Water leaking into tunnel

31 Rusted Beam

32 Rusted Beam Replace beam during next shutdown opportunity (work expected to be <$35K)

33 Stalactites

34 Stalactites

35 Stalactites Laboratory Analysis: Primary Components: Calcium, Strontium, Silicon, Sodium, and Barium Lesser Components: Aluminum, Arsenic, Iron, Magnesium, Silver, Titanium, and Zinc Verdict: Naturally occurring ore migrating from outside the tunnel and being deposited similar to a stalactite in a cavern.

36 Cracks

37 Visible Rust

38 Visible Rust

39 Water Leaking into Tunnel

40 Conclusions and Recommendations No structural issues are believed to be present. Cracking and leaks could be addressed with some combination of grouting and/or weko seals, but the cost and effort does not seem warranted by the observed conditions. Recommend inspecting tunnel again in 2020 (5 years), which is sooner than recommended by EWSP (10 years).

41 Questions and Discussion