Making the Right Decision to Rehabilitate: An 1894 Vintage ... · Preliminary Design Report Findings and Recommendations •Alternative 2: Aluminum multi-span roof Preferred long-term

Making the Right Decision to Rehabilitate: An 1894 Vintage Reservoir

• Annual Fall Conference, Las Vegas, NV• Wednesday, October 28, 2015• Session 16 – Operator• Keeping you Out of Trouble on Capital Projects--Part I• 10:00 a.m. to 11:00 a.m.

11/11/2015 AFC15 Slides 1

AWWA CA/NV Presentation on Forbes Hill Tank

Carl A. Gowan, P.E., MMWDGary Ho, S.E., Beyaz & Patel

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Agenda

• History/Background• Project Purpose/Options• Project Schedule/Public Outreach• Preliminary Design Report• Design• Construction• Summary

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History/Overview

• Marin Municipal Water District founded in 1912

• 147 square miles• 188,200 population• 60,000 service connections• Service elevations from sea level to 1200 feet

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Site Plan

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Water Demand & Supply

• 32,000 AF/YR• 45 MGD maximum day • Seven lakes and Agency Intertie • Two full scale treatment plants (20 MGD, 30

MGD)• One finishing treatment plant for Intertie (12

MGD)

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Four Upper Lakes

Three Lower Lakes

SGTP

BTTP

Intertie TP

Forbes Hill

Tank

Schematic

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• Constructed 1894/1895; 2.4 MG• Relined 1927; Waterproofed 1951• Enlarged 1984; 4 MG; Included steel

shell & floating cover• Seismic upgrade 1998

Forbes Hill Reservoir (Now known as Forbes Hill Tank)

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11/11/2015 11Existing Floating Hypalon Cover

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Existing Floating Hypalon Cover

• Water quality risk• 2004-2012 Worker safety & maintenance

issues• Open space in 1960’s era homes and

community• Adjacent pump station

Forbes Hill Tank

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• Increase protection for water • Reduce maintenance• Improve worker safety• On-site renewable energy• Minimize community disruption

Project Purpose

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Evaluated Options

• Replace liner and cover; $1.7 million• Replace liner and new roof; $3.7 million• New tank; $12.7 million

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• Design study; summer/fall 2013; 6 months• Final design; winter/spring 2013/2014; 6 months• Site preparation; summer/fall 2014; 4 months• New roof; winter/spring 2014/2015; 6 months• Solar panels; winter/spring 2015/2016; 6 months

Project Schedule

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Public Outreach• Marin Independent Journal

(press release)• Communications with

neighbors

Century-old reservoir slated for overhaul (Marin IJ, Nov. 18, 2014)

Hello Neighbors,

Thanks to the Hepburn Heights residents for allowing access for the concrete pour this past Tuesday. I’ve attached the Contractor’s 3-week Look Ahead Schedule for your view. Just a couple minor items for you to consider:

1. The Contractor will have a small crew onsite tomorrow, Saturday, excavating footings inside the reservoir. This is mostly hand excavation work using shovels and pneumatic spades. This is the first time we’ve had Saturday work on the project, which may bemore increasingly necessary in the coming months. As a reminder, we have a relatively short window to complete this project before next May in order to maintain water service during the dry season. The Contractor is allowed to work Saturdays to accomplish this task. We’ll continue to monitor noise levels and do what we can to mitigate the impact to neighbors.

2. The Contractor may utilize a truck mounted crane next Thursday, 11/20, to remove slabs of concrete from the reservoir. As with the previous concrete pours, we’d ask that Hepburn residents park cars closer to the side of the road to allow adequate access. I will send a reminder email next week if the the crane delivery is to take place.

Thanks for your cooperation and as always, feel free to contact me as needed at (707) 344-8203.

Sincerely,

Clay Kuzma | The Covello Group, Inc. | Cell: (707) 344-8203

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Engineering Design Phase

• PDR• Design Phase• Bid Phase• Construction Phase

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Objectives

• Evaluate alternative roof systems• Support solar panels• Low profile roof structure• Limit construction to winter months

(November through April)

Preliminary Design Report

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Preliminary Design ReportRoof Replacement Alternatives

Alternative 1: Steel multi-span conceptAlternative 2: Aluminum multi-span conceptAlternative 3: Steel clear-span conceptAlternative 4: Aluminum clear-span concept

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Preliminary Design Report

Alternative 1: Steel Multi-Span Concept Drawings

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Preliminary Design Report

Alternative 2: Aluminum Multi-Span Concept Drawings

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Preliminary Design Report

Alternative 3: Steel Clear-Span Concept Drawings

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Preliminary Design Report

Alternative 4: Aluminum Clear-Span Concept Drawings

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Preliminary Design ReportData Summary

Factor

AlternativeSteel

Multi-Span Roof1

Aluminum Multi-Span Roof

2

Steel Clear-Span Roof

3

AluminumClear-Span Roof

4

Advantages Lowest Peak Profile (6’)

Low Rim Profile (1’)Low Peak Profile (7’)Lightest Concept (Weight)Least ExpensiveLow Maintenance CostGreen DesignRecycle CreditStronger Panels No Int. Columns

No Interior ColumnsLow Maintenance CostGreen DesignRecycle CreditStronger Panels

Disadvantages

Interior Columns (24)Seal Around Int. ColsHigh Maintenance CostHigh Ventilation RequirementsMaintenance Downtime

High Reflectance Interior Columns (26)Seal Around Int. Cols

Medium Profile (10’)Heaviest ConceptMost ExpensiveHigh Maintenance CostMaintenance DowntimeHigh Ventilation Requirements

High Profile(15’)High Reflectance

Construction Schedule 8-10 months 8-10 months 7-9 months 7-9 monthsReservoir Downtime(5 Winter Months) 5-6 months 5-6 months 4-5 months 4-5 monthsMaintenance Schedule

Inspection (7.5 years)Roof Recoat (20 years) Inspection (7.5 years)

Inspection (7.5 years)Roof Recoat (20 years) Inspection (7.5 years)

Initial Capital Cost $2,203,000 $2,616,000 $2,486,000 $3,125,000

O&M Cost$1,000,000

($500K/20 years) $20,000$1,000,000

($500K/20 years) $20,000

Total Capital Cost $3,203,000 $2, 636,000 $3,486,000 $3,145,000

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Preliminary Design ReportComparison Analysis

Factor

Alternative

Steel Multi-Span Roof

1

Aluminum Multi-Span Roof

2

Steel Clear-Span Roof

(Truss)3

AluminumClear-Span Roof

4

1a. Minimize Visibility-Peak Profile0.40 (9)

(6’)0.47(7’)

0.67(10’)

1.00(15’)

1a. Minimize Visibility-Rim Profile0.40(2’)

0.20(1’)

1.00(5’)

0.20(1’)

1c. Minimize Visibility-Reflectance 0.501.00

(0.50) 0.501.00

(0.50)

2. Support Solar Panels - - - -3. Construct Inside Security Lines - - - -4. No Interference with MERA Facilities - - - -

5. Closure Panel - - - -6. Out of Service Wintertime Construction Period

1.00(5-6 months)

1.00(5-6 months)

0.82(4-5 months)

0.82(4-5 months)

7a. Constructability: Noise Impact 0.50 0.50 1.00 1.00

7b. Constructability: Truck and Vehicle Traffic, Crane, etc. 1.00 0.50 1.00 0.508. Life Cycle Cost (Construction, O&M, Re-Coat)

0.91($3.2M)

0.74 (0.74)($2. 6M)

1.00($3.5M)

0.89 (0.89)($3. 1M)

9. Operation and Maintenance Cost1.00

($1,000K)0.02

($20K)1.00

($1,000K)0.02

($20K)

10. Construction Timeline1.00

(8-10 months)1.00

(8-10 months)0.89

(7-9 months)0.89

(7-9 months)

Totals 6.715.43

(4.90) 7.88 6. 32(5.78)11/11/2015 26

Preliminary Design ReportFindings and Recommendations

• Alternative 2: Aluminum multi-span roofPreferred long-term roof solutionCorrosion resistanceMaintenance freeLowest score/Best alternativeMost effective life cycle costLow rim heightLowest peak profile height from top of shell

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Design PhaseMajor Design Components/Elements

• Aluminum multi-span roof• Liner• Underground overhead power line serving

Marin Emergency Radio Authority (MERA)• Overflow pipe modifications• Outlet structure modifications• Strict qualifications for subcontractors and

suppliers

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Design Phase

Roof Plan

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Design Phase

Longitudinal Section

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Design Phase

Exterior Column Support11/11/2015 31

Design PhaseDesign Challenges

• Coordinate preliminary roof design with roof supplier

• Roof support on exterior columns• Columns designed to resist lateral loads (roof

suppliers)• Design schedule

6 months (November 2013 to May 2014)50%, 85% and final submittalsDesign review meetings

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Bid PhaseBid and Award

• Six competitive bids• 30% spread between bidders• Low bidder: AZTEC Consultants• Bid price: $3.04 million

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Construction PhaseConstruction Challenges

• Reservoir shutdown requirements• Outlet structure revisions• Change orders• Final work on-going, complete in January

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Scheduled Activity Date Begin Date End

Construction August 1, 2014 April 30, 2015

MERA Undergrounding

September 2014 October 2014

Tank out-of-service October 15, 2014 April 30, 2015

Liner, roof, and pipe installations

October 2014 April 2015

Clean, disinfect, fill, test

March 2015 April 2015

Construction PhaseConstruction Schedule

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Construction Phase

Construction Photos

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Existing Floating Hypalon Cover

Crane location

11/11/2015 37Overhead Power Line

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MERA Underground Work

11/11/2015 39Reservoir with Floating Cover Removed

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Demo Existing Liner

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Column Footing Complete

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First Column for New Aluminum Roof

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New Aluminum Roof

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New Aluminum Roof Framing

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Tension Ring Strut/Shoe

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Existing Outlet Pipes

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Tunnel Piping Removal

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Outlet Structure Reconstruction

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Outlet Pipe

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Outlet Tunnel

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New Outlet Pipes

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Filling Reservoir

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Overflow Piping

111th Aerial Photography

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New Aluminum Roof

• Repair liner leaks• Touch up paint on overflow box• Install missing blots inside tank• Repair peeling weather stripping• Turn over all project files

Outstanding Punch-List Items

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Tank Project Cost

Category Budget Projected Total

Construction, Final* $3,042,200 $3,060,195

Design Services $379,394 $375,863Project and

ConstructionManagement $471,956 $372,058Less: MERA Reimbursement, Final ($93,550) ($93,116)Total $3,800,000 $3,715,000

*Change orders total net cost of $17,995 = 0.6% of original contract

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• Install solar panels on new roof– Operate Grove Hill

Pump Station– Estimated Cost

$65,000– Ten-year payback– Completion March

2016

Solar Project

111th Aerial Photography

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• Project Management• Construction Management• Design• Construction• Community Outreach

Lessons Learned

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Questions?

• Contractor: Aztec Contractors• Construction Manager: The

Covello Group• Design: Beyaz & Patel, Inc.• Liner Design: Hilts Consultants• Civil Works Design: IEC

Consultants• Roof Supplier: CST Covers• Liner Manufacturer: Burke

Environmental Products• Liner Fabricator and Installer:

MPC Containment System