Industrial Tank

Modesto, CA

Yosemite Avenue ( H

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DECEMBER 2010

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Preliminary Design Report

Industrial Tank 13 and Pump Station

12/03/10

12/03/10

City of Modesto Industrial Tank 13 and Booster Pump Station PRELIMINARY DESIGN REPORT FINAL December 2010

City of Modesto Industrial Tank 13 and Booster Pump Station PRELIMINARY DESIGN REPORT TABLE OF CONTENTS Page 1.0  2.0  3.0 

BACKGROUND ...........................................................................................................1  SITE LAYOUT AND DRAINAGE .................................................................................2  PRESTRESSED CONCRETE RESERVOIR...............................................................3  3.1  Reservoir Accessories.......................................................................................3  3.2  Reservoir Structural Requirements ...................................................................4  4.0  BOOSTER PUMP STATION DESIGN CRITERIA.......................................................4  4.1.1  Pump Station Building........................................................................ 4  4.1.2  Pump Selection.................................................................................. 4  4.1.3  Valve Selection .................................................................................. 5  4.1.4  Process Piping ................................................................................... 6  4.2  HVAC Design ....................................................................................................6  4.2.1  Pump Room ....................................................................................... 6  4.2.2  Electrical Room.................................................................................. 6  4.2.3  Chlorine Room ................................................................................... 7  4.3  Surge Protection................................................................................................7  4.4  Chlorine Storage and Feed System ..................................................................7  5.0  PUMP STATION STRUCTURAL AND ARCHITECTURAL .........................................8  6.0  LANDSCAPING PLAN.................................................................................................8  7.0  ELECTRICAL SYSTEM CONTROLS / SCADA...........................................................9  7.1  Electrical Design Criteria ...................................................................................9  7.1.1  Main Switchboard Type and Capacity ............................................. 10  7.1.2  MCC Type and Capacity.................................................................. 10  7.1.3  Electrical Design Standards............................................................. 10  7.1.4  Grounding System ........................................................................... 10  7.1.5  Standby Generator Sizing and Selection ......................................... 11  7.1.6  Application of Conduit Materials and Minimum Sizes ...................... 11  7.1.7  Enclosures for Corrosive Locations ................................................. 11  7.1.8  Switchboard and MCC One Line Diagrams ..................................... 11  7.1.9  Conduit and Wiring schedules ......................................................... 12  7.2  Pump Station Control and Monitoring..............................................................12  7.2.1  SCADA Scheme .............................................................................. 12  7.3  Security Design Criteria...................................................................................12  7.3.1  Site Access and Control................................................................... 12  7.3.2  CCTV System .................................................................................. 13  7.3.3  Intrusion Detection and Fire Alarm .................................................. 13  8.0  COST ESTIMATE ......................................................................................................13  RECOMMENDATION ..........................................................................................................15 

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LIST OF APPENDICES ABCDEF-

35% Preliminary Design Drawings Technical Memorandum – INDUSTRIAL #13 TANK MATERIAL EVALUATION List of Specifications Design Data Surge Analysis Geotechnical Report

LIST OF TABLES Table 1  Table 2  Table 3  Table 4  Table 5  Table 6  Table 7  Table 8 

Reservoir Design Criteria ................................................................................. 3  Distribution System Pressure Criteria .............................................................. 5  Pump Selection Criteria ................................................................................... 5  Process Piping Design Criteria ........................................................................ 6  Chlorine Storage and Feed System ................................................................. 7  Seismic Design Parameters............................................................................. 8  Electrical Equipment Loads ............................................................................. 9  Project Cost Estimate Summary .................................................................... 14 

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City of Modesto

INDUSTRIAL TANK 13 AND BOOSTER PUMP STATION PREDESIGN REPORT 1.0

BACKGROUND

In 1994, Phase One of the Modesto Regional Water Treatment Plant, owned by Modesto Irrigation District, entered into operation providing potable water to the City of Modesto at a rate of 40 million gallons per day to supplement the City’s groundwater sources. Since Phase One, the City water consumption has increased while the City’s groundwater supply has decreased as a result of several wells being taken out of service. Phase Two of the Modesto Regional Water Treatment Plant, initiated in 2007, will double the treatment plant capacity and create a need for additional storage and conveyance infrastructure within the City. The Industrial Tank 13 and Booster Pump Station project will include a water storage tank and booster pump station to service the southeast portion of Modesto. The Tank 13 site is located on Codoni Avenue, approximately half a mile south of Yosemite Boulevard within an industrial area. The 5.3 acre site will include a 4.0 Million Gallon (MG) tank, 12.0 Million Gallon per Day (MGD) pump station, and a retention basin with a 1.0 MG holding capacity. A 24 inch transmission main, through a separate project, will convey water from a Modesto Irrigation District turnout structure on the north side of Yosemite Boulevard to the Tank 13 site. A new 24 inch diameter pipe, also through a separate project, will return water back from the new pump station to an existing City transmission main in Yosemite Boulevard. The potable water storage tank will have the following features: 

4.0 MG capacity.



Pre-stressed concrete, bid competitively for Type I (post-tensioned) or Type III (tilt up).



Low profile flat roof with a 180 foot diameter.

A new pump building will house electrical equipment, pumps, a standby generator, a restroom, and a sodium hypochlorite room. In the vicinity of the pump building there will be a buried meter vault, a fuel tank, and a surge tank. A new MID transformer will also be located on the frontage of Codoni Avenue. The pump station will have the following features: 

Firm capacity of 8,333 gallons per minute (gpm) [12.0 MGD].



Four horizontal split-case pumps (three duty, one standby).



Diesel standby generator: 600 kilowatt (kW) capacity.



3,500 gallon surge tank

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The project site will also allow for the following potential future improvements: 

A second water storage tank.



An additional potable water well.



A second pump station.

The project features are discussed in more detail in the following sections of the Preliminary Design Report.

2.0

SITE LAYOUT AND DRAINAGE

The project site is 5.3 acres and is bounded by a Modesto Irrigation District canal on the north and industrial sites on the west and south. The east portion of the site fronts Codoni Avenue. Refer to the civil site drawings in Appendix A for the project components discussed in this section. The site is currently occupied by the City of Modesto Well No. 277. The existing well produces approximately 800 gpm and will remain in place during construction. After construction, the well will be enclosed within the new security fence and the existing access driveway to Well No. 277 will be removed and accessibility will be provided using a new 20 foot wide driveway. Except for the power supply, this well will not be connected to the new facilities and will continue to feed directly into the City distribution system. AWWA C200 Cement mortar lined and coated steel pipe below grade and fusion bonded epoxy coated and lined pipe above grade will be used for conveying potable water for all yard piping. The improvement of this site will increase site runoff that will be contained in an on-site retention basin. The City of Modesto has requested a 1.0 MG retention basin to contain runoff and tank overflow events. The percolation rate at the basin site has been determined to be 0.11 gal/sq.ft by the Geotechnical Report composed by Blackburn Consulting dated December 2010. Surface runoff into Codoni Avenue will be reduced and limited to the driveway and landscape areas that front Codoni Avenue. A drainage swale will be located along the south limits to convey surface runoff to the basin. A storm drain pipe will be located along the north limits to collect tank overflow/drain and additional surface runoff. The project site will use decorative wrought iron security fencing fronting Codoni Avenue. The wrought iron fencing will be placed 35 feet from the right-of-way line. To deter trespassing, eight foot high “no-climb” security fencing topped with three strands of barbedwire will be placed along the back and side property lines.

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A new 20 foot wide driveway on Codoni Avenue will provide site accessibility. The driveway will have a motor operated sliding gate with a Knox box for emergency access.

3.0

PRESTRESSED CONCRETE RESERVOIR

The 4.0 MG reservoir will be built using prestressed concrete construction in accordance with AWWA D-110. The contract documents will be written to allow bidding based on either a D110 Type I (post-tensioned) or a Type III (tilt-up) to be supplied. The reservoir will have a finished concrete exterior and will not have any additional aesthetic treatment. The reservoir will be constructed ‘at grade’ and will have a flat roof to increase safety while accessing the roof. Table 1 lists the overall design criteria of the reservoir. Table 1

Reservoir Design Criteria Item

Quantity

Capacity, Million Gallons

4.0

Diameter of Tank, feet

180

Side-water depth, feet

22.5

Construction Type1 Roof Type

AWWA D110 Prestressed Concrete Type I or Type III Flat Roof

Notes: (1)

3.1

AWWA D110 Type I and Type III will be competitively bid

Reservoir Accessories

The reservoir will be equipped with the following accessories and appurtenances: 

Reservoir Mixing System. The reservoir will be equipped with a PAX mechanical mixing system. This mixing system will be submerged near the center of the reservoir and will operate continuously. The mixer will be mounted on a tripod system at the bottom of the reservoir.



Fall Protection. The reservoir will have both an interior and exterior ladder, both ladders will have Saf-T-Climb rails installed for use with an anti-fall harness system. The exterior ladder will have an anti-climb cage around the ladder to prevent unauthorized access to the top of the reservoir. Near the top access hatch, the reservoir will have safety railing installed near the edge of the reservoir.



Water Quality Sampling. The reservoir will have a water sampling station provided on the exterior of the reservoir. The sampling station will be constructed of stainless steel

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and will contain three sampling stations to collect water at three different heights through the reservoir. 

3.2

Level Control and Monitoring. The reservoir level will be controlled using a combination altitude/pressure sustaining valve located in the pump building. The level in the reservoir will be monitored by SCADA and the PLC via a pressure transducer that will also be located at the reservoir.

Reservoir Structural Requirements

The reservoir will be constructed in accordance with the following standards: 

2010 California Building Code (CBC).



AWWA D110-04 (Type I or Type III).



ACI 350.

Geotechnical investigations concluded that a traditional spread-footing and slab on grade foundation will be adequate for soil conditions. The large site allows ample space for construction staging for both Type I and Type III tanks. The Geotechnical Report prepared for this project by Blackburn Consultants is contained in Appendix F of this PDR.

4.0 4.1.1

BOOSTER PUMP STATION DESIGN CRITERIA Pump Station Building

The pump station building will contain the pumps, a standby generator, and electrical equipment for existing Well No. 277 and this project. The pump station building will be built using CMU block construction and a metal truss roof system. The pump station will be approximately 40 feet wide by 82 feet long. Below is a list of the major features of the pump station building: 

Four horizontal split case pumps.



A bridge crane to allow operations and maintenance staff to pull pumps and valves from the pump room.



Sodium hypochlorite storage and feed equipment.



Standby generator.



Restroom.



Security - intrusion alarms at exterior doors.

4.1.2

Pump Selection

Design criteria were selected for the pump station based on pressure requirements in the distribution system. The pumps were selected to deliver the maximum flow rate at the

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maximum pressure expected in the distribution system. Table 2 lists the pressure criteria used to select the pumps. Table 2

Distribution System Pressure Criteria Item

Description

Minimum Pressure (psi)(1) Average Pressure (psi)

50

(1)

55

(1)

Maximum Pressure(psi)

60

Note: (1)

Based on pressures observed in distribution system piping along Codoni Avenue

Table 3 lists the pump design criteria. A general layout and section of the pump station are shown on sheets M-1 and M-2 in Appendix A. Pump curves and system curves for the pump station are included in Appendix D. Table 3

Pump Selection Criteria Item

Configuration

Description 3 duty + 1 standby

(1)

Pump Capacity

(1)

Firm Capacity

2,778 gpm per pump 8,333 gpm

(1)

Total Head

148 feet

Shutoff Head

200 feet

Pump Type

Horizontal Split Case Pumps

Drive

Variable Speed

Motor Enclosure

TFEC

Motor hp (each pump) Pump Efficiency

(1)

150 hp 86% at Best Efficiency Point

Note: (1)

4.1.3

Based Pump Model: American Marsh Pump 10x10x12 HD

Valve Selection



Combination Altitude/Pressure Sustaining Valve will be used to control water height in the reservoir. The valve will also be equipped with a differential pressure flow meter assembly that will be used to measure inflow into the reservoir. Singer will be the sole supplier of the valve to match existing City equipment.



Standard AWWA butterfly valves will be used for isolation of the pumps and the pump station.

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

A plug valve will be used to throttle pressure from the transmission main to the suction manifold of the pumps when bypassing the reservoir during maintenance and inspection activities. During this mode of operation, the pump station will be operated in manual control.

4.1.4

Process Piping

The pump station piping will be AWWA C200 cement fusion bonded and coated steel piping for above ground piping and cement mortar lined and coated piping for below grade piping. All piping will be sized to meet the velocity criteria in Table 4. A 16 inch bypass line, shown on Drawing C-1 in Appendix A, will allow the City to manually operate the pump station if the reservoir is out of service. The bypass line can be throttled using the plug valve on the bypass line. This bypass can only be used during manual operation. Table 4

Process Piping Design Criteria Item

Quantity

Maximum Suction Pipe Velocity

4 ft/s

Maximum Discharge Pipe Velocity(1)

8 ft/s

Notes: (1) Velocity criteria may be exceeded at flow meter or at other process equipment.

4.2 4.2.1

HVAC Design Pump Room

The heat generated within the pump room will be ventilated by one side-wall mounted exhaust fan on the south side of the pump station. The exhaust fan will operate using thermostat controls in the pump station; operating when temperatures in the pump station exceed 90 degrees Fahrenheit (F). The exhaust fan will have a capacity of 4,500 cubic feet per minute (cfm). Intake louvers will be located on the west side of the pump station. These louvers will provide air-flow through the pump room. 4.2.2

Electrical Room

The pump station electrical room will be air conditioned to maintain a maximum of 90 degrees F. A 5 ton air conditioning unit and air handling unit will be required to reduce the temperature to 90 degrees F from the heat generated by the VFDs, switchgear, well pump motor control center, and other electrical equipment used. A split system air conditioner will be used with an air handling unit inside of the pump station and a condensing unit placed at the exterior of the pump station building.

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4.2.3

Chlorine Room

The chlorine room will be ventilated by one side-wall mounted exhaust fan on the south side of the pump station. The exhaust fan will operate by thermostat control and will be interlocked with the rooms light switch to ensure a well ventilated room upon entry. The fan will have a capacity of 4,500 cfm to meet a recommended ventilation rate of 60 air changes per hour (AC/hr).

4.3

Surge Protection

A surge analysis of the system has been conducted. The analysis is included in Appendix E of this report. Two scenarios were analyzed, which may potentially result in detrimental transient pressures in the vicinity of the Tank 13 booster pump station. They are sudden loss of power resulting in pump shut down, and a valve closure down stream of the pump station on the discharge pipe. Results indicate a 3,500 gallon surge tank will sufficiently mitigate the surge from the first scenario. For the accidental valve closure scenario, the analyses showed that a controlled rate of valve closure, t > 3 minutes would allow acceptable pressures to be maintained in the vicinity of the pump station.

4.4

Chlorine Storage and Feed System

A chlorine storage and feed system will be housed in the chlorine room. Liquid sodium hypochlorite will be stored in the room and will be pumped via diaphragm chemical metering pump inside the chlorine room to an injection point downstream of the altitude valve in the pump room to boost chlorine residual in the reservoir. The chlorine feed system will operate based on chlorine dose set-points chosen at SCADA and reservoir inflow data received from the altitude valve flowmeter. The design criteria for the chlorine storage and feed system is presented in Table 5. Table 5

Chlorine Storage and Feed System Item

Chlorine Storage Chlorine Concentration Pump Type

Quantity 150 gallons of Hypochlorite 12.5% Diaphragm Chemical Metering Pumps

Pump Configuration

1 Duty Pump + 1 Standby Pump

Piping

Double Contained CPVC Piping

A polyethylene storage tank will be used to store sodium hypochlorite. Secondary containment will be provided by a concrete sump that will receive vinyl ester protective coating.

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5.0

PUMP STATION STRUCTURAL AND ARCHITECTURAL

The Pump station will be constructed in accordance with the 2010 California Building Code (CBC). Geotechnical investigations have determined that a conventional spread footing and slab on grade construction will be adequate for the construction of the pump station. The building will be constructed of steel reinforced mortar filled Concrete Masonry Units (CMU) with a steel truss and metal roof. The foundation will be a conventional spread footing with a concrete slab on grade. Table 6 lists the seismic design parameters that will be used for the construction of the pump station building. Table 6

Seismic Design Parameters Item

Ss, S1 – Acceleration Parameters FA, FV – Site Coefficient

Quantity 0.739g, 0.274g 1.209, 1.852

SMS,sM1– Adjusted MCE* Spectral Response Acceleration Parameters

0.893 g, 0.507 g

SDS,sD1– Design Spectral Acceleration Parameters

0.595 g, 0.338 g

TL, Long Period Transition Period

12 s

Importance Factor

1.50

Seismic Use Group

IV (Essential Facility)

The general aesthetics of the building will be constructed to match the West Tank #12 Pump Station. The building will be constructed of CMU block and the exterior of the building will be finished with split face block for the bottom six courses of block. The top half of the building will have a stucco finish. Architectural layout and elevations are shown on drawing A-1 and A-2 in Appendix A.

6.0

LANDSCAPING PLAN

The landscape design for the Modesto Tank 13 will be focused primarily on screening and ease of maintenance. It will consist of all new landscape material. The plant selections will be arranged in a tiered format with low ground hugging shrubs in the foreground with smaller shrubs and finally taller screening trees for the backdrop. Plant selections will be chosen based on their proven survivability, hardiness, and ease of maintenance. The trees will be a mixture of screening conifers and smaller flowering deciduous broadleaf. The irrigation system will be designed and adhere to applicable water conserving ordinances. The timer will have multi-station programming available. A rain/freeze/thaw shut-off switch will be installed. Quick-Coupler valves will be provided at key locations to provide water access in the landscape for maintenance purposes. December 3, 2010 – FINAL

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7.0

ELECTRICAL SYSTEM CONTROLS / SCADA

7.1

Electrical Design Criteria

This section presents the power distribution requirements for the proposed Tank 13 and Booster Pump Station including estimation of the total load associated with proposed facilities. Also, it includes the criteria for the electrical materials and equipment to be used as a basis for the final design. A summary of the major electrical design criteria is provided here: 

Main utility service for the proposed facilities shall be 480-volt and will replace the existing 480V service currently used to service the well site.



Total new electrical connected load for the proposed facilities would be approximately 590 kilovolt-amperes (kVA) when all equipment is running (or approximately 890 amperes at 480 volts, 3 phase). However, the average electrical demand load will vary with the number of pumps running and related output.



The existing utility pad mounted transformer will need to be replaced and relocated based upon final site configuration. The new location should allow access by the serving utility, Modesto Irrigation District (MID), as well as meet the site security needs. Also, the secondary of the new pad should include provisions for future secondary tie ins should a second electrical service be required (i.e., future expansion and/or future regional pumping facility).



The MID 480-volt power service entrance from the transformer to the electrical meter enclosure shall be with underground cables, to conform to their requirements.

The pump motors will include variable frequency drives on all pumps. The following Table 7 includes the connected electrical equipment loads and the estimated demand for the new pump station. Table 7

Electrical Equipment Loads New Process Load

Connected Load (kVA)

Demand Load (kVA)

Miscellaneous Lighting, Controls, Mechanical, and Receptacles

60

60

Existing Well Pump

80

80

Pump No. 1

150

150

Pump No. 2

150

150

Pump No. 3

150

150

Pump No. 4

150

Redundant – Standby

Total

740

590

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7.1.1

Main Switchboard Type and Capacity

The main switchboard (MSB) will be a NEMA 3R assembly located within the same yard as the MID pad mount transformer. It will contain the main service disconnect as well as the feeder to the automatic transfer switch (ATS). There will be an ATS connected for the operation and control of the standby generator. The ATS, an open transition type, should be located within the electrical room for environmental and security concerns. The estimated electric connected load of the new equipment will be approximately 590 kVA, which corresponds to approximately 890 amperes. The initial equipment cost for either switchboard rating is very similar at the bidding time when specified manufacturers compete for supplying the products; therefore, the larger switchboard rating of 1,200 amperes should be specified because it will include ample spare capacity for any future changes. 7.1.2

MCC Type and Capacity

The new MCC will be NEMA 4/12 assemblies with active ventilation were required. It will contain the feeder breakers, pump’s VFDs, as well as all the miscellaneous loads. The MCC will also include RTU and control functions of the facility less the existing well site. The well site controls will be local only at the pump. The MCC should be capable of allowing for a future 150 hp well pump VFD should the existing well become contaminated. 7.1.3

Electrical Design Standards

Electrical design shall duplicate the efforts of West Tank 12 for commonalty of function and operation. Electrical design shall conform to the latest editions of the California Electrical Code and local ordinances. Where the requirements of more than one code or standard are applicable, the more restrictive shall govern. 7.1.4

Grounding System

An effective grounding system shall be designed to limit the maximum resistant from main service equipment to grounding electrodes to a magnitude less than 5 ohms. The minimum size of grounding electrode conductors will be No. 3/O AWG and it shall be used to connect the equipment to grounding rods. Also, the noncurrent carrying parts of all electrical equipment, devices, panel-boards, and metallic raceways shall be bonded to the grounding electrode system.

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7.1.5

Standby Generator Sizing and Selection

A standby diesel generator will be sized to provide electrical power to the entire pump station in case power is lost from the utility. The standby diesel engine generator shall be located inside the pump station. The generator will have the following design requirements: 

Estimated Capacity. The estimated capacity of the generator will be 600 kW in order to run the entire facility.



Emission Requirements. The generator will need to meet Tier requirements as determined by the SJARB (San Joaquin Air Resources Board) during the final design. The current Tier requirement is Tier 3 for a generator this size.



Fuel Storage. The diesel storage tank will be housed in a pad mounted double containment fuel tank, specified in accordance to City of Modesto Fire Prevention Department requirements. The diesel storage tank will be sized for 24 hours of operation with the gen-set at full load. No transfer or belly tank is anticipated; however, the tank’s final location might need to consider the gen-set’s fuel pumping capabilities.



Sound Attenuation. Given that the site is located within an industrial park, a minimal attempt to control the sound will be implemented. The generator will be equipped with critical grade mufflers for the exhaust system, and minimal silencers on air intake louvers in order to achieve an approximate sound level of 85dB within 30 feet of the control building.

7.1.6

Application of Conduit Materials and Minimum Sizes

Galvanized rigid steel conduit, flexible seal-tight conduit, polyvinyl chloride-coated rigid steel conduit, and rigid nonmetallic polyvinyl chloride conduit shall be used according to their suitable applications, in different parts of the pump station. All the related material such as couplings, connectors, and fittings shall be manufactured with same materials and process as corresponding conduit. 7.1.7

Enclosures for Corrosive Locations

Electrical equipment, enclosures, and wiring materials installed outdoor or in wet or corrosive locations shall be listed as type NEMA 4X. 7.1.8

Switchboard and MCC One Line Diagrams

Switchboard and MCC one line diagrams will indicate the rating or bus sizes, short circuit rating for each bus, connected motors or miscellaneous load, and size of conduit and wires (power and control) for each load. It will also show schematic and layout reference drawings.

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Switchboard and MCC elevations will indicate locations of feeder breakers or starters. Sheet E002 in Appendix A shows the one line drawing for the MCC. 7.1.9

Conduit and Wiring schedules

The electrical design will include a conduit and wiring schedule with explicit information of all conduit identification and conduit sizes. Also, the wiring schedule will include data about the type of conductors, insulation, the quantity and sizes of conductors per raceway, as well as the origin and destination for each conduit section.

7.2

Pump Station Control and Monitoring

A general overview of the Pump Station’s P&ID can be seen on Sheet I001 in Appendix A, which depicts the general configuration of the proposed tank and pumping station. A further level of detail can be reviewed on subsequent sheets. The existing well site will share common control infrastructure with regards to SCADA, but all functionality and control for hand mode operation and status will remain at the well site for ease of maintenance. 7.2.1

SCADA Scheme

The SCADA for the project will consist of a HSQ RTU with radio communications to Public Works over the current licensed frequency. The SCADA RTU will also serve as the PLC for the pump station and existing well site for automatic operation as well as monitoring. The RTU will be located within its own section in MCC line up. Also being considered at the time of this study is possibly the use of TCP-IP protocol for telemetry (i.e., Internet type connection). The exact configuration of such a system is being explored by City staff on whether wirelesses IP or fiber optic cable to City Water offices on Codoni Rd is the most feasible and reliable methodology. The design team will need to coordinate the design requirements with City staff during the final design process.

7.3

Security Design Criteria

This section presents the security requirements for the proposed Tank 13 and Booster Pump Station including a brief overview of the general systems anticipated being deployed. This shall be criteria for the electrical materials and equipment to be used as a basis for the final design. A summary of the major items are contained below. 7.3.1

Site Access and Control

The site security should include a complete security fence and encompass the entire site. Access into the site should be by motorized vehicular gate with control via HID card reader or keypad. The utility transformer and main switchboard will be located in a “sub-yard” to allow the serving utility access while keeping the balance of the site security. The “sub-yard” will have man door access into the City side for ease of access. The exact details of the December 3, 2010 – FINAL

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configuration will be defined during the final design process with the City and MID such that all requirements are adequately satisfied. Security illumination will be accomplished with City standard light poles. 7.3.2

CCTV System

The system shall consist of a DVR and various cameras located throughout the facility to monitor the activities throughout the facility at all times. Surveillance cameras shall be lowlight type and suitable for outdoor use and located to monitor the following areas: 

Main site entrance.



Tank perimeter and access ladder.



Generator fuel tank/con-vault.



Main entrances into control building.

The system should have the capability to record and store events for an extended period of time and allow remote viewing from Internet/LAN (if available). The DVR should also have an UPS attached to preserve operation during an utility outage while the generator comes online. 7.3.3

Intrusion Detection and Fire Alarm

The system shall monitor various aspects of the site and send an alarm to SCADA and/or a monitoring company. The system shall be operated and controlled via a keypad located within the electrical room. The system shall monitor the following items within the facility: 

Door contacts at all man and vehicle access doors.



Tamper alarm at tank access hatch.

Fire alarm monitoring shall also be provided within the generator room, as required. Fuel storage within the space might require smoke detection and fire sprinklers, and as such will need to be designed accordingly to the California Fire Code and NFPA 72.

8.0

COST ESTIMATE

Given that the design of the pump station is still at a “preliminary” level of completion, this construction cost estimate is considered to be budget-level estimates with accuracies of -10 percent to +40 percent in accordance with the recommendations of the Association for the Advancement of Cost Engineering (AACE). The preliminary construction cost for this project is estimated at $6.58 million.

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Table 8

Project Cost Estimate Summary Item

Cost

Pump Station

$ 857,000

Reservoir

$ 2,163,000

Civil and Site Work

$ 490,000

Electrical and Instrumentation

$ 1,200,000

Landscaping

$ 18,000 $ 4,728,000

DIRECT CONSTRUCTION COST Contingency

15%

$ 5,437,000

Subtotal General Contractor Overhead, Profit & Risk

15%

3%

TOTAL ESTIMATED CONSTRUCTION COST

$ 188,000 $ 6,441,000

Subtotal Sales Tax (Applied to 35% of Direct Cost)

$ 816,000 $ 6,253,000

Subtotal Escalation to Midpoint

$ 709,000

8.375%

$ 139,000 $ 6,580,000

Notes: 1 – Cost does not include property acquisition. 2 – Cost Based on All Cities ENR of 8,920 October 2010 The cost estimate was prepared from the preliminary design concepts, selections of major equipment (pumps, generator, mechanical equipment, etc.), and estimates of temporary facilities required. To account for the preliminary nature of this work, we applied the following contingency factors to the construction cost estimates: 

Design Contingency - 15 Percent - to account for the preliminary nature of the estimates.



General Contractor Overhead and Profit – 15 Percent – to account for overhead and profit for the Contractor. This value also includes general conditions such as mobilization, demobilization, temporary facilities, bonds, insurance, etc.



Escalation to Construction Mid-Point - 3 Percent Annual Rate - estimated escalation to the mid-point of construction that is estimated to be October 2012.

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RECOMMENDATION In summary the development of the Industrial Tank 13 and Booster Pump Station will conform to Phase Two of the Modesto Regional Water Treatment Plant by assisting the City of Modesto in creating additional potable water storage and providing reliable distribution system pressure. The Industrial Tank 13 and Booster Pump Station will contain the following improvements: 

4.0 MG capacity pre-stressed concrete reservoir



Pump station building 

Pump Room 

Firm capacity of 12.0 MGD



Four horizontal split-case pumps (three for duty, one backup)



Electrical Control Room



Chemical Room



Restroom



600 kW diesel standby generator



Fuel tank for standby generator



1.0 MG retention basin



3,500 gallon surge tank



Electric transformer pad



Surge Tank



Perimeter fencing



Motor operated sliding gate with Knox Box



Yard Improvements



Security



Integrated SCADA

December 3, 2010 – FINAL

15

City of Modesto

APPENDIX A – PRELIMINARY DESIGN DRAWINGS Drawing List: 1.

Sheet G01 Cover Sheet

2.

Sheet C01 Civil Notes

3.

Sheet C02 Topographic and Demolition Plan

4.

Sheet C03 Dimension Plan

5.

Sheet C04 Grading Plan

6.

Sheet C05 Site Piping Plan

7.

Sheet A-1 Building Floor Plan

8.

Sheet A-2 Architectural Elevations

9.

Sheet M-1 Pump Station Mechanical Plan

10.

Sheet M-2 Pump Station Mechanical Sections

11.

Sheet E001 Electrical Plans

12.

Sheet E002 Electrical Plans

13.

Sheet I001 Electrical Plans

14.

Sheet I002 Electrical Plans

15.

Sheet I003 Electrical Plans

16.

Sheet L1 Landscape Plan

17.

Sheet L2 Irrigation Plan

December 3, 2010 - FINAL

LANDSCAPE PLAN

IRRIGATION PLAN

City of Modesto

APPENDIX B – INDUSTRIAL 13 TANK MATERIALS EVALUATION

December 3, 2010 - FINAL

2

11/29/10

CITY OF MODESTO INDUSTRIAL TANK 13 TANK MATERIAL EVALUATION FINAL November 2010

11/29/10

CITY OF MODESTO INDUSTRIAL TANK 13 TANK MATERIAL EVALUATION TABLE OF CONTENTS Page No. 1.0 

INTRODUCTION ........................................................................................................1 

2.0 

EVALUATION CRITERIA ...........................................................................................1  2.1  Capital Cost Evaluation ................................................................................. 1  2.2  Operations and Maintenance Cost Evaluation .............................................. 3  2.3  Life Cycle Cost............................................................................................... 3  2.4  Reliability ....................................................................................................... 4 

3.0 

WELDED STEEL TANK .............................................................................................4  3.1  Capital Cost ................................................................................................... 5  3.2  Operations and Maintenance Costs .............................................................. 6  3.3  Life Cycle Cost............................................................................................... 6  3.4  Reliability Issues ............................................................................................ 7 

4.0 

PRESTRESSED CONCRETE TANKS.......................................................................7  4.1  D 110 Type I - Prestressed Concrete Tanks ................................................. 8  4.2  D 110 Type III – Prestressed Concrete Tanks (Tilt-up) ................................. 8  4.3  Capital Cost ................................................................................................... 8  4.4  Operations and Maintenance Costs .............................................................. 9  4.5  Life Cycle Cost............................................................................................. 10  4.6  Reliability ..................................................................................................... 10 

5.0 

TANK MATERIAL EVALUATION .............................................................................11 

APPENDIX – Cost Proposals LIST OF TABLES Table 1  Table 2  Table 3  Table 4  Table 5  Table 6  Table 7  Table 8  Table 9 

Operations and Maintenance Costs ................................................................. 3  Welded Steel Tank Capital Costs .................................................................... 5  Welded Steel Tank Operations and Maintenance Costs ................................. 6  Welded Steel Tank Life Cycle Costs ................................................................ 7  D 110 Concrete Tanks Capital Cost ................................................................ 9  Concrete D 110 Tank Operations and Maintenance Costs............................ 10  Life Cycle Cost for D 110 Concrete Tank ...................................................... 11  “Optimal” Tank Cost Analysis ........................................................................ 12  “Baseline” Tank Cost Analysis ....................................................................... 12  LIST OF FIGURES

Figure 1 

Exhibit 1 - Tank Diameter Options ................................................................... 2 

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Industrial Tank 13

TANK MATERIAL EVALUATION 1.0

INTRODUCTION

The City of Modesto (City) has hired Northstar Engineering and Carollo Engineers to prepare a preliminary design for the Industrial Tank 13 and pump station. These facilities will provide emergency, operational, and fire flow storage for the southeast portion of the City’s distribution system. The tank will receive water from a new 24-inch transmission main along Codoni Avenue, and will feed water to a new 12 million gallon per day (mgd) pump station at the tank site. The tank will hold a total usable volume of 4.0 million gallons (MG) and space will be made available on the site for the future construction of a similarly sized tank and pump station. This technical memorandum evaluates potential materials of construction for the 4-MG tank. Considerations include capital cost, operations and maintenance costs (O&M), and reliability. Three types of tank construction will be evaluated in this report: 

AWWA D 100 welded steel tank.



AWWA D 110 Type I prestressed concrete tank.



AWWA D 110 Type III prestressed concrete tank (Tilt-up).

For each tank material costs are presented for two configurations, a common baseline tank geometry of 180-foot diameter and 22-foot sidewall height, as well as an optimal tank geometry that result in the lowest cost for each tank material. It is assumed that the tank will be at-grade construction and the geotechnical evaluation will result in a traditional foundation design recommendation. Figure 1 shows the potential site layout for the Industrial Tank 13 with the smallest optimal tank diameter option used in this analysis (133 feet) as well as the baseline 180-foot diameter tank. This figure shows that space exists for siting multiple tank geometries with space remaining for future expansion.

2.0

EVALUATION CRITERIA

This section of the report presents assumptions and evaluation criteria used for the comparison of each tank material type identified in the previous section of this memorandum.

2.1

Capital Cost Evaluation

Capital cost estimates were prepared for each of the alternatives based on the conceptual design criteria presented herein. Costs are not intended to be inclusive of all project

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elements and should therefore not be used for project budgeting purposes. Only elements directly impacting tank material selection have been included to allow an accurate comparison to be made. Budgetary cost information was requested of a provided by several suppliers for both concrete and steel tanks. This information was used as a basis for capital costs presented in Sections 3 and 4. No subsurface investigations were conducted to verify geologic information. In addition, layouts are based on existing site boundary information. To account for the preliminary nature of this work, we applied a 10 percent design contingency to the capital cost estimates.

2.2

Operations and Maintenance Cost Evaluation

Operations and maintenance costs vary between steel and concrete tanks. These costs will include cost of structural inspection, cleaning, expected structural repair, and recoating of the welded steel tanks. Table 1 lists the assumed unit costs for O&M tasks. Table 1

Operations and Maintenance Costs Maintenance Required

O&M

Unit

Inspection / Cleaning Cost(1)

$/Hr $100

Recoating Cost(2)(3)

$/SF-Coated Surface Area

Concrete Repair

$/Repair

Cost

Steel Tank X

$8.00 $30,000

Type I Type III Concrete Concrete X

X

X

X

X

Notes: (1) Cleaning and inspection cost based on inspection of the tank by a professional inspection company. (2) Recoating costs based on recent competitive bids for stripping and recoating of steel tank with high solids epoxy. (3) Recoating costs will include a 20% project implementation cost for design and construction management of recoating projects. (4) Concrete repair assumes minor cosmetic and nonstructural cracking repair. Major structural repair is not assumed for this analysis.

2.3

Life Cycle Cost

A life cycle analysis was performed to allow a direct comparison of both capital and O&M costs for all of the proposed alternatives. Annual and projected future costs related to O&M were ‘present worth’ costs taking into account the ‘time value’ of money. This provides a

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good comparison of similar alternatives with different cash flow characteristics. For the purposes of the analysis the following criteria were used: 

Discount Rate: 6 percent -The discount rate is based on historical bond rates available to most cities and municipalities.



Inflation Rate: 3 percent - Inflation rate is based on the consumer price index over the last 30 years.



Life Cycle period: 60 years – Well maintained tanks can have a useful life that can meet or exceed 60 years. Modern cathodic protection systems, coating systems, and modern construction methods have extended the life of steel and concrete tanks, therefore a 60-year life cycle was used.

Future costs to present worth costs are calculated using the following equation: P = F * (1+i)-(n-1) P = ‘Present worth’ Cost F = Future Cost i = Annualized interest rate n = Number of years * = Multiplied by

2.4

Reliability

The analysis of each tank type or material also included a brief qualitative evaluation of reliability. If a type of tank construction offers more reliability than another, it was noted in the analysis. For the purposes of this analysis, down time for O&M procedures was determined to reduce a tank’s reliability.

3.0

WELDED STEEL TANK

The City has historically used welded steel reservoirs to provide distribution system storage due to the lower initial cost compared to concrete. To estimate projected costs for a welded steel tank for Industrial Tank 13 the following assumptions were used: 

AWWA D 100. The tank will be constructed in accordance with AWWA D 100 standards. It is also assumed that the tank will include knuckle type roof and standard appurtenances, such as access hatches, vents, overflow pipe and weir, tank drain, unanchored foundation, sample nozzle, and ladders with safety climb devices.



Ring wall Foundation. It is an assumed that native soil conditions are such that a ring wall foundation can be used.

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

Impressed Current Cathodic Protection. It is assumed that an impressed current cathodic protection system will be used for both the underside and inside of the tank.

3.1

Capital Cost

Tank estimates were obtained from Crosno Constructors and Chicago Bridge and Iron (CBI). The average of the two quotes was used for this analysis. Each supplier provided two quotes, one for a 180-foot diameter tank with a 21-foot side-water depth, and the other an ‘optimally’ sized tank to minimize capital cost. A comparison of capital costs in Table 2 shows $354,000 or 19 percent cost savings with an optimally sized steel tank over the baseline tank size. The optimal tank configuration would require the tank have a diameter of 133 feet, a side wall depth of 38 feet, and a total height of approximately 45 feet with freeboard and a knuckle roof, versus a total tank wall height of 25 feet with the baseline tank dimension. Table 2

Welded Steel Tank Capital Costs Item

‘Optimal’ Tank Size

Baseline Tank Size

Diameter of Tank, ft

133

180

Side-water depth, ft

38

21

Tank Wall Height, ft

45

25

Welded Steel Tank

$1,225,000

$ 1,514,000

Ring Wall Foundation(1)

$84,000 $

Cathodic Protection(2)

$ 25,000

$ 25,000

Engineered Fill Under Tank

$ 4,000

$8,000

Subtotal of Capital Costs

$ 1,338,000

$ 1,660,000

$ 134,000

$ 171,000

$ 1,472,000

$ 1,826,000

$0.37

$0.46

Design Contingency(3) Total Capital Cost Capital Cost per Gallon of Capacity

113,000

Notes: (1) Assumes a 3 foot deep ring wall, with a two foot width. (2) Assumes impressed current cathodic protection system for inside and outside of the tank. (3) Design contingency for items not identified in this level of analysis and are based on 10% of the capital cost.

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3.2

Operations and Maintenance Costs

It is expected that the City will have to perform annual inspection and maintenance on the tank. Based on experience with other municipalities, it is expected that an average of 40 hours of maintenance will be dedicated to the tank annually for cleaning and structural inspection. It is also assumed that every 15 years the tank will need to be recoated. Energy costs for an impressed current system were estimated at $500 per year. Table 3 lists the expected O&M costs of the welded steel tank O&M. Table 3

Welded Steel Tank Operations and Maintenance Costs Cost

Operations / Maintenance Item

Unit Cost

Amount

‘Optimal’ Tank Size

Baseline Tank Size

$100 / hr

40 hr

$ 4,000

$ 4,000

$ 500 / year

1 year

$ 500

$ 500

$4,500

$4,500

Annual Costs Inspection / Cleaning Costs Power costs

Total Annual Costs Recurring Costs Recoating Cost(1)(3)(4) Project Implementation Costs(2)

$8.00 / SF

107,800 SF / 78,500 SF(3)

$ 628,000

$ 862,000

LS

1

$ 126,000

$ 167,000

$ 754,000

$ 1,034,000

Total Reoccurring Costs

Notes: (1) Recoating Includes costs of stripping and coating of interior and exterior of the tank. Costs rounded to nearest thousand dollars. (2) Project Implementation Factor of 20% for design, implementation, construction management, and inspection of the recoating of the tank. (3) Square foot amount for baseline and optimal tank sizes respectively. (4) Recoating was assumed every 15 years.

3.3

Life Cycle Cost

Life cycle costs for the welded steel tank option include capital and O&M costs. Table 4 lists present worth costs for anticipated O&M over the life of the tank and total capital costs. Present worth O&M costs were calculated using the equations shown in Section 2.3. Table 4 shows that there is a significant savings in the life cycle cost using the optimal dimensions versus the baseline dimension. This cost savings is due to the reduction in tank surface area reducing both the initial capital costs as well as the continued recoating costs of the tank.

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Table 4

Welded Steel Tank Life Cycle Costs ‘Optimal’ Tank Size Cost(4)

Baseline Tank Cost(4)

$ 1,472,000

$ 1,826,000

$ 125,000

$ 125,000

Present Worth of Recoating at 15, 30, and 45 years(2)(3)

$ 1,024,000

$ 1,149,000

Total Life Cycle Cost

$ 2,621,000

$ 3,355,000

Criteria Capital Cost Present Worth of Annual O&M Costs(1)(3)

Notes: (1) Present worth factor for annual O&M costs over 60 years: 27.675. (2) Present worth factor for recoating costs at 15, 30 & 45 years: 0.641, 0.411, 0.264 respectively. (3) Present worth = Future cost * present worth factor. (4) Costs were rounded to the nearest thousand.

3.4

Reliability Issues

It is expected that a welded steel tank will need to be recoated every 15 years. Each recoating process typical takes 6 to 10 weeks. During this time the tank would be completely out of service. The City should evaluate the reliability of the water supply system without the tank in service during these planned outages. Also during annual coating/structural inspection and cleaning, the tank is typically taken off line. If the tank cannot be taken offline, then professional divers can inspect and clean the tank without taking the tank out of service. It is fairly common for “elephant foot” type buckling to occur in earthquakes for unanchored welded steel tanks. Buckling and wall uplift frequently damage piping connected to the tank wall. The risk of earthquake damage to the steel tank wall and piping can be reduced by anchoring the tank to a foundation and by providing flexibility at piping connections.

4.0

PRESTRESSED CONCRETE TANKS

While welded steel tanks have always been lower in initial cost to construct than prestressed concrete tanks, life cycle cost comparisons have been much closer. With recently added competition in the prestressed concrete market, capital costs have been lowered to make costs even more competitive to steel tanks. To estimate projected costs for a prestressed concrete Industrial 13 tank the following assumptions were used: 

AWWA D 110 Construction. It is assumed that the tank will be constructed to meet or exceed AWWA D 110. It is also assumed that D 110 Type I (Post-tensioned) and

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Type III (Tilt-up) will be bid competitively against each other. Due to the location of the tank in a Zone III seismic zone, it is also assumed that higher than minimum D 110 standards will be applied for added reliability. It is assumed a thicker roof, floor slab and shotcrete cover will be applied over the entire tank. No allowance for architectural features or exterior coating was provided in this analysis. 

Conventional Foundation. It is assumed for this analysis that soils allow for a conventional spread footing and concrete base foundation.



Dome Roof. Dome roof construction can be a lower cost option for concrete tanks. However, dome roofs add additional height to the tank. If a lower profile is required a flat roof can be specified. Flat roofs on concrete tanks can add approximately 10% to the cost of a tank. Due to the location of the tank in an industrial area it is assumed that a dome roof will be acceptable to local businesses and residents. The City may want to consider allowing for either a flat or domed roof during contract document preparation.



At-Grade Construction. It is assumed that due to the area of construction that visual impacts and height restrictions will not dictate the final height of the tank. Therefore, at grade construction was assumed for the tank.

4.1

D 110 Type I - Prestressed Concrete Tanks

Budget quotes from DYK were obtained for this analysis, and are provided in the Appendix. Type I D 110 tanks are constructed using a cast-in-place corewall with vertical posttensioning reinforcing. It is assumed that the tank will have the following design features: 10-inch core wall with vertical prestressing, galvanized prestressing, 1.5-inch shotcrete cover, 6-inch thick floor, 5-inch dome roof, and 18-inch wall footing.

4.2

D 110 Type III – Prestressed Concrete Tanks (Tilt-up)

Budget quotes from DYK and Natgun Inc were obtained for this analysis, and are provided in the Appendix. AWWA D 110 Type III prestressed concrete tanks are constructed using a tilt up wall with vertical prestressing. It is assumed that the tank will have the following design features: minimum wall thickness of 6-inches, galvanized diaphragm, galvanized prestressing, 1.5-inch shotcrete cover, 6-inch thick floor, 18-inch thick wall footing, and a 5-inch thick cast in place dome.

4.3

Capital Cost

The capital costs of both the Type I and III tanks are listed in Table 5. The costs presented show both the optimal configuration of the tank and the 180-foot diameter that will be used for comparison. DYK and Natgun both presented budget estimates for optimally sized tanks

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Table 5

D 110 Concrete Tanks Capital Cost Type III

Type I ‘Optimal’ Tank Size(1)

Baseline Tank

‘Optimal’ Tank Size(1)

Baseline Tank

Diameter of Tank, feet

148

180

145

180

Side-water depth, ft

32 22 32 22

Tank Wall Height, ft

47

39

47

39

$ 1,975,000

$ 2,100,000

$ 1,913,000

$ 2,088,000

Design Contingency(2)

$ 198,000

$210,000

$ 191,000

$ 209,000

Total Capital Cost

$2,173,000

$ 2,310,000

$ 2,104,000

$ 2,297,000

$0.54

$0.58

$0.53

$0.57

Item

Capital Cost

Capital Cost per Gallon of Capacity

Notes: (1) Optimal Tank Dimension based on lowest capital cost tank dimensions. (2) Design Contingency based on 10% of the capital costs. with a diameter of 148 and 145 feet, respectively. The cost differential between the baseline and optimal tank dimensions for the two tanks was approximately $137,000 and $193,000 for Type I and III tanks respectively, resulting in a savings of 6 and 8 percent over the baseline tank dimensions. However, there is a significant difference in tank footprint and height. The optimally sized tank would be have a side-water depth of 32 feet, with a top dome height of 47 feet, while the 180-foot tank would have a side-water depth of 22 feet and a top dome height of 39 feet.

4.4

Operations and Maintenance Costs

As with the steel tank alternative, some annual inspection and cleaning will be required. It is estimated that the annual tank cleaning and inspection will be the same for the concrete tank as for the welded steel tank. We have assumed some structural repairs may be required after 30 years, estimates of structural repairs vary widely, but it is expected that repairs will be minor (i.e. cosmetic cracking, grout repair and spalling), so we have assumed a cost of approximately $30,000 per repair. Reoccurring O&M costs for cleaning, structural inspection and repair are summarized in Table 6.

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Table 6

Concrete D 110 Tank Operations and Maintenance Costs

Operations / Maintenance(1)

Unit Cost

Amount

Cost

$ 100 / hr

40 hrs

$ 4,000

Annual Costs Inspection / Cleaning Costs(2)

Total Annual Costs

$ 4,000

Reoccurring Costs Concrete Repair(3)

$30,000 / repair Total Reoccurring Costs

$ 30,000 $ 30,000

Notes: (1) O&M costs are expected to be equal for both Type I &III tanks. (2) Inspection and cleaning costs are expected to be similar to steel tank. (3) Concrete repair assumes minor cosmetic and nonstructural cracking repair. Major structural repair is not assumed for this analysis.

4.5

Life Cycle Cost

Life cycle costs for the concrete tank options include O&M costs. Capital cost and present worth costs of O&M are listed in Table 7. Within the level of accuracy of this life cycle cost estimate there is little if any difference between all four prestressed concrete tank alternatives considered. The cost difference between ‘optimally’ sized tanks and the baseline tanks is much lower ($137,000 and $ 192,000 difference for Type I and III tanks respectively) than the welded steel tank ($734,000 difference). If a prestressed concrete tank is selected, tank dimensions will have minimal effect on capital and O&M costs. The break even point for the baseline tank is after the first recoating of the steel tank, which is assumed at 15 years.

4.6

Reliability

Concrete tanks generally require much less maintenance than steel tanks due to the lack of coatings and cathodic protection systems to maintain, and therefore do not require as frequent downtime. A well constructed concrete tank will have to be taken out of service during structural repairs (expected at 30, and 45 years), and for as little as one week at a time. Professional tank diving services can perform routine tank inspections and cleanings without ever having to take the tank out of service. Concrete tanks are inherently more reliable that steel tanks due to the lower required downtime during the 60-year life cycle due to O&M activities, especially recoating.

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Table 7

Life Cycle Cost for D 110 Concrete Tank Type I

Type III

‘Optimal’ Tank Size Cost

Baseline Tank cost

‘Optimal’ Tank Size Cost

Baseline Tank cost

$ 2,173,000

$ 2,310,000

$ 2,104,000

$ 2,297,000

Present worth of Annual O&M Costs(1)(2)(4)

$ 111,000

$ 111,000

$ 111,000

$ 111,000

Present worth of structural repairs(2)(3)4)

$ 21,000

$ 21,000

$ 21,000

$ 21,000

$ 2,305,000

$ 2,442,000

$ 2,236,000

$ 2,428,000

Criteria Capital Cost(4)

Total Life Cycle Cost(4)

Notes: (1) Present worth factor for annual O&M cost over 60 years: 27.675 (2) Present worth factor for structural repair costs at 30 & 45 years: 0.411, 0.264 respectively (3) Present worth = Future cost * Present worth factor. (4) Costs were rounded to the nearest thousand. Concrete tanks in general do not display similar buckling and uplift like failures seen in welded steel tank because of their inherent greater wall stiffness and weight. There have been hundreds of Type I style, cast-in-place tanks built over several decades in the western United States. Many have been built in high seismic areas, and we are not aware of any significant damage to these tanks due to earthquakes. These tanks have a flexible wall base with steel cables tying the bottom of the wall to the foundation for the purpose of resisting seismic loads. Type III tank use a precast wall system with a steel diaphragm. They are relatively new to the western United States. Currently information on the long term seismic exposure and performance history does not exist. This style of tank uses a somewhat similar seismic force resisting system. The seismic cables are connected to the precast wall using layers of shotcrete. The seismic load must be transferred to the diaphragm and precast concrete wall by concrete bond. This is a more indirect load transfer mechanism that may have more risk of failure in an earthquake.

5.0

TANK MATERIAL EVALUATION

Table 8 compares the cost of the alternatives for an ‘optimally’ sized tank, providing the lowest life cycle cost for each tank type evaluated. Table 9 compares the baseline tank size for each tank evaluated for the Industrial Tank 13. The following conclusions were made from the analysis: November 2010

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Table 8

“Optimal” Tank Cost Analysis Concrete Tank

Criteria

Welded Steel Tank

Type I

Type III

Capital Cost

$ 1.47 M

$ 2.17 M

$ 2.10 M

O&M Costs

$ 1.15 M

$ 0.13 M

$ 0.13 M

Total Life Cycle Cost

$ 2.62 M

$ 2.30 M

$ 2.24 M

Less reliable due to recoating

More reliable due to low frequency of tank ‘down time’

More reliable due to low frequency of tank ‘down time’

Reliability

Note: (1) O&M Costs are presented as present worth values.

Table 9

“Baseline” Tank Cost Analysis Concrete Tank

Criteria

Welded Steel Tank

Type I

Type III

Capital Cost

$ 1.83 M

$ 2.31 M

$ 2.30 M

O&M Costs

$ 1.53 M

$ 0.13 M

$ 0.13 M

Total Life Cycle Cost

$ 3.35 M

$ 2.44 M

$ 2.43 M

Less reliable due to recoating

More reliable due to low frequency of tank ‘down time’

More reliable due to low frequency of tank ‘down time’

Reliability

Note: (1) O&M Costs are presented as present worth values.



Welded Steel Tank Has the Lowest Capital Cost. The total capital cost of the welded steel tank is the lowest of the alternatives. Capital cost of the steel tank ranged from $1.47 – 1.83 Million, while concrete tank ranged from $2.10 – 2.31 Million.



Tank Geometry Impacts Steel Tank Cost. The optimization of steel tank geometry reduces both the capital and reoccurring O&M costs for a steel tank. Optimizing concrete tank geometry did not result in significant life cycle cost savings compared to steel tank.

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

Concrete Tank Has the Lowest O&M Cost. The largest O&M cost in this analysis was for the recoating of the welded steel tank option. Concrete tanks require very little maintenance, mostly cleaning and periodic structural inspection of the tank, which is required for both types of tanks. The highest O&M cost for the tank alternatives is the cost of recoating the welded steel tank.



Concrete Tanks Have the Lowest Life Cycle Cost. Concrete tank options present the lowest life cycle costs. The life cycle cost of a welded steel tank ranged from $2.62 – 3.35 M, while life cycle costs for concrete tanks ranged from $2.24 – 2.43 M. The high cost of recoating the tank leads to a higher life cycle cost for the steel tank. While the concrete tank is not entirely ‘maintenance free’, it is expected that the required maintenance will be significantly less than the steel tank alternative.



Concrete Tank Has Greater Reliability. Concrete tanks are not subject to the frequent recoating required for welded steel tanks. Recoating of a tank can take up ten weeks, which will require the tank to be taken out of service. In contrast concrete tanks only need to be taken out of service during minor structural repairs, which are expected to take place far into the service life of the tank and for significantly less time.

Based on the results of the evaluation, it is recommended that a prestressed concrete tank be selected for the Industrial Tank 13 Project. All prestressed concrete tank alternatives evaluated provide a significant life cycle cost savings versus a welded steel tank. To obtain competitive bids the city may wish to consider allowing both Type I and III tanks to be provided by the contractor. Because of the minimal impact on cost of the tank dimension between 143 and 180-foot diameter alternative, selection of the tank characteristics can be discussed and selected based on other non-cost factors during the upcoming CAMPTM meeting.

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Industrial Tank 13

APPENDIX – COST PROPOSALS

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NATG N Wirewound Concrete Tanks Established 1929

Natgun Corporation 101 Pacifica – Suite 250 Irvine, CA 92618 Telephone 949-585-5111 Facsimile 949-585-5113

June 11, 2010

Michael Hartlaub, P.E. Carollo Engineers 2700 Ygnacio Valley Road, Suite 300 Walnut Creek, CA 94598 REFERENCE:Proposed 4.0 MG Water Storage Tank – Modesto, CA Benefits of Prestressed Concrete Budgeting Information Dear Mr. Hartlaub: Thank you for your interest in prestressed concrete tanks. We ask that you consider the following benefits of utilizing an AWWA D110 prestressed concrete tank: Elimination of Future Maintenance Costs and Burdens to City Residents: Prestressed concrete tanks offer reliable no maintenance service for the life of the tank. As you are aware welded steel tanks must be regularly maintained by sandblasting, and recoating the tank. The costs to sandblast and paint continue to rise, and new regulations often result in a requirement to shroud the entire tank, adding even more cost to the project. By selecting a prestressed concrete tank neighboring business’s will not be subjected to the inconvenience of painting crews, and the water agency will no longer need to budget for future maintenance. I have provided a spreadsheet detailing the future potential structural maintenance costs for a welded steel tank. The model assumes that 4.0 MG welded steel tank is to be recoated every 15 years at an estimated cost of $7.50 per square foot for the exterior recoating, and the interior coating. This value was developed based on the average recent bid results for the maintenance of welded steel tanks. Using this analysis it can be forecasted that the City will be responsible for over $940,000.00 for structural maintenance every 15 years and approximately $2,800,000.00 based on a 60 year life span of the welded steel tank. Section Summary - By specifying a prestressed concrete tank, The City of Modesto will benefit by having a no maintenance product. This will eliminate the need to budget for expensive future O&M projects that are required by welded steel tanks.

CORPORATE OFFICE:

11 TEAL ROAD, WAKEFIELD, MA 01880, TELEPHONE: 781-246-1133

Address: 351 Cypress Lane ● El Cajon, CA 92020 ● Mailing: P.O. Box 696 ● El Cajon, CA 92022-0696 Phone: (619) 440 – 8181 ● Fax: (619) 440 – 8653 ●Web: www.dyk.com ● [email protected]

June 16, 2010 Mr. Michael James Hartlaub, P.E. Carollo Engineers, P.C. 2700 Ygnacio Valley Rd, Suite 300 Walnut Creek, CA 94598 Subject:

Preliminary Budget Estimate Modesto, California

Dear Mr. Hartlaub, Thank you for contacting DYK regarding the City of Modesto’s upcoming 4.0 MG “Industrial” reservoir. Per your request, the estimate below includes four options for a circular prestressed circular tank. Wall Construction, Prestressing and Seismic Survivability The West Coast Standard for circular, prestressed concrete tanks is a cast-in-place corewall with vertical post-tensioning reinforcing (AWWA D110, Type 1). DYK’s prestressed concrete tanks built under these guidelines have performed in near proximity to all major seismic events in California, Washington, Oregon and Hawaii since our Company started in 1962. A DYK tank is synonymous with seismic performance and resilience. Due to the seismic zone the project is located in, we strongly recommend a corewall that is in horizontal and vertical compression. Compression enables concrete to behave in a more ductile manner and better absorb energy released during an earthquake. Options 3 and 4 of the estimate represent a Type I corewall which has both vertical and horizontal compression. DYK recommends the use of galvanized single wire or seven wire prestressing and thicker concrete cover over the prestressing. DYK has applied over 19,000 miles of galvanized prestressing steel, and has never had a corrosion problem when using galvanized material, not one. In stark contrast, we know of dozens upon dozens of corrosion failures of tanks using nongalvanized single wire and minimal concrete cover including a tank DYK worked on with Carollo to repair corroded prestressing on a tank’s dome ring in Salt Lake City (mid 90s). Once the prestressing material is selected, determining how to produce the tension in the wire is important. DYK was found on the premise that drawing wire through a diameter reducing die and covering with only an inch of gunite/shotcrete was risky business. Our founder saw the shortcomings of this method, and set out to change the Industry. DYK has always used mechanical tensioning methods (non-die drawing) to develop the tension in the prestressing material. The prestressing is the heart of the system, so we take the utmost care in applying it to the tank shell. DYK uses continuous electronic recording and correction to ensure the prestressing is applied within a tight tolerance of +/- 320 lbs. Our concerns with drawing wire

through a die is that it creates excessive heat (>200° F) and the prestressing is subject to stress fractures which typically lead to early corrosion. Mechanical tensioning does not generate heat or stress fracturing. While the minimum requirements in AWWA D110 still allow Tank Contractors to employ antiquated methods of tensioning the prestressing wire (die drawing) and then cover the prestressing with only an inch of pneumatically applied concrete (shotcrete) all Tank Contractors have the ability to provide mechanical tensioning, galvanized material and thicker covers. Concrete Cover and Durability For long term durability, DYK has found the tank will ultimately perform best with 1.5” of cement rich shotcrete covering the galvanized prestressing. DYK also recommends the floor and roof have adequate concrete covers to better perform over their anticipated 100 year service life. The appropriate cover based on American Concrete Institute (ACI) 350 Code is 2-inches, a code that Carl Gentry, Carollo Engineers, was active in composing. Estimate While the above is a brief introduction to DYK’s opinions on the design and construction of a durable water tank in the Western US, we realize the Owner has to evaluate the cost and benefit each feature offers. DYK is a versatile company and can provide design and construction services for various concrete tanks, including tilt up prestressed concrete tanks (AWWA D110, type 3) and conventionally reinforced concrete tanks (ACI 350). If the Owner ultimately decides that a tilt up tank will meet their needs, we recommend that the design include 1.5” shotcrete cover, galvanized prestressing and diaphragm, mechanical tensioning, continuous reinforcing between adjacent wall panels (meeting ACI 350, Ch. 21), 6” thick floor and a 5” thick cast-in-place dome (options 2 and 4, see table below). The estimate below shows the cost difference between a Standard West Coast tank design and a tilt up corewall. It is assumed that the tilt up wall will a minimum thickness of 6”, galvanized diaphragm, galvanized prestressing, die drawing the prestressing, 1.5” shotcrete cover, 6” thick floor, 18” thick wall footing and a 5” thick cast-in-place dome. The estimate for the Type 1 corewall is based on previous design parameters set by Carollo designed prestressed concrete tanks: 10” thick corewall with vertical prestressing, galvanized prestressing, 1.5” thick shotcrete cover, 6” thick floor and 18” thick wall footing. As requested by Carollo, the estimate will account for a tank with a cast in place concrete dome, which is different than previous Carollo projects that have column supported two-way low rise slabs. The cast in place concrete dome has a minimum thickness of 5” to meet the concrete cover required by ACI 350. Yes, it will cost more to build a robust and durable tank appropriate to the environment, but the added service life will far outpace that cost. Our philosophy is, “Build a concrete tank right and enjoy a structure that will truly require minimal maintenance.” A minimum standards prestressed concrete tank will perform for 20 to 30 years, and then require some attention. We assume that an Owner could just build a good quality welded steel tank and get 20 years too! All options include design and construction by DYK, complete including all work associated with the floor, wall footing, wall, roof (designed for IBC minimum live load) and standard appurtenances attached to the tank. The tank is designed in accordance with AWWA D110 and ACI 350. Further cost savings may be realized should an experienced local tank contractor construct the tank, which has been specified by Carollo in the past. The estimate does not include exterior paint on the above grade portions of the wall for aesthetics and damp proofing on the below grade portions of the wall (if any). The estimate

assumes competent subgrade and does not include an allowance for any earthwork, subgrade preparation, piping, groundwater, fencing, roadways, etc.

4.0 MG “Industrial” Tank Modesto, CA (June 2010) Options Option 1 Option 2 Option 3 Option 4

Estimate1

Description Type III, DYK recommended design, 180’ diameter, water depth Type III, DYK recommended design, 148’ diameter, water depth Type I, vertical/horizontal prestressing, 180’ diameter, water depth2 Type I, vertical/horizontal prestressing, 148’ diameter, water depth2

22 32’ 22’ 32’

$2,100,000 $1,975,000 $2,275,000 $2,125,000

1. Please note that the above estimate is based on the current construction cost and does not include inflation. You may wish to add an inflation allowance depending on when the project is expected to bid. 2. Estimate is based on previous Carollo designs.

Since the cost of a prestressed concrete tank is dependent upon many parameters, including the dimensions, lateral earth pressures and seismic parameters, we would be happy to review the above estimate to ensure it is in agreement with the City’s requirements when additional information is known about the project. If you have any questions on the enclosed, please feel free to contact me at 800-227-8181 or [email protected].

Best Regards, DYK Incorporated

Thomas W. Bloomer II, P.E. Regional Manager, Business Development

June 11, 2010 Carollo Engineers Michael Hartlaub, P.E. Page 2

Prestressed Concrete Reinvests 70% of Tank Cost Into Local Economy: When the investment is made in a prestressed concrete tank, a large portion of the construction cost is immediately reinvested in the local economy. The majority of the material and expense cost for construction of the tank is from local sources. This includes utilizing local concrete suppliers, and lumber yards, as well as reinforcing steel and equipment rentals. The majority of the cost of a steel tank is in the manufacturing and shipping of the steel plates resulting in very little stimulus to the local economy. Section Summary - By specifying a prestressed concrete tank, the City of Modesto will benefit because a significant portion of the construction cost is spent within the local economy. Enhanced Seismic Reliability: Prestressed concrete tanks designed in accordance with AWWA D110, ASCE 7-05, local building codes and national standards are the most conservative choice when considering performance during a seismic event. There are countless examples of extensive buckling and failure of steel tanks as a result of seismic events. By contrast, we are not aware of any structural damage to a AWWA D110 prestressed concrete tank due to seismic activity. In addition, due to the increase dead weight of the dome roof structure, the amount of freeboard required for a prestressed concrete tank is considerably less than that required for a welded steel tank. Section Summary - By specifying a prestressed concrete tank, the City of Modesto will benefit through the conservatism built into every AWWA D110 prestressed concrete tank for resisting seismic induced forces. Tank Sitting Options: Another benefit to the concrete option is that the tanks can be partially buried. From an aesthetic perspective, it can be desirable to minimize the surface area that is exposed, so the tank appears smaller and less obtrusive. In addition, the ability to partially bury a prestressed concrete tank can save on overall construction costs. For example, the project may require the removal and replacement of the top 5-feet of soil for a steel tank to be placed at grade. A prestressed concrete tank can be buried 5-feet, saving on the cost for importing select fill material. Section Summary - By specifying a prestressed concrete tank, the City of Modesto will benefit by having the option to partially bury the tank decreasing construction costs, and increasing the tank aesthetics.

June 11, 2010 Carollo Engineers Michael Hartlaub, P.E. Page 3

Tank Budget: Based on 2010 construction costs, a suitable budget estimating figure for a 4.0 MG wirewound precast, prestressed concrete water storage tank with free standing clear spanning concrete dome, with a diameter of 180’ and a side water depth of 21’ is $1,900,000.00. Approximate onsite construction time required for a 4.0 MG water storage tank is 16-18 weeks, not including site work. Please note this budget includes a standard spread footing and membrane slab. If the tank has significant differential backfill or requires a non-typical foundation the budget may need to be re-evaluated. Based on 2010 construction costs, a suitable budget estimating figure for a 4.0 MG wirewound precast, prestressed concrete water storage tank with free standing clear spanning concrete dome, with a diameter of 145’ and a side water depth of 32.5’ is $1,850,000.00. Approximate on-site construction time required for a 4.0 MG water storage tank is 16-18 weeks, not including site work. Please note this budget includes a standard spread footing and membrane slab. If the tank has significant differential backfill or requires a non-typical foundation the budget may need to be re-evaluated. The budget-estimating figure includes the tank complete including the foundation, hatch, vent, and overflow and small piping appurtenances. The figure does not include site work or additional tank accessories. Local, state, and federal taxes, if applicable, are not included in the above price. The above tank is designed and constructed in accordance with AWWA standard D110, Type III for precast concrete wall with steel diaphragm, wire prestressing, ASCE 7-05, local building codes and National Standards. In developing your project we would recommend the use of the performance specification for the tank. The performance specification references standards and codes (AWWA D110, ACI 350, ACI 372, ASCE 7-05, CBC etc.) which are carefully written by consulting engineers, owners, and manufacturers, based on decades of proven design and construction practices. It also allows you to efficiently and cost effectively specify enhancements to referenced standards and codes when it is determined there is value to do so. The performance specification also ensures that the tank will be designed by an experienced tank designer. Shop drawings and calculations will be submitted to the consulting engineer for review. The performance specification provides a conservative, efficient, and competitive way to procure the tank for the upcoming project.

June 11, 2010 Carollo Engineers Michael Hartlaub, P.E. Page 4

To assist in developing the contract documents Natgun can provide you with the following information: 1. Preliminary design drawings in electronic format 2. Complete performance specification in electronic format 3. Geotechnical requirements for wire-wound concrete tanks and geotechnical report review 4. Value engineering from our Engineering and Estimating departments 5. Site layout and estimated site work cost from our Estimating Department 6. Review of preliminary drawings and specifications to provide updated tank and site work budget estimates The above services will assist in providing a quality project with complete budgeting information and minimal questions at bid time. Thank you for this opportunity to be of service. Please feel free to contact me if you have any questions or if I can be of any further assistance. Sincerely, NATGUN CORPORATION 

Kevin Peacock Kevin G. Peacock California Regional Manager 101 Pacifica Drive Suite 250 Irvine, CA 92618 Direct: 949-698-2740 Email: [email protected]

Michael Hartlaub From: Sent: To: Subject:

Mitch C Scott [[email protected]] Tuesday, June 22, 2010 11:06 AM Michael Hartlaub Re: Tank Estimate

Mike, just to let you know I did receive your email but for some reason it was hung up in my  spam folder.    Here are the budget estimates you requested:    Capacity  Diameter  Height       CP    Tank &  paint  Total  4.0 MG   180'    22.75' + 3' knuckle radius  $25,000  $1,565,000  $1,590,000  4.0 MG   133'     39.75' + 3' knuckle radius  $15,000  $1,210,000  $1,225,000    The budgets estimates were based upon the following:    1.  Tank design: Section 14, 1/16" C.A. on all plate & structural, 3'  freeboard  2.  Tank coatings: 15 mil interior epoxy coating system & 6 mil exterior epoxy/urethane  coating system    Mike, I did not include anything for the foundations as I thought you may have a better feel  for that based upon the recent project you are doing in Yuba City.  I think tank is 3.6 MG  tank.    If you need any other information please let me know.    Thanks,    Mitchell Scott  Business Development Manager  CB&I Inc.  Direct dial: (805) 503‐6131  Mobile: (805) 441‐6997  Fax: (805) 546‐8105  Email: [email protected]                                                                                                Michael Hartlaub                                                                                                                  To                                          "Scott, Mitch C"                   06/21/2010 11:23                                           cc                AM                                                                                                                                 Subject                                          Tank Estimate                                                                                                                                                                                                                                                                                                                                             1

                                                                                                                                                                  Hello Mitch,    I’m working on a project where our client is evaluating using Steel and Concrete for a new  4.0 MG Reservoir. It is in the City of Modesto. I was wondering if you could help me with  some budgetary numbers. Here are the following design parameters:    Size: 4.0 MG  Diameter: 180’  Foundation: Ring Wall  Roof: Knuckle roof    Include the following costs in the budget:  Assume 1/16 corrosion allowance  An impressed current cathodic protection system      Thanks. mjh      Michael James Hartlaub P.E.  Carollo Engineers, P.C.  2700 Ygnacio Valley Rd, Suite 300  Walnut Creek, CA 94598  (925) 932‐1710 (Phone)  (925) 478‐1666 (Cell)  (925) 930‐0208 (Fax)  [email protected] 

2

Michael Hartlaub From: Sent: To: Subject:

Wade Crosno [[email protected]] Monday, June 28, 2010 8:34 AM Michael Hartlaub RE: estimate

By my estimate with the same perameters as the Sanborn project, specifically corrosion allowance, Cathodic protection  interior of tank.  It would be about $1,488,000.    Regards,  Wade Crosno  Crosno Construction Inc.  Office  (805) 343‐7437  Fax       (805) 343‐1006  Cell      (805) 458‐3958        From: Michael Hartlaub [mailto:[email protected]] Sent: Thursday, June 24, 2010 9:57 AM To: Wade Crosno Subject: RE: estimate Thank you Wade. mjh Michael James Hartlaub P.E. Carollo Engineers, P.C. 2700 Ygnacio Valley Rd, Suite 300 Walnut Creek, CA 94598 (925) 932-1710 (Phone) (925) 478-1666 (Cell) (925) 930-0208 (Fax) [email protected] From: Wade Crosno [[email protected]] Sent: Thursday, June 24, 2010 9:56 AM To: Michael Hartlaub Subject: RE: estimate

I will have it out end of day tomorrow. Regards, Wade From: Michael Hartlaub [mailto:[email protected]] Sent: Thursday, June 24, 2010 8:50 AM To: Wade Crosno Subject: estimate Hello Wade, 1

I was wondering if you had a chance to look at that modesto cost estimate we talked about last week. Thanks so much. mjh Michael James Hartlaub P.E. Carollo Engineers, P.C. 2700 Ygnacio Valley Rd, Suite 300 Walnut Creek, CA 94598 (925) 932-1710 (Phone) (925) 478-1666 (Cell) (925) 930-0208 (Fax) [email protected]

2

City of Modesto

APPENDIX C – LIST OF SPECIFICATIONS

December 3, 2010 - FINAL

CITY OF MODESTO INDUSTRIAL #13 RESERVOIR AND BOOSTER PUMP STATION SPECIFICATIONS TABLE OF CONTENTS VOLUME 1 DIVISION 0 - BIDDING REQUIREMENTS CONTRACT FORMS, AND CONDITIONS OF THE CONTRACT TBD

DIVISION 1 – GENERAL REQUIREMENTS TBD

DIVISION 2 – SITE CONSTRUCTION 02050

BASIC SITE MATERIALS AND METHODS

02084

UTILITY STRUCTURES

02200

SITE PREPARATION

02240

DEWATERING

02260

EXCAVATION SUPPORT AND PROTECTION

02300

EARTHWORK

02312

CONTROLLED LOW STRENGTH MATERIAL

02318

TRENCHING

02620

FILTER FABRIC

02621

STABILIZATION FABRIC

02742

ASPHALTIC CONCRETE PAVING

02762

PAVEMENT MARKINGS

02772

CONCRETE CURBS, GUTTERS, AND SIDEWALKS

02810

IRRIGATION SYSTEM

02820

GATES AND AUTOMATIC OPERATORS

02821

CHAIN LINK FENCES AND GATES

02900

PLANTING

02952

PAVEMENT RESTORATION AND REHABILITATION

DIVISION 3 CONCRETE 03055

EPOXY BONDING REINFORCING BARS AND ALL THREAD RODS IN CONCRETE

03071

EPOXIES

03072

EPOXY RESIN/PORTLAND CEMENT BONDING AGENT

December 3, 2010 - FINAL

CITY OF MODESTO INDUSTRIAL #13 RESERVOIR AND BOOSTER PUMP STATION SPECIFICATIONS TABLE OF CONTENTS 03102

CONCRETE FORMWORK

03150

CONCRETE ACCESSORIES

03200

CONCRETE REINFORCEMENT

03300

CAST-IN-PLACE CONCRETE

03380A

TYPE I PRESTRESSED CONCRETE TANK

03380B

TYPE III PRESTRESSED CONCRETE TANK

03366

TOOLED CONCRETE FINISHES

03600

GROUTS DIVISION 4 – MASONRY

04090

MASONRY ACCESSORIES

04100

MORTAR AND MASONRY GROUT

04220

CONCRETE MASONRY UNITS DIVISION 5 – METALS

05120

STRUCTURAL STEEL

05310

STEEL DECK

05500

METAL FABRICATIONS DIVISION 6 – WOOD AND PLASTICS DIVISION 7 – THERMAL AND MOISTURE PROTECTION

07110

DAMPPROOFING

07190

WATER REPELLENTS

07214

BATT INSULATION

07220

ROOF AND DECK INSULATION

07260

VAPOR RETARDERS

07520

ROOFING UNDERLAYMENT

07600

FLASHING AND SHEET METAL

07650

SELF-ADHERED ROOF UNDERLAYMENT

07840

FIRESTOPPING

07900

JOINT SEALERS

07916

PRECAST CONCRETE JOINT SEALER

December 3, 2010 - FINAL

CITY OF MODESTO INDUSTRIAL #13 RESERVOIR AND BOOSTER PUMP STATION SPECIFICATIONS TABLE OF CONTENTS DIVISION 8 – DOORS AND WINDOWS 08110

STEEL DOORS AND FRAMES

08710

DOOR HARDWARE

08800

GLAZING

DIVISION 9 – FINISHES 09250

GYPSUM BOARD

09220

PORTLAND CEMENT PLASTER

09652

RESILIENT BASE AND ACCESSORIES

09910

PAINTS

09960

COATINGS

VOLUME 2 DIVISION 10 – SPECIALTIES 10400

IDENTIFICATION DEVICES

10520

FIRE PROTECTION SPECIALTIES

10810

TOILET ACCESSORIES DIVISION 11 – EQUIPMENT

11312

HORIZONTAL SPLIT CASE PUMPS DIVISION 13 – SPECIAL CONSTRUCTION

13206B

HYDRO-PNEUMATIC SURGE TANKS

13410

BASIC MEASUREMENT AND CONTROL INSTRUMENTATION MATERIALS AND METHODS

13411

CONTROL STRATEGIES

13422

FLOW FIELD INSTRUMENTS

December 3, 2010 - FINAL

CITY OF MODESTO INDUSTRIAL #13 RESERVOIR AND BOOSTER PUMP STATION SPECIFICATIONS TABLE OF CONTENTS 13423

LEVEL FIELD INSTRUMENTS

13424

PRESSURE FIELD INSTRUMENTS

13427

PANEL INSTRUMENTS

13429

MISCELLANEOUS INSTRUMENTS AND ACCESSORIES

13442

INSTRUMENT AND CONTROL PANELS

13452

REMOTE TELEMETRY UNIT (RTU)

13453

PROGRAMMABLE LOGIC CONTROLLER (PLC) AND HUMAN MACHINE INTERACE (HMI)

13485

INSTRUMENT INDEX

13486

RTU INPUT/OUTPUT SCHEDULE AND LOCAL PLC INPUT/OUTPUT SCHEDULE DIVISION 15 – MECHANICAL

15050

BASIC MECHANICAL MATERIALS AND METHODS

15052

BASIC PIPING MATERIALS AND METHODS

15061

PIPE SUPPORTS

15062

PREFORMED CHANNEL PIPE SUPPORT SYSTEM

15075

MECHANICAL IDENTIFICATION

15082

PIPING INSULATION

15110

VALVES

15111

BALL VALVES

15112

BUTTERFLY VALVES

15114

CHECK VALVES

15115

GATE, GLOBE, AND ANGLE VALVES

15116

PLUG VALVES

15117

SPECIALTY VALVES

15119

AIR AND VACUUM RELIEF VALVES

15120

PIPING SPECIALTIES

15121

PIPE COUPLINGS

15122

FIRE HYDRANTS

15142

DISINFECTION OF DOMESTIC WATER LINES

15251

DUCTILE IRON PIPING

15252A

STEEL PIPING

December 3, 2010 - FINAL

CITY OF MODESTO INDUSTRIAL #13 RESERVOIR AND BOOSTER PUMP STATION SPECIFICATIONS TABLE OF CONTENTS 15254

CAST-IRON SOIL PIPING

15255

STAINLESS STEEL PIPING AND TUBING

15260A

REINFORCED CONCRETE GRAVITY PIPING

15265

PLASTIC PIPING AND TUBING

15400

PLUMBING FIXTURES AND EQUIPMENT

15430

EMERGENCY EYE/FACE WASH AND SHOWER EQUIPMENT

15732

AIR CONDITIONING UNITS

15830

FANS

15852

LOUVERS

15855

AIR HANDLING UNITS

15936

HEATING, VENTILATING, AND AIR CONDITIONING CONTROLS

15954

HVAC SYSTEMS TESTING, ADJUSTING, AND BALANCING

15956

PIPING SYSTEMS TESTING

15958

MECHANICAL EQUIPMENT TESTING DIVISION 16 – ELECTRICAL

16050

GENERAL REQUIREMENTS FOR ELECTRICAL WORK

16060

GROUNDING AND BONDING

16075

ELECTRICAL IDENTIFICATION

16123

600 VOLT OR LESS WIRES AND CABLES

16130

CONDUITS

16133

DUCT BANKS

16134

BOXES

16140

WIRING DEVICES

16150

WIRE CONNECTIONS

16210

UTILITY COORDINATION

16222

LOW VOLTAGE MOTORS UP TO 500HP

16232

SINGLE DIESEL FUELED ENGINE GENERATOR ABOVE 200 KW

16272

DRY TYPE TRANSFORMERS

16285

TRANSIENT VOLTAGE SURGE SUPPRESSORS

16290

POWER MEASUREMENT

16305

ELECTRICAL SYSTEM STUDIES

December 3, 2010 - FINAL

CITY OF MODESTO INDUSTRIAL #13 RESERVOIR AND BOOSTER PUMP STATION SPECIFICATIONS TABLE OF CONTENTS 16411

DISCONNECT SWITCHES

16412

LOW VOLTAGE MOLDED CASE CIRCUIT BREAKERS

16422

MOTOR STARTERS

16442

INDIVIDUALLY MOUNTED CIRCUIT BREAKER SWITCHBOARDS

16444

LOW VOLTAGE MOTOR CONTROL CENTERS

16445

BRANCH CIRCUIT PANELBOARDS

16491

TRANSFER SWITCHES

16494

LOW VOLTAGE FUSES

16500

LIGHTING

16950

FIELD ELECTRICAL ACCEPTANCE TESTS

December 3, 2010 - FINAL

City of Modesto

APPENDIX D – DESIGN DATA .

December 3, 2010 - FINAL

Pump Curve and System Curves for Industrial Booster Pump 13 250

Pumps at 1,800 RPM

Design Point: 8331 gpm, @ 148 TDH (FT)

To otal Head (feet)

200

System Pressure: 60 psi 150

100

System y Pressure: 50psi p 1 Pump Running 2 Pumps Running 3 Pumps Running Low System Pressure High System Pressure

50

Pumps at 1,235 RPM 0 0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Flow (gpm)

8,000

9,000

10,000

11,000

12,000

13,000

Pump Data Sheet - American-Marsh Pumps Company: Carollo Engineers Name: City of Modesto Date: 11/30/2010

Pump:

Search Criteria:

Size: 8x10-15 HD

Flow: 2777 US gpm

Type: 340_HSC Synch speed: 1800 rpm

Speed: 1760 rpm Dia: 13.75 in

Curve: CS-15550

Impeller:

Specific Speeds:

Ns: 1708 Nss: 18589

Dimensions:

Suction: 10 in Discharge: 8 in

Fluid: Water SG: 1 Viscosity: 1.105 cP Motor: Standard: NEMA Enclosure: TEFC

Size: 150 hp Speed: 1800 Frame: 445T Sizing criteria: Max Power on Design Curve

Power: 200 hp Eye area: ---

---- Data Point ---Flow:

2777 US gpm

Head:

150 ft

Eff:

85%

Power:

123 hp

NPSHr:

9.56 ft

250

15 in 60 65

225 200

Temperature: 60 °F Vapor pressure: 0.2563 psi a Atm pressure: 14.7 psi a

NPSHa: ---

Pump Limits: Temperature: 250 °F Pressure: 250 psi g Sphere size: 0.0625 in

Head: 148 ft

70

75

80

82

13.75 in

84

86

87

---- Design Curve ---202 ft

Shutoff dP:

87.3 psi

Min flow:

554 US gpm

BEP:

175

86% @ 2768 US gpm

NOL power: 128 hp @ 3484 US gpm -- Max Curve --

86

87

85.5

Head - ft

Shutoff head:

84

150 11.75 in

82 60 65

125

70

80 75

75

70

200 hp

100

Max power: 170 hp @ 4010 US gpm

150 hp 75

125 hp

75 70

75 hp

50

100 hp

25

NPSHr - ft

0 50

500

1000

1500

2000

500

1000

1500

2000

2500

3000

3500

4000

4500

2500

3000

3500

4000

4500

25

0

US gpm Performance Evaluation: Flow US gpm

Speed rpm

Head ft

Efficiency %

Power hp

NPSHr ft

3332

1760

126

84

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City of Modesto

APPENDIX E – SURGE ANALYSIS

December 3, 2010 - FINAL

Technical Memorandum November 30, 2010 Page 2 For the accidental valve closure scenario, the analysis found that the valve should be closed no faster than three minutes in order to maintain adequate system pressure downstream of the valve. If possible, the valve should be designed with an actuator that has gearing requiring manual closure over at least three minutes. If this is not feasible, operational guidelines should be provided to indicate minimum closing times. The following sections summarize the methods and results of the hydraulic transient analysis. 

Overview



Modeling Assumptions



Analysis Criteria and Results

OVERVIEW

Hydraulic transients are generated in water distribution systems any time changes in flow, and corresponding changes in velocity, occur within the system. Hydraulic transients are generated under normal operating conditions, due to operational changes, such as pump starts and stops, valve opening or closing, or hydrant operations, or due to unanticipated operations, such as a pump station power failure or a main break. Transients are propagated through the distribution system at the speed of sound, about 3,500 ft/second in systems consisting of metal pipes. The pressure changes associated with transients can be quite large compared with normal operating pressures. For normal system operations, transients can be controlled through making operational changes slowly. For uncontrolled operational conditions, mitigation must be incorporated into facility design. West Yost evaluated the City of Modesto’s Industrial Tank and booster pump station using the City of Modesto Contiguous System hydraulic model, developed for past planning studies by West Yost. The model uses the InfoWater software, and is set up to evaluate peak hour normal operating conditions for existing demands, and for buildout of the City’s Sphere of Influence. The transient analysis uses the InfoSurge software, an analysis software that uses the University of Kentucky surge analysis code, which has been used widely for many years for hydraulic transient analysis. The InfoSurge software uses hydraulic information defined within the InfoWater model, along with additional information needed for the hydraulic transient analysis to evaluate hydraulic transient scenarios. For the Industrial Tank booster station, the primary concern would be a low pressure event following pump station power failure. MODELING ASSUMPTIONS

The Industrial Tank will be a 4 MG ground-level circular storage tank with a booster pump station that will deliver up to 12 mgd through a new 24-inch pipeline along Codoni Avenue to an existing 24-inch water line in Yosemite Boulevard. The pump station discharge line will connect to the new Codoni Avenue line approximately 2,300 feet south of Yosemite Blvd. Figure 1 shows a schematic of the tank and pump station in relation to other nearby distribution system facilities.

o\c\458\02-10-01\wp\11301010_1TMsurge

Technical Memorandum November 30, 2010 Page 3 The booster station will have three duty pumps and one standby pump, and all pumps will be equipped with variable frequency drives. The normal operating pressure will be 55 to 65 psi.1 The pump station will be equipped with a standby generator to bring pumps on-line following a pump station power failure. The generator will be capable of operating the pump station at design flowrate. The following information was used to define facilities associated with Industrial tank and booster pump station: 

Undated piping schematic by Carollo Engineers showing pipeline lengths and minor loss coefficients.



Pump station mechanical piping plan and section drawings, received on October 5, 2010.



Pump curves based on certified performance curves for West Tank and Pump Station, which are anticipated to be similar to planned pump selections for Industrial Tank booster station.



Pumps assumed to have check valves to prevent reverse flow on loss of power. Check valves are assumed to be fast-acting to prevent reverse flow through the pumps.



Pump re-start following power failure: generator start up and transfer time of 10 seconds, per electrical designer (15 seconds used in analysis). Following generator startup, pump ramp-up times per City of Modesto normal startup protocols: the first pump assumed to be called after 15 seconds of low pressure and would ramp up to full speed in 30 seconds. Subsequent pump starts would be sequential and delayed a minimum of 60 seconds each.2



General station elevations per NorthStar: Tank base elevation of 112 ft, with maximum water level of 22.5 ft and average water level of 20 feet; pump elevations of 118 feet, and station piping elevations of 115 ft.



Generalized pipeline transient wave speed of 3,600 feet/second.

Modeling information for the hydraulic transient analysis was input into the City of Modesto distribution system hydraulic model. The file ‘Option A – ver August 2010.mxd’ update of the model was used for the analysis. This model includes buildout system improvements associated with future supply Option A under consideration by the City. Option A would provide additional surface water supply to south Modesto from a Regional Surface Water Treatment Plant supplied with Turlock Irrigation District water. The City is also considering a second supply option, Option B, which would provide additional groundwater supply to meet future needs. The system response to operations at Industrial Tank that could induce hydraulic transients would be similar for Option A and B, so only the Option A scenario was evaluated.

1

Normal operations during peak hour of maximum day at buildout of Sphere of Influence indicates that the Industrial Tank booster pump station would have a normal discharge pressure of 66 psi (calculated from elevation 118 feet) with three booster pumps operating (station flow = 12.4 mgd). Design condition is based on pump operation with tank depth of 20 feet (hydraulic grade line elevation 134 feet).

2

E-mail correspondence from Thomas Kara, City of Modesto to Dave Jones, West Yost, dated September 22, 2010. o\c\458\02-10-01\wp\11301010_1TMsurge

Technical Memorandum November 30, 2010 Page 4 ANALYSIS CRITERIA AND RESULTS

For pump station power failure, the primary risk is for partial to full vacuum conditions to occur at or in the vicinity of the pump station, and the associated risk of vapor cavity collapse upon repressurization of distribution system pipelines. Analysis Criteria

Minimum pressure criteria used for the analysis are based on regulatory requirements established in Title 22 of the California Code of Regulations. Section 64602 of Chapter 16, the California Waterworks Standards, requires that the distribution system be operated to maintain a minimum of at least 20 psi at distribution system service connections at all times, to avoid the potential for cross-contamination to occur. Violation of the 20 psi minimum pressure conditions requires reporting to and consultation with the California Department of Public Health (DPH) District Engineer. Loss of pressure below 5 psi in the distribution system would require bacteriological testing to demonstrate that cross-contamination has not occurred. Analysis Scenarios

Three scenarios were evaluated: 

Booster pump station power failure under buildout peak hour conditions with the pump station operating at design flowrate;



Failure of one booster pump while operating at design flowrate, under buildout peak hour conditions



Accidental valve closure of a manually-operated butterfly valve on the 24-inch discharge pipeline where it connects to an existing pipeline on Codoni Avenue.

Results for each of the scenarios are summarized below. Scenario 1 - Pump Station Power Failure

Power failure at the Industrial Tank booster pump station was evaluated with the pump station operating at its design flowrate. The analysis scenario is peak hour of maximum demand day under buildout conditions within the City of Modesto system for the future supply option with a new supply to South Modesto from Turlock Irrigation District. For this scenario, the system demand is 242 mgd, with 80 mgd supplied from wells, 79 mgd supplied from Modesto Irrigation District’s MID Modesto storage and booster station, and 11 mgd supplied from the future Turlock Irrigation District terminal storage reservoir and booster station. The remaining 72 mgd is supplied from storage tanks within the City system. Industrial Tank booster station is operating at 12.4 mgd. Figure 2 shows the pressure at the booster pump station discharge header following pump station power failure. The power failure is assumed to occur at 10 seconds into the simulation. Pump 1 is assumed to re-start 30 seconds after power failure (at t = 40 s into the simulation, assuming 15 s for generator transfer and 15 seconds of low pressure signal), with the pump ramping up to full speed over 30 seconds (t = 70 s). Immediately upon power failure, the pressure drops to subatmospheric conditions (-9 psi). The pressure gradually increases as wells within the system o\c\458\02-10-01\wp\11301010_1TMsurge

Technical Memorandum November 30, 2010 Page 5 increase their production in response to the reduction in system pressure associated with the power failure. The system pressure has reached a new equilibrium by about 30 seconds into the simulation, even though the Industrial Tank booster pump is not re-started until 40 seconds into the simulation. Figure 3 shows minimum pressures that occur within the vicinity of the Industrial Tank booster pump station. The pressures reach full vacuum conditions along Codoni Avenue, and in the vicinity of the former Beard wells located east of Codoni Avenue (the wells have been abandoned and were not operated in the modeling scenarios). Pressures are also less than 20 psi at several locations along Yosemite Blvd and in its vicinity. For mitigation, installation of a hydropneumatic surge tank was evaluated. (In this instance, installation of a vacuum relief valve would not be protective of system pressure since it would not mitigate the initial pump station loss of pressure). The purpose of the hydropneumatic surge tank is to provide sufficient flow to the system to avoid low pressure conditions until the system pressure equalizes following the power failure. The analysis indicates that installation of a 3,500 gallon hydropneumatic surge tank, with an initial air volume of 40 percent would keep pressures in the vicinity of the pump station above 20 psi. The minimum pressure at the discharge header is 22 psi. Figure 4 compares the pressure trace at the pump station discharge header for the no mitigation scenario to the scenario with a 3,500 gallon surge tank. Figure 5 shows the minimum pressures in the vicinity of the Industrial Tank pump station with the surge tank installed. Minimum system pressures remain above 20 psi.3 Figure 6 shows outflow from the surge tank (outflow is shown as positive flow, inflow is shown as negative flow). The figure indicates that there is outflow from the tank for the first 23 seconds following pump station power failure (t = 10 to t = 33 seconds), after which there is flow into the surge tank. For this scenario, the first pump is restarted at t = 40 seconds, and doesn’t provide significant flow to the system until t = 55 seconds. This indicates that the surge tank must only provide flow to the system until wells within the system increase their output in response to reduced system pressure. Therefore, surge tank sizing is not a function of the time to re-start pumps following the power failure. The surge tank should be designed with a minimum 12-inch piping connection to the discharge header, providing unrestricted flow from the tank. The tank should be designed for a steady-state air to water volume of 40% air, 60% water. Scenario 2 - Failure of One Pump While Operating at Design Flowrate

This scenario assumes failure of one booster pump at the Industrial Tank booster pump station while operating at its design flowrate. System demand and supply conditions are the same as Scenario 1, and the 3,500 gallon surge tank recommended for Scenario 1 is assumed to be in place. For this scenario, minimum pressure at the pump station discharge header drops to 51 psi, indicating no other mitigation is required.

3

The figure shows pressures less than 20 psi on nodes representing the suction side of well pumps. These results can be disregarded since they do not reflect pressures that would be seen in the system. o\c\458\02-10-01\wp\11301010_1TMsurge

Technical Memorandum November 30, 2010 Page 6 Scenario 3 – Accidental Valve Closure on Discharge Header

This scenario assumes that a manually operated valve on the 24-inch discharge pipeline where it connects to the existing 24-inch pipeline on Codoni Avenue is accidently closed when the pump station is operating at its design flowrate. System demand and supply conditions are the same as Scenario 1, and the 3,500 gallon surge tank recommended for Scenario 1 is assumed to be in place. Following valve closure, discharge pressure at the pump station would rise, and the pumps would sequence off due to high pressure. The analysis indicates that even if pumps were run to shutoff head conditions, the shutoff head for the pumps is sufficiently low that pressures would only increase to 104 psi, which should be well within the pressure rating of pump station piping.4 Downstream of the valve, pressures in the vicinity of the pump station would drop as the valve closes. The amount of pressure drop would depend on the speed of the valve closure. Initially, a valve closure time of 1 minute was assumed. Then the valve closure time was increased until downstream pressures of at least 20 psi could be maintained. Table 1 reports the closing time and associated pressure immediately downstream of the valve. Table 1. Accidental Valve Closure Scenario, Valve Closing Speed and Downstream Pressure

Valve Closure Speed (minutes)

Minimum Pressure Immediately Downstream of Valve, psi

1

-5

2

14

3

22

Valve closure characteristics were based on DeZurik AWWA dome-style butterfly valve, assuming a uniform closure rate. Butterfly valves typically have relatively non-linear flow characteristics, with roughly 90 percent of the flow change occurring through the last 10 percent of valve stroke. As Table 1 indicates, model results indicate that a valve closure time of 3 minutes would result in maintaining downstream pressures greater than 20 psi. Figure 7 compares the pressure trace downstream of the closed valve for the three closing times reported in Table 1 (valve closure starts at t = 5 seconds; complete valve closure occurs at t = 65 seconds, t = 125 seconds or t = 185 seconds). For the 3-minute closure scenario, the minimum pressure immediately downstream of the valve is 22 psi, immediately after valve closure. The pressure increases following valve closure, as wells in the system increase their output in response to lower system pressure conditions.

4

Tank hydraulic grade line of 132 ft plus pump shutoff TDH of 220 feet = shutoff hydraulic grade line of 352 ft, and associated pressure of 101 psi at elevation 118 ft, the assumed pump centerline. o\c\458\02-10-01\wp\11301010_1TMsurge

Technical Memorandum November 30, 2010 Page 7 The station isolation valve located on the discharge header should be designed with appropriate gearing and actuator response to limit closure times to at least 3 minutes, if possible. If this is not feasible, operating guidelines should be provided along with the design for minimum closure times to limit the potential of generating pressures lower than the 20 psi minimum requirement.

o\c\458\02-10-01\wp\11301010_1TMsurge

Figure 1. Proposed Industrial Tank and Vicinity

o\c\458\02-10-01\wp\102810_2figures Last Revised: 10-28-10

NorthStar Engineering Group City of Modesto – Industrial Tank Hydraulic Transient Analysis TM

Figure 2. Pump Station Power Failure while Operating at Design Conditions (Flowrate = 12.4 mgd), No Mitigation 80 No Mitigation 70

Pump Station Discharge Pressure (psi)

60

50

40

30

Modeling Scenario:   Peak Hour of Maximum     Day at Buildout, System  Demand = 242 mgd

20

10

0 0

10

20

30

40

50

60

70

80

‐10

‐20

o\c\458\02-10-01\wp\1113010_3figuresforTM Last Revised: 11-30-10

Time (seconds)

NorthStar Engineering Group City of Modesto – Industrial Tank Hydraulic Transient Analysis TM

Figure 3. Pressure in the Vicinity of Industrial Tank – Booster Station Power Failure While Operating at Design Flowrate. No Mitigation Scenario – System Conditions: Peak Hour of Maximum Day at Buildout, System Demand = 242 mgd

Former Beard Wells (offline)

o\c\458\02-10-01\wp\113010_2figures Last Revised: 10-28-10

NorthStar Engineering Group City of Modesto – Industrial Tank Hydraulic Transient Analysis TM

Figure 4. Pump Station Power Failure while Operating at Design Conditions (Flowrate = 12.4 mgd), Comparison of Surge Tank and No Mitigation Scenarios 80 No Mitigation 3,500 Gallon Surge Tank

70

Pump Station Discharge Pressure (psi)

60

50

40

30

Modeling Scenario:   Peak Hour of Maximum     Day at Buildout, System  Demand = 242 mgd

20

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o\c\458\02-10-01\wp\1113010_3figuresforTM Last Revised: 11-30-10

Time (seconds)

NorthStar Engineering Group City of Modesto – Industrial Tank Hydraulic Transient Analysis TM

Figure 5. Minimum Pressures in Vicinity of Industrial Tank – Pump Station Power Failure with 3,500 gallon Surge Tank System Condition: Peak Hour of Maximum Day at Buildout, System Demand = 242 mgd

Former Beard Wells (offline)

o\c\458\02-10-01\wp\113010_2figures Last Revised: 10-28-10

NorthStar Engineering Group City of Modesto – Industrial Tank Hydraulic Transient Analysis TM

Figure 6. Surge Tank Outflow Following Pump Station Power Failure while Operating at Design Conditions (Flowrate = 12.4 mgd), 3,500 Gallon Surge Tank 10000 Surge Tank Outflow 8000

Modeling Scenario:   Peak Hour of Maximum     Day at Buildout, System  Demand = 242 mgd

Surge Tank Outflow (gpm)

6000

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o\c\458\02-10-01\wp\1113010_3figuresforTM Last Revised: 11-30-10

Time (seconds)

NorthStar Engineering Group City of Modesto – Industrial Tank Hydraulic Transient Analysis TM

Figure 7. Accidental Valve Closure on Pump Station Discharge Pipeline, Comparison of Different Valve Closure Rates 80 Valve Closure, 1 minute Valve Closure, 2 minutes 70

Valve Closure, 3 minutes

Pressure Downstream of Valve (psi)

60

50

40

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Modeling Scenario:   Peak Hour of Maximum     Day at Buildout, System  Demand = 242 mgd

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NorthStar Engineering Group City of Modesto – Industrial Tank Hydraulic Transient Analysis TM

City of Modesto

APPENDIX F – GEOTECHNICAL REPORT

December 3, 2010 - FINAL

Industrial Tank 13 and Pump Station Modesto, California

Geotechnical Report

Prepared by: BLACKBURN CONSULTING December 2010

Prepared for: NorthStar Engineering Group 909 14th Street Modesto, CA 95354

Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California

TABLE OF CONTENTS 1

INTRODUCTION...................................................................................................... 1 1.1 1.2 1.3 1.4

2

Purpose............................................................................................................................1 Scope of Services ............................................................................................................1 Site Description ..............................................................................................................1 Project Description ........................................................................................................1

SUBSURFACE CONDITIONS ................................................................................ 2 2.1 2.2

Soil ...................................................................................................................................2 Ground Water ................................................................................................................2

3

LABORATORY TEST RESULTS........................................................................... 2

4

INFILTRATION RATES.......................................................................................... 3

5

SEISMICITY.............................................................................................................. 4 5.1 5.2 5.3

6

2007 California Building Code (CBC) Seismic Design Parameters ..........................4 Liquefaction Potential ...................................................................................................4 Seismic Settlement Potential .........................................................................................4

RECOMMENDATIONS........................................................................................... 5 6.1 Grading ...........................................................................................................................5 6.1.1 Soil Excavatability ...................................................................................................5 6.1.2 Original Ground and Subgrade Preparation ..........................................................5 6.1.3 Fill and Compaction ................................................................................................5 6.2 Foundations ....................................................................................................................6 6.2.1 Booster Pump and Associated Building...................................................................6 6.2.2 Water Storage Tank .................................................................................................7 6.3 Utility Trenches..............................................................................................................7 6.3.1 Trench Excavatability and Stability.........................................................................7 6.3.2 Backfill .....................................................................................................................8

7

RISK MANAGEMENT............................................................................................. 8

8

LIMITATIONS .......................................................................................................... 8

APPENDIX A Figure 1 – Vicinity Map Log of Test Borings (Sheet 1 and 2) APPENDIX B - Laboratory Test Results

Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California

1

BCI File No. 1877.1 December 2, 2010

INTRODUCTION 1.1 Purpose

Blackburn Consulting (BCI) prepared this Geotechnical Report for the Industrial Tank 13 and Pump Station project in Modesto, California. This report contains surface and subsurface condition descriptions, and geotechnical design/construction recommendations. This report is intended for NorthStar Engineering Group (NSE), the design team, and the City of Modesto to use during design and construction. This report shall not be used or relied upon by others, or for different locations and/or projects without the written consent of BCI. 1.2 Scope of Services To prepare this report, BCI: 1. Reviewed available aerial photographs and geologic/topographic maps of the site. 2. Discussed the project with Jeff Black of NSE. 3. Drilled, logged and sampled 4 exploratory borings to depths ranging from 10 to 71 ½ feet on June 17, 2010. 4. Performed laboratory tests on representative soil samples from the exploratory borings. 5. Performed geotechnical engineering calculations and analysis to develop our recommendations. 1.3 Site Description The site is approximately 5 acres and located south of Yosemite Blvd. (SR 132) along Codoni Ave. in Modesto, California. The site is relatively flat with elevations ranging from 110 to 115 feet above mean sea level (MSL). An existing pump with a driveway is located at the northeast corner of the site. The pump is surrounded by a chain link fence. The remainder of the site consists mainly of an open field with seasonal grass and weeds. The entire site is surrounded by a cable fence with a gate on the east side. 1.4 Project Description Based on our discussions with Jeff Black, proposed improvements consist of the following: • • •

4 million gallon potable water storage tank founded on a shallow ring foundation, 12 million gallon-per-day booster pump station founded on a shallow mat foundation, and Site drainage basin.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California 2

BCI File No. 1877.1 December 2, 2010

SUBSURFACE CONDITIONS

BCI observed four exploratory borings to depths of 10 to 71½ feet on June 17, 2010 to characterize the subsurface conditions at the site. The approximate locations of the exploratory borings are shown on LOTBs. Below, we summarize the subsurface conditions encountered in the exploratory borings. More detailed information is shown on the LOTBs in Appendix A. 2.1 Soil In general, we encountered alternating layers of medium dense to dense silty sand, medium dense to very dense poorly graded sand, and very stiff to hard sandy silt to the depths explored. In Boring B1, we encountered dense poorly-graded sand between 8 and 18 feet. In Boring B2, we encountered medium dense poorly-graded sand from about 12 to 18 feet and 33 to 45½ feet underlain by hard and very stiff sandy silt. 2.2 Ground Water We encountered free ground water at 38 ft. below the ground surface in Boring 1 and 65 ft. below the ground surface in Boring 2 during our subsurface exploration on June 17, 2010. The California Department of Water Resources website indicates a ground water level of approximately 43 to 74 feet below the ground surface in the site vicinity. The ground water level is highly dependent on irrigation practices, rainfall, and seasonal changes. Ground water is not expected to detrimentally impact the proposed project design or construction. 3

LABORATORY TEST RESULTS

BCI performed laboratory tests on some of the soil samples obtained from the exploratory borings to classify the soil and obtain parameters for analysis. Tests included: • • • •

Moisture Content and Unit Weight Grain Size Analysis Atterberg Limits Triaxial Compression

BCI performed laboratory tests in conformance with current ASTM and/or Caltrans test procedures. We present the laboratory test results in Appendix B.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California 4

BCI File No. 1877.1 December 2, 2010

INFILTRATION RATES

Based on the planned detention basin depth of 10 feet, infiltration at the site will primarily be fine to medium grained, dense silty sand. Based on the soil types that we logged and sampled, we would expect infiltration rates of 0.14 to 0.22 inches per hour. To field test infiltration rates, BCI completed constant head tests in uncased boreholes. We used an infiltration test method and calculations based on the US Bureau of Reclamation field manual for gravity testing1. The following summarizes the general test method: • Drilled an 8-inch diameter hole to test depth. • Developed (cleaned) the borehole with water and a bailer (using water fed into the hole). • Placed a layer of coarse gravel at the bottom of the hole (minimum of 6 inches), and set a water feed pipe and an observation pipe (each 2-inch in diameter). • Saturated the bottom of the hole with approximately 50 gallons or more of water. • Provided a metered supply of water into the feed pipe until a minimum of three successive measurements of the water level, taken at 5-minute intervals, were within 0.2 feet of each other. The water flow rate was adjusted to obtain a stabilized water level within the hole. The test water height within the hole is a minimum of 5 times the borehole diameter to reduce influence from the bottom of the hole. In Table 1 below, we summarize the test data and infiltration values obtained.

Test Hole No. B3 B4

Table 1: Infiltration Test Data Summary Depth to Approx. Constant Infiltration Hole Depth Test Water Boring Flow Rate Rate (ft) (ft) Diam. (ft) (gpm) (inches/hr) 10 4 0.67 0.20 0.22 10 4 0.67 0.13 0.14

Our field tests show generally low infiltration rates1 (approximately 0.18 inches per hour) for most of the silty sands at proposed facility depth. An infiltration rate of 0.18 inches per hour corresponds to 0.11 gallons per ft2 per hour. The infiltration rates we provide above can be used in preliminary design of the proposed facilities. Consider the rates as approximate and use an appropriate safety factor in design. Due to the alluvial nature of the soils underlying the sites, there can be significant lateral and vertical variation in soil type and infiltration rates. Consider further evaluation of soil profiles and infiltration rates for final design.

1

United States Bureau of Reclamation, 1998, Engineering Geology Field Manual, Second Edition, Vol. 2

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California 5

BCI File No. 1877.1 December 2, 2010

SEISMICITY 5.1 2007 California Building Code (CBC) Seismic Design Parameters

Based on our exploratory borings, we provide the California Building Code (CBC) design parameters in Table 2. Table 2 below shows the 2007 California Building Code and ASCE 7-05 seismic design parameters for the site. BCI determined the values using a site latitude of N 37.632º and longitude of W120.912° with the Earthquake Ground Motion Parameters - Version 5.0.9a developed by the United States Geological Survey. Table 2: Seismic Design Parameters Site Class

D

Ss – Acceleration Parameter

0.739 g

S1 – Acceleration Parameter

0.274 g

Fa – Site Coefficient

1.209

Fv – Site Coefficient

1.852

SMS – Adjusted MCE* Spectral Response Acceleration Parameter

0.893 g

SM1 – Adjusted MCE* Spectral Response Acceleration Parameter

0.507 g

SDS – Design Spectral Acceleration Parameter

0.595 g

SD1 – Design Spectral Acceleration Parameter

0.338 g

TL – Long-Period Transition Period**

12

* Maximum Considered Earthquake ** Figure 22-15, ASCE 7-05

5.2 Liquefaction Potential Liquefaction can occur when loose to medium dense, granular, saturated soils (generally within 50 ft of the surface) are subjected to ground shaking. Our subsurface exploration indicates that the site is underlain by medium dense to dense sands and very stiff to hard silts. Current ground water levels at the site are approximately 38 ft below grade. Based on the subsurface soil and groundwater conditions, we consider the potential for detrimental liquefaction to be very low to nonexistent. 5.3 Seismic Settlement Potential During a seismic event, ground shaking can cause seismic settlement of relatively loose granular soil above the water table, which can result in settlement of the ground surface.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California

BCI File No. 1877.1 December 2, 2010

BCI evaluated potential seismic settlement of the native medium dense to dense sand above the groundwater level using the Tokimatsu and Seed (1987) method outlined in “Geotechnical Earthquake Engineering Handbook”, Robert W. Day, 2002. Using this method and a PGA of 0.23g, our analysis indicates that seismic settlement of the native sand above the groundwater table will be negligible. 6

RECOMMENDATIONS 6.1 Grading

Where referenced in this report, use the most current ASTM D 1557 test methods to determine relative compaction and optimum moisture. Compacted soil should not be considered suitable (even if it meets relative compaction requirements) if it is unstable and pumps or flexes excessively under construction equipment loads, as determined by BCI. 6.1.1

Soil Excavatability

Based on the conditions observed in our subsurface explorations and our experience, the on-site soil should be excavatable with typical grading equipment such as scrapers, dozers, backhoes and excavators. 6.1.2

Original Ground and Subgrade Preparation

Clear the site to remove vegetation, concrete, debris, abandoned utilities, soft or unstable areas, and other deleterious materials. Process and compact the exposed subgrade, cut, and fill areas as follows: 1. Scarify the exposed soil to a depth of 8 inches. 2. Moisture condition subgrade soil to within 2% of optimum moisture content and compact it to at least 90% relative compaction. Increase the minimum relative compaction to 93% in portions of fill deeper than 10 feet and upper 6 inches of pavement subgrade. 6.1.3

Fill and Compaction

The on-site soil may be used as fill provided it is free of debris and visible concentrations of vegetation, and has a maximum particle size of 2 inches. Imported fill must meet the following requirements: • • •

No concentrations of organics, debris, and other deleterious materials. Maximum particle size of 2 inches. Expansion index less than 20, per ASTM D4829.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California •

BCI File No. 1877.1 December 2, 2010

Contain at least 25% passing the No. 4 Sieve and at least15% fines passing the No. 200 Sieve; Caltrans Class 2 aggregate base is considered acceptable and does not need to meet these gradation requirements.

Place and compact fill as follows: 1. Place fill in loose lifts no thicker than 10 inches prior to compaction. 2. Moisture condition fills to within 2% of optimum moisture content. 3. Compact fill to at least 90% relative compaction. Compact fill deeper than 10 feet below finish grade, the upper 6 inches of pavement subgrade and pavement aggregate base to at least 93% relative compaction. 6.2 Foundations The following footing dimensions are considered minimum recommendations based on the soil conditions at the site. The structural engineering should design the foundation dimensions based on the anticipated loads. 6.2.1

Booster Pump and Associated Building

Building Building footings should be a minimum 12 inches wide and extend a minimum 12 inches below the lowest adjacent finished grade. Use an allowable bearing capacity of 2,700 psf to design the footings. This value may be increased by one-third if wind and/or seismic loads are included. For the above allowable bearing capacity, we estimate total settlement < ½” and differential settlement < ¼”. To resist lateral movement, use a coefficient of friction of 0.45 and a passive earth pressure of 200 psf per foot of depth. Clean footing excavations of debris and loose soil prior to placing concrete. Slope the ground surface away from footings a minimum of 2% for a distance of 5 feet to prevent ponding of water next to the footings. Booster Pump Provided the mat foundation is designed to evenly distribute the load to the underlying soil, a subgrade modulus (kS) of 20 k/ft3 may be used for design. The subgrade moduli (KS) is equal to the load applied to the underlying soil in thousand pounds per square foot (ksf) divided by the induced settlement in feet. Two inches of immediate (elastic) settlement is typically acceptable for mat foundations. However, the designer should determine the magnitude of acceptable total and differential settlement. We estimate that differential settlement across the mat foundations will be equal to or less than half of the total settlement.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California

BCI File No. 1877.1 December 2, 2010

The subgrade modulus may be increased by one-third if wind and/or seismic loads are included. The above subgrade modulus must include the weight of the contents, equipment, structure and foundation. To resist lateral movement, use a coefficient of friction of 0.45 and passive earth pressure of 200 psf per foot of embedment depth. 6.2.2

Water Storage Tank

The water tank walls will be supported on a perimeter ring foundation and the tank bottom will be founded on a layer of crushed rock or compacted aggregate base. The perimeter ring footing should be a minimum 18 inches wide and extend a minimum 18 inches below the lowest adjacent finished grade. Use an allowable bearing capacity of 2,700 psf to design the ring footing. This value may be increased by one-third if wind and/or seismic loads are included. For the above allowable bearing capacity, we estimate total settlement < ¾” and differential settlement < ½” during construction and an additional ¼” to ½” of uniform settlement when the tank is filled. We do not anticipate detrimental long-term settlement. To resist lateral movement, use a coefficient of friction of 0.45 and a passive earth pressure of 200 psf per foot of depth Clean footing excavations of debris and loose soil prior to placing concrete. Slope the ground surface away from footings at a minimum of 2% for a distance of 5 feet to prevent ponding of water next to the footings. 6.3 Utility Trenches 6.3.1

Trench Excavatability and Stability

Based on our subsurface exploration and experience, the near surface sands and silts should be excavatable using conventional trenching equipment such as backhoes and excavators. The contractor should determine the proper construction technique for excavation and backfill operations to mitigate caving. For planning and preliminary design, anticipate sloping requirements for Type C materials. At a minimum, all shoring should be in accordance with current CalOSHA requirements. In accordance with these requirements, the soil type for shoring design should correspond to the weakest layer. The contractor is responsible for final excavation and shoring design and construction based on actual excavation conditions encountered during construction.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California 6.3.2

BCI File No. 1877.1 December 2, 2010

Backfill

On-site soil may be used for trench backfill provided it contains no rock fragments larger than 3” in maximum dimension and is free of concentrations of debris and vegetation. Import fill must meet the requirements in Section 6.1.4. Place trench backfill in maximum 8” lifts, moisture condition to within 2% of optimum and compact to a minimum 90% relative compaction. Compact portions of fill deeper than 10 feet and within the upper 6 inches of pavement subgrade to at least 95% relative compaction. We may allow a loose lift thickness of up to 18 inches for the first lift over the pipe if required by the manufacturer. Jetting is not acceptable for compaction. Compaction should be based on ASTM D 1557 test method. 7

RISK MANAGEMENT

Our experience and that of our profession clearly indicates that the risks of costly design, construction, and maintenance problems can be significantly lowered by retaining the geotechnical engineer of record to provide additional services during design and construction. For this project, BCI should be retained as the Geotechnical Engineer of Record to: • Review and provide comments on the civil plans and specifications prior to construction. • Monitor construction to check and document our report assumptions. At a minimum, BCI should monitor grading, and foundation excavations. • Update this report if design changes occur, 2 years or more lapse between this report and construction, and/or site conditions have changed. If BCI is not retained to perform the above applicable services, we are not responsible for any other party’s interpretation of our report, and subsequent addendums, letters, and discussions. 8

LIMITATIONS

BCI performed services in accordance with generally accepted geotechnical engineering principles and practices currently used in this area. Where referenced, we used ASTM or Caltrans standards as a general (not strict) guideline only. We do not warranty our services. BCI based this report on the current site conditions. We assumed the soil and ground water conditions are representative of the subsurface conditions on the site. Actual conditions between test pits could be different. BCI provides slab-on-grade recommendations based on our geotechnical engineering experiences to date. However, even with the recommended mitigation efforts, some moisture vapor will pass through the slab and the slab itself will absorb and release moisture vapor. Therefore, even if the above mitigation recommendations are used, damage can occur. Consult with floor covering specialists and toxicologists for additional recommendations.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California

BCI File No. 1877.1 December 2, 2010

Our scope did not include evaluation of on-site hazardous materials. Logs of our exploratory borings are presented in Appendix A Figure 2. The lines designating the interface between soil types are approximate. The transition between soil types may be abrupt or gradual. Our recommendations are based on the final logs, which represent our interpretation of the field logs and general knowledge of the site and geological conditions. Modern design and construction are complex, with many regulatory sources/restrictions, involved parties, construction alternatives, etc. It is common to experience changes and delays. The owner should set aside a reasonable contingency fund based on complexities and cost estimates to cover changes and delays.

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Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California

BCI File No. 1877.1 December 2, 2010

APPENDIX A Figure 1 – Vicinity Map Log of Test Borings (Sheet 1 and 2)

Z:\Active Projects\1877.1 City of Modesto Industrial Tank, Pump Station and Transmission Mains\CAD Drawings\1877.1-vicinity map.dwg, 11/18/2010 12:52:34 PM, DWG To PDF.pc3

Project Location

Map Source: 2009 Google - Map data 2009 Google 1720 G Street Modesto, CA 95354 Phone (209) 522 6273 Fax (209) 522 6274 www.blackburnconsulting.com

VICINITY MAP

File: 1877.1

Industrial Tank 13 and Pump Station Modesto, California

December 2010 Figure 1

B4

B2

B1

B3

PLAN 115

Z:\Active Projects\1877.1 City of Modesto Industrial Tank, Pump Station and Transmission Mains\CAD Drawings\1877.1-LOTB.dwg, 11/18/2010 12:53:35 PM, DWG To PDF.pc3

110.3

B4

110.2

B3

112.2

B2

112.0

B1

115

105

105

95

95

85

85

75

75

65

65

55

55

45

45

35

35 PROFILE ENGINEERING SERVICES

GEOTECHNICAL SERVICES

PREPARED FOR THE

INDUSTRIAL TANK #13 AND PUMP STATION

LOG OF TEST BORINGS 1 of 2

APPARENT DENSITY OF COHESIONLESS SOILS GROUP SYMBOLS AND NAMES

FIELD AND LABORATORY TESTING

MOISTURE

CONSISTENCY OF COHESIVE SOILS

PERCENT OR PROPORTION OF SOILS

PARTICLE SIZE PLASTICITY OF FINE-GRAINED SOILS

Z:\Active Projects\1877.1 City of Modesto Industrial Tank, Pump Station and Transmission Mains\CAD Drawings\1877.1-LOTB.dwg, 11/18/2010 12:53:39 PM, DWG To PDF.pc3

CEMENTATION

BOREHOLE IDENTIFICATION

ROTARY BORING ENGINEERING SERVICES

HAND BORING

DYNAMIC CONE PENETRATON BORING GEOTECHNICAL SERVICES

CONE PENETRATON TEST (CPT) SOUNDING PREPARED FOR THE

SOIL LEGEND INDUSTRIAL TANK #13 AND PUMP STATION

LOG OF TEST BORINGS 2 of 2

Geotechnical Report Industrial Tank 13 and Pump Station Modesto, California

BCI File No. 1877.1 December 2, 2010

APPENDIX B Laboratory Test Results