City of SomertonOrange Grove (OG) & Rancho Mesa Verde (RMV)

Water System ImprovementsCDBG Contract 110-15

ADDENDUM #2

Date: October 27, 2015

The purpose of this addendum is to inform the proposing parties regarding the Orange Grove (OG) & Rancho Mesa Verde (RMV) Water System Improvements. Reminder: Acknowledge receipt of this addendum on the Bid Form.

The Bid Due Date and Time have NOT been modified. Sealed bid shall be received until 4:00 PM Local Time, Thursday, November 12, 2015, Somerton City Hall, City Clerk, 110 N. State Ave, Somerton, AZ 85350.

Attachments:

1. Pre-bid conference sign-in sheet

2. Section 13110 Welded Steel Potable Water Storage Tank

General Modifications:

1. None

Questions & Clarifications:

1. Special Inspection Form, as required by Yuma County for testing and special inspections, is a deferred submittal and shall be in the Contractor’s scope of supply. Specifications Sections 14000 Quality Control and 01454 Testing & Laboratory Services shall be referenced. Contractor is responsible all inspections and testing with the exception of Electrical Inspections. Electrical inspection(s) will be contracted and paid for by the Owner (or Engineer), however, Contractor will be responsible for coordination for these inspection(s) with Owner (or Engineer).

Response: N/A

2. Can you please provide some clarification for us pertaining to the Orange Grove & Rancho Mesa Verde Water System Imps. Project? The specs state that this is a federally funded project, but I cannot find any reference to “Buy America” or “American Iron & Steel (A.I.S.)”, so can you please advise if there are any domestic requirements for this project?

Addendum #2 – OG & RMV Water System Improvements October 27, 2015PACE #9972 Page 2 of 2

Response: Because this is not an ARRA (American Recovery and Reinvestment Act) funded project, it is not tied to the “buy American” requirements.

3. Regarding Spec. Section: Division 13 – Special Construction, Section 13100 Bolted Steel Potable Water Storage Tanks. Can the steel potable water storage tanks be welded rather than bolted?

Response: Due to requests, a new specification section, Section 13110 Welded Steel Potable Water Storage Tank has been added to the project and it is attached to this addendum. Therefore, bid for tank must either be a Bolted Steel Potable Water Storage Tank per Specification Section 13100 or a Welded Steel Potable Water Storage Tank per new Section 13110. No other types will be accepted. At this time, contractor and/or tank suppliers must review the specifications and decide if a specific tank is considered an “or equal”, however Bidder must also understand that the final determination will not be made until after the project is awarded and the shop drawing submittals are reviewed.

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SECTION 13110

WELDED STEEL POTABLE WATER STORAGE TANK

PART 1 -- GENERAL

1.1 THE REQUIREMENT

A. CONTRACTOR shall design, fabricate, and erect a welded steel water storage tank on a ring-type foundation,

including the steel tank, pipe connections, manways, ladders, hatches, safety masts, vents, overflow assemblies,

instrument nozzles, and other appurtenances shown on the drawings and specifications. The tank shall meet all

requirements and standards for storing potable water and shall be disinfected prior to being brought on line.

1.2 REFERENCES AND RELATED SECTIONS

1. AWWA D-103-09, D104-11, D106-10 & C652-11 Standards of the American Water Works Association

2. NFPA-22 Standards for Water Tanks for Private Fire Protection

3. Uniform Building Code

4. NSF 60 & 61

5. NACE SP0188 & 6A192

6. SSPC SP10

7. Section 09800 – Special Coatings

8. Section 09660 – Coating Systems for Water Storage Tanks

1.3 SUBMITTALS

A. Submittals shall be furnished in accordance with Sections 01300 - Submittals

B. CONTRACTOR shall provide complete design calculations and detailed drawings signed and stamped by a Civil

Engineer licensed in the state of California.

C. CONTRACTOR shall supply detailed tank drawings and supplemental information including the following:

1. Tank dimensional drawings

2. Foundation design

3. Cathodic protection

4. Accessories and appurtenances

5. Coatings

1.4 QUALIFICATIONS OF FABRICATORS

A. The materials shall be furnished by one supplier who is regularly engaged in the manufacturer of steel water

storage tanks and has experienced factory-qualified representatives that can supervise the field assembly.

B. All materials shall be new and of current manufacturer and shall be guaranteed against defects in workmanship in

accordance with other sections of these Specifications.

1.5 QUALIFICATIONS OF INSTALLERS

A. For the fabrication, erection and testing of the work in this Section, use only thoroughly trained and experienced

personnel who are completely familiar with the requirements for this work and with the installation

recommendations of the manufacturers and these Specifications.

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B. All welders shall be certified for the particular type of welding required prior to starting welding on the site,

including equipment to be used, positions, procedures, base metals and electrodes or base filler wires from the

same specifications, classifications, or group number that will be encountered on their assignment.

C. Certification testing shall be performed by an approved testing laboratory. Costs of such testing shall be borne by

the Contractor. The Contractor shall maintain current records of all welding certifications. A copy of each welding

certification shall be submitted to the Owner for approval a minimum of 48 hours in advance of any welding to be

performed.

D. Qualifications of welding procedures, welders and welding operators shall comply with Section 8 of AWWA

Dl00.

1.6 DELIVERY, STORAGE, HANDLING

A. All plates, supports, members, and miscellaneous parts shall be packaged for shipment in such a manner to prevent

abrasion or scratching of the finish coating.

B. In the event of damage, immediately make all repairs and replacements necessary for the approval of the Owner

and at no additional cost to the Owner.

C. When damaged material cannot be repaired to the satisfaction of the Owner, it shall be removed from the jobsite at

no additional cost to the Owner.

D. Material shall be stored in a safe location protected from the elements where damage could result.

1.7 WARRANTY

A. The tank manufacturer shall warrant the tank against any defects in workmanship and materials for a period of five

(5) years from date of shipment.

B. The tank erector shall warrant the tank against any defects in workmanship for a period of five (5) years from date

of shipment.

PART 2 -- PRODUCTS

2.1 ACCEPTABLE SUPPLIERS

A. Superior Tank Company Inc.

B. Engineer-approved equal

2.2 WELDED TANK STRUCTURE

A. The materials, design, fabrication, and erection of the welded steel tank shall conform to applicable local, state and

federal generations, including AWWA Standard for Welded Carbon Steel Tanks for Water Storage D-100-11 and

local seismic and building codes.

B. Design shall provide for easy painting of structural and appurtenant members after erection. Beams of standard

structural shapes with columns shall be used rather than long-span roof trusses. Where design for ease of painting

after erection is not feasible, steel shall be shop sand blasted and shall receive shop applied primer, intermediate and

finish coatings.

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C. Detailed drawings and supporting structural analyses signed by an Arizona registered civil or structural engineer

shall be submitted by the Contractor for approval not later than 30 calendar days after award of the contract. The

drawings shall show the following information:

• Plate thickness and width,

• Number and size of structural members,

• Construction and erection details of all accessories and related work,

• Size and spacing of hold-down anchorages, if required,

• Adequacy of bearing pressures under the center column footing and other column footings, where

required, and

• All other pertinent data concerning the construction of the tank.

D. The standard height and diameter shall meet or exceed the capacity requirement of 180,000 gallons of usable

volume.

E. The foundation shall be ring-type, not anchored, and supported by structural fill per the Geotechnical Report.

F. Allowable soil bearing pressure for supporting loads shall be per Geotechnical Report.

2.3 ACCESSORIES

A. All exterior accessories shall be painted and coated by the manufacturer to match tank exterior. Accessories and

appurtenances shall be supplied in locations shown on the plans and as specified below:

1. Locking roof hatch 36’ x 36”

2. Inlet and outlet connections

3. Screened stainless steel mushroom vent

4. Shell Manway 24’ diameter

5. Exterior galvanized ladder meeting OSHA requirements

6. Overflow assembly

7. Drain

8 Nozzles for instruments

9. Fill down comer

10. Valve, valve riser, and sample port assembly, as shown on the plans

11. Galvanized guardrail and toeboards

12. Aluminum exterior level indicator with stainless steel float, float cable, guide wires, anchors, tensioner

assemblies, and target pulley

2.4 DIELECTRIC BARRIERS:

A. There shall be a dielectric barrier wherever stainless steel and carbon steel touch.

B. No welding of stainless steel to carbon steel will be permitted below the water level.

PART 3 -- EXECUTION

3.1 ERECTION AND INSPECTION

A. Inspection and testing shall conform to AWWA D100-11. Testing equipment and the cost thereof shall be

furnished by the Contractor.

B. Welds in the tank shell and roof shall be tested by the Contractor by means of spot radiographic inspection where

required by AWWA D100 and as directed by the Owner.

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C. All radiographs shall be performed by an independent testing laboratory approved by the Owner. The radiographs

shall become the property of the Owner, and the Owner shall have the right to review all information obtained.

D. The first 10 feet of each welder’s work shall be checked, and then up to 5 percent of all the welding shall be

radiographed as directed by the Owner.

E. The Contractor shall provide logs of each welders work throughout the project.

F. All welds in the tank bottom shall be tested by the Contractor and repaired as required by AWWA Standard

Specification by vacuum, using soap suds, linseed oil, or other suitable materials for detection of leaks. Joint may

also be tested by the magnetic-particle method.

G. In vacuum testing, the gauge should register partial vacuum of at least 5 in. Hg.

H. Tank coatings shall be applied in accordance with Section 09800 - Special Coatings and Section 09960 - Coating Systems for Water Storage Tanks.

3.2 TESTING

A. Following completion and erection and cleaning of the tank, the tank shall be tested for liquid tightness by filling

the tank to its overflow elevation. Any leaks disclosed by this test shall be corrected by the erection contractor in

accordance with the tank manufacturer’s recommendations. If repairs are required, the interior and exterior coatings

shall be protected during repairs, coatings shall be touched up as necessary, and the tank shall be retested to the

satisfaction of the Engineer before the work is accepted.

B. Filling and emptying the tank shall be the responsibility of the CONTRACTOR. For hydrostatic testing purposes,

untreated water from the onsite well can be used, provided the well WORK is complete, distribution piping in the

road is installed (Not a Part), site piping is installed, and the non-potable wharf hydrant is operable. Pumping rate

from well is estimated at 10 GPM. If additional water is needed, CONTRACTOR shall provide water by hauling

or other means.

C. External pumping may need to be provided for pressurized spray application of well water. The well pump will

NOT supply adequate pressure for spraying at the treatment site.

D. After completion of hydrostatic testing, the tank shall be disinfected in accordance with the requirements of

AWWA standard C652-11.

E. Prior to emptying the tank, the hydrostatic testing water shall be de-chlorinated with NSF-approved Captor

Solution (Calcium Thiosulfate), or other Engineered-approved means.

F. De-chlorinated hydrostatic testing water can be applied onsite as irrigation or used onsite for dust control.

F. Tank shall be emptied of all non-potable hydrostatic testing water prior to bringing reverse osmosis system online

and filling the tank with potable water.

- END OF SECTION -