Well 11-11B Wellhouses Project Addendum #1.pdf

Addendum No. 1 – Well 11 & 11B Pumping Stations Project - Page 1 of 3

ADDENDUM NO. 1

CITY OF PENDLETON

Well 11 & 11B Pumping Stations Project Issued: August 12, 2024

Bid Opening Date: August 22, 2024 @ 2:00 pm

TO ALL PLANHOLDERS:

This Addendum provides the following clarifications/corrections to the Bid Documents and Contract for the above-referenced Project. All bidders shall acknowledge receipt and acceptance of this Addendum by completing the spaces, signing where indicated below and submitting it with the Proposal. Bids submitted without signing for the Addendum may be considered informal.

Opening Date:

Bid Opening Date is now August 22, 2024 at 2:00 pm. Previous date was August 16, Specification Amendments:

City staff support and understand the risk involved to install 8-inch bowl assembly at Well 11. City is also purchasing and installing a 250 HP variable frequency drive for Well 11B and is upsizing the Well 11B pumping system accordingly.

Well 11: change: access tubes to be 3/4-inch stainless steel with last 20-feet plus to be 1/2-inch Sch 80 PVC extended no less than 1-foot through discharge head to assure regulatory compliance for water level measurements.

Well 11B: discharge head modification: discharge head to accommodate 8-inch column in lieu of 12-inch column specified and shown in drawings; otherwise, meeting all the same requirements.

Well 11B: change: well column piping shall be 8-inch; otherwise, meeting all the same requirements.

Well 11B: change: pump assembly shall provide 900 gpm at 650-feet of total dynamic head; otherwise, meeting all the same requirements.

Well 11B: change: 250 HP motor replaces 150 HP motor; otherwise, meeting all the same requirements.

Well 11 / 11B: addition: 416 SS sand collar is allowable.

Questions and Answers:

In Information to Bidders, it states that Contractor will need to account for access installation of the pumping systems after the pump pedestals (M-106 / M-205) have been completed, with minimum 7-days concrete cure, and before CMU wall construction commences. We understand the well modification needs to occur prior to concrete work for building and pedestal. This leads us to three related questions:

What is the reason for the pump installation occurring prior to the CMU wall construction?

Addendum No. 1 – Well 11 & 11B Pumping Stations Project - Page 2 of 3

Generally, it is much easier and faster to install without the building walls. City has coordinated previous pumping systems installations with this in mind. With the bid packet rebidding, the timeline for coordination has passed in early October. Pumping equipment installation will have to be coordinated with wellhouses Contractor for spring 2025 installation.

What is the estimated date that CMU wall construction is to occur?

Was mid-October. With rebid, timeframe will not be met.

If the pump installer has the capability, will it be allowed for pump installation to occur after building construction complete (allows flexibility of schedules & don't recommend the motor installation to be stored in open weather)?

Yes, this will be the case and coordinated with the wellhouse Contractor and City staff.

Well 11 is noted that the open bore hole was measured with a diameter of 9-plus-inches.

The 6" column coupling is 7.39" OD and the 1" stainless tube coupling is 1.56" OD. If you offset the couplings the diameter across is about (7.39 + 1.44) 8.83". This is too restrictive. If there are any significant doglegs, even the 6" column alone could be tight or put in a bind.

Suggest that no probe tubes be installed and either utilize an airline (3/8" OD tubing) and/or sonic water level sensor (installed at surface & have ability to integrate an output signal).

Another option for consideration is change to submersible pump/motor, reduce gpm design, reduce to 4" column, and this should allow the 1" probe tube, also suggest PVC schedule 80 flush joint instead of the stainless pipe. Which direction would the City prefer to go to address the down hole constraints in Well 11?

Great points – there has been follow-up calls with OHA Drinking Water Program and Oregon Water Resources Department. City desires to install 8-inch bowl assembly and 6-inch column. City must have access tubes installed at Well 11 and will reduce the requirement to 3/4-inch stainless steel with 1/2-inch PVC through the discharge head, per the recommended minimum requirement of OAR 690-210-0280. 3/4-inch PVC under this requirement is replaced by 3/4-inch stainless steel.

Well 11 specification 1.a) states 8" discharge piping connection, drawing M-202 calls out 8" dismantling joint, and drawing M-205 Detail 1 calls out 12" Discharge Flange. Is the discharge flange to be 8"?

Yes, discharge connection is to be 8-inch.

Specification part 1.f) & 2.e) notes "adjustable vertically by means of a nut in the driver, but 1.g) & 2.f) notes solid coupling shall be provided at the discharge head for setting the impeller to bowl running clearance. One suggests a head nut which is in line with the motor being vertical hollow shaft, but the other suggest solid shaft motor coupling in the discharge head. Please clarify, is this to be a vertical hollow shaft motor with head nut to adjust impeller running clearance with a shaft coupling in the discharge head (not for adjusting, only to connect the line shaft to the motor shaft)?

Vertical hollow shaft with non-reverse rachet is required for City’s municipal wells.

In Part 1.h) & 2.g) will a 416SS sand collar be allowed, currently only bronze is specified?

Yes.

Addendum No. 1 – Well 11 & 11B Pumping Stations Project - Page 3 of 3

In Part 4.a)1. & 4.b), what is OHP?

OHP is overhead & profit.

What is the estimated substantial completion date of the well house project?

Precon meeting was held 7/17/2024. Rotschy, as Contractor, is to begin site work mid-August, reach punch-list by July 2025, and contractually complete the project by October 31, 2025. Wellhouses are expected to be completed winter/spring 2025.

CITY OF PENDLETON

Jeff Brown, Public Works Director 500 SW Dorion Avenue

Pendleton, OR 97801

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