Amendment 0002 W911WN21Q0767 .pdf

AMENDMENT TO SOLICITATION

1. This is an amendment to a combined synopsis/solicitation for commercial items prepared in accordance with the format in Subpart 12.6, as supplemented with additional information included in this notice.

2. RFQ Number: W911WN21Q0767

3. Title: New Miter Gate Operating and Valve Operating Hydraulic Cylinders, Braddock L/D

4. Amendment Number: 0002

5. Description of Amendment:

The purpose of this amendment is to: 1) Provide responses to questions received; 2) Replace in its entirety Specifications (Attachment 1) with the revised version as Specifications, Rev (Attachment 1) containing revision to sections 2.1.1, 2.1.2, 2.1.2.1 and 2.1.2.2; and 3) Replace in its entirety Reference Drawings (Attachment 2) with the revised version as Reference Drawings, Rev (Attachment 2) with an additional drawing page; and 4) Provide clarification on the scope for the Gate Cylinders and for the Valve Cylinder. The due date for quotes has not been revised.

a. The following Specifications sections have been revised which are highlighted yellow. The revised specifications are attached to this amendment and replace the initial specifications.

2.1.1 General

Added Paragraph

2.1.2 Hydraulic Cylinders

Added Option D

2.1.2.1 Piston Rods

Edited First Paragraph

2.1.2.2 Pistons

Edited First Paragraph

b. The Reference Drawings have been revised.

Added Piston Rod Detail Drawing as last page.

c. Listed below are responses to nine (9) questions received.

Q1: Section 2.1.2.2 Pistons states piston must be cast iron conforming to ASTM A536 Grade, 80-55-06 or 10-50-05. Would A36, A516 Gr. 70, or other applicable plate material be acceptable?

A1: They would not be acceptable. The piston must be cast iron conforming to ASTM A536, Grade 80-55-06 or 70-50-05. The Specifications have been revised.

Q2: Reference Section 2.1.2.2: 10-50-05 is not a recognized grade of material in ASTM A536. Can you please confirm this value is not a typo, and if so, what should the grade be?

W911WN21Q0767

Amendment 0002

A2: 10-50-05 is indeed a typo from a source that got carried into the contract. Section 2.1.2.2 Pistons should read "The piston shall be cast iron conforming to ASTM A536, Grade 80-55-06 or 70-50-05." The Specifications have been revised.

Q3: Of the three options available in Section 2.1.2, each states "or equivalent material as approved". Option A Rolled plate, ASTM 516 Grade 70 is simply a spec for plate material.

ASTM 516 Grade 70 minimum tensile strength is 70 ksi, with a minimum yield of 38 ksi.

The ASTM 106 Grade C material suggested is simply a spec for an equivalent seamless carbon steel pipe. ASTM 106 Grade C minimum tensile strength is 70 ksi, with a minimum yield of 40 ksi. Can you please further express why ASTM 106 Grade C material would not be approved as an equivalent material?

A3: After analysis, seamless carbon steel pipe conforming to ASTM A106 Grade C would be considered an equivalent material. Therefore, Option D has been added and it will be considered a valid alternative. The Specifications have been revised.

Q4: The specification suggest several design changes from the existing cylinders. The most notable being the ability to replace rod end sealing and wiper components "without having to disconnect any components from the end of the piston rod". Please clarify if the "disconnect any components from the end of the piston rod" is referring to the disconnecting of piston itself, or the components attached externally to the cylinder at the tapered shaft connection of the piston rod.

A4: The Specification takes precedent over the drawings in cases where there is a discrepancy between the two. “Without having to disconnect any components from the end of the piston rod” refers to disconnecting any components attached externally to the cylinder at the tapered shaft connection of the exposed end of the piston rod.

Q5: For the piston rod specified materials "conforming to ASTM A108, Type C 1045, or ASTM A108, Type CR 4140", this information is incomplete for proper material specification. Can you please provide the minimum mechanical properties required for these two materials? Additionally, this information will be needed when considering safety factor analysis.

A5: Fabricate each piston rod from carbon steel conforming to ASTM A108, Type C 1045 or Type CR 4140 with a minimum tensile strength of 90,000 psi to 110,000 psi. Section 2.1.2.1 on the Specifications have been revised.

Q6: The hydraulic cylinder section 2.1.2 states:

"The outside of the finished cylinder shall be turned concentric with the bore, and the interior shall be honed to the dimensions, tolerances, and finish shown in the reference drawings. The finished wall thickness shall not be less than that shown. Flanges shall be welded to the cylinder parallel with each other and perpendicular to the cylinder center line. Tolerances shall be as shown. After completion of all welding, the cylinder shall be stress relief heat treated." The tolerances for concentricity, bore diameter, outer diameter, wall thickness, and flange perpendicularity are not included on the two drawings. Is there additional information available regarding this cylinder barrel?

A6: Tolerances for the concentricity and the bore diameter are indicated on the reference drawings. The outer diameter tolerance is +/- 0.015”. The flange perpendicularity tolerance is 0.004”.

Q7: What is the factor of safety for the hydraulic cylinder as it relates to the operating pressure that cylinder needs to be rated for?

A7: Design all hydraulic cylinders to withstand a maximum operating pressure of 2,000 psi with

W911WN21Q0767

Amendment 0002 a factor of safety of 5 based on the ultimate strength of the material or 2 based on the yield strength of the material. Apply a factor of safety of 3 to the compression load when designing the hydraulic cylinders to resist buckling. Section 2.1.1 on the Specifications have been revised.

Q8: Please confirm if the tapered portion of the shaft is to be nickel and hard chrome plated.

A8: The tapered portion of the shaft is to be nickel and hard chrome plated.

Q9: What is the depth and tolerance of the key slot in the shaft?

A9: Please see the Piston Rod Detail drawing included in the reference drawing set.

d. Clarification on the scope for the Gate Cylinder and for the Valve Cylinder.

For the Gate Cylinders:

The contractor will provide the hydraulic cylinder, including the metal supports on the bottom of the cylinder. The contractor is NOT responsible for providing any of the steel embedded in concrete, including the Cylinder Seats (Mk 22/6-17) or the Cylinder Channel (Mk 22/6-16).

The contractor will NOT be required to provide the “rack and pinion” or other components to the left of the end of the piston rod as shown on drawing 037-L2-22/5.1. The contractor will provide the hydraulic cylinder and its components. Anything connected at the tapered shaft connection on the exposed end of the piston rod is NOT to be supplied by the contractor.

For the Valve Cylinder:

The contractor will provide the hydraulic cylinder, including the metal supports on the bottom of the cylinder. The contractor is NOT responsible for providing any of the steel embedded in concrete, including the Front Cylinder Seat (Mk 28/6-17), the Rear Cylinder Seat (Mk 28/6-20) or the Cylinder Channel (Mk 28/6-18).

The contractor will NOT be required to provide the “guide supports” (ie. Mk 28/7-1) or other components to the left of the end of the piston rod as shown on drawing 037-L2-28/5.1. The contractor will provide the hydraulic cylinder and its components. Anything connected at the tapered shaft connection on the exposed end of the piston rod is NOT to be supplied by the contractor.

6. Quotes remain due Thursday, 12 November 2020, 11:00 AM EST. Quotes will be accepted via email LRP.Contracting@usace.army.mil and Cc: Janie.L.Roney@usace.army.mil .

mailto:LRP.Contracting@usace.army.mil mailto:Janie.L.Roney@usace.army.mil