Amendment 2 Q and A.pdf

Solicitation #W912BU-22-B-0018 for Amendment #2

Questions and answers

Question #3 – On drawing #866-B410-02, Towknees, Rub Rails, & Fenders listed in Clause C410 Hull Outfit, the drawing shows the four corners of the barge being outfitted with 1 inch by 12 inch hardwood rubbing strips. When these strips are scaled from the drawing, they are shown to be 6 inch by 12 inch. Please confirm the size of these wood strips.

Answer to #3:

The four corners of the barge shall be outfitted with 6 inch by 12 inch hardwood rubbing strips.

Question #4 – Would the Corps consider a bolting detail for the hull side shell fenders similar to that shown for the bow/stern fenders?

Answer – The Government will accept using a horizontally mounted fender detail depicted in Detail 2-12A on drawing #866-B410-02, sheet #2, in lieu of Detail 2-11A on the same drawings and sheet. If utilizing Detail 2-12A in lieu of Detail 2-11A, the fender type (10 inch by 10 inch rubber with UHMWPE face) shall be utilized with the bolting detail.

Question #5 – the specifications and drawings are not clear on whether the fairleads should be balanced head fairleads or roller fairleads as listed in contract Clause C420.

Answer – The fairleads for the barge shall be in accordance with contract drawing #866-B420- 01, revision 2 for maximum wire size of ¾ inch.

Question #6 – For the spud handling system, the sheaves are specified as bronze bored, equipped with roller bearings. There appears to be two different sheave designs. Please clarify.

Answer – There are two different sheave designs. The deck sheaves shall be 30 inch, and the spud sheaves shall be 36 inches.

Question #7 – Spud winch performance (from Clause C554, paragraph C) – in the near freefall mode, the winch shall be designed to automatically arrest the rotation of the drum in less than 1/4 rotation of the drum once the spud hits the bottom. Thereby preventing unspooling of the wire.

To meet this requirement, would the Government accept slack rope detection using hydraulic thrusting actuators? This would reduce the chance of bird nesting, but not necessarily meet the requirement of the ¼ rotation. Please advise if this is acceptable.

Answer – The Government requires that there shall be no unspooling of the wire from the spud winch drums once the spuds hit bottom. Based on the contractor’s final selection of the spud winches, either method of automatically arresting the rotation of the drum in less than ¼ rotation or the use of hydraulic thrusting actuators is acceptable to prevent bird nesting of the wire.

Question #8 – Spud winch requirements – based on feedback from winch suppliers, the requirements appear to have mixed performance and horsepower from two different winch types.

There are also questions on the rated line pull and speeds.

Answer – The Government has reviewed the spud winch requirements based on all of the questions received. Drawing #866-B522-02 has been marked up to clarify the winch requirements. Contract Clause C554 – Spud Handling System has been revised as well to clarify the requirements. The revised drawing and specifications shall be used for bidding proposes.

C554 SPUD HANDLING SYSTEM REVISED AS PART OF AMENDMENT #2

A. CONTRACT DRAWINGS

866-B215-01 GENERAL ARRANGEMENT

866-B330-02 MACHINERY & WINCH FOUNDATIONS

866-B522-02 SPUD HANDLING SYSTEM ARRANGEMENT

866-B550-03 SPUD WINCH SIZING CALCULATIONS

B. GENERAL REQUIREMENTS

The contractor shall provide and install four (4) electric spud winches in the locations shown on the contract drawings. The contract shall update the drawings during the Engineering Phase. The updated drawings (#866-C522-02 and #866-C550-03) shall reflect the equipment selected by the contractor. The drawings shall be submitted to the COR for review.

The winches shall be electrically powered through Variable Frequency Drives (VFD’s). See contract Clause C750, MOTORS & CONTROLLERS for system requirements.

All sheaves in the spud handling system shall be bore sheave type with SAE 660 bronze bushings for the spud sheaves and roller bearings for the deck sheaves. Sheaves shall be as shown on the contract drawing and as determined by the contractor during the Engineering Phase.

The winches shall be provided with wire rope installed for spud operations. The winch wire shall be 6 strand x 19 wire (6x19) Independent Wire Rope Core (IWRC), Extra Improved Plow Steel (EIPS). The contractor shall provide the COR with a “Certificate of Examination and Test of Wire Rope Before Being Taken Into Use” (U.S. Department of Labor – Occupational Safety and Health Administration Form No. 5) for each continuous run of rope installed on the winches. The certification shall be performed to the requirements of 29 CFR, part 1919 and be in accordance with the requirements of 29 CFR 1918.

Suitable guards shall be provided around exposed wire rope for personnel safety, and painted yellow. Keepers shall be provided to prevent the wire rope from jumping off the sheaves due to slackness of the wire.

Each spud winch shall be mounted to a heavy steel foundation to be designed by the contractor as per contract clause C330.

C. SPUD WINCH PERFORMANCE

Each spud winch system shall be capable of developing a full drum single line pull of 17,500 lbs.at a minimum line speed of 45 ft./min. The line pull shall increase to 46,000 lbs. at or near zero line speed, to assist in removing the spuds buried in the bottom soil. Each winch shall have a minimum drum capacity for 200 feet of wire rope, based on using 1-1/4 inch wire rope. The ratio of barrel drum diameter to wire rope diameter shall not be less than fourteen. The design shall ensure easy spud line replacement.

The spud winches shall have infinitely variable speed power up and power down, and a near free fall lowering capability. The winches shall be equipped with brakes rated at twice the spud dry weight of holding force. The brakes shall automatically set when:

there is any failure in the electric system powering the winch and the control lever is in the center position. Unless moved by the operator, the winch control handle shall always be in the center position.

In the near freefall mode, the winch shall be designed to automatically arrest the rotation of the drum in less than ¼ rotation of the drum once the spud hits the bottom, thereby preventing un-spooling of the wire.

The spud winches shall also be provided with a weekend/unattended mode, consisting of a manually-operated jaw clutch capable of completely disconnecting the drum from the drive train, to permit wire to payout as river level rises. The system shall be kept under tension in order to prevent excessive slack wire should the river level fall.