Repair to Penstock #5 Gate Amistad Dam

Purpose of the Project

The United States Section of the International Boundary and Water Commission (USIBWC) requires upgrading the Penstock No. 5 Hydraulic Gate including installation of new stainless steel hydraulic piping and pressure testing the piping at Amistad Dam is located about 15 miles from downtown Del Rio, TX.

Background

Penstock #5 was originally designed to be a “dual gated” 15-foot irrigation outlet (penstock).  Both gates were designed as tractor (cable operated) gates and weigh 48,000 pounds each.  The dual gates are generally referred to as the Upstream Penstock Gate (aka head gate) and the Downstream Penstock Gate (aka operating or irrigation gate) and are positioned approximately 10 feet apart.  Depending on the action or results desired these gates could be lowered 190 feet down their respective Upstream or Downstream gate slots or could be hung in the penstock service bay, located 190 feet above the penstock invert, for servicing.

During construction, the downstream (irrigation) gate was replaced with a hydraulic slide gate. The upstream (head gate) was left as originally designed and is currently in the down (or closed) position.  Upstream of both penstock #5 gates is a bulkhead gate slot; however (by design) only one (1) Bulkhead Gate was delivered at Amistad during construction and it is currently being used in Penstock# 4. 

The hydraulic gate has been in the closed position since at least 2010, and the following observations were made during the last, (unsuccessful) attempt to operate the gate:

A.    Hydraulic Operating System

1.     The Hydraulic Gate Pump was completely operational and quickly built adequate pressure to the control valve

2.     When the control valve was moved to the open gate position, the hydraulic fluid was heard feeding the hydraulic feed lines; however, pressure was quickly lost.

3.     Visual observation down the gate slot (maybe 40-50 feet down the slot) indicated a spray of hydraulic fluid being lost from the feed lines.

4.     There was no indication of gate movement; probably due to the loss of hydraulic pressure.

B.    Hydraulic Gate

1.     The last time the gate was physically inspected is believed to be in the 1980's.

2.     Access to the back side of the gate (downstream side) is 190-foot down the 4 foot by 24 foot penstock gate slot and through an approximate 2.5 foot opening behind the gate.

3.     The current physical condition of the gate (wear, corrosion, etc.) is unknown.

4.     Similarly, the physical condition of the concrete portion of the penstock where the gate frame in embedded in the concrete, as well as that of the Concrete/ Penstock liner interface is unknown.

5.     The hydraulic gate was known to have a "chatter" problem at certain gate openings: and during normal operations in 1998 it was reported that the gate would "bleed off" and would not hold a gate opening.

6.      The hydraulic gate is framed (and seals) to the upstream side of the penstock concrete.

General Description of the Work

1.     All the work shall be performed by a professional contractor with experience in mechanical/ hydraulic systems. The Contractor shall have a minimum of 3 years of experience in identical or similar systems and shall submit a list of clients and their respective contact information for reference.

2.     The work shall be carried out by experienced professional crew properly trained in this type of work. The Contractor shall maintain adequate staffing level to complete the works within the Contract period.

3.     The Contractor shall designate and assign an experienced on-site representative to be present during all on site activities. The Contractor on-site representative shall have a minimum three-year experience in identical or similar projects.

4.     The Contractor shall provide all labor, equipment, materials, supplies, utility and incidentals to complete the project as identified under this SOW. Potable water and electric power supply may be available to the contractor free of charge.

5.     All Vendors are encouraged to attend the pre-bid conference and site visit; and verify site conditions including the voltage of any accessible electric power source. The Contractor is deemed to have field verified the existing conditions prior to submitting his proposal and prior to commencement of the work.

6.     The contractor may install a site office at a location near the dam. The site has been used for setting a temporary office by contractors in the past. 

7.     The Contractor shall be responsible for all safety and quality control features required for work of this nature.

8.     The Contractor shall be fully responsible for repairs or replacement of all damages to existing conditions resulting from the actions or lack thereof of the contractor, his employees, his subcontractors or their employees.

Performance Period 

All work shall be completed within Forty-Five (45) calendar days from the Notice to Proceed.   

Other Information

The magnitude of this project is between $100,000 and $250,000.  The solicitation, plans, and specifications are expected to be posted on or about 15 May 2018. The solicitation will be available for a minimum of thirty (30) calendar days, and award of the contract is expected on or before June 30, 2018.