Revisions_to_Specifications.pdf

Section 3.2.2 of the specification as advertised is shown below.

3.2.2 Outlet Works Condition Assessment

As part of the base bid, the condition assessment will include:

• Non-destructive testing of the outlet works conduit steel pipe wall thickness and depth of corrosion penetration.

• Condition and remaining thickness of concrete lining. The original lining was 3/8 inch thick.

• Evaluation of welds, antivortex plate, valve seals, and any other elements of the outlet works as warranted as the condition assessment is conducted.

Non-destructive testing could include magnetic resonance, sonar, radar or any method that will allow an accurate assessment of the structures integrity of the steel conduit and components. The Forest Service will provide all information and preliminary quotes obtained from vendors in its research into available methods.

The Contractor will provide a summary assessment of the outlet works within one week of the completion of testing. Depending on the testing results the COR may require a full condition assessment report. If required, the full condition assessment report will be submitted by the Contractor not less than one month after the completion of testing.

Delete Section 3.2.2 and replace with the following.

3.2.2 Outlet Works and Bays 4 and 5 Condition Assessment

As part of the base bid, the condition assessment will include:

• Non-destructive testing of the outlet works conduit steel pipe wall thickness and depth of corrosion penetration.

• Condition and remaining thickness of concrete lining. The original lining was 3/8 inch thick.

• Evaluation of welds, antivortex plate, valve seals, and any other elements of the outlet works as warranted as the condition assessment is conducted.

• Evaluation of the condition of the concrete in Bays 4 and 5 of the dam using concrete coring and/or impact echo techniques to locate areas where concrete may be damaged or degraded.

Non-destructive testing for evaluation of the outlet works could include magnetic resonance, sonar, radar or any method that will allow an accurate assessment of the structures integrity of the steel conduit and components.

Coring for Concrete Evaluation in Bays 4 and 5

It is estimated that approximately six cores may be gathered to locate and/or verify concrete degradation and grout penetration. The exact number of cores will vary depending on conditions encountered and is subject to the approval of the COR.

The dam thickness varies from approximately 1.8 feet in the upper half tapering from the midpoint/slope break in each bay to approximately 4 feet in thickness near bedrock.

The cores shall be obtained in a manner that minimally impacts the structural integrity of the dam. They may not be placed within 5 feet of locations previously cored during the execution of this contract or previous coring efforts in 1954 or 1984 if visible.

Coring will be conducted in conjunction with construction activities planned in 2015 which requires coordination with the construction Contractor.

• Cores will be logged using generally accepted techniques. They will be located on a plan drawing and geospatially referenced against a local and/or geographic coordinate system. UTM 1927 or UTM 1983 is acceptable geographic coordinate systems.

• Core boxes will be stored in a location approved by the Contracting Officers Representative (COR).

• Core holes will be backfilled as required to insure long term stability and seepage control. The method used to backfill holes is subject to approval by the COR.

Impact Echo for Concrete Evaluation in Bays 4 and 5

Impact echo surveys will be confined primarily to zones where seepage impacts are most evident as defined by the COR. The lower half of arches 4 and 5 are the primary areas of concern. Impact echo surveys will be confined to areas with visible seepage impacts as defined by the COR.

Between 500 and 2000 square feet of dam face may be surveyed. The exact square footage is dependent on field conditions encountered and is subject to the approval of the COR. Areas across the downstream dam face could be added depending on funding.

• Surveys will be utilized locate non-homogeneities and or voids in the concrete - zones that will require structural remediation through the injection of epoxy grout or urea silicate.

Vendors known to provide the condition assessment services described in this section include the following:

• Twining, Inc., contact: Andrew Tan, phone 562-513-1502 or via email atan@twininginc.com.

• Vector Corrosion Services, Inc., contact: Brian Pailes, phone 813- 501–0050 or via email brianp@VCServices.com.

The Contractor will provide a summary assessment of the outlet works and Bays 4 and 5 within one week of the completion of testing. Depending on the testing results the COR may require a full condition assessment report. If required, the full condition assessment report will be submitted by the Contractor not less than one month after the completion of testing.

The accepted items will be paid at the contract price per unit of measurement for the pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section.

Anything not listed will be considered incidental and shall be included in the cost of the listed items.

Paragraph 5 of Section 4A.6 (related to payment of grout) of the specification as advertised is shown below.

Portland Cement and additives: Portland cement and additives will be measured for payment on the basis of the number of bags (94 pounds) of cement used in the grout satisfactorily placed in grout holes, or wasted when such wasting is not due to the Contractor's negligence. Microfines, fly ash, sand, water, and admixtures are incidental.

Unit of measure: 1 cubic foot bag (94 pounds).

Delete Paragraph 5 and replace with the following.

Portland Cement and additives: Portland cement and additives will be measured for payment on the basis of the quantities of Portland cement, microfine cement, sand, bentonite, and fly ash used in the grout satisfactorily placed in grout holes, or wasted when such wasting is not due to the Contractor's negligence. Water and admixtures are incidental to Portland cement.

Unit of measure: Portland cement will be measured by the 1 cubic foot bag (94 pounds). Other components will be measured as shown in the Schedule of Items.

mailto:atan@twininginc.com mailto:brianp@VCServices.com