stabilization of pensacola dam west abutment project

ADDENDUM 2

STABILIZATION OF PENSACOLA DAM WEST ABUTMENT PROJECT

LANGLEY, OKLAHOMA

GRAND RIVER DAM AUTHORITY CONTRACT NO. 41492

DESIGN ENGINEERS:

Shannon & Wilson, Inc. 2043 Westport Center Drive Saint Louis, Missouri 63146

and

Burns & McDonnell 9400 Ward Parkway

Kansas City, Missouri 64114

Date: 17 May 2013 To All Planholders: The following changes, additions and/or deletions are hereby made a part of the Project Manual for the Stabilization of Pensacola Dam, West Abutment Project, Langley, Oklahoma, as fully and completely as if they were fully set forth therein: Table of Contents REPLACE: The Table of Contents from the Project Manual, in its

entirety, with the version enclosed herewith (1 page). REVISION SUMMARY: Number of Pages for Bid Form and Section 01025 revised. Bid Form REPLACE: The Bid Form from the Project Manual, in its entirety, with

the version enclosed herewith (2 pages). REVISION SUMMARY: Item 7 deleted and Optional Item 13 added. Section 01025 REPLACE: Specification Section 01025 from the Project Manual, in its

entirety, with the version enclosed herewith (10 pages). REVISION SUMMARY: Description of Item 7 removed and description of Optional

Item 13 added. Section 02310 REPLACE: Specification Section 02310 from the Project Manual, in its

entirety, with the version enclosed herewith (5 pages). REVISION SUMMARY: Parts 1.01, 3.01, and 3.02 revised to add trimming of rock

overhangs to the scope of .mechanical scaling. All bidders shall acknowledge receipt of this Addendum 2 when submitting their bid.

PROJECT MANUAL TABLE OF CONTENTS

GRAND RIVER DAM AUTHORITY

STABILIZATION OF PENSACOLA DAM WEST ABUTMENT PROJECT

Pages

Bid Form 2

DIVISION 1 – GENERAL REQUIREMENTS 01010 Summary of Work 3 01025 Measurement and Payment 10 01040 Coordination, Communication and Meetings 4 01050 Field Engineering and Construction Surveying 3 01092 References and Abbreviations 6 01114 Demolition and Waste Disposal 3 01120 Supplemental Insurance Requirements 1 01140 Work Restrictions and Regulatory Requirements 8 01300 Submittals 7 01320 Construction Schedules 3 01575 Erosion and Sediment Control 4

DIVISION 2 – SITE WORK

02110 Clearing and Grubbing 2 02310 Scaling and Excavation 5 02340 Ground Anchors and Slope Mesh 17 02444 Fences 7

APPENDICES

Appendix A – Shannon & Wilson Geotechnical Engineering Report

Appendix B – Historical Photographs and Design Drawings

Appendix C – Example Copy of GRDA Pro Forma Contract

DESIGN DRAWINGS

Sheets 1 through 9

GRAND RIVER DAM AUTHORITY STABILIZATION OF PENSACOLA DAM

WEST ABUTMENT PROJECT BID FORM (PAGE 1 OF 2)

ITEM DESCRIPTION ESTIMATED QUANTITY UNIT UNIT PRICE EXTENDED

PRICE BASE BID ITEMS

1 Mobilization and Demobilization 1 LS $ $ 2 Erosion and Sediment Control 1 LS $ $

3 Demolish, Remove, and Dispose of Low Fence, Drape Mesh, and Geofabric 1 LS $ $

4 Disassemble, Store, and Reassemble Security Fence 1 LS $ $ 5 Furnish, Install, and Remove Temporary Fencing 1 LS $ $ 6 Design, Furnish and Install New Low Chain Link Fence 75 LF $ $ 7 Not Used --- --- --- ---

8 Excavate and Dispose of Spoil from Toe of Slope (up to 2,000 Cubic Yards) 2,000 CY $ $

9 Excavate and Dispose of Spoil from Toe of Slope (2,001 to 2,500 Cubic Yards) 500 CY $ $

10 Excavate and Dispose of Spoil from Toe of Slope (2,501 to 3,000 Cubic Yards) 500 CY $ $

11 Furnish and Install Ground Anchors 12,000 LF $ $ 12 Furnish and Install Slope Mesh and Erosion Control Mat 40,000 SF $ $

TOTAL BID PRICE (BASE ITEMS) $ TOTAL BID PRICE (written out words):

GRAND RIVER DAM AUTHORITY STABILIZATION OF PENSACOLA DAM

WEST ABUTMENT PROJECT BID FORM (PAGE 2 OF 2)

ITEM DESCRIPTION ESTIMATED QUANTITY UNIT UNIT PRICE EXTENDED

PRICE OPTIONAL ITEM

13 Scale Rock Slope and Trim Overhangs 1 LS $ $ TOTAL PRICE FOR OPTIONAL ITEM (written out words):

01025-1

SECTION 01025 MEASUREMENT AND PAYMENT

PART 1 – GENERAL 1.01 SECTION INCLUDES

A. Measurement and payment criteria applicable to the Work.

B. Defect assessment and non-payment for rejected Work. 1.02 AUTHORITY

A. Measurement methods delineated in the individual specification sections complement the criteria of this section. In the event of conflict, the requirements of the individual specification sections govern.

B. The Contractor shall make all measurements and compute quantities. Measurements

and quantities are subject to the Engineer's review and verification. C. The Contractor shall assist the Engineer by providing necessary equipment, workers,

and survey personnel as required to verify measurements and quantities. 1.03 UNIT QUANTITIES SPECIFIED

A. Quantities indicated in the Bid Form are for bidding and contract purposes only. Quantities and measurements supplied or placed in the Work, verified and approved by the Engineer, determine payment.

B. If the actual Work requires more or fewer quantities than those quantities indicated on

the Bid Form, the contractor will provide the required quantities at the unit prices contracted.

1.04 ABBREVIATIONS

A. The following are abbreviations used in paragraphs related to Measurement and Payment:

1. LS - Lump Sum 2. LF - Linear Foot 3. CY - Cubic Yard 4. SF - Square Foot


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1.05 MEASUREMENT OF QUANTITIES

A. Measurement by Volume: Except for excavation quantities, measured by cubic dimension using average length, width and height or thickness. For excavation quantities, measurement will be the differential volume calculated from three-dimensional models of the ground surface developed from surveys performed before and after excavation, as described in Section 01050: Field Engineering and Construction Surveying.

B. Linear Measurement. Measured by linear dimension, at the item centerline or average

chord. C. Stipulated Price Measurement: Items measured by weight, volume, area, or linear

means or combination, as appropriate, as a completed item or unit of the Work. 1.06 PAYMENT

A. All work activities for the project shall be incorporated into one of the pay items on the Bid Form. No payment will be made for any other work.

B. Payment Includes: Full compensation for providing all required labor, products, tools,

equipment, plant, transportation, services and incidentals; erection, application or installation of an item of the Work; all disposal costs; and overhead and profit.

C. Final payment for Work governed by unit prices will be made on the basis of the actual

measurements and quantities accepted by the Engineer multiplied by the unit price for Work which is incorporated in or made necessary by the Work.

D. All GRDA contracts may provide for partial payment based upon work completed. If

such partial payments are made, the contract shall provide that up to ten percent (10%) of all partial payments made shall be withheld as retainage. At any time the Contractor has completed in excess of fifty percent (50%) of the total contract amount, the retainage may be reduced to five percent (5%) of the amount earned to date if GRDA has determined that satisfactory progress is being made, and upon approval by the surety.

E. Lump sum bid items will not be measured. Payment for lump sum bid items, less

retainage, will be made according to the schedule described for the specific lump-sum items as described in the following paragraphs.

1. Payment for lump-sum bid items is subject to acceptable construction progress.

F. Measurement and payment for unit price items listed in Bid Form shall be as defined in the following paragraphs.


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Item 1: Mobilization and Demobilization

1. Mobilization and Demobilization includes mobilization of all Contractor and subcontractor personnel, equipment, and temporary construction facilities to the site; obtaining security clearances for Contractor and subcontractor personnel; demobilization and site clean-up; providing temporary utility infrastructure; preparing and updating construction schedules; construction surveying and staking; providing all insurance and bonds required to complete the Work; and all project specific field and office overhead.

2. The cost of all Work specified in Division 1 - General Requirements, unless specifically covered in other bid items, will not be paid separately, but shall be included in the lump sum price bid in the Schedule for Mobilization and Demobilization.

3. Mobilization and Demobilization is a lump-sum bid item and will not be measured. Payment will be made according to the following schedule, based on the lump sum price shown on the Bid Form for Mobilization and Demobilization: Seventy-five percent with the first progress payment for mobilization and twenty-five percent with the final progress payment for demobilization.

4. The first progress payment for this line item will be subject to the following:

a. Receipt of all required preconstruction submittals.

b. Receipt and approval of the baseline construction schedule submittal.

c. Receipt of Schedule of Values submittal for lump sum items.

d. Initial delivery of equipment and materials to the project site.

5. The Bid Price for Mobilization and Demobilization is limited to a maximum of twenty-five percent of the Total Bid Price shown on the Bid Form.

Item 2: Erosion and Sediment Control

Erosion and Sediment Control includes the installation, maintenance, and removal of all sediment control devices, including hay bales, silt fence, detention ponds, and any other approved Best Management Practices for protection of water courses and wetlands. This item also includes removal and disposal of all accumulated sediment captured by the sediment control devices.

Erosion and Sediment Control is a lump-sum bid item and will not be measured. Payment (less retainage) will be made according to the following schedule, based on the lump sum price bid shown on the Bid Form for Erosion and Sediment Control: Fifty percent with the first progress payment after Work under this Item has begun and fifty percent with the final progress payment.


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Item 3: Demolish, Remove, and Dispose of Low Fence, Drape Mesh, and Geofabric

Demolish, Remove, and Dispose of Low Fence, Drape Mesh, and Geofabric includes demolition, removal, transportation, and disposal of all existing drape mesh, geofabric, and as much of the fastening hardware as practical, in accordance with the Specifications. This item also includes disassembly, removal, transportation, and disposal of the existing low chain link fence as shown on the Drawings and described in the Specifications.

Demolish, Remove, and Dispose of Low Fence, Drape Mesh, and Geofabric is a lump-sum bid item and will not be measured. Full payment (less retainage) will be made as part of the first progress payment after all Work associated with this Item is complete.

Item 4: Disassemble, Store, and Reassemble Security Fence

Disassemble, Store, and Reassemble Security Fence includes disassembly, storage, and reinstallation of those portions of the existing security fence that would otherwise interfere with other portions of the Work. This item also includes furnishing and installing any replacement parts necessary to restore the security fence to its preconstruction condition.

Disassemble, Store, and Reassemble Security Fence is a lump-sum bid item and will not be measured. Payment (less retainage) will be made according to the following schedule, based on the lump sum price bid shown on the Bid Form for Disassemble, Store, and Reassemble Security Fence: Fifty percent with the first progress payment after disassembly and fifty percent after reinstallation of the security fence, in accordance with the Specifications.

Item 5: Furnish, Install, and Remove Temporary Fencing

Furnish, Install, and Remove Temporary Fencing includes the installation, maintenance, and removal of the temporary security fence, temporary perimeter fence, and the temporary safety fence or barrier, as described in the Specifications.

Furnish, Install, and Remove Temporary Fencing is a lump-sum bid item and will not be measured. Payment (less retainage) will be made according to the following schedule, based on the lump sum price bid shown on the Bid Form for Furnish, Install, and Remove Temporary Fencing: Fifty percent with the first progress payment after installation of all temporary fencing and fifty percent with the final progress payment.


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Item 6: Design, Furnish and Install New Low Chain Link Fence

Furnish and Install New Low Chain Link Fence includes procuring, furnishing, and installing a contractor-designed chain link fence in accordance with the Specifications at the location(s) shown on the Drawings.

Measurement for payment will be made in linear feet of fence installed at the location(s) shown on the Drawings. Payment will be made at the unit price per linear foot shown on the Bid Form for Furnish and Install New Low Chain Link Fence.

Item 7: (Not Used)

Item 8: Excavate and Dispose of Spoil from Toe of Slope (up to 2,000 Cubic Yards)

Excavate and Dispose of Spoil from Toe of Slope (up to 2,000 Cubic Yards) includes all Work required to excavate, haul, and dispose of unclassified earth material (including loose rock) from area(s) at the toe of the rock slope, as depicted on the Drawings or as directed by the Engineer. The spoil to be excavated as part of this line item includes both materials deposited naturally and as a result of scaling activities.

The exact volume of spoil to be excavated is not known. This Item covers excavation, transport, and disposal of the first 2,000 cubic yards of material. If the total quantity of material to be excavated exceeds 2,000 cubic yards, measurement and payment for the additional quantity will be covered under Items 9 and 10.

Measurement for payment will be made per bulk cubic yard of in-place material excavated, based on survey measurements made prior to and after removal of spoil. No payment will be made for excavation outside of the area(s) described by the Contract Documents unless specifically approved by the Engineer. Payment will be made at the unit price per cubic yard shown on the Bid Form for Excavate and Dispose of Spoil from Toe of Slope (up to 2,000 Cubic Yards).


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Item 9: Excavate and Dispose of Spoil from Toe of Slope (2,001 to 2,500 Cubic Yards)

Because the exact volume of spoil to be excavated is not known, the Bid Form includes multiple Items that cover excavation, transport, and disposal of various volumes of spoil excavated from the toe of the slope. The purpose of the multiple Items is to allow the Contractor to adjust unit prices to reflect economy of scale.

Excavate and Dispose of Spoil from Toe of Slope (2,001 to 2,500 Cubic Yards) includes the same general tasks as described for Item 8, but applies to excavation of 2,001 to 2,500 cubic yards of material. This Item shall only apply after the first 2,000 cubic yards have been excavated.

Measurement for payment will be made per bulk cubic yard of in-place material excavated, based on survey measurements made prior to and after removal of spoil. No payment will be made for excavation outside of the area(s) described by the Contract Documents unless specifically approved by the Engineer. Payment will be made at the unit price per cubic yard shown on the Bid Form for Excavate and Dispose of Spoil from Toe of Slope (2,001 to 2,500 Cubic Yards).

Item 10: Excavate and Dispose of Spoil from Toe of Slope (2,501 to 3,000 Cubic Yards)

Refer to the first paragraph under Item 9.

Excavate and Dispose of Spoil from Toe of Slope (2,501 to 3,000 Cubic Yards) includes the same general tasks as described for Item 8, but applies to excavation of 2,501 to 3,000 cubic yards of material. This Item shall only apply after the first 2,500 cubic yards have been excavated.

Measurement for payment will be made per bulk cubic yard of in-place material excavated, based on survey measurements made prior to and after removal of spoil. No payment will be made for excavation outside of the area(s) described by the Contract Documents unless specifically approved by the Engineer. Payment will be made at the unit price per cubic yard shown on the Bid Form for Excavate and Dispose of Spoil from Toe of Slope (2,501 to 3,000 Cubic Yards).

If the total excavation quantity exceeds 3,000 bulk cubic yards, a change order will be negotiated with the Contractor for the overrun. The Change Order will apply only to the quantity in excess of 3,000 cubic yards.


01025-7

Item 11: Furnish and Install Ground Anchors

Furnish and Install Ground anchors includes furnishing all ground anchor materials, including epoxy-coated threadbar, centralizers, cement grout, all anchorage and connection hardware, and other miscellaneous supplies, as well as all labor and equipment necessary to drill holes, install, and grout ground anchors (including secondary grouting of “birds beaks”) in accordance with the Specifications at the locations shown on the Drawings or as directed by the Engineer. This Item also includes furnishing and installing grout socks on up to 10 percent of the ground anchors, furnishing calibrated stressing and measuring equipment, and proof testing of selected anchors in accordance with the Specifications. Measurement for payment will be made per lineal foot of steel threadbar installed at locations approved by the Engineer. Payment for ground anchors installed to the satisfaction of the Engineer will be made at the unit price per linear foot shown on the Bid Schedule for Furnish and Install Ground anchors. There will be no differentiation between Type I and Type II ground anchors for the purposes of measurement and payment.

If a ground anchor is abandoned at the direction of, or with approval by, the Engineer as a direct result of difficult ground conditions (voids, caving conditions, etc.), payment for the abandoned ground anchor will be made at one-half the unit price shown on the Bid Schedule for Furnish and Install Ground anchors. Payment shall include furnishing all labor, equipment, and materials for sealing the abandoned hole with a minimum 3-inch thick mortar patch.

Ground anchors abandoned due to contractor negligence or which do not meet the testing requirements will not be measured and no payment will be made.

Item 12: Furnish and Install Slope Mesh and Erosion Control Mat

Furnish and Install Slope Mesh and Erosion Control Mat includes furnishing and installing steel wire mesh, boundary ropes, erosion control mat, and all appurtenances, as described in the Specifications at the location(s) shown on the Drawings. This Item includes all connections to ground anchors, all connections between prefabricated mesh panels, and all connections between the steel wire mesh and erosion control mat.

Measurement for payment will be made per square foot of steel wire mesh installed at locations approved by the Engineer. No separate payment will be made for installing the boundary ropes or erosion control mat. Payment for will be made at the unit price per square foot shown on the Bid Schedule for Furnish and Install Steel Wire Mesh and erosion control mat.


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Item 13: Scale Rock Slope and Trim Overhangs

Scale Rock Slope and Trim Overhangs includes all labor and equipment required to scale (remove) loosened material from the existing rock slope within the area(s) depicted on the drawings, as described by the Specifications. This Item includes all scaling regardless of method. It also includes all labor and equipment required to mechanically trim areas of overhanging rock, as described in the Specifications, as well as any hand excavation of rock that may be necessary around the ground anchor heads.

Scale Rock Slope and Trim Overhangs is an Optional Item that may or may not be authorized by the Owner. The Owner reserves the right to negotiate scope and cost with the selected Contractor prior to authorizing the work associated with this Item.

Scale Rock Slope is a lump-sum bid item and will not be measured. If authorized by the Owner, full payment (less retainage) will be made as part of the first progress payment after all Work associated with this Item is complete.

1.07 DEFECT ASSESSMENT A. Replace the Work, or portions of the Work, not conforming to the Plans and

Specifications, at no additional cost to the Owner. B. If, in the opinion of the Engineer, it is not practical to remove and replace the Work, the

Engineer will direct one of the following remedies:

1. The defective Work may remain, but the bid price will be adjusted, at the discretion of the Engineer.

2. The defective Work will be partially repaired, to the satisfaction of the Engineer,

and the price will be adjusted, at the discretion of the Engineer. C. The individual specification sections may modify these options or may identify a

specific formula or percentage price reduction. D. The authority of the Engineer to assess the defect and identify payment adjustment is

final. 1.08 NON-PAYMENT FOR REJECTED WORK

A. No payment will be made for any of the following:

1. Products wasted or disposed of in a manner that is not acceptable. 2. Products determined to be unacceptable in the opinion of the Engineer, before or

after placement. 3. Products not completely unloaded from the transporting vehicle.


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4. Products placed beyond the lines and levels of the required Work. 5. Products remaining on hand after completion of the Work. 6. Removal, loading, hauling, and disposing of rejected Products. 7. Overly wet or frozen earthfill material. 8. Excavation or fill made for the convenience of the Contractor. 9. Overexcavation and backfill of overexcavation not approved by Engineer. 10. Work performed that has been rejected and/or determined to be defective, except

as described in Paragraph 1.07, above. 11. Stockpiling materials, unless specifically included in the description of a Line

Item. 12. Rehandling materials.

1.09 CHANGES TO THE WORK

A. Changes to the Work will be handled in accordance with the executed contract between the Owner and the Contractor. 1. An example copy of GRDA’s Pro Forma Contract is provided in Appendix C.

Refer to Section 3.7. B. Prices for additional Work may be negotiated with the Contractor. The Owner may

request written documentation of the cost of materials, operating costs for equipment, and labor costs associated with performance of the additional Work as back-up during the negotiation process.

C. Except in the case of an emergency, the Contractor shall obtain written authorization

from the Owner before performing any Work that will result in a Change Order. PART 2 – PRODUCTS Not Used.


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PART 3 – EXECUTION 3.01 APPLICATION AND PAYMENT PROCEDURES

D. The Owner’s payment procedures, including instructions to the Contractor for submitting monthly requests for partial payment, will be as described in the executed contract between the Owner and the Contractor. 1. An example copy of GRDA’s Pro Forma Contract is provided in Appendix C.

Refer to Section 3.2.

END OF SECTION 01025-Measurement and Payment.docx

02310-1

SECTION 02310 SCALING AND EXCAVATION

PART 1 – GENERAL 1.01 DESCRIPTION

A. The Work covered by this section consists of furnishing all labor, equipment, and materials for the following tasks:

1. Removing loosened blocks of bedrock from the near-vertical cliff at the upper

portion of the slope (scaling).

2. Trimming rock overhangs from the near-vertical cliff at the upper portion of the slope.

3. Excavating and removing loose soil and up to boulder-sized material (talus

and colluvium) that has been formed and/or deposited on the bedrock surface by natural weathering processes.

4. Scaling loosened blocks of rock from the exposed bedrock surface following

excavation and removal of the talus and colluvium. 5. Excavating and removing material that has been scaled from the slope. 6. Protecting all existing infrastructure on or at the toe of the slope during all

scaling and excavation activities. 7. Transportation and disposal of excavated soil and rock. 8. All supplementary Work incidental to the services outlined above, whether or

not specifically indicated in the Contract Documents.

B. Scaling is expected to include both mechanical scaling and hand scaling. C. Inflatable bladders may be used to remove large blocks of rock that are too large to

remove with hand scaling bars. D. The use of explosives is prohibited.

1.02 RELATED SECTIONS

A. Section 01114 – Demolition and Waste Disposal B. Section 01300 – Submittals


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C. Section 01575 – Erosion and Sediment Control D. Section 02340 – Ground Anchors and Slope Mesh

1.03 SUBMITTALS

A. Procedure: Section 01300: Submittals B. Submit the plan and schedule for scaling, trimming, and excavation 14 days prior to

starting the Work. The plan shall include descriptions of the methods and equipment for scaling and excavation, survey equipment, methods of stockpiling, loading, hauling, and disposal of waste material, and the proposed disposal location.

1.04 DEFINITIONS

A. Mechanical Scaling: The removal of loosened, drummy, or unstable slabs or blocks of rock from the bedrock surface (including the cliff) using mechanical means, such as dragging scaling equipment across the face.

B. Hand Scaling: Removal of loosened, drummy, or unstable slabs or blocks of rock

from the bedrock surface (including the cliff) by personnel using rock climbing techniques to rappel down the slope. Hand scaling equipment typically includes hand-operated pry bars, pneumatic bladders placed in cracks between the rock to be scaled and the cliff face, and similar tools.

C. Unclassified Excavation: Removal of any combination of topsoil, earth, weathered

rock, intact rock, cobbles, boulders or other subsurface material. 1.05 REFERENCES

A. 29 CFR 1926, Subpart M (Fall Protection) B. 29 CFR 1926, Subpart CC (Cranes & Derricks in Construction)

1.06 EXISTING SITE CONDITIONS

A. One vertical boring was drilled from the crest of the slope by Shannon & Wilson. Information about the subsurface conditions encountered are described in a document titled “Geotechnical Engineering Report, GRDA Pensacola Dam, West Abutment Stabilization, Langley, Oklahoma” by Shannon & Wilson dated August 17, 2011. A copy of this report is included as Appendix A to the Project Manual.

B. A limited number of historical photographs taken during construction and copies of

original design drawings are available and included as Appendix B to the Project Manual.


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C. There is no available boring or test pit information about the thickness of the talus wedge or the depth to bedrock within the slope mitigation area.

PART 2 – PRODUCTS NOT USED PART 3 – EXECUTION 3.01 GENERAL

A. The Contractor shall notify the Engineer at least 48 hours in advance of the

commencement of any phase of scaling or excavation and/or of any delays or work stoppages.

B. Scaling, excavation, and rock trimming shall be accomplished with equipment,

methods, and workmanship that will minimize disturbance or damage to sound, intact bedrock.

C. All excavation shall be performed in a safe manner. Loose material shall be scaled

from the cliff face prior to excavation of the talus wedge. Appropriate measures shall be taken to protect personnel and equipment from falling material.

D. The Contractor's excavation, rock trimming, and scaling methods shall be such that

after completion of excavation all peripheral surfaces are sound and not cracked or loosened.

E. Contractor shall protect the Powerhouse, other nearby structures, pipelines, and

utilities from damage during scaling and rock trimming operations. F. Contractor shall coordinate with the Owner to identify the locations(s) of buried

utilities or other critical infrastructure within the work area and take all reasonable measures to protect such infrastructure from damage during scaling and excavation activities.

G. All scaling, rock trimming, and excavation shall be performed in accordance with

applicable OSHA regulations. Safety shall at all times remain the sole responsibility of the Contractor.

3.02 MECHANICAL SCALING AND ROCK TRIMMING

A. Contractor shall mechanically scale the vertical cliff portion of the slope before permitting hand scaling crews to rappel down the slope and before clearing and grubbing below the cliff and excavating the talus wedge. The purpose of mechanical scaling is to remove smaller-sized material.


02310-4

B. Mechanical scaling equipment may consist of an unhinged “caterpillar” track, heavy marine anchor chain, tugboat chain, dragline chain, or other Engineer-approved device that can be hung over the crest and dragged across or used to impact the slope face to effectively remove loosened material.

C. Where overhangs exist, the contractor shall utilize mechanical trimming as part the

scaling process. Trimming may utilize line drilling with expansive mortar or other non-explosive demolition agent, mechanical impact breakers, or other Engineer-approved techniques.

D. Contractor shall protect existing 30-inch pipeline, pipe cradles, powerhouse, small-

diameter above-ground steel pipeline, and all other infrastructure from impact or other damage caused by material scaled from the cliff face during mechanical scaling operations.

3.03 HAND SCALING

A. Contractor shall hand-scale loose or unstable blocks of rock from the slope that cannot be removed by mechanical scaling.

B. Contractor shall protect existing 30-inch pipeline, pipe cradles, powerhouse, small-

diameter above-ground steel pipeline, and all other infrastructure from impact or other damage caused by material scaled from the cliff face during hand scaling operations.

C. Hand scaling of the cliff shall be performed only after mechanical scaling is

complete. Hand scaling of the remainder of the slope shall be performed following excavation of the talus wedge.

D. Hand scaling may consist of rope access crews on slope using pry bars, pneumatic

bladders (“air bags”), or other approved means and methods. E. Contractor is responsible for providing suitable anchorages for climbing ropes.

3.04 EXCAVATION

A. Excavate and remove all unclassified material above the existing bedrock surface within the areas designated on the Drawings. Contractor shall excavate to the intact bedrock surface, to the satisfaction of the Engineer.

B. Contractor shall protect existing 30-inch pipeline, pipe cradles, powerhouse, small-

diameter above-ground steel pipeline, and all other infrastructure from damage during excavation and removal of spoil.


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C. Removal of excavated spoil is expected to require hoisting or conveying material to the crest of the slope.

D. The Contractor shall assume all responsibility for deductions and conclusions as to the

nature of the materials to be excavated and the difficulties of making and maintaining the required excavations.

E. All excavations are the responsibility of the Contractor and shall conform to all

Federal, State, and/or local safety requirements.

3.05 DISPOSAL OF SCALED AND/OR EXCAVATED MATERIALS

A. Excavated and scaled material shall be removed from the site and disposed of in accordance with the requirements of Section 01114 – Demolition and Waste Disposal.

B. The Contractor shall prevent debris from polluting soil, groundwater, or surficial

runoff until disposal in accordance with the requirements of Section 01575 – Erosion and Sediment Control.

END OF SECTION

WIP/02310-Scaling and Excavation.docx

The following questions have been received in regard to bidding the “Stabilization of Pensacola Dam West Abutment” project, associated clarification are included in italic herein or within the addenda text: 1. There appears to be a conflict regarding whether the bid is a combination of Lump Sum and Unit

Quantity Items (as shown on page 15 “Unit and Task Price Schedule”), and that referenced on page 13, stating “… and to accept the not-to-exceed sum of:…”. Please clarify. See Addendum No. 2 Text

2. Refer to Bid Item #7 ( Scale Rock Slope) – This item does not have a bid (unit) quantity, and extent of mechanical & hand scaling is at discretion/approval/direction of Engineer. As stands presently, this makes for a rather “subjective” bid on the part of the contractors. Is the bid set up so that quantities of existing talus, PLUS expected scaling quantities, are figured in Bid Item #8 (Excavate and Dispose of Spoil from Toe of Slope (up to 2,000 Cubic Yards), and any additional scaling past what Engineer expects for base bid, is dealt by Bid Items #9 & #10?

See Addendum No. 2 Text

3. If not, can Engineer provide further direction on how to quantify for bidding purposes Bid Item #7?


4. Refer to 01050-1 1.02 - Our Field Engineers who are fully capable of providing base, intermediate, and final quantity surveys (with accompanying computer assisted modeling/quantities) do not hold State of Oklahoma PLS stamp. Can PLS requirement be waived, if we accept any associated risk/cost? There is no boundary work associated with this project – PLS requirement will not be required.

5. Has any geo-tech engineering been done to establish what weight loads are acceptable/safe on the top of the bluff, in regards to weight of the expected job crane? See Addendum No. 2 Text

6. Regarding Rock Anchor Installation, detail shows overall length of anchor to be 13 LF. Spec. section 02340-8 G.4, indicates an overall length of 15 LF ((3) centralizers spaced 5’ apart). Spec’s govern?


7. Chain Link fencing requires stamp of Oklahoma PE (02444-2 A.1). Is this correct/necessary? Also, 02444-4 B.12 refers to “Contractor’s Engineer…”. Is the intent to have contractor’s bid costs associated providing Professional Engineering services, in addition to the Engineer of record? There is no boundary work associated with this project – PLS and PE requirement will not be required.

8. Is there a list of local persons (with contact information) interested in receiving the excavated spoils?

It is the vendor’s responsibility to find persons interested in receiving the excavated spoils.

9. When will the sign-in sheet with all contractors present for the pre-bid meeting be provided? Email Nita Wade at [email protected] to request a copy.

10. I mentioned to GRDA management personnel during the pre-bid, that it appears to me that a simple, much less costly, and safer alternative to hoisting out the talus (scaling/excavation spoils) and hauling to an offsite location, would be to “fly-in” small, excavation/material moving equipment, and push the materials at the toe of the talus slope, north into the void of the arch (see attached photo). It could be a simple, efficient/fast, straight forward and practical solution to a more tough/expensive/risky procedure otherwise. GRDA personnel I spoke with thought it was a good idea, and worth exploring. If this is something that is determined for consideration and further investigation, we will be available, and happy to meet with GRDA and Engineering Design professionals onsite, to discuss further.

Storage of the waste material, change of access to the base of the arch and differential loading on the buttress wall resulting from deposition of the material, if any, would require approval of the Federal Energy Regulatory Commission (FERC). GRDA recognizes this may be a logical and possible solution but timing and duration of the solution may be problematic within the time frame of the contract. GRDA will support any proposed submittal made by the successful contractor for such a proposal to FERC but the responsibility for developing the proposal and risk for final FERC conclusion shall be the responsibility of the successful contractor.

11. What is the acceptance criteria for the scaling? Since this is a lump sum item I would like to see more definition on what would be required to have the scaling accepted as complete.

There are no specific acceptance criteria for scaling. The primary purpose of scaling is to provide a safe environment for personnel working either on the slope (via rope access) or at the base of the slope. Because safety is the sole responsibility of the Contractor, the amount of scaling to perform is up to the Contractor’s discretion. That said, the Engineer and Owner will not accept blatant safety hazards, such as (but not necessarily limited to), obvious loose blocks or material that is dislodged solely by the action of rappel ropes sliding laterally across the rock face.

mailto:[email protected]

Additionally, it is the design intent to minimize the amount of loose material that will trapped behind the mesh immediately after construction, although the Engineer and Owner anticipate that scaling for safety will also achieve this goal.

12. Why is the testing based on the yield strength of the bar and not on the design load criteria?? Testing is based on the design load of 42.5 kips for a No. 9, Grade 75 steel bar. See Section 02340, Part 1.04, Item B and Section 02340, Part 3.06, Item D, Number 3, Subpart a.

13. Are the anchors there to hold the mesh in only or are they designed to hold in the rock mass in any way? If they are designed just to hold in the mesh and surface material the weakest link is the mesh and the bars should only be tested to see if they can withstand the shear load of the mesh. The anchors are also intended to reinforce the rock mass in a composite system with the mesh. All anchor testing shall be as described in the Specifications.

14. Do you have to perform mechanical scaling on the slope?? There are several areas that have overhangs so the mechanical scaling as defined in the specifications will not work because you cannot get the anything dragged over the slope with any efficiency and the procedure will be ineffective over most of the slope because of these overhanging featrures??

Section 02310, Part 3.02, Item A states that mechanical scaling shall be performed. Section 02310, Part 3.02, Item B describes methods by which mechanical scaling may be accomplished. The methods described are not intended to be prescriptive, and the Contractor is free to utilize other means and methods. The primary intent of mechanical scaling is to improve safety for rope access and other onsite personnel, particularly with respect to smaller-sized material that may be inefficient for hand scalers to remove. The Engineer will consider Contractor-proposed alternate approaches. However, alternate approaches shall not compromise safety, nor shall it be likely to result in trapping an excessive volume of material behind the new mesh immediately after installation.

15. What is the purpose of excavating in the rock slope for the Tecco Plates?? Especially in the area where the rock is weak and the spacing is 5 feet we will be creating further weathering problems in the future if we do the excavation around the plates. Excavating around the plates is a procedure that is used for soils to maintain pressure but will be counterproductive for rockwork and will exasperate the weathering process.

The intent of excavation for plates is to create maximum contact and tension between the mesh and the rock mass. The Engineer will consider Contractor-proposed alternate approaches after award, but alternate approaches must demonstrate an equal or better condition for contact and tension between the rock mass and mesh.

16. Is/will traffic control (and to what extent) be required for loading trucks, and subsequent pulling

out to driving lanes, with excavated materials (south side of HWY. 28 adjacent to “man-gate” near display turbine)? Before, we loaded a relatively small amount of haul trucks in this location, and they would pull onto HWY 28 west bound with little active traffic control. This could be a significant item, as contractor will be disposing of a significantly larger amount of spoils than previously, and our interpretation of schedule shows we could be having an active construction site at high tourist season, and depending on levels of traffic control required will impact cost/productivity. Impacts to State Highway 28 traffic will require approval by the Oklahoma Department of Transportation Division 8 Engineer.