A.03.09 - KTR Questions - 2.pdf

Portsmouth Seepage Barrier Questions

07 December 2020

1. 3.2.1 CQC System Manager

“…..The CQC Manager shall be a professional engineer, registered in the United States, and shall have completed the USACE Construction Quality Management for Contractors course.

In addition, “……An alternate for the CQC System Manager shall be identified in the Plan to serve in the event of the System Manager's absence. The requirements for the alternate shall be the same as for the designated CQC System Manager, and the alternate shall be a full‐time, permanent employee of the Prime Contractor.”

Would the USACE approve a CQC System Manager, and his/her alternate CQC, who is a permanent employee of the Contractor with more than 5 years of experience in

Large/Complex USACE dam/levee remediation projects but without the professional engineer registration?

We consider that if the experience in QC/QA USACE procedures, including management of

RMS, is granted with successful experience, then a deep understanding in Seepage

Barrier/Cutoff Wall construction in large/complex projects is significant more relevant for the success of the project than the PE registration.

Please clarify.

The CQC System Manager and any alternates are to meet the requirements listed in the specifications. There will be no waivers to these requirements.

08 December 2020

2. Drawing GI003 “General Notes” indicates in note 3 of general notes:

“… 3. The top of the levee may be lowered to a minimum elevation of 542, which is approximately equivalent to a 500 to 600 year return flood frequency on the Ohio River. If a flood event is predicted to result in pool elevations which will be within 5 feet, vertically of the work platform surface, the contractor will be directed to stop work and evacuate all personnel and all equipment from the work platform. River levels may be monitored at NOAA’s link as follows:

https://water.weather.gov/ahps2/hydrograph.php?wfo=iln&gage=poro1. ….”

Can the contractor cut the levee below elevation +542’ to install the temporary bypass?

No, the levee may not be lowered below 542.

3. Section 31 55 00 Paragraph 3.1 General. If guide walls for excavation and construction of the seepage barrier are installed, can these remain in place after completion of the COW so no removal is required?

The end of construction condition must be consistent with impervious material consistent with the materials specifications for the seepage barrier or the impervious cap (31 00 00 paragraph 2.2) to the full level of protection. If the guide wall is in compliance with these specifications, then it may be left in place. Structural steel will be allowed as part of the guide wall, if the guide wall is to be left in place. It is noted that the guide wall must not be a safety or aesthetic impediment post‐construction.

4. Section 31 56 00 Paragraph 1.5 Submittals

Critical Area Construction Plan, requires:

“…….Additionally, plan shall include description of methods to either excavate and/or otherwise treat the bedrock surface, to achieve the required "positive" seepage cutoff at that interface.”

Could you explain the intent of “positive” seepage cutoff at the interface foundation soils/bedrock?

The interface of the seepage barrier critical section and the bedrock is crucial. The intent of the positive seepage cut‐off is to ensure adequate reduction of flows and lengthening of the seepage path to the ponding area. The stationing associated with the culvert is currently coincident with the shortest seepage path to the ponding area. Incomplete cut‐off could lead to increased gradients within the ponding area and an increased risk for internal erosion events. The “benchmark” for positive seepage cutoff is 5’ embedment into bedrock, however other methods may be proposed at the critical section to provide “equal” or similar effectiveness of cutoff. Below are a few potential options that may satisfy the requirements:

Contractor may propose a much wider seepage barrier at the critical section.

Contractor may propose use of injection grouting or similar technique at barrier / bedrock interface.

Contractor may propose a combination of techniques and methods to treat the critical section interface with the bedrock.

Offeror’s proposal will be evaluated technically to determine how effective the proposal will be at cutting off (fully or mostly) seepage at or in the vicinity of this interface. The goal is to have seepage cutoff equal or greater to 5 foot of embedment of a conventional barrier wall.

14 December 2020

5. There is a potential conflict on the durations to be considered after completion of the Demonstration section seepage barrier and subsequent report.

Section 31 56 00 indicates:

1.5 Submittals:

SD‐02 Shop Drawings As‐Built Profile; G The as‐builts of the demonstration section shall be submitted to the Government one month after all testing is complete.

SD‐06 Test Reports Seepage Barrier Demonstration Section Report Detailed report including the equipment and procedures used for the demonstration section, and demonstrating (based on acquired quality data) the barrier performance requirements of these specifications. This report should include all testing data from the demonstration section. The report shall be submitted in paper and PDF formats, with accompanying video on DVD as applicable. The submission is due to the Government within 15 calendar days of completion of the Demonstration section.

Demonstration Section Boring Logs; G Submit logs for borings specified in Paragraph DEMONSTRATION SECTION within 5 calendar days of borings completion. The as‐builts of the demonstration section shall be submitted to the Government one month after all testing is complete.

1.9.2 Quality

A written Seepage Barrier Demonstration Section Report detailing the equipment and procedures used, and demonstrating (based on acquired quality data) the barrier performance with respect to performance requirements of these specifications shall be submitted to the Contracting Officer within 15 calendar days of the completion of the demonstration section.

3.9.2.3 Testing of Post Placement Samples

Samples taken as specified in Paragraph SEEPAGE BARRIER BACKFILL SAMPLING PROCEDURES shall undergo the compressive strength and permeability testing as specified in the Paragraph BACKFILL SAMPLE TESTING, only after curing for twenty‐eight days.

This reference indicates:

The permeability tests shall be performed in accordance with ASTM D5084 Method A, and shall be continued until inflow‐outflow measurements or flow rates demonstrate that steady state seepage conditions are evident. The permeameter cell shall be sized to accommodate the full 6‐inch height of the sample. Sample trimming shall be limited in order to maximize the original sample height.

And SECTION 31 57 00 VERIFICATION DRILLING AND TESTING indicates

1.4 SEQUENCING AND SCHEDULING

a. The location of verification drill holes for the installed seepage barrier shall be determined by the Contracting Officer, with a maximum spacing of approximately 100 feet along the centerline of the seepage barrier from Station 199+38.76 to 219+92 and a maximum spacing of 50 feet within the reach of the demonstration section from Station 199+38.76 to

201+38.76. Drill hole locations shall be determined within 18 days after placement of seepage barrier.

Core drilling shall not commence until 21 days after placement of the seepage barrier.

3.4.1 Test Coordination and Documentation

The Contractor shall provide the Contracting Officer with 48 hours written notification of any field permeability test. The notification shall include the location and exact time of the test. The test shall be conducted no fewer than 28 days after completion of installation of the seepage barrier at the test location on a non‐holiday weekday in the presence of the Contracting Officer.

Based on all above, it is estimated that:

1) There are 5 verifications holes on the demonstration section, typically performed after the last element of the seepage barrier, some of which may start, subject to USACE election of the hole location, up to 21 days from the installation of the last demonstration section element, but for other requirements, the related testing would start at least 28 days from the element completion. Bottom line, it is estimated verification test report completion will take much longer than 15 days. ( it estimated could finish between 30 to 40 days from end of wall, subject to USACE’s direction.)

2) Then there are post placement tests to be included in the demonstration section report that may start up to 28 days from the last element placement, and may take several days to be completed ( i.e. lab permeability test ) that can take weeks as specified…

That been said, it will not possible to submit the Demonstration Section report for USACE review, with all information required within 15 days from the last element installation as it could be interpreted is the specs intent.

Therefore, please clarify:

a. What is the definition of “Completion of the Demonstration Section” (as date when:

1: last element is installed, or 2: all testing is completed)?

The “completion of the demonstration section” is defined as the last element being installed and testing completed.

b. Please clarify any test exemptions to be considered in the demo section report.

Tests should not be exempted from the demo section report, and should be included as indicated in the Specifications. Instances of exemption will be considered on a case by case basis by the Contracting Officer.

c. Please clarify if the approval of a revised submittal of the seepage wall is required after approval of the demo section, before production section could start.

The Seepage Barrier Construction Plan shall be revised and finalized based on the successful performance of the demonstration section, submitted to the Contracting Officer, and shall be used for the subsequent production phase seepage barrier work, as per Section 31 56 00, Paragraph 1.9.2.

d. Please clarify how this information shall be used in the definition of the project duration of 730 days from NTP, as there are no milestones from start of production section.

The Contractor should propose a schedule to include the demonstration schedule within the 730 days from NTP.

6. Specs indicate:

The permeability tests shall be performed in accordance with ASTM D5084 Method A and shall be continued until inflow‐outflow measurements or flow rates demonstrate that steady state seepage conditions are evident.

Please clarify if the permeability test can be suspended before steady state, if test proofs the permeability quality requirement has been exceeded.

The test shall be completed in accordance with the ASTM referred to in the specifications. If situations arise where the permeability requirement has been surpassed, yet steady state conditions are not yet met, early termination of the test may be further discussed with the COR and will be decided on a case‐by‐case basis.

7. Please clarify the intent of Cut off wall permeability within rock below culvert.

The intent is to ensure adequate reduction of flows and lengthening of the seepage path to the ponding area. The stationing associated with the culvert is currently coincident with the shortest seepage path to the ponding area. Incomplete cut‐off could lead to increased gradients within the ponding area and an increased risk for internal erosion events.

8. “While General Note 3 under drawing sheet GI003 indicates ”The top of the Levee may be lowered to a minimum elevation of 542, which is approximately equivalent to a 500 to 600 year return flood frequency of the Ohio River, the notes on the cross sections details in drawings CS501 and CS302 to CS305, show “Construction Platform for Seepage Barrier Construction Min elevation 542.0’. While these notes are similar, they do not match.

Please clarify which of these two notes shall be considered to define the top elevation of the all‐weather surface on top of the work platform.

The top of the levee may be excavated temporarily to the subgrade of the all‐weather surface a maximum of 1.0 feet below 542 immediately prior to placement of the all‐weather surface. The top of the all‐weather surface shall not be below 542.

16 December 2020

9. Reference is made to the solicitation document, “Section 00 21 16 ‐ Instruction to Proposers, Ch.3 Proposal File, b. Content Requirement, VOLUME I Technical”.

Section 2‐Factor 2 – EXPERIENCE, at Subfactor A‐Specialized Experience and Similar Work Type”, requires:

“Provide descriptions of the Offeror's history of dam/levee seepage barrier construction projects completed or substantially completed by the construction team which are similar to this project in nature and scope. These descriptions shall include at least one project (no more than ten) completed within the last ten years…..”

Concurrently, Section 4‐Factor 4 requires:

“Offerors should submit at least one Past Performance Questionnaire for each project submitted under Factor 1 (Technical Capability and Specialized Experience)”.

Please clarify if the required past performance questionnaire shall be actually relevant to the specialized experiences submitted under Factor 2, Subfactor A (instead of Factor 1).

Confirmed. The required past performance questionnaire shall be for each project submitted under Factor 2, not Factor 1.

10. As per sheet drawing no. B102 and B103, it is not clear which piezometers (existing or proposed) are dual piezometers or open tube piezometers. Can you please clarify?

The existing dual piezometers are: CD‐19‐02, CD‐19‐09, and CD‐19‐14. These will also be the dual piezometers following construction.

11. Can you please provide details on the depth of well/piezometer tip elevations for the existing and proposed piezometers?

Please see the attached PDF of piezometer data for existing piezometer screen elevations.

The piezometer tip is within 2 feet below the lowest sensing elevation. The proposed piezometers will be screened at approximate elevation 470 feet.

12. As per drawing no. B103, pressure transducers are called out in Dual Piezometer detail A5 but not in Open Tube Piezometer detail A7, so it is unclear if the automated piezometers and cable are to be included. Please clarify?

All automation will be completed by others. Revision to the specs clarifying this is included in Section 31 55 00, Paragraph 3.2.2.

13. If the automation features are required for the piezometers, please provide additional specific requirements regarding the piezometer sensor and data logging, communication equipment, and data management requirements? Thank you.

All automation will be completed by others. Revision to the specs clarifying this is included in Section 31 55 00, Paragraph 3.2.2.

14. Can you please specify the exact diameters required for the piezometer borings?

The piezometers may be installed with a boring diameter of 6 to 10 inches. In the past, dual nested piezometers were installed with an 8 inch diameter boring, and single piezometers were installed with a 6 inch boring diameter.

15. Do all the piezometers borings need to be sampled and SPT performed?

New piezometer borings shall be logged during drilling, in accordance with Section 31 32 23.

Drilling methods for piezometer placement is NOT limited to hollow stem auger and SPT methods.

16. The perimeter security fence that is to be installed appears to be of a permanent nature.

Upon completion of the project is this fence to be removed in its entirety or is it to be left in place?

Temporary perimeter fence must be removed. Only the permanent fence around the gate well platform shall remain after construction.

17. If the fence is to be removed, are all posts and concrete footings to be removed or can the posts be cut flush with the top of the footing and abandoned in place?

All fence concrete footings for temporary fence shall be removed upon completion of the project.

17 December 2020

18. Section 32 92 10 Seeding indicates:

“3.1.1 Seeding Time Seed shall be installed from 1 March to 15 May for spring establishment; and from 15 August to 1 October for fall establishment.

3.4 SEED ESTABLISHMENT

The seed establishment period to obtain a healthy stand of grass plants shall begin on the first day of seeding work under this contract and shall continue through the remaining life of the contract.”

Seeding time season is very limited in the contract, and its start is subject to site restoration works that have high sensibility to the many adverse weather days in the area.

Then, 52.211‐10 COMMENCEMENT, PROSECUTION, AND COMPLETION OF WORK (APR 1984) indicates:

“The Contractor shall be required to (a) commence work under this contract within fourteen

(14) calendar days after the date the Contractor receives the notice to proceed, (b) prosecute the work diligently, and (c) complete the entire work ready for use not later than seven hundred and thirty (730) calendar days.”

For the purpose of measuring the project contract duration, please clarify relationships to consider in the schedule between completion of the works ready for use as defined in r FAR 52.211‐10 , the end of project in the schedule, and final seeding phases, including seeding establishment. Thank you.

All permanent seeding shall be installed and established within the 730 calendar day completion period. Contractor shall plan accordingly to schedule for final vegetation establishment within the 730 days.

19. Please confirm that the bidders will not have the opportunity to collect their own boring samples and make other on‐site intrusive investigations regarding the character, quality and quantity of sub‐surface materials and conditions, including classification and thickness of rock variation and classifications, prior to submission of price proposals.

Sub‐surface investigations will not be permitted prior to the submission of proposals.

Bidders may arrange with the Contracting Office to observe samples collected during the

2019 explorations program.

20. We request a bid extension of at least two weeks. We are expecting a long list of Q&A's as well as multiple critical documents in the addendum that will affect our approach, cost and proposal. When considering the holidays, we will need additional time to properly review and incorporate all this information into our proposal.

As indicated on beta.sam, the RFP due date has been moved to January 26, 2021.

21. No rock strength data has been provided to date, and it was indicated during the site visit that no UCS testing of the rock cores was performed. Is there a reason this was not performed, and what rock strength should the contractors base our assumptions for the proposal?

UCS testing was not completed as part of the explorations program. This was partially due to the available funding at the time of drilling. The rock is interbedded siltstone/fine‐grained sandstone, and shale. The shale is very soft to medium‐soft. The siltstone/fine‐grained sandstone is hard to medium‐hard. These designations were determined in congruence with EM 1110‐1‐1804, Appendix B.

22. Please state the type of sampler and hammer were used for the SPT's performed in the borings, specifically Boring CD‐19‐5.

SPT sampling was performed with a standard 2‐inch SPT sampler driven with an automatic 140 lb. hammer on a Diedrich D‐120 drill rig. CD‐19‐20 and CD‐19‐21 were driven with an automatic 140 lb. hammer on a Geoprobe 7822 DT drill rig.

23. Please provide all piezometer data for piezometers on or near the levee.

PDF of collected Piezometer and relief well readings is attached with the question responses.

24. Spec 40 05 13 2.3.4 Carbon Steel Coatings calls out that newly installed pipe should be coated on “inside and outside diameter”. Is this accurate? If so, the coating spec, 09 97 02, does not call out an interior coating system. Please advise.

Yes, interior and exterior of pipe is to be coated using the same paint system for both.

25. Please provide a copy of the attendance sheet from the site visit.

The attendance sheet is included at the end of the “Portsmouth Seepage Barrier – KTR Questions” attachment on beta.sam.

26. Please provide a list of plan holders.

Only the attendance sheet can be provided which includes the names and companies who were present at the site visit. This attendance sheet can be found on beta.sam as indicated above.

27. The bid includes “CCY” as a unit under the breakout for Item 37. While BCY, CY, ECY, and

LCY abbreviations are identified, CCY is not. Please identify.

CCY is compacted cubic yards.

28 December 2020

28. On the Q&A sent out with amendment 2 Question 77 was answered that we would need to use RMS. Is there a cost to the contractor to use this website?

RMS is a free program.

29. Also, in the spec section 1 30 00 Data Management it says that the contractor has to set up

A) and information management system and B) secure ftp site for this project. Is the RMS the ftp site and the management system?

RMS and an ftp site will both be required for this project. The ftp site is intended to be utilized for bulk data collected daily. As indicated in the specifications, the Government is required to have access to this ftp site. RMS will contain all project information once completed and assembled. All contract data will be approved through RMS.

30. We request a two week extension for the proposal deadline due to the volume of information received in Amendment 02 and the timing of the holidays to enable us to thoroughly review all documents and communicate with our subject matter experts and subcontractors to provide the government with the most comprehensive proposal package.

31. Question #43 and Question #57 conflict with each other. Please clarify.

This has been revised in the specifications following these responses. The response to questions 43 and 57 should read: The strength requirement was selected for the ability to core the seepage barrier after install. Past case studies have shown that lower strength barriers are more likely to have a lower RQD, and to be damaged by gravels within the core.

The higher strength was also chosen to reduce the risk of erosion in points where the barrier maybe damaged or defective. The minimum UCS will be reduced to 200 psi, and the 10 point moving average will be revised to 250 psi. It is noted that all performance criteria and testing requirements must be met, and the minimum strength may be revised if the ability to achieve these requirements is not met (i.e. satisfactory core samples.)

32. The specifications make multiple mentions that we should replace all existing waterlines, however, there are no water line replacements shown on the plans. Please clarify.

Existing waterlines will only need to be replaced if impacted during construction.

33. Please specify the type and frequency of monitoring required for the stadium.

There is no monitoring required. The stadium existing condition shall be thoroughly documented and the contractor shall take measures to protect the existing structure. Per specification 01 57 20.00, 3.6; “The Contractor shall install all protection for these resources so designated on the drawings and shall be responsible for their preservation during this contract.”

34. With the large amount of new information received, we are requesting an additional 2 weeks to bid this project.

35. In light of the extraordinary amount of information provided in the December 23rd issuance of Amendment 2 for the referenced project, please extend the bid date a minimum of 2 additional weeks to permit sufficient time to review and incorporate this information into our bid for the project.

36. In Section 00 10 00 – Solicitation what does the acronym CCY stand for?

CCY is compacted cubic yards.

37. Question (43) response states: “The minimum UCS will be reduced to 200 psi, and the 10 point moving average will be revised to 250 psi.” Question (57) response states: “The minimum UCS will remain at 250 psi, and the 10 point moving average will be revised to 300 psi.” The revised specification section 31 56 00 paragraph 1.4.e remained unchanged.

Please clarify what the minimum UCS and 10 point moving average will be. This information is critical to mix design.

The response to both questions 43 and 57 should read: The strength requirement was selected for the ability to core the seepage barrier after install. Past case studies have shown that lower strength barriers are more likely to have a lower RQD, and to be damaged by gravels within the core. The higher strength was also chosen to reduce the risk of erosion in points where the barrier may be damaged or defective. The minimum UCS will be reduced to 200 psi, and the 10 point moving average will be revised to 250 psi. It is noted that all performance criteria and testing requirements must be met, and the minimum strength may be revised if the ability to achieve these requirements is not met (i.e.

satisfactory core samples.)

38. The original solicitation released 3 pdf documents, including:

• B.08.02 W9123720R0008.Pdf with 119 pages including form 1442, price breakout schedule, Contract Clauses, Instruction to Proposers, Supplementary Conditions and past performance questionnaire.

Amendment #2, released 32 documents, including 8 videos, but in particular

• B.08.03+‐+W9123720R0008+‐+Amendment+0002.pdf, with 4 pages

• Section+00+10+00+PRice+Breakout+Schedule+Rev_01.doc, with 4 pages

• Section+00+22+00+Evaluation+Factors+Rev_01.doc, with 11 pages

• Section+00+22+00+Instructions+and+Conditions+Rev_01.doc, with 11 pages

• Section+00+73+00+Davis+Bacon+Wage+Rates+Rev_01.pdf, 39 pages

Therefore, these 5 files compiled add to 69 pages.

Could you please provide one compiled document that replaces/updates B.08.02

W9123720R0008.Pdf, with changes tracked so all modifications introduced to this volume can be traced and incorporated into the proposal?

Due to system limitations, the files cannot be combined as a result of their size. A “Summary of Changes in Solicitation” document was uploaded to beta.sam.

39. With reference to notes of drawing CS100 and CS703, Please clarify if temporary road crossings, designed to allow channel flow discharge and thus preventing high ponding level in the ponding area, would be permitted over Lawson’s Run both throughout and/or outside the duration of the bypass pumping plan implementation.

Confirmed. Temporary road crossing(s) may be permitted during construction, even outside of the bypass pumping operation duration, however all crossings must be removed upon completion of construction. Details of said crossings are subject to USACE review and approval.

40. We are in receipt of Amendment #2 dated 12/23/2020. As you know the amount of information included in this amendment is quite extensive. Since this information needs to be distributed to all suppliers, vendors and potential subcontractors during a timeframe encompassing two major holidays; we respectfully ask that more time is granted for everyone to receive and examine these new documents in their entirety with a bid date extension of no less than 4 weeks. We feel that a revised bid date is imperative for a project of this magnitude and complexity considering the amount of new information just distributed to the bidders less than a week ago. Also, kindly note that we are still waiting to get answers on many questions requested earlier.

41. During a high‐water event, at what river level will the flood gate be closed near River Ave?

The floodgate at River Avenue will be closed at approximately 531 elevation (flood stage of

61.9 feet).

42. Please clarify actual operation conditions and sealing capacity of the existing culvert sluice gate.

The sluice gate is electrically operated and is used frequently to keep river water out of the city. It is uncertain how much leakage occurs around the gate seals.

43. CD102 and CD103 mention demolition of the 36” pump station discharge pipes and reference plan drawing M‐102. I cannot locate this plan drawing, should the note be referencing another note?

Note should be revised to reference M‐101, not M‐102.

44. Also, can the bid due date be extended in lieu of the additional information provided on

12/23/20?

45. If structures are removed in the abandoned baseball field to harvest clay material, to what extent is restoration required? Do structures and ball fields need to be replaced in kind?

Yes, replacement in kind is required. Restoration is addressed in the demolition specifications and on the plans.

46. Is open cut excavation an acceptable method for IEIT cutoff wall installation?

Open cut excavation would be considered as an acceptable method for installation. The contractor should account for the need for slurry support or other methods to maintain the stability of the excavation. Methods shall be in accordance with Specifications section 31 56

00.

47. IEIT Installation contractors believe the 350 PSI cutoff wall requirement is extraordinarily high and not allow the cutoff wall to move naturally with existing ground. This may result in fracturing of the wall. Will a lower PSI be allowed?

The strength requirement was selected for the ability to core the seepage barrier after install. Past case studies have shown that lower strength barriers are more likely to have a lower RQD, and to be damaged by gravels within the core. The higher strength was also chosen to reduce the risk of erosion in points where the barrier maybe damaged or defective. The minimum UCS was revised to 200 psi, and the 10 point moving average was revised to 250 psi. It is noted that all performance criteria and testing requirements must be met, and the minimum strength may be revised if the ability to achieve these requirements is not met (i.e. satisfactory core samples.)

48. The plans state the contractor is responsible for not disturbing the existing stadium foundations due to vibrations from construction equipment. Is the contractor required to provide vibration monitoring and if so to what extent?

There is no monitoring required. The stadium existing condition shall be thoroughly documented, and the contractor shall take measures to protect the existing structure. Per specification 01 57 20.00, 3.6; “The Contractor shall install all protection for these resources so designated on the drawings and shall be responsible for their preservation during this contract.”

49. What provisions are there if rocks are in the soil mixture cause the verification cores to fall apart? Coring should only be used for inspection and video verification of the soil mixed material. Unconfined compressive strengths are better represented through sampling of the wet soil mixture.

This will be considered on a case by case basis. The Contractor shall use methods and best practices to reduce damages to the cores during drilling. All data available will be considered when evaluating the acceptance of a section.

50. Can cement be added dry to a water‐soil mixture that will achieve a desired slump?

Cement may be added to the water‐soil mixture to achieve the desired slump; however, the material must still meet the requirements specified for that material’s purpose.

51. Can construction and subsequent Demonstration Section begin near the Critical Area of

209+73 or 210+03 and continue away from either of these stations?

The demonstration section shall not be performed at the most critical location of the seepage barrier (the center). After completion of the demonstration section and all associated testing and reporting, work may begin at the critical section and proceed out.

The demonstration section shall be located as indicated in the Plans.

52. Is there a weight limit on the dam?

There is not a specified weight limit for the levee. The Contractor shall ensure that the work platform is in accordance with Section 31 55 00 of the specifications. This includes the submittal of a work platform plan to be approved by the COR/ACO.

53. Can the number of verification borings be reduced, or limited, if the method of installation used proves to be satisfactory in providing the bottom elevation of the barrier wall? The

Method of installation used has an impact on the need and frequency of verifications and or quality control tests.

Concur, the method impacts the need and frequency for verifications and quality control tests. The QC tests will be in accordance to the specifications and the approved Seepage

Barrier Construction Plans.

54. Quality Control Tests are mentioned, for example in the Seepage Barrier Construction, but where is a frequency requirement for them? It is mentioned they are in the Approved Seepage Barrier Construction Plan which will be approved after Award.

The nature of this specification as a performance‐based specification allows for a variety of methods to be proposed. Therefore, the frequency of testing is dependent on the method being employed for installation. The Contractor shall propose the testing program necessary to verify the installation of their specific method.

55. Can the bid date be extended?

56. Addendum 2 provided water testing data from the WWTP as well as the Ohio River.

Standard ASTM C1602 determines suitable water according to the content of Chloride, Sulfate as SO4, Alkalies as Na2O+0.658 K2 and Total Solids ‐ all in ppm. The tests from the WWTP and the Ohio River state the values for Alkalies of the Ohio River water but do not list appropriate units and it states total suspended solids for the WWTP effluent water but not the total solids. Please provide the parameters and units to allow the contractor to evaluate suitability of the water sources.

The information provided is the only information available at this time.

57. Is there a possibility that the submission due date for this Bid may be extended?