Pre-Bid_Questions_and_Answers.pdf

BIDDER QUESTIONS AND RESPONSES

PHASE 5 BASIN COFFERDAM,

NEW RIVER, HINTON, WV

BLUESTONE LAKE

BLUESTONE DAM DSA

IFB NO. W9123719B0003

TO ALL HOLDERS OF BID DOCUMENTS

The following are responses to questions received from bidders at the pre-proposal meeting.

Question 1: Does the 24/7 work schedule include weekends and holidays?

Answer: Yes.

Question 2: Will any work take place above the dam?

Answer: Yes, reference Drawing S-505 for installation of the drift and debris hatch cover plate.

Question 3: When do you anticipate award and Notice To Proceed?

Answer: The Government anticipates making an award by late February or early March 2019. Notice to Proceed will depend on the timing of Contractor submittals such as Accident Prevention Plan, security clearances, etc.

However, the solicitation is written that once the contract is awarded, the 274 calendar day period of performance starts.

Question 4: Is there an allocated timeframe the Contractor will be required to support Corps with dewatering? How long will it take? Is that part of the 24/7? And the 14-day hang around?

Answer: The dewatering should take approximately 2-3 days. Yes, the requirement for 24/7 is part of the dewatering duration and the 14 days on-site after the dewatering is complete.

Question 5: All the work has to be done by November 30?

Answer: Refer to Box 11 on Standard Form 1442 of the solicitation for the mandatory period of performance. See notes regarding stilling basin restrictions on Drawing GI005.

Question 6: Will dewatering only occur on one side?

Answer: Yes, dewatering will occur only on the right side looking downstream.

Question 7: Can you provide engineering calculations for formwork that you’ve completed?

Answer: As indicated on note 003 on contract drawing S-004, the Contractor shall be responsible for handling, additional bracing, leveling, and stability of the frame during hoisting and placement of the concrete.

Computations will not be provided to the Contractor given it is their responsibility to ensure the frame is stable for its intended use.

Question 8a: Regarding foundation prep underneath cells, is that closure of the bottom of the cells to the rock, or overall cleaning of the area?

Answer a: In regards to sheet piling foundation preparation and inspection, the foundation shall be cleaned and inspected in accordance with Specification Section 31 41 16, Paragraph PLACING. In regards to concrete placement foundation preparation and inspection, the foundation areas to receive concrete shall be prepared and inspected in accordance with revised Specification Section 03 31 30, Paragraph UNDERWATER ROCK FOUNDATIONS and newly added Paragraph UNDERWATER CONCRETE SURFACES included in Amendment No.

0002.

Question 8b: What is the inspection requirement, Corps divers? It will be challenging to describe to divers how clean they have to get it.

Answer b: See Amendment No. 0002 for Inspection Requirements.

Question 9: Will it be hand work or machine work for cleaning?

Answer: The selected method of foundation preparation for concrete placement is the responsibility of the Contractor in accordance with the contract, subject to Government approval. Refer to Specification Section 03 30 00 and revised Specification Section 03 31 30, Paragraph UNDERWATER ROCK FOUNDATIONS and newly added Paragraph UNDERWATER CONCRETE SURFACES included in Amendment No. 002.

Question 10: Tremie normally means water remains in the cells, and this will be done underwater. That’s going to be diver handpicking or vacuuming, is that correct?

Answer: See response to Question No. 9.

Question 11: Regarding the bid item for evacuation, how do you deal with deadline if significant evacuation time period?

Answer: An evacuation would be required if the Government predicted inflow to the dam would necessitate for any of the Crest Gates to operate and discharge water over the face of the main spillway to prevent the dam from being overtopped. Hydrologic models suggest there are storms which can lead to this situation. If an evacuation is necessary between the dates of NTP through November 30, 2019, the contractor will be reimbursed. If evacuations push the completion date beyond November 30, 2019 the Contractor will need to remove all floating equipment from the basin. Evacuation days will extend the contract completion date day for day. No payments for delay will be paid from November 30, 2019 – May 1, 2020.

Question 12: If all 16 gates open, can plant still be in water?

Answer: Intent is yes

Question 13: Is that considered evacuation?

Answer: No, the Contractor is to design a mooring system in accordance with Drawing GI005. The Contractor shall be responsible for selecting the design discharge and loads associated with their mooring system. The Contractor shall be required to remove all personnel and equipment from the stilling basin when the design discharge and loads are exceeded.

Question 14: Who determines whether the evacuation pay item is exercised?

Answer: Government.

Question 15: How did the Government come up with 3 evacuations? What is it based on?

Answer: An evacuation would be required if the Government predicted inflow to the dam would necessitate for any of the Crest Gates to operate and discharge water over the face of the main spillway to prevent the dam from being overtopped. Hydrologic models suggest there are storms which can lead to this situation. Three evacuations were chosen as a conservative estimate.

Question 16: Has there been any analysis over the past 5 years of how much time you can work in the basin with 5 gates open?

Answer: Last summer, not very many times with 5 gates open. The Contractor will have to review the information on the drawings.

Question 17: There’s a correlation with 5 gates open to the hydrographs we have?

Answer: At summer pool when the discharge is greater 7,500 cfs there are more than 5 gates open.

Question 18: With the short timeframe is there a reason the submittal review times are still 30-60 days for some submittals? We can’t count on that in our schedule. You’re looking at 5 month window before concrete is approved.

Answer: The submittal review times will not be revised.

Question 19a: If moored to the side, is that a weather day?

Answer a: Yes.

Question 19b: Is there a way to shorten 7 day duration between cast in place concrete pours on transition sections? 4 pours with 7 days curing between each pour.

Answer b: The 7 day curing duration for transition section cast-in-place concrete will not be shortened at this time. The Contractor shall develop their bid as such.

Question 20: Can you also look at drilling for instrumentation? In section 02 31 10, it looks like rock core and sampling investigation.

Answer: Drilling for instrumentation will include sampling of rock. The samples will be provided to the Government as described in Section 02 32 10 Paragraph CARE AND DELIVERY OF SAMPLES.

Question 21: The environmental spec doesn’t list a WVNPDES permit. Has one been obtained?

Answer: Yes.

Question 22: Note 17 on Page S001 has an intended construction sequence.

Can you go over that one more time?

Answer: This sequence is suggested, not required. Basically fill the upstream cell, build the upstream transition, work your way downstream, and tie-in at downstream end.

Question 23: The schedule is still questionable. Should be 2-season job.

Could you share your schedule, durations you anticipate for cleaning, for example. What kind of work durations did you think it would take as a guideline?

Answer: No.

Question 24: If we can’t accomplish working 24/7 and complete the job, what is the option? What happens if job isn’t done in November for unforeseen circumstances?

Answer: If the Contractor does not complete the work within 274 calendar days, due to reasons other than weather days or actions taken by the Government, liquidated damages would start taking effect on the 275th day after the contract is awarded and would continue through the restricted period referenced on Drawing GI005 until the work is completed or accepted, in accordance with FAR Clause 52.211-12.

Question 25: The 274 is calendar days. Since we’re not going to work during winter, are LDs for weather days?

Answer: See answer to Question No. 24 above.

Question 26: The 5 months that we’re not able to work, are you going to make us pay damages?

Answer: See answer to Question No. 24 above.

Question 27: What happens if we have a question to your answers?

Answer: Always submit your questions. We will provide an answer as soon as possible.

Question 28: Have you guys talked to local concrete suppliers? Problem is there’s a lot of pipeline work going on right now, and it’s hard to get 32 yards from suppliers in the area.

Answer: Yes, the Government has talked to local concrete suppliers. We’ve been able to do tremie placements of that size based on work in the past.

Question 29: Can you highlight the available space for batch plant?

Answer: Specification Sections 03 30 00 and 03 31 30 call for the use of ready mix concrete for the cofferdam. The Contractor may propose the use of a batch plant including its location in lieu of using ready mix subject to approval by the Contracting Officer.

Question 30: There is an apparent conflict in the contract documents. The required time of performance is 274 calendar from award. However, the

Solicitation provides for a 60 calendar day award period, and, at the pre-bid meeting the USACE was clear that their expectation was for the project to be complete prior to December 1, 2019. If we subtract 274 calendar days from an expected completion date of November 30, 2019, then award must occur no later than March 1, 2019. Based on the above, should Item 13D of Form 1442 be reduced from 60 calendar days to 24 for consistency?

Answer: A review period of 60 calendar days from the date of the bid opening is unlikely (Refer to Question 3 above). However, in the event award is not made until a later date, the Contractor would still be afforded 274 calendar days to complete the work outside of the restricted period and the contract completion date would be modified accordingly.

Question 31: Also, in the event award is not made by March 1, 2019 or if, for any reason, the contractor is entitled to a time extension that pushes the required completion date beyond November 30, 2019, please confirm that said time extension would include the delay time plus the 153 calendar days between November 30, 2019 and May 1, 2020, and that such time extension would also include an allowance for the time required to re-deploy floating plant into the spillway basin commencing May 1, 2020.

Answer: November 30, 2019 is not a completion date. It is a date the floating plant must be removed from the water. Reference Drawing GI005. The Contractor would still be allowed to work on the banks during this period.

No work of any kind may occur within the stilling basin during this time.

However, in the event the contractor is entitled to a time extension such that work must resume the following spring, the time extension would include the delay time, plus the 153 calendar days within the restricted period, and time required to de-deploy the floating plant. If such a delay is due to fault or negligence on the part of the Contractor, refer to Question 24 above.

Question 32: Your suggested construction sequence is to construct the cofferdam cells from upstream to downstream prior to constructing the transition cells. The transition cells include 17.5 feet of cast-in-place concrete that, according to specifications, must be placed in maximum 5’ lifts with a minimum of 7 calendar days between lifts. Assuming one day per pour, the current specification requires 4 pours x 8 days per lift or 32 calendar days per transition after completion of sheet piles and tremie pours. This is nearly 12% of the entire contract duration. Please consider a reduction is the aforementioned 7 calendar day restriction.

Answer: See answer to Question No. 19b.

Question 33: Note 1 on Plan Sheet GI005 reads “The Contractor shall not have a floating plant or be permitted to work in the stilling basin from December 1 through April 30.” Note 15 on the same sheet requires the Contractor to construct pedestrian access from the West Training Wall to the Upstream Transition. Therefore, please clarify the prohibition of work in the stilling basin during the restricted period. Is it permissible to work in the stilling basin during this period, if said work can be accessed and supported without the use of a floating plant?

Answer: No. As indicated in Note 1 on Drawing GI005, the Contractor shall not be permitted to work in the stilling basin from December 1 thru April 30.

Question 34: Is the time restriction for fish spawning or flooding concerns?

Answer: Potential for high discharge.

Question 35: Is the platform material used in Phase 4 available for use in this contract?

Answer: No.

Question 36: When is phase 4 scheduled to be complete? Will they be completely out of the CWL at NTP?

Answer: October 2019. Yes, they will be completely out of the CWL.

Question 37: Are any other contract scheduled to be let in the timeframe of this schedule? Will the CWL need to be shared?

Answer: There is a potential for other contracts to be awarded.

Question 38: Will you provide the engineering calculations performed on the formwork so we can check the design before bid to know if modifications are needed with our construction plan?

Answer: See response to Question No. 7.

Question 39: Can the LIDAR scan be provided before construction to assist in development of design plans and as-built?

Answer: No.

Question 40: Are submittal review times going to remain 30 days and 60 days?

Answer: See response to Question No. 18.

Question 41: Sheet piles are to be delivered after April 20, 2019. Is there a date for actual delivery or is that the earliest date they can all be delivered?

Answer: The Contractor shall coordinate the delivery of the sheet piling with the Contracting Officer after April 20, 2019 as indicated in Specification Section 01 60 00.00 40, paragraph 3.9.1. An actual set date for delivery is not provided in the specifications.

Question 42: Will drilling in the basin be allowed to set templates for the sheet piles?

Answer: Yes, drilling will be allowed as approved by the Contractor Officer.

Question 43: Do baffle blocks and end seal need to be completely demolished or can they be selectively demo’ed for installation of new features?

Answer: The baffle blocks and end sill need to be completely removed as indicated on Drawing S-003.

Question 44: Can you provide a table of open gates to discharge so the hydrographs on HHxxx sheets can be used to determine schedule. Or, provide a table of dates and open gates?

Answer: See response to Question No. 17.

Question 45: Can the hydrograph data be provided electronically in excel?

Answer: No.

Question 46: What CFM discharge from the dam does the mooring plan need designed to?

Answer: See response to Question No. 13.

Question 47: What CFM discharge from the dam does evacuation happen?

Answer: See response to Question No. 15.

Question 48: Please define what work can be completed with more than 5 gates open?

Answer: No work can be completed in the stilling basin with more than 5 gates open.

Question 49: If work cannot be completed because more than 5 gates are open but evacuation is not ordered are those considered delay days or weather days?

Answer: Weather days.

Question 50: How hard will the sheets be required to be hit with a hammer?

Specifications require driving sheets but rock is anticipated with no overburden and sheets cannot be driven.

Answer: The contractor is responsible to provide the necessary driving energy in order to seat the piling on top of the rock as shown on the contract drawings.

Question 51: Can Air Lifted material generated during foundation cleaning be discharged back into the Stilling Basin? This material is already in the basin and only being moved this would not be the standard discharge of sediment laden construction generated water from surface runoff.

Answer: Yes, as long as performed in accordance with Section 01 57 20.00 10

ENVIRONMENTAL PROTECTION.

Question 52: If the contractor so chooses can casing for instruments and anchors be installed after the concrete and fill in the coffer cells?

Answer: No, casing must be installed before fill and concrete (except tremie in the bottom of cells), as indicated on drawing S-001.

Question 53: Are there enough sheets in the government supplied sheets for the fabrication needed or will the contractor need to supply those sheet for the fabrication?

Answer: Yes, there are enough sheets.

Question 54: Can you provide the latest photos of the bottom of the stilling basin when drained in 2014/2015? Specifically related to Specification Section 31 32 23 Foundation Drilling and Grouting.

Answer: Photographs from 2014/2015 are not available, however photographs from 2004 will be uploaded as a separate attachment.

Question 55: Paragraph 1.3.1 defines a zone as “approximately 10 feet along the borehole” and identifies 2 zones. Drawing B-402 also shows the 2 zones.

Is the intent to drill zone 2 from the bottom of zone 1 to the bottom of the grout curtain elevation 1343 unless the criteria in paragraph 3.5.10 Criteria to Performa Additional Downstage occurs while drilling zone 2? Is the intent to water test and grout zone 2 in 10 foot upstages, or as a single stage provided zone 2 can be advanced from the bottom of zone 1 to the bottom of the grout curtain elevation 1343?

Answer: The intent is to drill Zone 2 from the bottom of Zone 1 to the bottom elevation of the grout curtain and to grout it as one stage unless the criteria in paragraph CRITERIA TO PERFORM ADDITIONAL DOWNSTAGE GROUTING is met. See revised paragraph ZONE in Amendment No. 0002.

Question 56: Paragraph 1.3.18. Is an instrumented packer required for the underdrain water pressure testing and grouting?

Answer: Yes. See Section 31 32 23, paragraph PRESSURE TESTING EQUIPMENT AND

MATERIALS.

Question 57: Paragraph 1.8.1 and 1.8.2. Both the Grouting Inspector and the Automated Grouting Control and Data Collection System Operator positions are required to be a registered Professional Geologist or registered Professional Engineer. If the person who fulfills the roll of Grouting Inspector will be responsible for the data produced by the Automated Grouting Control, and Data Collection System and the Automated Grouting Control and Data Collection System Operator personnel report to the Grouting Inspector, do the Automated Grouting Control and Data Collection System Operator personnel still require to be a registered Professional Geologist or registered Professional Engineer?

Answer: Concur. The Automated Grouting Control and Data Collection System Operator does not require a P.G. or P.E.

Question 58: Paragraph 1.8.1 and 1.8.4. Can a single individual fulfill the role of both the Grouting Inspector and the Drilling Inspector provided they have qualifications that meet both of these roles?

Answer: A single individual can perform both duties but not at the same time. If drilling and grouting will be performed at the same time, each operation must have its own inspector with no other duties. See revised paragraphs GROUTING INSPECTOR QUALIFICATIONS and paragraph DRILLING INSPECTOR QUALIFICATIONS in Amendment No. 0002.

Question 59: Paragraph 1.9.2. Can the time required for grout to harden be based on the initial set time for the last grout mix that was injected into a stage?

Answer: Specification Section 31 32 23 paragraph RESTRICTIONS requires 16 hours for grout to harden. Any alternative to this requirement may be proposed by the Contractor to the Government for consideration.

Question 60: Paragraph 2.1 states in part “Six grout mixes shall be proposed (including 4 base mixes, 1 mix with an anti-washout admixture, and 1 sand mix for the grouting program”, which conflicts with that notes at the bottom of the Curtain Grout Mixes table in paragraph 3.5.12.1 which states “Mix E shall be an accelerated C mix with an initial set time of not more than two hours measured at the temperature at which the grout will be placed.” Please clarify the requirements for the 6 grout mixes.

Answer: The table CURTAIN GROUT MIXES has been revised to read that Mix E is a high viscosity mix with anti-washout admixture.

Question 61: Paragraph 3.5.12.1 Curtain Grout Mixes table notes that “Mix E shall be an accelerated C mix with an initial set time of not more than two hours”. In our experience, it is not possible to achieve an initial set time of not more than two hours using accelerators. We respectfully request that the product name and manufacturer, of an acceptable accelerator than can achieve an initial set time of not more than two hours, be provided in the specification.

Answer: The table CURTAIN GROUT MIXES has been revised in Amendment No. 0002 to read that Mix E is a high viscosity mix with anti-washout admixture.

Question 62: Paragraph 2.1.1. Can water from the New River be used if it is tested and meets the requirements of ASTM C1602/C1602M?

Answer: No. The quality of water at the site fluctuates continuously due to variability in water quality as a result of rain events and reservoir releases.

Question 63: Paragraph 2.1.3.2. There is no bid item for Water Reducer, please provide a bid item for this grout ingredient.

Answer: A bid item has been added in Amendment No. 0002. See Specification Section 31 32 23 paragraph MEASUREMENT AND PAYMENT.

Question 64: Paragraph 2.1.3.3. There is no bid item for Superplasticizer, please provide a bid item for this grout ingredient.

Answer: A bid item has been added in Amendment 0002. See Specification Section 31 32 23 paragraph MEASUREMENT AND PAYMENT.

Question 65: Paragraph 2.1.3.4. There is no bid item for Viscosity Modifier, please provide a bid item for this grout ingredient.

Answer: A bid item has been added in Amendment No. 0002. See Specification Section 31 32 23 paragraph MEASUREMENT AND PAYMENT.

Question 66: Paragraph 2.1.3.5. There is no bid item for Anti-Washout Admixture, please provide a bid item for this grout ingredient.

Answer: A bid item has been added in Amendment No. 0002. See Specification Section 31 32 23 paragraph MEASUREMENT AND PAYMENT.

Question 67: Paragraph 2.1.3.5. The test method “COE CRD-C 61 (1989A) Test Method for Determining the Resistance of Freshly Mixed Concrete to Washing Out in Water” is applicable to Freshly Mixed Concrete that contains coarse aggregate and low water content. The specified grout mixes have high water to cement ratios and will not behave in a similar fashion, even with the addition of anti-washout admixture. In our experience, it is not likely that the specified grout mixes with an anti-washout agent would meet the requirements of the specified test method. We respectfully request that this test method be removed.

Answer: The paragraph has been revised by Amendment No. 0002.

Question 68: Paragraph 2.1.3.7. There is no bid item for Accelerator, please provide a bid item for this grout ingredient.

Answer: Accelerator has been removed from the mix requirements in Amendment No. 0002.

Question 69: Paragraph 2.2. What size of permanent casing is required? In addition, how much is the permanent casing to stickup above the top of the concrete cap elevation 1417.0?

Answer: Casing must be sized to permit drilling and packing the hole size that is selected by the Contractor (minimum nominal 3 inch size). The top of the casing should be flush with the finished surface of the concrete (see Section 31 32 23, paragraph INSTALLATION OF CASING FOR GROUT HOLES, Amendment No. 0002).

Question 70: Drawing B-402 shows a 3 inch minimum diameter cored grout hole.

The closest standard rotary sized hole, NQ sized, produces a 2.98 inch diameter hole. Is this acceptable?

Answer: Specification Section 31 32 23 has been revised in Amendment No.

0002 to allow nominal 3 inch size (to include NQ size).

Question 71: Paragraph 3.2.4 and 3.5.3. Can water actuated down-the-hole hammer drilling, or top hole percussion with continuous water flush drilling be utilized for grout hole drilling?

Answer: Coring is required per revised Specification Section 31 32 23, see Amendment No. 0002.

Question 72: Paragraph 3.2.5. The contractor is required to provide an Automated Grouting Control and Data Collection System. There is not bid item for this. We request that a lump sum bid item be added for this. If no bid item is added, then which bid items should the contractor include the costs of the system?

Answer: Specification section 31 32 23, paragraph MEASUREMENT AND PAYMENT, PLACING GROUT has been revised to include the Automated Grouting Control and Data Collection System. See Amendment No. 0002.

Question 73: Paragraph 3.3. If the Contractor collects all drilling and grouting effluent and treats the effluent, can the treated water be discharged into the New River provided it meets environmental discharge requirements?

Answer: No.

Question 74: Paragraph 3.3. There is no bid item for the Waste Material Capture, Removal, Treatment and Storage System, please provide a lump sum bid item for this item.

Answer: Costs will be incidental to the drilling.

Question 75: Paragraph 3.4. Based on our understanding of the work, please confirm that the intent is to use divers in order to perform the Grouting of the Spillway Apron Underdrain System.

Answer: The Contractor can employ the use of divers, barges, cofferboxes, platforms, or other means, provided they comply with environmental, safety, and contract requirements and are approved by the Contracting Officer.

Question 76: Paragraph 3.4. Are water pressure testing and grouting to be done using the Automated Grouting Control and Data Collection System?

Answer: Yes. See Specification Section 31 32 23 paragraph AUTOMATED GROUTING CONTROL AND DATA COLLECTION SYSTEM in Amendment No. 0002.

Question 77: Paragraph 3.4. The only bid item provided is for flushing of the drains. How will the Contractor be compensated for the water pressure testing, grout materials, and grout injection required for the Grouting of the Spillway Apron Underdrain System?

Answer: Compensation for pressure testing and grouting the spillway apron underdrain system will be made using the same bid items for pressure testing and placing grout in grout holes. The Specification Section 31 32 23 paragraph MEASUREMENT AND PAYMENT has been updated in Amendment No. 0002 to explicitly include pressure testing and placing grout for the spillway apron underdrain system. Grout materials are covered by the applicable bid items.

Question 78: Paragraph 3.4 and Drawing B-401. Please clarify the extents of the underdrain grouting work. The Plan view has an oval that encompasses monoliths 33 to half way between monoliths 37 and 38. Detail 1/B-401 does not appear to coincide with this or with specification throughout section

3.4. Can a more detailed drawing highlighting the exact drains to be grouted be provided?

Answer: See Amendment No. 0002 to specification 31 32 23 paragraph GROUTING OF THE SPILLWAY APRON UNDERDRAIN SYSTEM and Drawing B-401. Prospective bidders are encouraged to visit the Huntington District’s Geotechnical Warehouse to view additional information.

Question 79: Paragraph 3.4.1, the last sentence in part states “and requirements for drilling through”. We cannot find any other reference with regards to the requirement to drill holes into, or through, the existing underdrain system. Please clarify if holes are to be drilled into, or through, the existing underdrain system.

Answer: Grout holes in Cell 1 will penetrate the spillway apron in the vicinity of the underdrain system. Grout holes in Cell 1 are oriented in such a way as to improve chances of intercepting the lateral pipes that connect the system together to increase the chance that the system can be thoroughly grouted in the vicinity of the cofferdam. Specification Section 31 32 23, paragraph DRILLING AND GROUTING OF GROUT HOLES, GENERAL has been revised in Amendment No. 0002 to more clearly state that interception of the system during drilling in Cell 1 should be anticipated. Paragraph CRITERIA TO PERFORM ADDITIONAL DOWNSTAGE GROUTING has also been updated to explicitly include drilling into the underdrain system piping as one criteria for additional downstaging.

Question 80: Paragraph 3.4.2 and Drawing B-401. The 4” drain pipe shown on Drawing B-401, Section A/B-401 is approximately 12’6” long but the specification states that up to 25 feet long needs to be cleaned out. Please clarify the intent, as we understand the 4” drain pipe is to be flushed out to the bottom of the apron. In addition, do all 9 of the 4” drain pipes need to be cleaned?

Answer: The section included on drawing B-401 is a typical spillway apron section, however the founding elevation across the basin varies. The deepest section of the spillway apron includes a drain pipe that is approximately 25 feet long. All nine drains are to be cleaned.

Question 81: Paragraph 3.4.2 states that the drains will be cleaned “to the satisfaction of the Contracting Officer”. Please clarify or elaborate on the extent of the cleaning that is required that will satisfy this requirement.

Answer: Silt, sand, gravel and mineral buildup is to be removed from the pipe outlets. See Specification Section 32 31 23 paragraph GROUTING OF THE

SPILLWAY APRON UNDERDRAIN SYSTEM.

Question 82: Paragraph 3.4.2. Does the Grouting of the Spillway Apron Underdrain System need to be completed prior to commencing work on the Grout Curtain?

Answer: The system must be grouted before construction of the cofferdam which must be completed before beginning work on the grout curtain.

Question 83: Paragraph 3.5.1, 3rd paragraph states in part “The Contractor shall provide access and any assistance for separate and independent measurements by the Contracting Officer.” How much time should the Contractor allow for each hole for the independent grout hole alignment measurements to be performed by the Contracting Officer?

Answer: Quality assurance measurements will generally require sufficient time to perform a survey of the top of casing location and verify the azimuth and batter, or check the depth of hole with a weighted tape during drilling and grouting. If issues are identified, other inspections or measurements may be necessary.

Question 84: Paragraph 3.5.1, 5th paragraph states in part “For any grout hole the Government elects to inspect with a borehole camera, the Contractor will perform flushing the borehole of cuttings and will allow one day for suspended particles to settle prior to camera logging.” Please provide a bid item for flushing the holes, or advise which bid item this should be included in.

Answer: Cooperation of the Contractor to perform flushing of the grout holes to allow for camera logging by the Government, and time for the Government to perform camera logging, is considered incidental to drilling work. See Specification Section 31 32 23 paragraph DRILLING AND GROUTING, GENERAL, Amendment No. 0002.

Question 85: Paragraph 3.5.1. On how many holes is the Contractor to perform a borehole deviation survey?

Answer: The tolerance requirement for the drilled hole has been removed from Paragraph DRILLING AND GROUTING OF GROUT HOLES, GENERAL, in Amendment No.

0002. A tolerance is specified for the azimuth and batter of the casing and the drill setup in this paragraph.

Question 86: Paragraph 3.5.1, 5th paragraph states in part “It may be anticipated that the Government will require this work on up to 12 holes in the course of the drilling program.” How much time should the Contractor allow for each hole for the Government to perform downhole camera logging?

Answer: Camera logging of a borehole is likely to require not more than two hours to be performed.

Question 87: Paragraph 3.5.1. Please provide electronic copies of the as-built information for the underdrain system that is referenced in the specifications.

Answer: As-built cross sections of monoliths where grouting of the underdrain system is to be performed have been included in the FIO drawings in Amendment No. 0002. Additional information is available at the Government’s geotechnical warehouse. Contractors are encouraged to view prior to bid.

Question 88: Paragraph 3.5.5 states in part “Holes for curtain grouting shall be downstage grouted in the order shown on the drawings.” There is no order shown on the drawings, please clarify this.

Answer: Amendment No. 0002, Specification section 31 32 23, paragraph SEQUENCE OF GROUTING OF HOLES, has been revised to include additional description of the sequence of grouting. A table has also been added to this paragraph and a reference to additional details on drawing B-402.

Question 89: Paragraph 3.5.5 c. states “After placing the grout, the packer shall be left in place until the grout pressure drops to that pressure required, after which the packer is removed.” There appears to be words missing after “that pressure required”, please clarify.

Answer: See Amendment No. 0002.

Question 90: Paragraph 3.5.14 states “After the grouting of any stage or stop of a hole is finished, the pressure shall be maintained by means of a packer until the grout has set to the extent that it will be retained in the hole.” Packers are normally moved to the next stage within the hole, or to other holes once grouting of any stage or stop if finished. Allowing the grout to set would be problematic. Please clarify the intent of this statement.

Answer: Specification refers to holes with artesian flow and revised in accordance with Amendment No. 0002.

Question 91: Paragraph 3.5.16. Please clarify that all the grout ingredients required for backfilling of hole will be paid for at the contract unit prices and not just the “portland cement therein”.

Answer: Specification section 31 32 23 paragraph BACKFILLING OF HOLES has been revised in Amendment No. 0002 to allow for payment of materials used to make grout under the applicable payment items.

Question 92: Paragraph 3.5.19.2.4. On how many holes is the Contractor to perform an optical televiewer survey?

Answer: Section 31 32 23 paragraph SUBMERSIBLE, HIGH-DEFINITION COLOR SIDE- VIEW OPTICAL CAMERA has been deleted from the specification. The Contractor will not be required to provide a borehole camera.

Question 93: Paragraph 3.6.2. If a hole is advanced through the reinforced concrete into the underlying bedrock and encounters an anchor bar 3 feet along the drill hole below the top of rock, will the 3 feet of rock be measured for payment under this item?

Answer: Correct.

Question 94: Paragraph 3.6.10. Please clarify how Placing Grout will be measured and how it will be paid. Paragraph 3.6.10.1 conflicts with paragraph 3.6.10.2.

Answer: The paragraphs have been revised in Amendment No. 0002.

Question 95: General - If drilling of additional holes is required beyond secondary grout holes, drilling through the concrete cap, granular fill and tremie concrete of the cofferdam will be required in order to install the permanent steel casing. How will the Contractor be compensated for the drilling that would be required?

Answer: No additional holes will be drilled beyond those required in the specification.

Question 96: General – The Contractor is responsible for performing borehole deviation surveys and optical televiewer borehole surveys. In which bid items should the contractor include the costs of performing these items?

Answer: These items have been deleted from the specification in Amendment No. 0002.

Question 97: General – Can drilling and grouting equipment be left on the cofferdam while the foundation drilling and grouting work is being performed or does all equipment need to be removed from the cofferdam on a daily or weekly basis?

Answer: Drilling and grouting equipment can be left on the cofferdam in accordance with the specifications.

Question 98: Specification Section 31 32 23 Foundation Drilling and Grouting, Paragraph 2.1.4 outlines the test requirements required for the sand. We recently completed a project for another Army Corps district that had similar testing requirements. The bid item for sand is 9,600 pounds.

With such a small quantity, the costs of the test that are required by paragraph 2.1.4 will be in the order of 25 times the actual cost of the sand.

Would the government consider reducing the testing required considering the small quantity of sand that is required?

Answer: The test requirements are revised in accordance with Amendment No.

0002.