USACE_RESPONSES_TO_QUESTIONS_-_DATED_16_SEPTEMBER_2019.pdf

THE USACE’s RESPONSES TO A CONTRACTOR’S QUESTIONS FOLLOW (a FORMAL AMENDMENT UNDER THE RELEVANT SOLICITATION NO. W912P6-19-B-0023 is scheduled for release September 16, 2019)

1) Can the existing stone be used as the 10 inch stone base shown on C-106?

A1. No boring data is available, it is assumed the existing subgrade is capable of being compacted to the standards defined in the specification. It is the contractor's responsibility to compact the subgrade to the required density prior to placing any pavement by any compaction means necessary to meet the requirements. If the existing subgrade is of insufficient quality to be compacted by any method, then the contract clause for a differing site condition will be used to correct the deficiency. Sheet C-104 and C-105 were revised in Amendment 003, note was added.

2) On the drawings C-106 the sub base it is stated as CA-6 stone, if existing stone is used will there be any testing required to prove the existing stone type of material is CA-6?

A2. All testing requirements are defined in Section 32 11 23

3) On C-106 it shows a depth of 10” for the CA-6 sub base, will the existing ground need to be excavated to the subgrade of the sub base then backfilled to the subgrade of the concrete?

A3. No boring data is available, it is assumed the existing subgrade is capable of being compacted to the standards defined in the specification. It is the contractor's responsibility to compact the subgrade to the required density prior to placing any pavement by any compaction means necessary to meet the requirements. If the existing subgrade is of insufficient quality to be compacted by any method, then the contract clause for a differing site condition will be used

4) Can the site be excavated to sub grade of concrete and assume the existing stone is fine in place?

A4. No boring data is available, it is assumed the existing subgrade is capable of being compacted to the standards defined in the specification. It is the contractor's responsibility to compact the subgrade to the required density prior to placing any pavement by any compaction means necessary to meet the requirements. If the existing subgrade is of insufficient quality to be compacted by any method, then the contract clause for a differing site condition will be used

5) If bed rock is found and it is below subgrade of the concrete can the concrete be poured on top of bedrock or is there a minimum stone sub base needed under the existing concrete pavement?

A5. On sheet C-106, note 1 says: if the solid rock is found above the 8" (concrete depth), the rock should be removed to achieve 8" concrete depth and construct without the subbase.

6) The existing ground access wells that are being removed and replaced, does the existing ground rod need to be replaced as well or just the housing?

A6. Just the ground access wells are being replaced, there is no worked to be performed on the ground rod itself.

7) What depth below bottom of concrete does the 10 x 10 Copper grid get placed? Is there a maximum or minimum depth of this?

A7a. The copper grid is placed directly on top of the subgrade prior to concrete placement as described in specification section 01 11 00 paragraph 1.1.1.

A7b. There is no defined tolerance because the grid rests on top of the subgrade and concrete is placed directly onto the grid.

8) The temporary gravel stockpile area is to remain after the project? As in no material is to be hauled off site?

A8. There is no requirement to remove any material from the site, all material relocate to the stockpile shall be left in the stockpile at the end of the contract.

9) Will there need to be erosion control around the temporary pile when we are complete?

A9. Section 01 57 20.01 03 Environmental Protection for Illinois, includes the requirements for erosion control of the stockpiles.