Jeff_II_-_Contractor_Questions_(11-8-2012).pdf

1. The answer to RFI No. 7 in Amendment 3 says that Section 0234 Subsection 3.3.a will be clarified by an amendment. There is no change to Subsection 3.3.a in Amendment 3. When can we expect the amendment?

A. No future amendment is anticipated. The test requirements apply only to the treated (jet grouted) soil and thus compression and permeability tests should be taken every 3 feet of treated depth.

2. The answer to RFI No. 40 in Amendment 3 says that Bid Item0019 will be changed by an amendment. The Bidding Schedule in Amendment 3 does not change Bid Item 0019. When can we expect the amendment?

A. No future amendment is anticipated.

3. The answer to RFI No. 44 in Amendment 3 says that Section 0234 Subsection 3.6 will be revised by an amendment. There is no change to Subsection 3.6 in Amendment 3. When can we expect the amendment?

A. No future amendment is anticipated. If the contractor elects to test the compressive strength before 28 days and the concrete has achieved the required strength (100 psi) and he has the approval of the Contracting Officer, he may begin excavation at that time.

Additionally, the jet grout must have achieved the required permeability (1x 10-6 cm/sec or less) before excavation will be allowed.

4. The answer to question 53 states that 4B must also be completed between June 2 and August 30 of 2014 along with 4F. The solicitation thus far has not stated that 4B must be completed during this time. It states that the Street Car track can only be down during this time. Please note that 4B can be constructed without taking the Street Car track out of service which we believed was the intent of Drawing 313. If 4B and 4F are required to be constructed during this 90-day period, AND grout curing is 28 days, AND concrete curing is 7 days, AND we have to complete all of 4F prior to moving to 4B due to traffic rerouting of St. Charles, this has created conditions that are impossible. 35 days of cure per phase equals 70 days of cure time. This leaves of 20 calendar days to construct the boxes. We assume that the government intends for 4B to be constructed outside of the 90-day constraint and not at the same time as 4F. Please advise.

A. The answer to RFI 53 is correct. The street car can only be taken out of service between 2 June 2014 and 30 August 2014, thus phases IVB and IVF must be completed during this time period. In Phase IVB, traffic on St. Charles is detoured across the streetcar tracks.

There will be constant traffic across the streetcar line and traffic control devices blocking the tracks, so the streetcar will not be able to operate. In Phase IV, the waterlines and box culvert will be installed. The street car tracks must be removed and the streetcar will not be able to operate.

The grout needs to achieve the required strength (100 psi) and permeability (1x10-6 cm/sec or less) before excavation and construction of the box culvert may begin. However, if this occurs in less than 28 days, construction of the box culvert may begin at that time.

5. Please reference Section 02252 1.4.1(d), which states "The sheet pile case analysis shall not include a cantilever sheet pile analysis." Does this mean that a) disallow any cantilever in the sheet pile above the bracing; b) sheet pile above the bracing need not be analyzed; or c) the first case analysis is with the brace and full excavation instead of a case in which excavation has been done to allow brace installation?

Answer: Per Section 02252, "The contractor shall be required to install internal bracing before excavating more than three feet (3 ft.) below the surface of the retaining structure". Due to this limitation, the designer does not need to analyze the sheetpile as a cantilever before installing the upper brace. The designer will need to analyze the braced sheetpile with full excavation.

We understand that the brace is required prior to excavating more than 3’, but is there a strict requirement on when the brace can be removed? Is this meant to specifically disallow any condition where the upper brace is removed? Normally, installation and removal of the brace is not a pre-defined criteria, but considered contractor means and methods, subject to review and approval in the TRS submittal.

A. The specifications include a similar requirement when removing the bracing. Per Section 02252, paragraph 3.4.1, “The retaining structure bracing shall not be removed until suitable backfill is satisfactorily placed and compacted to an elevation approximately three feet (3 ft.) below the surface of the retaining structure.”