36C24418R0652-0006001.pdf

460-321 New Parking Garage

RFIs responses through 1/23/2019

Q1: Reference the “Temporary Parking” drawing set. There are two (2) storm drain pipe outlets / headwalls occurring on the north side of the South Lot. Only one of them is somewhat addressed on sheet C201 where Note 6 states to provide Rip Rap. Please clarify how we are to handle the water coming out of these pipes?

A1: The headwall in the parking lot shall have rip rap placed around it. The other is outside the parking lot and nothing needs to be done, it will be allowed to drain into the lot.

Q2: Can spoils from the temporary parking lots be stockpiled on site for restoration of the lots?

A2: Yes, but only as approved by DNREC. Contractor to coordinate as required

Q3: Refer to sheet CU101. Is the storm drain line coming from the south side of the deck 12” PVC for the entire distance to where is connects to the existing curb inlet, or is it just 12” PVC where it exits the building to 5’ out and then converts to HDPE? Please clarify.

A3: Covert to HDEP 5' outside the garage

Q4: Refer to sheets SB002 and SB101. Should the pile cap located at column line 7-A.8 be labeled PC96b in lieu of just PC96?

A4: Yes, pile cap should be labeled PC96b.

Q5: Detail 8/S0.2 illustrates a concrete driveway on the exterior of the building at each drive entrance, but sheet CS101 shows asphalt paving. Which is correct?

A5: The pavement at the edge of structure should change to asphalt.

Q6: Reference Contract Drawing SB001, Drilled Piers, Notes 2A, 2B, 2C, Geotechnical Report prepared by Urban Engineers date November 18, 2013, page 4, paragraph A (Foundations – Drilled Shafts) and specification section 31 63 26, paragraph 1.5. The notes on the Contract Drawings note that the drilled shafts shall bear 6” into hard shale at the low point, or 1 ft. into weathered shale and to notify the engineer if the bearing strata varies by more than 2’-0” from the plan elevation before placing concrete. The geotechnical report notes that the drilled shafts should be socketed into “relatively sound” bedrock for a minimum depth of 3 ft. The report notes that for design purposes, the top of the “relatively sound” bedrock may be assumed at depths of 62 ft. beneath the top of gneiss bedrock, corresponding to an elevation of about 23. The geotechnical report notes that the

“relatively sound” bedrock will be characterized by rock core recoveries greater than 85% and probe holes must be performed beneath the bottom of the sockets to a distance of at least twice the socket diameter to observe the condition of the rock beneath each shaft. Please clarify the following:

a. Depth of socketing into the bedrock (relatively sound bedrock) for the caissons?

b. Who will determine the depth of the “relatively sound bedrock” during the drilling operation, i.e., Geotechnical Engineer (VA Hired or Contractor Hired)?

c. Based on Specification Section 31 63 26-1.5 defines rock auger refusal as less than 6” in 15 minutes with the specified drill rig. Do we assume that the auger refusal at less than 6” in 15 minutes meets the 85% rock recovery standard?

d. Based on the Geotechnical Report and Specification Section 31 63 26 is there a need to also perform the noted probe holes based on the ground water tables noted, depth of the drilled shafts, depth of the probe holes (twice the socket diameter)?

A6: a. Minimum 3'-0" socket required

b. Contractor hired Geotechnical Engineer

c. Onsite Geotechnical Engineer to confirm when "relatively sound" bedrock has been reached

d. From geotech report pg. 5: "Probe holes must be performed beneath the bottom of the sockets, to a distance of at least twice the socket diameter, to observe the condition of the rock beneath each shaft."

Q7: Generator:

1) Can you confirm if there is an existing Supply or Day tank?

2) Or will all that be avoided and all we need is the subbase tank for the Generator and nothing more?

3) If there is an existing supply tank, will the mechanical contractor supplying the controls and pumps?

4) How is return going to be addressed? Will it be done by gravity or will extra equipment need to be provided?

A7: 1) No existing supply tank or day tank.

2) Subbase tank as listed in Spec section 263213, para. 2.5.B - double wall tank sized for 96 hrs run time at 100% load.

3) No existing supply tanks, no new controls.

4) Subbase tank eliminates the need for return equipment.