QnA 4.20.23.pdf

Questions and Answers during Advertisement for CA FLAP LA CR2N40(1) Santa Anita Canyon Road

April 20, 2023

Questions Answers 1 Is there a job walk or can we arrange to visit the jobsite? If not, we assume site can be visited at any time?

No organized site visit will be held. There is a locked closure gate and the beginning of the project that is managed by LA County, Public Works and the Angeles National Forest. Access via the gate can be allowed through the county’s contacts provided below.

Robert Arriola:

rarriola@dpw.lacounty.gov (626)614-6462

Timothy Finn tfinn@dpw.lacounty.gov (626)632-7121

2 For the ground anchors at the Secant Piles - Can strand be substituted for bar tendons for the ground anchors?

Yes, strand and bar tendons are acceptable. Both must be adequately protected from moisture.

3 Can we use smaller diameter piles in bedrock, so we don’t have to advance the casing into bedrock?

No. The design of the wall relies on both the lateral geotechnical capacity and the reinforced concrete, moment capacity in the bedrock that is associated with the full sized shafts. A reduction in bearing area (smaller diameter shaft) or a reduction in the diameter of the rebar cage would result in insufficient capacity for the critical load case. Full sized shafts with rebar are required in the bedrock.

4 We plan to utilize the proposed basin area as a staging area when drilling. Is this acceptable?

Contractor assumes all risks for equipment located in the site should a debris event occur during construction.

5 Other than full road closures, we assume that we can close half of the road when needed for other activities?

See 156.07 in the Special Contract Requirements

6 On the 6” pulverized material, are there a proposed finish surface (FS) elevations we are to construct to? No grades are provided on the plans showing whether this is 6” pulverize, haul processed material to site 2 (stockpile) then haul back pulverized material. Is

Sheet A9 addresses all of the pulverization efforts. The 6-inch depth is measured from the top of the existing surface. Per the SCRs and notes on the sheet, the materials are pulverized in place and graded/compacted to the mailto:rarriola@dpw.lacounty.gov mailto:tfinn@dpw.lacounty.gov there a yield of material which will stay at site 2 if we are matching like in kind to the existing FS elevation; or is there a 0.25’ cut with the 3” HMA. Appears from reading this that the intent is to raise the top of pavement and FS elevation 0.25’.

Please confirm.

limits shown on the typical. Then, 3-inches of AC is added on top, thereby raising the grade of the existing roadway 3-inches.

Sheet F2 shows the transitions of the thicker pavement to the existing at the ends for the overlay improvements.

At Site 2, the pulverized materials are removed from the site while the secant wall work is performed, then placed as base materials per the notes on Typical Section Sheet A7.

The contractor is to provide grade checks per the SCRs to re-establish the roadway centerline to grade + 3-inches.

7 Please define the amount of time to assume for the “rockfall mitigation consultant”. Is it full time during the rockfall scaling and drapery work?

Rockfall mitigation is required during the scaling operations, and while the rock bolts are being tested.

8 We would like to request an extension to the solicitation due date.

We would like to request 10-14 days if possible.

Amendment A001 was published on 4/18/23 which extended the bid opening date by one week.

9 I have a technical question please for the SECANT PILE WALL INSTALLATION: The standard size temporary casing that will be used for the installation of the shafts is 1200mm (47.24 Inches) Outside diameter and 1120mm (44.09in) inside and the tooling size (augers etc.) is 1060mm (42in) diameter. This will result in Queen size shafts of 47.24in diameter and King size shafts of 47.24in in the upper section and 42in in the rock socket. Moreover the rebar cage of the king shafts will need to be 42in in the upper section (as per the current design) and 38” in the rock socket.

Please confirm if this is acceptable.

No. The design of the wall relies on both the lateral geotechnical capacity and the reinforced concrete, moment capacity in the bedrock that is associated with the full sized shafts. A reduction in bearing area (smaller diameter shaft) or a reduction in the diameter of the rebar cage would result in insufficient capacity for the critical load case. Full sized shafts with rebar are required in the bedrock.