QnA 10.2.2020.pdf

Questions and Answers during Advertisement for

CO FLAP US50(1) Little Blue Creek Canyon

September 17, 2020

Questions Answers

1 Are there electronic CAD files for the project that can be made available to contractors? Having the electronic files increases the efficiency and accuracy of our earthwork take-offs.

No, electronic CAD files will not be provided.

2 The Ditch Armoring at STA. 614+25 – 614+80 LT is not shown on the cross sections. Will cross sections be provided showing the

Ditch Armoring at STA 614+25 – 614+80 LT.? If yes, please provide.

Armoring is not shown in sections. Armoring to be field fitted to meet the existing slope, and fit within the criteria shown on the sheet. Cross Sections showing the armoring will not be provided.

3 The Bank Stabilization at STA 615+80 to 616+10 LT is not shown on the cross sections. Will cross sections be provided showing the bank stabilization at STA 615+80 to 616+10 LT? If yes, please provide.

Stabilization is not shown in sections. Armoring to be field fitted to meet the existing slope, and fit within the criteria shown on the sheet. Cross

Sections showing the armoring not to be provided.

4 Will the FHWA consider changing the Mumble strips (sinusoidal) specification to a standard CDOT rumble strip detail?

No, bid the project using mumble strips.

5 To install the Riprap per the cross sections and typical section(s) on sheets G2-G3, excavation and backfill will be required. Please confirm the excavated quantities will be paid under 20401-0000

Roadway Excavation.

Excavation required to place the stream armoring is incidental to the pay item. Excavation material generated is shown under Available Material in the grading summary.

Refer to the SCR’s and the FP-14 for work considered incidental.

Excavation for these quantities is not measured for payment and not paid for under the 20401-000, Roadway Excavation Item.

September 23, 2020

6 Will bids be accepted for alternate pipe materials for the culverts/drainage? I would propose corrugated HDPE pipe which meets CDOT requirements.

No, but a value engineering proposal may be considered after contract award.

7 Does FHWA require the assistance of a blasting consultant for approval of contractor submittals? Not at this time.

8 The geotechnical report references two reports that were done by YA and Associates.

Will the FHWA provide these reports? The Geotechnical report indicates that the YA reports should be referenced while reading the Geotechnical Reports. The actual bore logs are needed to evaluate the temporary shoring for the retaining walls and to design the support of excavation required for the

Rockery Walls and the GRS walls. In Table 2 “Summary of the YA Borings

Performed within the current CO US50(1) Alignment” no elevations are given , which requires inaccurate scaling from cross-sections to determine the rock elevation for the 12 bores that were taken for the retaining wall. In addition, It’s necessary to make a determination of the quality of the in-situ material above the rock to assess the predicted “hang time” of the excavation to design the support of excavation required.

These reports will be uploaded to the solicitation.

9 Has the FHWA obtained the required approvals for the successful contractor to obtain construction water by pumping water from the Blue River

FHWA has not obtained water rights. The successful contractor will need to coordinate this on their behalf.

October 1, 2020

10 The section 262 GRS specifications require design in accordance with FHWA HRT-17-080. For walls less than 25 feet in height, should the reinforcement be placed to the cut slope starting at

0.5H at the bottom and increasing until an RL of 0.7H is achieved, as indicated in FHWA HRT-

17-080 Section 4.3.4.5 on Pages 32 and 33? Or, should the reinforcement be 0.5H for the entire wall height?

For proposed wall heights of less than 25 vertical feet, a reinforcement length of 0.5H is the minimum required. For wall heights equal to or greater than 25 ft. a 0.7H factor is required.

11 From section 107.11, How many stocked fire boxes will be required? The number of fire boxes and equipment may vary depending upon the time of year, activities being performed, orders/regulations in place by parties listed in SCR107.11. It is the responsibility of the Contractor to determine the number of boxes required to satisfy these requirements. Submit proposed boxes and locations for approval, and update as required.

12 From section 108.04 ADDED- Interim Completion Date states, “No day closures will be allowed after July 31, 2021 in this area”, does that require that all contract bid items from Sta.

587+00 to Sta.617+00 must be 100% complete prior to July 31, 2021?

The July 17, 2021 – Interim Completion

Date Incentive does not require that all contract bid items from Sta. 587+00 –

617+00 be completed prior to or on July 31, 2021. All work that requires daytime full closures is considered work that may not be performed during nighttime operations, or work that cannot be performed without delaying traffic beyond allowable limits.

October 2, 2020

13 The IFB, section 205.08(b) states "offset lifts up to 18" horizontally to allow for drill equipment clearance". Additionally, section 205.08 ( e) states "When the cut height will require more than one lift, maximum 18" offset between lifts is permitted to allow for drill equipment clearance". Since these two statements allow for overbreak up to 18", will the allowed overbreak be included in the quantity of rock excavation for measurement and payment?

See FP-14 204.16(a)(2)(b): Do not include over breakage from the backslope in rock excavation.

14 The IFB section 157.09 (b) states prior to beginning in-stream work, submit a temporary stream diversion plan (for) approval. Submit a diversion plan that addresses the following at a minimum: (a ) Constructing a diversion that can accommodate 350 CFS without encroaching within the limits of construction; (b)devices proposed for use and; (c) Proposed methods of installation, maintenance and removal." In the areas that require work in-stream work, specifically the Special Rock Embankment stream bank protection in the vicinity of 588+00 and

600+00 the stream channel is not large and it does not appear to be feasible to pass flows of 350

CFS without encroaching within the limits of construction. Please clarify this requirement.

FHWA believes this CFS requirement to be feasible. The approved means and methods must remain within the limits of construction shown, but should be outside the limits of the work being performed.

15 Are sealed bids allowed to be submitted in-person at the FHWA Central Federal Lands Division

Office, 12300 W. Dakota Avenue, Lakewood, CO 80228?

Yes

16 On page ITB page E-13, Section 108.01 (f) states “from October 16 to April 15, US 50 must be opened to two-way traffic during nighttime without delays. Coordinate with the CO for effective dates”. On ITB page E-37, Section 156.07 (1) states “from October 16 to April 1, US 50 must be opened to two-way traffic during nighttime without delays if winter weather is expected on

Yes, closures may be permitted provided

CO-92 is open, no winter weather is expected, coordinate nighttime closures for approval beyond the ranges shown and for

C-92 route. CO-92 is not plowed by CDOT during the night. Coordinate with the CO for effective dates”. Can we assume that nighttime closures are allowed after October 16 as long as

CO-92 is open and there is not winter weather?

effective dates of required openings with the

CO.

17 ITB page E-27 indicates the 4th paragraph from the bottom of the subsection should be deleted and substituted with “Reestablish missing control points and stakes before slope staking begins”.

We are not clear who has the responsibility to reestablish the missing control points.

Additionally there appears to be numerous monuments on the existing roadway that will be within the construction limits. While it may be possible to preserve some of these during construction, it will not be possible to preserve others. Who the responsibility to relocate these monuments?

Question 1: The revised language between the FP-14/ SCR’s reads: Preserve initial reference and control points. “Notify the CO of missing control points or stakes at least 10 days before beginning construction.

Reestablish missing control points and stakes before slope staking begins.”

Question 2: Refer to FP-14 107.02 for more information.

18 In the Federal proposal it suggests the former CDOT yard on US 50 could be used for this project. If this is possible, can you inform me as to what utilities are available at that site. I am planning a site visit later this week and wanted to make arrangements to view the site.

See SCR 105.04: Former CDOT yard, phone and electric hook-ups at pads may be available.

19 For the GRS segmental wall, the GRS Wall Backfill quantities on surrmary schedule A of

26,929 CY do not include the 3’ reinforced zone that is required to go back to the C/L of road as shown on special drawing 262-A. Can you verify that this reinforcing zone and the extra material not included in the retaining wall summary of quantities are required to support guardrail impact loading on the wall?

The reinforcing zone is not required for guardrail purposes.

20 The Wall summary also shows a small amount of wall backfill 1,217 CY that is not part of the reinforced zone. This quantity does not appear to be near enough to provide a 1:1 backfill zone as shown on drawing 262-A and will only cover a small amount of backfill at the front face of wall. There is no bid item for soil nail wall shoring, that would be required to avoid a 1:1 backfill zone behind the reinforced zone. MSE-4 boring shows weathered rock down 22.5’ or solid rock at 26’. Will a shoring pay item be added to allow walls to be installed as shown on cross sections? If no pay item is added, will contractor be responsible for temp shoring, or additional 1:1 slope back material plus required temp widening’s to get traffic around MSE Wall excavations?

Question 1: No shoring item will be added to the Contract. Refer to Answer to Q2 below.

Question 2: Contractor is responsible for excavation and backfill. Sheet G16, Note 5:

Slope or shore excavation according to

Section 208. See Section 156 for Public

Traffic Requirements. Refer to Sections 208, 209, 257 and 262 of the FP-14 and the

Special Contract Requirements.

21 Do we need to hold off the wall design until the final survey by the contractor is done and the updated TOW and BOW lines for each wall are developed by a contractor’s civil engineer? Or, we can move forward with the wall design based of the wall profiles provided on the project plans Sheets G10 through G17? This could have a major impact to both the schedule and costs.

Question 1: Retaining wall design should be performed after surveying. Refer to Section

257 of the SCR’s.

Question 2: Contractor is responsible for the retaining wall design. 25701-0000, Contractor Furnished Geosynthetic

Reinforced Soil (GRS) Retaining Wall

Design. Refer to Sections 257 and 262 of the

SCR’s.