MCD Industry Day Information(CT Edit).pptx

Moose Creek Dam Safety Modification Chena river Lakes Flood Control project Alaska District - CEPOA

Industry Day

Alaska District 12 December 2019

“The views, opinions and findings contained in this report are those of the authors(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other official documentation.”

Agenda Opening Comments (PTAC)

Contracting

Small Business Introduction

Project Overview (Project Manager/Lead Engineer)

Closing

One-on-One Meetings (If signed up through PTAC)

- See schedule for appropriate time

Contracting Points of Contact Contract Specialists

Contracting Officer Aldone Graham (Aldone.R.Graham@usace.army.mil)

Mailing Address

DISCLAIMERS

Questions regarding today’s industry day or any material presented shall be emailed to john.l.Mccomas@usace.army.mil no later than 20 December 2019

The information being presented today is draft/preliminary information for the Moose Creek Dam Safety Modification and is subject to change. No offers or proposals will be accepted at this time.

Once the formal solicitation is issued, the solicitation shall be reviewed in its entirety as changes may/will occur from the information presented today till the formal solicitation is released.

Any information presented today does not commit the Government to any particular Contracting means/methods as formal reviews and approvals will direct the acquisition.

Contracting

Contracting All information regarding this acquisition will be posted to https://beta.sam.gov (formally known as www.fbo.gov) once it is available for release.

Solicitation Number is W911KB21R0001 – FAR Part 15 Contracting by Negotiation

- Anticipating Best Value Tradeoff Source Selection

NAICS is 237990 Other Heavy and Civil Engineering Construction

- Small Business Size Standard $39.5 Million

Anticipated contract is FFP

Project Magnitude is between $100,000,000 and $250,000,000

Approved by SBA as Unrestricted Acquisition

Schedule Tentative Schedule (Calendar Year)

The second industry day tentatively scheduled for 2nd Quarter 2020 (Calendar Year) and may be held at Moose Creek Dam. Information regarding this visit will be posted to https://beta.sam.gov when it becomes available.

Solicitation and all amendments must be signed/acknowledged

Contractors must have an active registration in https://beta.sam.gov and must not be debarred and/or suspended to be considered for award.

USACE-CEPOA Small Business Specialist

Procurement Center Representative (Alaska)

System for Award Management https://beta.sam.gov/

Small Business Administration www.sba.gov

Alaska Procurement Technical Assistance Center https://ptacalaska.org/

Small Business Contacts/Helpful links

Moose Creek Dam Safety Modification Chena river Lakes Flood Control project Jenipher Cate Ph.D.

Project Manager

Coleman Chalup P.E.

Lead Engineer Dam Safety Program Manager

Robert Tedrick P.E.

Design Manager

Alaska District 12 December 2019

“The views, opinions and findings contained in this report are those of the authors(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other official documentation.”

All information is subject to change once the project is out for bid.

This information represents a 35% design

Project Location

OPERATIONAL SCHEMATIC

Population at risk Operational schematic

Reaches

Project Office Reach 1 Reach 2 Reach 3 Reach 4 Reach 5 Reach 6 Reach 7 Reach 8 Reach 9 Control Works/Chena River

FLOODWAY AND DAM

Control Works (1992 Pool of Record)

NEED TO UPDATE

Geology

Foundation is gravelly sand/sandy gravel that likely exceeds 1000 ft in thickness with a surficial blanket of silt.

The transition from sand and gravel to silt includes layers of sand and silty sand, including fine sand with Cu<3.

The sand and gravel includes gap graded and open work gravel lenses.

Sloughs from meanders and braids, as well as permafrost, complicate the near surface geology.

Chena River Tanana River

600 ft

MCD

SLOUGHS AND PERMAFROST LOCATIONS

Mapped Sloughs Mapped Permafrost

Geophysical Investigation

Capacitive-Coupled Resistivity (CCR) 50 foot depth Electrical Resistivity Tomography (ERT) 300 foot depth Ground Penetrating Radar (GPR) 50 foot depth

Thawed zone at surface

Permafrost at depth

Station 290+00 Cross-transect

Geophysical Investigation – ERT

File Name

Station 410+00 to 490+00 (North of Control Works) Station 230+00 to 390+00 (South of Control Works) Permafrost Embankment zone to ~490 feet NAVD88 High resistivity due to nature of the embankment (Brown to Red) Thawed zone to ~400 feet NAVD88 Lower resistivity due to thawed coarse grained soils (Blue to Green) Deeper frozen zone to ~200 feet NAVD88 High resistivity due to frozen soils (Brown to Red)

Geophysical Investigation – GPR

GPR

Harder to distinguish specific features Shows excavations and different phases of construction

Results Better understanding of permafrost.

Thawed zone between embankment and deeper permafrost across site.

See extent of features (Control Works, sloughs, and phases of work).

Embankment Design

Rock Fill

Geotechnical Investigation – USACE-CEPOA 53 additional borings with continuous sampling.

5,120 feet drilled.

Borings ranging from 60 to 130 feet deep.

Results Encountered permafrost.

Fine grained soil layer around 90 to 110 feet below the ground surface.

Ground truth for Geophysics performed.

Mix Design samples acquired.

Better understanding of foundation conditions.

Encountered zones with cobbles.

Centerline Boreholes

R3 R4 R5 R7 R6 R8 R9

Typical Centerline Boring

Depth of Barrier Wall at 464 feet NAVD88 Sands and Gravel Sand Water Table Type III Fill Semi-Pervious Fill Type I Fill Type II Fill Type II Fill

Typical Downstream Boring

Silt Sand Sands and Gravel Depth of Barrier Wall at 474 feet NAVD88 Water Table

Potential Failure modes

24 ft 40 to 80 ft

Silt Layer Coarse Sand and Gravel Layer

Pooling and Floodway from Chena River Stability Berm Upstream Water Stage <= 525 feet NAVD 88 Continuous Silty sand/fine sand Layer

Boils Boils Downstream – City of North Pole

Impervious silt blanket Moose Creek Dam During periods of high water stages in the Chena River, due to the silty sand and fine sand layer under the silt layer, three modes of failure can occur under the Moose Creek Dam: 1. backwards erosion and piping (horizontal exits), 2. backwards erosion and piping (vertical exits) and 3. contact erosion. These three modes of failure could act independently or together, eventually causing a failure in the dam, leading to flooding and potential risk of loss of life and damage to the cities of North Pole and Fairbanks, and other adjacent communities.

Horizontal Exit Vertical Exit Allowable Seepage Backwards erosion Potential Failure point Contact Erosion Piping

LEGEND

Potential Failure in Dam Fairbanks City of North Pole Backward Erosion and Piping with Vertical Exit Backward Erosion and Piping with Horizontal Exit Contract Erosion

PLAN (BARRIER WALL)

Centerline Boreholes with Barrier Wall Extents

R3 R4 R5 R7 R6 R8 R9

Potential Permafrost and Bedrock Area Potential Permafrost Potential Bedrock

Existing Crest

ALLOWABLE CREST HEIGHT REDUCTION

Low Point Drain

Barrier wall (control works tie-in)

Barrier Wall (Control Works tie-in)

Barrier wall tied into sloped concrete wall Sheet pile

Mix Design Findings To Date Bureau of Reclamation Design Standards No. 13: Embankment Design (Table 16.7.11-1)

FHWA Design Manual: Deep Mixing For Embankment and Foundation Support (Bench Scale Testing)

Bureau of Reclamation Used for comparison of Mix Design

FHWA

Used Bench Scale Testing to conduct Mix Design

Contractor will be required to perform their own Mix Designs after award of the contract.

Allowable Technology for Barrier Wall construction at moose creek dam Mix in place methods shall be utilized to mix the embankment and foundation materials with Bentonite and Portland Cement in order to construct a Barrier Wall through Moose Creek Dam.

Any methods that utilize a bentonite slurry trench to support the embankment while excavation of the barrier wall takes place will NOT be utilized at Moose Creek Dam. The potential loss of slurry could result in failure of the embankment into the excavation during construction due to highly pervious foundation materials.

12/4/2019

Proposed Construction Criteria/Constraints

Closing Comments Email questions to: John.l.Mccomas@usace.army.mil

These slides, attendee list and questions/answers will be posted to the industry day notification once all answers are consolidated.

Reminder: The Government reserves the right to not answer questions should they chose to do so.

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