20200628 Ver 1_U-5760 retaining walls and value engineering_original_20211208

Wanucha, Dave
From:Euliss, Amy
Sent:Monday, November 29, 2021 2:31 PM
To:Williams, Andrew E CIV USARMY CESAW (USA); Wanucha, Dave
Cc:James, Connie K; Blanton, William A
Subject:U-5760 retaining walls and value engineering_original
Attachments:U5760_Culvert_Extension.pdf; 5-38.jpg
Andy and Dave,

NCDOT received an Individual Permit in August 2020 to construct Big Mill Farm Road widening and extension in Forsyth
County. I believe you both attended the interagency meeting earlier this month where our Value Engineering studies
were discussed. We recently had a Value Engineering Study conducted on the Big Mill Farm Road project (U-5760) in
Forsyth County. The concept of reducing the wall came up during the value assessment. Following the study, our
Geotech folks further investigated the cost of the retaining wall. The wall would be @60’ tall (52,500 sq ft) and would
cost 5 million dollars to build. It was determined that reducing the retaining wall height to 21.5’ (11,200 sq feet) would
result in an additional 116’ of permanent stream impacts, increasing our mitigation costs by approximately 140,097.84
(116’ at a 2:1 ratio). The lower wall offers a reduction of $3,717,000. Additional fill will offset this cost slightly, but
borrow is estimated at $7/CY. If we increased the borrow through this area by 25% that would be another 50,000 CY, or
$350,000 so with the $141,000 additional mitigation cost, we would still be saving over $3,000,000. Additionally a
shorter wall height is preferred by construction and maintenance staff as it will be easier to construct and maintain.

We want to discuss the feasibility of this change from a permitting perspective prior to investing in the full redesign
cost. Please let me know your availably to discuss via a MS Teams call over the next couple of weeks.

For your reference, I have attached a preliminary plan sheet showing the lower wall height and proposed
impacts. Please note when you review the plan sheet (attached), it shows a driveway pipe. That pipe is no longer
there. I’ve attached a proposed revision plan sheet and a photo of the stream at the proposed impact site showing that
the pipe is no longer present.

I have also linked the permit application and the permit approvals below for your reference.

Permit application: https://xfer.services.ncdot.gov/pdea/PermApps/U-5760%20Forsyth%20May%207%202020.pdf
Permit approvals: https://xfer.services.ncdot.gov/pdea/PermIssued/U-5760%20Forsyth%20August%2010%202020.pdf

Thanks in advance.

Amy Euliss
Division 9 PDEA Engineer
North Carolina Department of Transportation

336 747 7802 office
[e-mail]

375 Silas Creek Parkway
Winston Salem, NC 27127-7167

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