20200504 Ver 1_Footing Correspondence_20211006

1
Travis Tyboroski
From:Robert E. Chandler <[e-mail]>
Sent:Thursday, May 27, 2021 12:03 PM
To:Travis Tyboroski
Cc:Jon Callahan; Patrick W Imhof
Subject:FW: Town Center - Bearing Capacity / Options (620308)
Travis-

See below from Engineering. I’d agree we’d probably want the foundation to be the same on both sides.

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Kevin Betancourt <[e-mail]>
Sent: Wednesday, May 26, 2021 7:50 AM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>
Subject: RE: Town Center - Bearing Capacity / Options (620308)

Hey Rob,

A 13’ wide x 2.5’ thick footing will work at 4000 psf with the 8ft of cover.

I don’t know that we would want two footing sizes though. We should probably just stick to the larger of the two.

Kevin

From: Robert E. Chandler <[e-mail]>
Sent: Tuesday, May 25, 2021 4:12 PM
To: Kevin Betancourt <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>
Subject: Town Center - Bearing Capacity / Options (620308)

Kevin-

See below. Any chance we could make this work with 4000 PSF on one side?

Thanks-

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
2
[e-mail]
www.ContechES.com

From: Travis Tyboroski <[e-mail]>
Sent: Tuesday, May 25, 2021 2:54 PM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: [EXTERNAL] RE: Town Center - Additional BridgeCOR Option (620308)

CAUTION: This email originated from outside of the organization. Exercise caution when
opening attachments or clicking links, especially from UNKNOWN senders.
Robert,

Talked to the Geotechnical Engineer. There is partially weathered rock on one side of the crossing, so he didn’t have
concerns there. Is there the option to adjust the footing size of one side to work with 4,000 PSF?

Travis Tyboroski, PE

From: Robert E. Chandler <[e-mail]>
Sent: Monday, May 17, 2021 1:58 PM
To: Travis Tyboroski <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: Town Center - Additional BridgeCOR Option (620308)

Travis-

Attached is what we came up with for a lower profile option. Note that below we had to up the bearing capacity to 4750
PSF to make this work.

Let us know what you think.

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Kevin Betancourt <[e-mail]>
Sent: Friday, May 14, 2021 1:37 PM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>
Subject: RE: Town Center - Options (620308)

Hey Rob,

Please see the attached BridgeCor Box Culvert. With this structure in 3ga, it can handle HL93 live load and 8’ of cover.
The footing design shown is a 9.75’ x 2.5’ footing that would work at a minimum bearing of 4750 PSF.

3
End area of this structure is 355.29 SF.

Let me know if any questions.

Thanks,
Kevin

From: Robert E. Chandler <[e-mail]>
Sent: Tuesday, May 11, 2021 7:26 AM
To: Kevin Betancourt <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>
Subject: FW: Town Center - Options (620308)

Kevin-

I need a BridgeCOR option which will yield 30’+ between the foundations with a rise in the neighborhood of 12’ and
height of cover ranging from 15-20’. We had previously assumed 4000 PSF.

Let me know what you think.

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Travis Tyboroski <[e-mail]>
Sent: Thursday, May 6, 2021 1:33 PM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: RE: [EXTERNAL] RE: Town Center - Options (620308)

That’s correct.

Travis Tyboroski, PE

From: Robert E. Chandler <[e-mail]>
Sent: Thursday, May 6, 2021 2:30 PM
To: Travis Tyboroski <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: RE: [EXTERNAL] RE: Town Center - Options (620308)

Travis-

I have a 31’-8” Span X 12’-8” two-radius arch which is in the ballpark. Do we need to yield 30’ between the footings
though?

Robert Chandler E.I.T.
Inside Bridge Consultant

4
CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Travis Tyboroski <[e-mail]>
Sent: Thursday, May 6, 2021 10:55 AM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: RE: [EXTERNAL] RE: Town Center - Options (620308)

I think we should assume FG of 285± to allow for water leaving 15-20’. Again, the lower the better.

Looks like 30’ span would get us out of the channel with about a foot on each side at the worst case.

Travis Tyboroski, PE

From: Robert E. Chandler <[e-mail]>
Sent: Thursday, May 6, 2021 11:03 AM
To: Travis Tyboroski <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: RE: [EXTERNAL] RE: Town Center - Options (620308)

Thanks Travis-

Here’s what I’m seeing on there:
· North Profile
o Invert – EL. 265
o FG – EL. 289
· Centerline Profile
o Invert – EL. 267
o FG – EL. 289
· South Profile
o Invert – EL. 267
o FG – EL. 289

So you have about 20-25’ to work in assuming you’re going to put the top of footing at the stream invert. That gives us
plenty of room to fit a number of options. What span do you think you need to avoid permitting?

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Travis Tyboroski <[e-mail]>
Sent: Thursday, May 6, 2021 9:47 AM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: RE: [EXTERNAL] RE: Town Center - Options (620308)
5

Robert,

CAD file of profiles at the southern and northern ROW as well as centerline are attached. Lowest profile option is best as
we need to get water across and ideally storm, but at this point the crossing design will be the limiting factor.

Travis Tyboroski, PE

From: Robert E. Chandler <[e-mail]>
Sent: Tuesday, May 4, 2021 1:18 PM
To: Travis Tyboroski <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: RE: [EXTERNAL] RE: Town Center - Options (620308)

Travis-

We have structural plate options with spans out past 60’. A main driver of what we can fit in there is the profile at the
crossing (how much vertical room we have to fit the arch).

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Travis Tyboroski <[e-mail]>
Sent: Tuesday, May 4, 2021 11:28 AM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: [EXTERNAL] RE: Town Center - Options (620308)

CAUTION: This email originated from outside of the organization. Exercise caution when
opening attachments or clicking links, especially from UNKNOWN senders.
Robert,

I think that’s where we’re looking to your team for some direction. I read the comments as: “you need a bigger span to
avoid impacts at the channel and side slopes”. The road layout is pretty well set by the City’s Comprehensive Plan so we
don’t have flexibility there.

Is there a larger span available?

Travis Tyboroski, PE

From: Robert E. Chandler <[e-mail]>
Sent: Monday, May 3, 2021 2:47 PM
To: Travis Tyboroski <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: RE: Town Center - Options (620308)
6

Travis-

I apologize it took me this long to get back to you.

I read that to say the proposed solution is still going to cause an impact so mitigation fees will be required. But it sounds
like relocating the crossing might get you to an area with a more narrow channel. The question I don’t see answered
here is what is that span requirement going to be? And if the structure is moved what will happen to the profile at the
crossing?

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Travis Tyboroski <[e-mail]>
Sent: Tuesday, April 27, 2021 9:06 AM
To: Robert E. Chandler <[e-mail]>
Cc: Patrick W Imhof <[e-mail]>; Jon Callahan <[e-mail]>
Subject: [EXTERNAL] RE: Town Center - Metal Arch Option - Proposal Drawing / Overlay (620308)

CAUTION: This email originated from outside of the organization. Exercise caution when
opening attachments or clicking links, especially from UNKNOWN senders.
Robert,

This project is coming back to life, and we’re working to get the Environmental approvals moving since those are
typically the longest lead items. See below for USACE comments on the bottomless arch design:

1. Please address the following concerns regarding the use of a bottomless arch culvert.
a. The Corps Wilmington District Raleigh Regulatory Field Office has had long experience with bottomless
arch culverts. We generally agree with NCDOT that the long-term success of such structures is
significantly enhanced when they are tied into shallow bedrock. Typically in the piedmont non-scourable
rock cannot be reached and bottomless arch culverts cannot be designed to NCDOT standards. Please
submit information on boring studies done by the applicant for feasibility of a bottomless arch culvert in
this location, as well as information explaining if the bottomless arch culvert meets NCDOT design
standards. Additionally, shading under the arch culvert leads to die off of any remaining woody
vegetation, which then leads to loss of aquatic function through stream bank erosion and widening out
from foundation to foundation. In cases where the structures are not tied into bedrock we have seen
numerous instances of foundation undercutting, often leading to replacement with traditional culverts.
b. Given that the project proposes impacts requiring 404 approval, we are evaluating both direct and
reasonably foreseeable indirect impacts to 404 resources associated with the project to ensure that the
individual and cumulative adverse environmental effects are no more than minimal (NWP General
Condition 23 and District Engineer’s Decision part 2). Based on the above, it is reasonable to conclude
that the proposed bottomless culvert would result in indirect impacts to the stream in the footprint of
the structure. As the proposed direct and indirect impacts to streams would exceed 150 linear feet,
please provide a compensatory mitigation plan for these impacts. The mitigation rule generally
prescribes purchasing stream credits first through a mitigation bank with stream credits available in this
7
8-digit HUC, or second through the NC Division of Mitigation Services; please provide a mitigation
acceptance letter from your proposed compensatory mitigation provider. Should the applicant elect to
move forward with the current design compensatory mitigation for the stream channel under the arch
will be assessed at a 1:1 ratio due to secondary adverse impacts to the stream channel under the arch
and compensatory mitigation will be assessed at a 2:1 ratio for the permanent stream channel loss
associated with the box culvert.
2. Based on plan drawings for Impact #2 it appears that the arch culvert is positioned within the stream channel
near the northern headwall. Please provide an explanation for the location and positioning of the arch culvert.
For example it appears that moving the culvert to the south would allow for the arch culvert to be positioned
outside the channel. Additionally, it appears that stormwater infrastructure will cross the stream channel in two
locations under the arch culvert. How will the stormwater features be installed? Please update the PCN and
plans accordingly.

The way I read these is that we may need to increase the span, especially to address comment #2. Let me know what
you think and what you need from us to get this re-started.

Thanks!

Travis Tyboroski, PE

From: Chandler, Robert <[e-mail]>
Sent: Monday, June 15, 2020 2:26 PM
To: Travis Tyboroski <[e-mail]>
Cc: Imhof, Patrick W <[e-mail]>; Jon Callahan <[e-mail]>
Subject: Town Center - Metal Arch Option - Proposal Drawing / Overlay (620308)

Travis-

Attached is a Proposal Drawing for your review. I’ve also attached a CAD of the overlay of this structure in your plan
view.

Let me know what else I can help with at this time.

Thanks-

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com

From: Travis Tyboroski <[e-mail]>
Sent: Thursday, June 11, 2020 3:10 PM
To: Chandler, Robert <[e-mail]>
Cc: Imhof, Patrick W <[e-mail]>; Jon Callahan <[e-mail]>
Subject: FW: Town Center - Metal Arch Option (620308) [Bearing Capacity]

See below from Geotech.

Travis Tyboroski, PE
8

From: Mark R. Potratz <[e-mail]>
Sent: Thursday, June 11, 2020 4:09 PM
To: Travis Tyboroski <[e-mail]>
Cc: Jon Callahan <[e-mail]>
Subject: RE: Town Center - Metal Arch Option (620308)

Travis, I am ok with using 4,000 psf in this area for the culvert foundation design.

The footings would need to be carefully checked and some repairs may be needed (over-excavate and backfill with lean
concrete) to achieve 4,000 psf. The repairs would be more likely at the B-29 side where the PWR is deeper.

Thanks!

Mark Potratz, P. E.

3200 Wellington Court, Ste 108, Raleigh, NC 27615
o: 919.954.1514 | c: 919.815.6479 | f: 919.954.1428
[e-mail]
www.geotechpa.com

From: Travis Tyboroski <[e-mail]>
Sent: Thursday, June 11, 2020 4:02 PM
To: Mark R. Potratz <[e-mail]>
Cc: Jon Callahan <[e-mail]>
Subject: FW: Town Center - Metal Arch Option (620308)

Mark,

Hope you’re doing well!

Quick question for you below on the proposed crossing at Sumner Town Center (specifically in the areas of B-28 and B-
29) from the bridge designer. We had previously confirmed 3,000 was ok.

Travis Tyboroski, PE

From: Chandler, Robert <[e-mail]>
Sent: Thursday, June 11, 2020 3:44 PM
To: Travis Tyboroski <[e-mail]>; Jon Callahan <[e-mail]>
Cc: Imhof, Patrick W <[e-mail]>
Subject: RE: Town Center - Metal Arch Option (620308)

Hey Travis-

I had some conversations with our Engineering Group this morning about your project and got some feedback. From
what I gathered from the CAD file, it looks like we need to yield about 30’ between the foundations to clear protected
area. As a first pass, our first recommendation would be a 40’ Span X 17’ Rise steel arch but due to its size, making the
foundations work at 3000 PSF isn’t going to happen. We bumped that bearing capacity up to 4000 PSF and we were able
to get footings to check at about 12’ wide and would yield about 32’ clear between them. Based on the grading I saw out
there this arch would have about 36” of cover on it. In my experience, the end treatments for an arch like this would be
either modular or cast in place.

After going through this information a bit I have a couple of questions for you:
1. Do you think it is feasible to get 4000 PSF bearing out there?
2. Would it be possible to shift the location of the structure so we don’t have such a high span requirement?
Perhaps it could be shortened slightly and moved to the South?

Let me know what you think.

Robert Chandler E.I.T.
Inside Bridge Consultant

CONTECH Engineered Solutions
Mob: [phone]
[e-mail]
www.ContechES.com