I-40 in North Carolina

[Beltway]

Some tidbits from a recent WLOS article regarding the I-40 rebuild:
Engineers plan to build massive retaining walls of roller-compacted concrete, a material more often used in dam construction. Those walls will be up to 30 feet thick and anchored directly into bedrock both horizontally and vertically.
Another technique, the interlocking pipe pile wall, involves drilling continuous steel casings into bedrock to form a sealed wall face.
The full rebuild is expected to cost about $1.36 billion, funded largely through federal emergency relief dollars approved by Congress. NCDOT estimates work will continue until at least 2028.

That is incredible, I didn't know the cost had risen that high. All that invested into a slide-prone corridor.

One source I found says it is only 18% federally funded. I need research more to find out if that is true.

The gorge is a known slide-prone zone. Even during initial construction, engineers flagged it as geotechnically risky. Tropical Storm Helene washed away entire lanes, and subsequent rains triggered more slides. This isn't a one-off, it's a pattern.

The current rebuild involves dam-grade retaining walls, interlocking pipe pile systems, and real-time slope sensors, essentially trying to engineer their way out of geology. On a winding alignment with a narrow cross-section.

That sum would probably fund a 10 to 15 mile relocation to high ground as I have sketched in the past. But that can't wait 5 to 10 years that it would take for EIS, design and construction to get I-40 open to 4 lanes again.

[RoadMaster09]

Honestly, for that section, I'd rebuild into the mountain with tunnels and forget about rebuilding towards the river. The next storm will likely wash it out anyway.

[ElishaGOtis]

Honestly, for that section, I'd rebuild into the mountain with tunnels and forget about rebuilding towards the river. The next storm will likely wash it out anyway.

Fictional but I wonder how that would compare to the estimated $1.4B price tag.

[74/171FAN]

Honestly, for that section, I'd rebuild into the mountain with tunnels and forget about rebuilding towards the river. The next storm will likely wash it out anyway.

Fictional but I wonder how that would compare to the estimated $1.4B price tag.

Yeah, any fictional ideas should be in this thread.  (https://www.aaroads.com/forum/index.php?topic=36362.0)

[ElishaGOtis]

Is the final design speed proposed to be the same at 55mph or will it be different? I'd imagine the speed limit will return to 55 once re-built but that's not necessarily the same thing (depending on the state, of course, as idk how NC works regarding that).

[bob7374]

NCDOT has awarded a contract to turn the NC 109 interchange in Winston-Salem from a half-diamond to a full-diamond, work to be completed by 2029:
https://www.ncdot.gov/news/press-releases/Pages/2025/2025-09-18-forsyth-interchange-award.aspx

Sign plans accompanying the project include the new signs on I-40 East at the Future NC 192 (now I-74 East) exit. Interestingly, they do not include any information indicating drivers could take NC 192 to get to I-74 East, just To Ridgwood Road like the westbound signs, but I assume GPS will route them that way.

[ARMOURERERIC]

Considering construction phasing, I don't think a SPUI could be constructed in Morganton anyway since the existing overpass would need to be kept open. There'd have to be a major shift to the east or west due to the larger structure, knocking out nearby properties with the approaches. At that point, you might as well go with the cheaper DDI.

Brier Creek is a good example of a delayed project (from 2018 to 2028 now) with an updated 2023 traffic forecast for 2050. The previous forecast looks like it was 2016/2040. It has gotten so bad there that I don't even go to Brier Creek anymore.

A fully upgraded U.S. 70 from I-540 to Durham would be a huge relief for I-40. Basically all of north Raleigh could utilize U.S. 70 for I-40/I-85 towards Greensboro.

I did not know about the public meetings on 40/64 hence did not attend.  My biggest agitation is that the local paper supposedly showed online all the alternatives, and a tight diamond was NOT one of them.  Even now, on local discussion forums many are like "where did that stupid option come from"?  I'm curious if the FHA approved  an option that the locals did not really have a chance to comment on.  All the other proposals had a 2 or 3 lane left turn pocket from 64w to 40e, a properly built tight diamond is going to need a 7 lane bridge for 64, 2 lanes each direction for 64, 2 lanes for left turns on 64 w, and 1 lane for lefts on 64e and the will have to be concurrent on the bridge due to the close signal spacing.  Hell the SPUI had a triple left, so obviously there was a noticeable need.

What stinks 8s with all these interchanges that were supposed to be done by 2020 now being pushed back, NCDot is having to spend millions just to keep 70 years old bridge decks usable for another 20 years.

Bring the exit 103 topic back up because on Friday and today, 2 commercial buildings were demolished on US 64/Burkemont Ave.  And in both cases the former owners publicly stated recently that it was NCDot ROW acquisition for the interchange.  From. What I understand, the plan is to build a new overpass west of the existing bridge, then demo the existing bridge and build the 2nd half of the new bridge.  The buildings demoed were the next 2 immediately north of the Citgo station in the nw quadrant.  Presentations back a few years ago did show these building needing to go.  What this means for the project timetable...who knows.