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).