Section of I-95 collapses after fire burns under overpass... 15

[KevinK2]

It looks like it's just a 6" step to get onto the existing road from the work area, suggesting concrete or asphalt comming soon. But rain is comming, latest update is steady rain starting at mdnight and all day Thursday. Not good.

 

[JohnRBaker]

Speaking of I-75 going through Michigan, how long did it take to build, then repair and rebuild, the infamous Zilwaukee Bridge over the Saginaw River back in the 80's?

https://en.wikipedia.org/wiki/Zilwaukee_Bridge

In the end, it took over nine-years to finish the bridge, replacing a drawbridge which opened once or twice a day for a sand dredge bringing casting sand from Saginaw Bay to a GM foundry. The irony is that during the time when they had shut down the construction, fired the original contractor, hired a new one, repaired the damage and finally restarted the construction (see the 'History' section of the above Wiki article), GM had decided to close the foundry, meaning that now the old drawbridge would've needed to only be opened four or five times a YEAR.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[SWComposites]

Yeah John, at least when I was growing up in MI, in the '60's and '70's, that ******* Zilwaukee draw bridge always seemed to open on Friday and Monday afternoons/evenings of holiday weekends. Grrrrr.

 

[JohnRBaker]

Where in Michigan did you grow up?

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[SWComposites]

Farmington.
We built a cottage on Otsego Lake near Gaylord; used to go up there a lot; still have it in the family.

 

[JohnRBaker]

My wife and I are from Lewiston, about 30 miles East of Gaylord. We used to drive to Gaylord as it was the closest movie theater back when we were in high school. Both my wife and I still have cousins in the area. And for about 17 months, in 1986-87, we lived in West Bloomfield and I worked in Farmington Hills.

Where in California are you located?

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[KevinK2]

At 8:41pm they are compacting again, and just began paving the far side. The first dump truck of black top is loading the paver now.

They have been using push compactors alot during last few hours. They did nothing close to this building up the lower support system, where it was also need, imho.

 

[KevinK2]

"Under the leadership of Governor Shapiro and Secretary Carroll, crews have worked around the clock to reopen the roadway safely and as quickly as possible". Too soon for taking bows.

Kevin Kelleher, PEME
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

 

[jerseyshore]

I'm assuming they didn't go crazy with compaction to save time and get this stretch reopened asap. A little dip in the roadway if it settles is probably not a big deal right?

 

[KevinK2]

I don't think they came close to properly compacting the lower support. SGW2009 descrbed the process he observed. Souded like they built ~ 10 ft x 18 foot wire mesh boxes, open at the top. Fill it with raw material that OEM said each piece was 92% air by volume, not counting the voids when filled to a 2 foot depth in the wire boxes.

He said the compaction was a bit hap hazzard.

I think over time, with occasional bumper to bumper 20-30,000 lb semis riding over with relatively resricted slow traffic on 3 lanes each way, steady setteling will be an issue.

From my prior comments from OEM about recommended compaction:

For roadway support (not an overpass), appears to be bulk thicknes limited to 12" max if using a push compactor, but it appeared to be used on the full 24" deep blocks.

And for the full 24", 600-1000 psf, 2 passes "with a tracked excavator or dozer"


Kevin Kelleher, PEME
Internal Mechanical Eng'g Consultant DuPont ESD Specialists

 

[jerseyshore]

A settled roadway is better than no roadway. Can't be much worse than the rest of the roads in this area. If it settles a lot they can just add more pavement overtop. Semi-temporary quick fix anyway.

 

[Milliontown]

When dealing with aggregate as large as the foamed glass aggregate being used here, there is not much compactive effort needed. Large aggregate is usually dense when placed, and will get denser with a little compaction. In fact, just driving equipment across the material will help compact it. This goes even more so when dealing with a large fill like this. More equipment as the lifts rise more locking in of the particles.

I also notice a concern with the air content in the aggregate. That air will not move or migrate unless the actual piece of aggregate the air is locked in physically breaks. This is not like a soil matrix where the air voids can be compressed. If anything, too much compaction will break the particles down making much more settlement than compacting less. I believe this is the case if the manufacturer recommends using tracked equipment for compaction. Tracked equipment can't be used to compact because the ground pressures are too low. Tracked equipment in this case will lower the load on the aggregate to prevent breaking, while still giving enough overall stress increase in the fill to lock in the large particles. I believe the techniques used here were a tradeoff, minimal compaction to lock in the particle but not break them. Plus this is an temporary emergency. This fill is not permanent.

 

[KevinK2]

Milliontown,
The process of building this light weight support was observed. Little effort was made to compact each 2 ft high "oversized brick" unit, capped with wire mesh. I think the voids you create between each of these odd shaped pieces is much higher than lower grades of crushed rock typically used in roadway construction.

When the minimally compressed material is compressed in final use, edges of each piece will be crushed, adding to settling. The low compression resistent properties listed by independent labs, whose links I have posted, were done per ideal conditions, with material in a cylinder, constrained in radial and vertical (bottom) directions, with a close fitting piston doing the compressing. Not like this real world.








Kevin Kelleher, PEME
Internal Mechanical Eng'g Consultant DuPont ESD Specialists

 

[kjoiner]

Hello,

I live near Atlanta and in addition to the I-85 fire that took out the bridge several years ago, we just had a 20 month closure of Cheshire Bridge road. A fire started under the bridge which then damaged and ignited a gas line which destroyed the bridge. From what I read, the bridge was steel and built in the 1930s.

Just like the I-85 bridge, no one really faces the consequences except the tax payer.

Kyle

 

[KevinK2]

Milliontown, I hope this video by the Foam Aggregate CEO gives you a better understanding of this Foamed Glass Aggregate that is being used, and the voids created when used like this app w/o significant compaction. Each cube has a common, 1-1/2" thickness, based on the mfg'ing belt conveyor process:

https://www.youtube.com/watch?v=3mdDeKTKB1I

Also, compaction is considered essential by AeroAggregates when the material is used as underlayment for roads, the only advertised application where it is supporting a load, per the company's video used by Penndot:

https://www.penndot.pa.gov/ProjectA...retate A New and Unique Lightweight Fill.pdf

Kevin Kelleher, PEME
Internal Mechanical Eng'g Consultant DuPont ESD Specialists

 

[JohnRBaker]

From looking at the live-stream below, it would appear that they're putting the finishing touches on the new road bed. If their goal is to have traffic crossing this temporary roadway by Saturday, I would say that they're going to make it with time to spare.

https://livestream.com/accounts/118...=false&defaultDrawer=&autoPlay=true&mute=true

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[KevinK2]

The far side looks completed, half the near side needs another layer and the paving machine is ready to start, couple of dump trucks full of paving material are already backed up.

Still a lot of work with the heavy barriers to create the final roadway, with transitions from multiple lanes to 3 each way.

Kevin Kelleher, PEME
Internal Mechanical Eng'g Consultant DuPont ESD Specialists

 

[TenPenny]

I'm fascinated by what they are doing now...a sweeper truck is making passes cleaning up the road surface; so far, it's been 4 trips over the same section...and the guys with brooms are sweeping more dirt onto the area that the truck has just covered. No, wait, it's 5 times so far...I have to admit, this is better than watching golf!

 

[Retiredat46]

Sweeping means they're getting ready for lane marking. I wonder how far back the transitioning from six to three lanes will begin, and if there will be any limitations on vehicle weight. I'm guessing they'll set the speed limit at 45 for the narrowest part, but enforcement will be very difficult.

 

[JohnRBaker]

If traffic is as heavy as they claim it is along that section of I-95, it'll probably be so heavy that speeds will already be pretty slow.

From the livestream, it looks like they've got the T-rails all in place to funnel the traffic down to the three-lane section on each side. Not sure haw far back they stretch but you can see that they're at least up to the narrowed section.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without