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

[JohnRBaker]

I was just watching the livestream and it looked like a white car was driving on what I assume was the Northbound side and it was being chased by a police car with it's red and blue lights flashing, catching-up with the white car just past the new section of roadway.

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

 

[Retiredat46]

I just saw the painting truck go by applying the last of the lane markings. I watched several work trucks go by, too. People driving standard full-size pickups should be pretty comfortable as long as they're not sandwiched between two big rigs. For someone like me who hasn't driven on an interstate in several years or over fifty mph in several months, it might be a white knuckle experience.

 

[Milliontown]

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.

I am aware of AeroAggregate and have been before this incident. My job working on Embankment Dams has given me a lot of experience working with compaction, aggregate, and compaction of large aggregate. Voids will be present for any aggregate. If this were to be backfillled with gravel there will still be voids, same with sand or finer soils. There are also voids present within the aggregate. These voids are trapped within the glass media and cannot move without breaking the entire aggregate block.

As I have tried explaining, these voids between blocks are and always will be present. Compaction of aggregate this large does not need very much compactive effort. The plate compactor being used in the presentation linked imparts a very low compactive effort, and combined with the fact that small of equipment being used on 12" lifts tells me that the compactive effort needed for these aggregate is low. As more material is placed, the lower lifts will also compact. Additionally, I believe the plate compaction shown is just used to lock in the particles on the upper portion of the 12" lift as the lower portion would be locked in during placement and spreading, with some equipment running over it. I believe this to be true for this repair as well, as the equipment being used to spread the material will also impart a compactive effort.

Another thing I have noticed in the presentation is the lack of larger compaction equipment. Again this tells me that the compactive effort needed is low, and that large equipment would actually break down the particles.

Would I have done it this way on a dam? Maybe not, but again this is an emergency temporary fill to get lanes open.

 

[KevinK2]

Milliontown,

"My job working on Embankment Dams has given me a lot of experience working with compaction, aggregate, and compaction of large aggregate."

If that included using the this specific aggregate, emabankment dams is an approved use of this material, using the layered approach. It is very stable in shear.


"Voids will be present for any aggregate. If this were to be backfillled with gravel there will still be voids, same with sand or finer soils."

I agree on the stable voids within the expanded glass particles. My point was the % voids per cubic foot, vary with aggregate, just like BSC vs FFC intersticial site volume in molecules: "The interstitial site in the BCC iron is smaller than the interstitial site in the FCC iron."

Unlike other aggregate, this suff has a constant thickness of about 1-1/2 inch, which, imho, contributes to less nesting, and larger voids.

"The plate compactor being used in the presentation linked imparts a very low compactive effort, and combined with the fact that small of equipment being used on 12" lifts tells me that the compactive effort needed for these aggregate is low."

Two 12" lifts were only used when they created a layered topping to the finished, wire caged support system, starting with ~12" compacted apparent black top, then compacted foam aggregate, another black top, then foam, final blacktop. This may have been just along the outer sides, with less layers in the middle.

Those observing the hand pushed compactor during the support buld up noted it was only used when the full ~24" unit rectangle was filled, likely to save time. And when a rubber tracked small tractor ran the length, it was pitching up & down on the irregular fill. This would contribute to even more voids pcf then just a pile of this aggregate.

Without a political deadline established early, and boasted about by Governor Shapiro at every press opportunity, including one with Biden, a better job would have happened.

I still hope it works.




Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

 

[Retiredat46]

We're about to find out how well it'll perform. They just had the reopening ceremony at the construction site, and traffic will soon start flowing with no additional weight restrictions.

Let's investigate setting up a GoFundMe page to buy PENNDOT a decent camera and related equipment for their live feed. What they have is pathetic with the blurriness, herky-jerky motion, and frequent test screen performance.

 

[KevinK2]

Design Loading Assumed ?

Most states like Delaware, limit semi trailer weight to 68,000 max for an 18 wheeler, with 34,000 lbs at each double axle. In a ~worst case senario, 6 rows of slow moving traffic, with bumper to bumper semis, that's 384,000 at center span possible, made worse if semis are before & after these 6 ones centered.

Average/typical loading will be much less.


Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

 

[JohnRBaker]

Yes, as seen on the livestream, traffic is flowing on what I think is the Northbound lane. I didn't see anything in the other lane and you still see lots of traffic on the surface street running parallel to the what I think is the Southbound lane. Well, this means that at least for one lane, they're open a day early as the last report that it was scheduled for the weekend.

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

 

[JohnRBaker]

And the traffic appears to be moving at normal speeds, but it's not very heavy yet. And it appears that there's no restrictions as I've seen 18-wheelers passing in the lane that's open. And now that traffic is moving over the new roadway, it appears to pretty close to normal width lanes, so it looks like the did a good job.

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

 

[JohnRBaker]

Traffic is now moving in both directions and it's starting to get heavy. There are what looks like some DOT vehicles monitoring traffic near repaired roadway.

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

 

[Retiredat46]

I looked at the live feed on my tablet where I can easily zoom in for a closer view. It's not encouraging. The edges of the asphalt appear to be breaking up where it meets the concrete in the places where the tires run most of the time. The worst places are several inches wide and deep and over a foot long. I wish someone else would take a look to confirm what I'm seeing or tell me I'm wrong.

 

[JohnRBaker]

It's starting rain and it's not very clear when it comes to details.

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

 

[sgw1009]

The camera system being used may be fairly high resolution, but there is a tremendous amount of compression being done to keep the required bandwidth low, so the pictures we are getting are fraught with artifacts.

 

[EdStainless]

The location that look odd to me is longitudinal portion of the joint that is right in the left-hand tire path in the right lane.
But until it dries off it will be difficult to tell if there is really an issue.
Even if they have to close it Sun night for resurfacing, they will still be way ahead of the game.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Retiredat46]

The places that looked iffy earlier now look fine. I think sgw1009 must be correct about it being artifacts of the video feed. Thanks for the explanation.

 

[FacEngrPE]

Just Posted
NTSB Ongoing Investigation
Mode Highway
Investigation No HWY23FH014
Event Date 6/11/2023
Location I95 Philadelphia, PA

https://www.ntsb.gov/investigations/Pages/HWY23FH014.aspx[/URL]]What Happened
​​​​This information is preliminary and subject to change. Release date: 29​ June 2023

​​On Sunday, June 11, 2023, about 6:17 a.m. eastern daylight time, a 2017 International truck-tractor in combination with a 2004 Heil Specification Package 406 tank-trailer (combination vehicle), operated by a 53-year-old driver, was exiting Interstate 95 (I-95) northbound on the Cottman Avenue off-ramp in Philadelphia, Pennsylvania. At this location, I-95 was an eight-lane divided highway with four lanes each in the northbound and southbound directions.

The combination vehicle, operated by an affiliate carrier leased to Penn Tank Lines, was transporting about 8,500 gallons of gasoline from Wilmington, Delaware, to a gas station located on Oxford Avenue in Philadelphia. The posted speed limit on I-95 in the vicinity of the crash was 55 mph, and the Cottman Avenue off-ramp was posted with a 25-mph speed limit and truck rollover warning sign.

The truck driver was unable to maintain control of the combination vehicle on the off-ramp. The truck rolled over and subsequently caught fire under the northbound lanes of the I-95 overpass.

As a result of the rollover and subsequent fire, the driver was fatally injured. The fire caused the northbound lanes of I-95 to collapse onto the Cottman Avenue off-ramp. The southbound lanes of I-95 were significantly damaged by the fire.

​Parties to the National Transportation Safety Board (NTSB) investigation include:

​Federal Motor Carrier Safety Administration
Pipeline and Hazardous Materials Safety Administration
Pennsylvania State Police
Pennsylvania Department of Transportation
City of Philadelphia, Pennsylvania

All aspects of the crash remain under investigation while the NTSB determines the probable cause, with the intent of issuing safety recommendations to prevent similar events.

 

[stcbus]

Without a political deadline established early, and boasted about by Governor Shapiro at every press opportunity, including one with Biden, a better job would have happened.

Aww it hurts you so much to actually see a competent government doing what a government should do.

This was handled by lots of experts outside of the lane PENDOTT or whatever. And certainly more capable than the opinions of me or a so called mechanical engineer.

 

[FacEngrPE]

Six months after a truck fire collapsed an I-95 bridge in Philadelphia, traffic moved from the temporary roadway to the recently completed outer lanes ahead of schedule on Nov. 6.

Nov 6 23 PenDOT update (Linked page is regularly updated with progress)
Traffic shifted from the temporary roadway onto the newly completed outer travel lanes of the new permanent bridge on Interstate 95. Crews will move and reset temporary construction barriers and repaint lane markings before shifting three lanes of northbound vehicles and three lanes of southbound vehicles onto the outer sections of the new span.