295 Retaining Wall Failure in Bellmawr, New Jersey 2

[MTNClimber]

https://6abc.com/i295-retaining-wall-bellmawr-new-jersey-rt-42-nj-dot/10448444/

Looks like a nice global stability failure. My contact believes the wall is supported on rigid inclusions by Menard. What a mess.

 

[JohnRBaker]

The report makes it sound like this collapse has had a major impact on traffic, but from the photos, it looks like that section of roadway was still under construction. It's not clear if that section of highway was even being used when the roadway collapsed.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

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

 

[hokie66]

John, I think it is the roadway below that is impacted, not the one on top which is under construction.

 

[FacEngrPE]

There has been a large amount of rain this spring on the east coast (and spring just started on March 20).
Previous discussions here that pointed out that this type of retaining wall is sensitive to management of runoff.

https://www.eng-tips.com/viewthread.cfm?qid=472222

 

[hokie66]

At first glance, I thought it was a typical Reinforced Earth structure. But they aren't discrete panels, and are not oriented the way that type wall is typically built. So does anybody know what it is? Whatever it is, this is not a good case study.

 

[FacEngrPE]

Short video from a different direction.

https://www.fox29.com/news/i-295-lane-closure-after-retaining-wall-partially-collapsed

This is not my expertise, just looking at the pictures the block arrangement looks similar to GeoMega MSE Wall as shown here HITEC Finalizes Comprehensive Technical Review of GeoMega MSE Wall System

 

[Ingenuity]

At first glance, I thought it was a typical Reinforced Earth structure. But they aren't discrete panels, and are not oriented the way that type wall is typically built. So does anybody know what it is?

The classic Reinforced Earth wall panels are cruciform in shape, but they also come in square and rectangular panels too.

The photo above by FacEngrPE looks like a RE-type (mechanically stabilized earth) wall.

As I understand, GeoMega (referenced above by FacEngrPE) is a Reinforced Earth wall product, using a geosynthetic tensile strip. I am not sure if this project in NJ used such reinforcement.

 

[hokie66]

Right, with the better resolution photo, I can see that the rectangles are discrete panels. And in the original photo at the top of the wall, I think I can see some strips. One critical thing in this type wall is the quality of the backfill which forms the gravity retaining element. The Reinforced Earth company has quite strict criteria, and if the right material is not easy to obtain in the vicinity of the construction, temptation can be to use what is available.

 

[JohnRBaker]

At least the 'wall' appears to have retained its tensile integrity as it did not rupture, but rather is looks like it slide down the hill. Perhaps the ground that failed was not what was used as the backfill, but rather what the structure was built on top off. just thoughts from an interesting observer.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

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

 

[hokie66]

The concrete panels in the photos are only the facade of the gravity retaining structure. Their primary structural purpose is to prevent erosion of the reinforced mass of earth behind the face. But you are correct, it is possible or likely that an unstable bearing condition below led to the failure.

 

[MTNClimber]

It looks like it could of been a global stability issue which is part of the external stability check an engineer does while designing an MSE wall. To solve this, the reinforcement length would need to be longer which is why you don’t see any reinforcement sticking out of the scarp in my original post.

 

[ACtrafficengr]

Can I assume there's no reasonable way to repair the damage other than take it apart and start over?

My glass has a v/c ratio of 0.5

Maybe the tyranny of Murphy is the penalty for hubris. -

http://xkcd.com/319/

 

[JedClampett]

Not only the damaged part would have to be removed, but probably the adjacent portion, too.
No owner in the world would accept a identical design to one that failed during construction.

 

[bones206]

Google maps link: Link Enable "globe view" for an interesting look at the pre-collapse construction.

 

[bones206]

 

[MTNClimber]

Looks like that area has been worked over a few times.

Coincidentally this aerial from 2016 has two slope failures where the wall ended up being constructed.

 

[hokie66]

Tough site, and they didn't figure it out.

 

[FacEngrPE]

The wet weather probably helped. Rainfall for Philadelphia, PA for march 2021 (closest weather station,.)

https://www.wunderground.com/history/monthly/us/pa/philadelphia/KPHL/date/2021-3[/URL]]

 

[MTNClimber]

Water is usually the reason for wall failures. The odd thing is, you can see the ground was paved with catch basins to remove the water from the area. One would think that water shouldn’t of been allowed to infiltrate into the ground behind the wall.

 

[bones206]

Maybe retaining wall drains discharging onto the slope?