Baltimore Bridge Collapse

[MightyGiants]

Unbelievable!   Workers were on the bridge and possible vehicles.  Beyond he initial tragedy this will create a long term problem in terms of use of the harbor and a major traffic issue for the east coast


https://x.com/ThatUchihaGuy/status/1772587001318875542?s=20

[MightyGiants]

https://x.com/rawsalerts/status/1772583287375954349?s=20

[Ed Vette]

It's surreal how that could have resulted in the complete demolition of the bridge. Even with the weight of that vessel, the other sections should have been independently supported. Linda told me she was on that bridge over a decade ago and it was scary back then.

[Jolly Blue Giant]

Last time such a disaster took place was on the Sunshine Skyway Bridge in the 80's...a bridge I've crossed many times. Hard to go over it now without recalling all the news at the time that shook the daylights out of me. Cars going over as well as a Greyhound bus with passengers

My mother was born and raised in St. Pete, so it was a regular visit as I grew up to meet up with relatives. Anyway, as soon as I saw that bridge in Baltimore go down in this morning's news, it snapped my memory right back into the collapse of the Sunshine Skyway. Horrible disaster

[MightyGiants]

https://x.com/postlocal/status/1772638010707767761?s=20

[MightyGiants]

It's surreal how that could have resulted in the complete demolition of the bridge. Even with the weight of that vessel, the other sections should have been independently supported. Linda told me she was on that bridge over a decade ago and it was scary back then.

Bridges are engineering marvels.  The problem with engineering marvels is that all the forces are balanced throughout the structure.  Take out one section using a massive cargo ship, and everything else will fail.

[Ed Vette]

Bridges are engineering marvels.  The problem with engineering marvels is that all the forces are balanced throughout the structure.  Take out one section using a massive cargo ship, and everything else will fail.

https://www.texasstandard.org/stories/fisherman-reveals-role-in-survivor-rescues-20-years-after-queen-isabella-causeway-collapse/

https://www.mysanantonio.com/news/local/texas/article/South-Padre-pauses-to-remember-bridge-collapse-2172603.php

[MightyGiants]

https://www.texasstandard.org/stories/fisherman-reveals-role-in-survivor-rescues-20-years-after-queen-isabella-causeway-collapse/

https://www.mysanantonio.com/news/local/texas/article/South-Padre-pauses-to-remember-bridge-collapse-2172603.php

That is a different type of bridge construction.   That type is essentially just planks of roadway laid on a series of supports.  You take out a section the other sections are unaffected. The bridge in Baltimore is a truss-style bridge.

With this bridge, there is also an arch, which makes the force distribution more complex.



If you watch the video as the main section collapses, it snaps in half at the next support; without the inner section to offset the forces of the outer section, that section just pulls itself off the untouched support.

[Jolly Blue Giant]

Bridges are engineering marvels.  The problem with engineering marvels is that all the forces are balanced throughout the structure.  Take out one section using a massive cargo ship, and everything else will fail.

Yes they are...fascinating feats of engineering. One of the smartest things they did when they rebuilt the Sunshine Skyway Bridge was to add massive concrete barriers before the bridge supports. So if a ship gets off course (because of wind and other climate issues - or just play human error), the barriers take out the ship before the ship takes out the bridge. Very few bridges have that safety function. I would think all big bridges (Golden Gate, George Washington, etc., would have those barriers

[Jolly Blue Giant]

That is a different type of bridge construction.  That type is essentially just planks of roadway laid on a series of supports.  You take out a section the other sections are unaffected. The bridge in Baltimore is a truss-style bridge.

With this bridge, there is also an arch, which makes the force distribution more complex.



If you watch the video as the main section collapses, it snaps in half at the next support; without the inner section to offset the forces of the outer section, that section just pulls itself off the untouched support.

Even before taking advanced engineering courses, I learned that the strongest way to build a race car cage, or horizontal beams (like a gantry), construction cranes, trusses, etc., was to use "triangles", that give it incredible strength. I was taught that as a teen when I worked with a stock car driver and we were building a cage around the driver. Ever notice overhead signs over multi-lane highways are nothing more than an enormous number of triangles? https://letstalkscience.ca/educational-resources/backgrounders/why-a-triangle-a-strong-shape

The first thing I noticed on the Baltimore Bridge was the "H-Shaped" foundations that struck me as an engineering flaw

[MightyGiants]

Yes they are...fascinating feats of engineering. One of the smartest things they did when they rebuilt the Sunshine Skyway Bridge was to add massive concrete barriers before the bridge supports. So if a ship gets off course (because of wind and other climate issues - or just play human error), the barriers take out the ship before the ship takes out the bridge. Very few bridges have that safety function. I would think all big bridges (Golden Gate, George Washington, etc., would have those barriers

Ric,

It appears three factors are at play (to explain why all bridges lack this sort of protection)

1)  Ships have grown substantially in size

2)  The cost is considerable for those sorts of protection systems

3)  Lack of political will.  Perhaps this very high profile disaster will change that

[MightyGiants]

Even before taking advanced engineering courses, I learned that the strongest way to build a race car cage, or horizontal beams (like a gantry), construction cranes, trusses, etc., was to use "triangles", that give it incredible strength. I was taught that as a teen when I worked with a stock car driver and we were building a cage around the driver. Ever notice overhead signs over multi-lane highways are nothing more than an enormous number of triangles? https://letstalkscience.ca/educational-resources/backgrounders/why-a-triangle-a-strong-shape

The first thing I noticed on the Baltimore Bridge was the "H-Shaped" foundations that struck me as an engineering flaw

Ric,

Nothing short of the system you posted in that picture would be able to withstand the force of a 900+ foot loaded cargo ship plowing into it.

[MightyGiants]

The way I figure it, clearing navigation will take a couple of weeks (first, the search and rescue efforts need to finish) as they will need to get large floating cranes in the area to remove the debris.  I figure at most a month


Replacing the bridge will take years, probably 5 years, give or take a couple of years.

Baltimore is the biggest port of importing cars so likely car prices will take a short term hit

[T200]

The way I figure it, clearing navigation will take a couple of weeks (first, the search and rescue efforts need to finish) as they will need to get large floating cranes in the area to remove the debris.  I figure at most a month


Replacing the bridge will take years, probably 5 years, give or take a couple of years.

Baltimore is the biggest port of importing cars so likely car prices will take a short term hit

Not to mention, the Baltimore port is where servicemembers ship their vehicles through when going to and returning from overseas.

[Jolly Blue Giant]

Now I'm in my "engineering mode" and will share this last bit of potential interest

When constructing long structures holding large signs that are subject to incredible winds at times, you never see one of these structures fail...even in hurricanes when buildings around the same area are reduced to rubble. Lightweight triangle structures are the heart of architects' arsenal of understanding strength. Notice that these gantries over highways don't even sag 

For the last 50 years of my life, I cannot help myself but to always look at the structure overhead signs on highways as well as bridges. It's innate to me. Actually fascinating...to me anyway





Even the support columns are built with triangles


Imagine the force of wind against these signs