A Female-Led Construction Company Built The Florida Bridge That Collapsed

[Tuttle]

https://squawker.org/culture-wars/a...pany-built-the-florida-bridge-that-collapsed/

 

[DustyJarCoffee]

Sasuga. w*Men.

 

[Deleted member 776]

Also that company likely got the contract to build the bridge because it was a minority business (Hispanic by the looks of it) and would find itself awarded construction contracts on that basis not on their competence to do the job.

If you watch the video its very weird how the bridge just literally drops. All structures whether its the empire state building or the George Washington bridge right down to your garden shed will have a degree of flex in them, its partly why they are so strong. The empire state building probably sways up to a meter either way in strong winds on the 102nd floor. You walk across the George Washington or Golden gate Bridge and you will feel the entire bridge structure bouncing under the traffic load.

This bridge just drops. In addition a few hours prior to the collapse a man passing under it reported a very loud snapping noise.

This is a post tensioned truss structure. Where high tension steel rods are used to tension two thin pieces of concrete which make up the deck (which has poor properties when used in tension) toegther so that they act like a much thicker, stronger more rigid structure. Large hydraulic jacks are used to tension the rods. The steel used in the tensioning rods would have a degree of elasticity but once over tensioned it will become brittle and loose its elasticity and snap very easily. Which is likely what the man heard walking under it. Once it snaps its basically just a brittle pice of concrete which can barely hold its own weight up. Once the support tower and the staying cables were built if the post tensioning rods had snapped it would have been ok. My guess is they knew something was up with it but decided to reopen the road and solve it later. Big mistake.

I've seen pictures of the aftermath and you can see some of these tensioning rods sticking out of the remains of the bridge quite a way with the blue hydraulic tensioning jacks on the end of the rods. Which suggests to me a catastrophic failure snapped them and shot half the rod out.

EDIT:

Highlighted in red. That is one of the post tensioning rods with the hydraulic tensioning jack on the end of it. The fact its stuck out like that suggests to me it probably shot out of there with some force when the rod snapped in the channel. Notice how it isn't mangled like the rest of the steelwork.

 

[Tuttle]

Also that company likely got the contract to build the bridge because it was a minority business (Hispanic by the looks of it) and would find itself awarded construction contracts on that basis not on their competence to do the job.

Definitely.

This bridge just drops. In addition a few hours prior to the collapse a man passing under it reported a very loud snapping noise.

I had a construction science teacher say that if you see concrete spalling on the underside of something like that to run because concrete fails catastrophically. That seem overly general, though, especially when steel-reinforced. If it was engineered to be a slight arch that might have been a fall-back but the ends were probably not secure so they would just slide out.

This is a post tensioned truss structure. Where high tension steel rods are used to tension two thin pieces of concrete which make up the deck (which has poor properties when used in tension) toegther so that they act like a much thicker, stronger more rigid structure. Large hydraulic jacks are used to tension the rods. The steel used in the tensioning rods would have a degree of elasticity but once over tensioned it will become brittle and loose its elasticity and snap very easily. Which is likely what the man heard walking under it. Once it snaps its basically just a brittle pice of concrete which can barely hold its own weight up. Once the support tower and the staying cables were built if the post tensioning rods had snapped it would have been ok. My guess is they knew something was up with it but decided to reopen the road and solve it later. Big mistake.

Ah.

I've seen pictures of the aftermath and you can see some of these tensioning rods sticking out of the remains of the bridge quite a way with the blue hydraulic tensioning jacks on the end of the rods. Which suggests to me a catastrophic failure snapped them and shot half the rod out.

EDIT:

Highlighted in red. That is one of the post tensioning rods with the hydraulic tensioning jack on the end of it. The fact its stuck out like that suggests to me it probably shot out of there with some force when the rod snapped in the channel. Notice how it isn't mangled like the rest of the steelwork.

[/QUOTE]

Very interesting.

 

[Deleted member 776]

I had a construction science teacher say that if you see concrete spalling on the underside of something like that to run because concrete fails catastrophically. That seem overly general, though, especially when steel-reinforced. If it was engineered to be a slight arch that might have been a fall-back but the ends were probably not secure so they would just slide out.

Its certainly not the best sign. Its a bad problem. Especially in Northern climates when you have freeze thaw action and a lot of salt gets dumped on the roads in the winter months. Once its gets into concrete its like cancer. In London just before the Olympics they had to close an elevated section of the M4 motorway because it was in such a bad state. Several other sections have had emergency work done on them the last few years to stop them collapsing.

My guess is the upper and lower deck of this bridge were designed to be a slight arch. They also look like they used pre-stressed construction for each deck. You can see the cables sticking out the end in some pictures. It may very well be that they fucked up with the pre-stressing or used sub standard concrete or steel work and that contributed to it. Incidents like these normally have a combination of factors leading to such a total failure.

 

[Indari]

Also that company likely got the contract to build the bridge because it was a minority business (Hispanic by the looks of it) and would find itself awarded construction contracts on that basis not on their competence to do the job.

If you watch the video its very weird how the bridge just literally drops. All structures whether its the empire state building or the George Washington bridge right down to your garden shed will have a degree of flex in them, its partly why they are so strong. The empire state building probably sways up to a meter either way in strong winds on the 102nd floor. You walk across the George Washington or Golden gate Bridge and you will feel the entire bridge structure bouncing under the traffic load.

This bridge just drops. In addition a few hours prior to the collapse a man passing under it reported a very loud snapping noise.

This is a post tensioned truss structure. Where high tension steel rods are used to tension two thin pieces of concrete which make up the deck (which has poor properties when used in tension) toegther so that they act like a much thicker, stronger more rigid structure. Large hydraulic jacks are used to tension the rods. The steel used in the tensioning rods would have a degree of elasticity but once over tensioned it will become brittle and loose its elasticity and snap very easily. Which is likely what the man heard walking under it. Once it snaps its basically just a brittle pice of concrete which can barely hold its own weight up. Once the support tower and the staying cables were built if the post tensioning rods had snapped it would have been ok. My guess is they knew something was up with it but decided to reopen the road and solve it later. Big mistake.

I've seen pictures of the aftermath and you can see some of these tensioning rods sticking out of the remains of the bridge quite a way with the blue hydraulic tensioning jacks on the end of the rods. Which suggests to me a catastrophic failure snapped them and shot half the rod out.

EDIT:

Highlighted in red. That is one of the post tensioning rods with the hydraulic tensioning jack on the end of it. The fact its stuck out like that suggests to me it probably shot out of there with some force when the rod snapped in the channel. Notice how it isn't mangled like the rest of the steelwork.

r u some kind of builder?

 

[Deleted member 776]

r u some kind of builder?

No. But i know a bit about engineering. One of my grandfathers was a mechanical engineer, the other was a structural engineer. My uncle was a builder. My father was an electrical engineer. I work as multi skilled maintenance although i don't have any formal engineering qualifications. I have my grandfathers books and notes and i helped him with projects and worked for my uncle sometimes growing up.

 

[Deleted member 3291]

No. But i know a bit about engineering. One of my grandfathers was a mechanical engineer, the other was a structural engineer. My uncle was a builder. My father was an electrical engineer. I work as multi skilled maintenance although i don't have any formal engineering qualifications. I have my grandfathers books and notes and i helped him with projects and worked for my uncle sometimes growing up.

might as well go for a bachelors in eng in your case, you seem like you would do good with that amount of dedication