Bridge collapse in Florida

[GreenLantern2814]

https://www.google.ca/amp/s/amp.theg...ollapse-latest

Didn't see a thread about this but a bridge on the FIU campus collapsed days after it was put in place. From what I understand, this portion was designed to be completed in a few hours. I've read some comments that spoke of the walkway being essentially unsupported, but that doesn't mean anything.

Awful, awful tragedy.

[darockwilder]

That is brutal.

[Johnny Makarov]

It's spring break down there or it would have been way worse!

[missdpuck]

Two companies involved in building the bridge had several previous violations elsewhere


Previous violations for companies behind bridgehttps://www.wptv.com/news/region-c-palm-beach-county/west-palm-beach/companies-behind-fiu-bridge-have-record-of-previous-violations


Sent from my Princess phone

[missdpuck]

Originally Posted by missdpuck

Two companies involved in building the bridge had several previous violations elsewhere


Previous violations for companies behind bridgehttps://www.wptv.com/news/region-c-palm-beach-county/west-palm-beach/companies-behind-fiu-bridge-have-record-of-previous-violations







Now 4 confirmed dead.



http://wpbf.com/article/pedestrian-b...446651?src=app


RIP.


Sent from my Princess phone

Sent from my Princess phone

[Northendzone]

Horrible story.

6 hours to install a bridge of 175 feet, seems very fast. The lawsuits will be flying over this one.....

[Ahuch]

Originally Posted by Northendzone

Horrible story.

6 hours to install a bridge of 175 feet, seems very fast. The lawsuits will be flying over this one.....

On the flip side, it feels like they've been building that new bridge over Deerfoot by 17 ave for about a year now

[GreenLantern2814]

Originally Posted by Ahuch

On the flip side, it feels like they've been building that new bridge over Deerfoot by 17 ave for about a year now

See, that sounds like it makes sense. It's a bridge.

[You Need a Thneed]

Originally Posted by Northendzone

Horrible story.

6 hours to install a bridge of 175 feet, seems very fast. The lawsuits will be flying over this one.....

They talk about this bridge being a “fast build”, but from what I can tell, it’s not too far out from what often happens with bridges. Yes they moved that huge structure all into place at once, but there was a lot more work to do on the bridge yet.

That being said, this bridge was supposed to look like a cable stayed bridge in the end, which, from how this was constructed, was essentially cosmetic. I don’t understand why someone would want to design a bridge that way.

The whole building method was supposed to eliminate disruption, but I don’t understand why a little bit more standard girder erection is too disruptive. Anyone around here been disrupted by the new bridge construction over Deerfoot? A couple of overnight road closures isn’t the end of the world. They had a road closure here too.

I’ve seen some photos that make this definately look like a structural failure in the main truss that was just put into place.

[You Need a Thneed]

Here’s a rendering of the finished bridge:



It looks like it’s supposed to be supported by the cables, but the cables weren’t in place yet, such a confusing nstallation method - seems overly complicated to me.

The various stresses on that main truss are much different on supporting itself temporarily, vs being supported on the cables. I suspect that the problem is that this span wasn’t strong enough to support itself without the cables.

[You Need a Thneed]

Also, what a terrible looking bridge design, IMO.

[afc wimbledon]

Originally Posted by missdpuck

Two companies involved in building the bridge had several previous violations elsewhere


Previous violations for companies behind bridgehttps://www.wptv.com/news/region-c-palm-beach-county/west-palm-beach/companies-behind-fiu-bridge-have-record-of-previous-violations


Sent from my Princess phone

The free market solves everything once again.

[You Need a Thneed]

In summary, if that truss can support itself without the cables, why put the cables on?

If the bridge can’t support itself without the cables, why was it put in place without them?

It really looks to me like it was designed to be held up by the cables, not to support itself. If the trusses were supposed to go in before the cables, the truss should have been on shoring until the time when the cables were all in, with the truss on the other side in place as well. As a cable stayed bridge, you can’t build just one side of the cables first, you have to go back and forth from side to side, as the weight from one side braces the other side.

This bridge seems to be like a very flawed design if the intention is to minimize disruption. If the bridge is actually supported by the cables, there is no way to build it without major disruption to the road below.

[Snuffleupagus]

Senator Rubio stated the cables were being tightened at the time of the collapse. how this road wasn't closed until the bridge was completed and safety checked is beyond comprehension.

Edit:

update. at least 6 dead now

[Wormius]

I actually though the engineering standards were supposed to much higher in the US. At least obtaining your PEng / PE was supposed to be more onerous.

Anecdotally though I was kind of surprised what is allowed in the US for example with the electrical code vs here in Canada. My re-wiring job would have been made a lot easier if I could have used some of the devices that the US apparently allows.

[You Need a Thneed]

Originally Posted by Snuffleupagus

Senator Rubio stated the cables were being tightened at the time of the collapse. how this road wasn't closed until the bridge was completed and safety checked is beyond comprehension.

Edit:

update. at least 6 dead now

Perhaps something to do with post tensioning cables within the deck itself. On the pictures of the rubble, there’s no sign of any cable stays, or any tower that holds them up. They were not in place yet.

Here’s a quick and ugly markup of what existed when it collapsed:

[Locke]

Beware the Ides of March?

[CaptainCrunch]

I heard on the news that this isn't the first time the company had a bad build.

[troutman]

My hockey buddies last night were talking about the Iron Ring that Canadian engineers wear (my Dad was proud of his):

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

The ring symbolizes the pride which engineers have in their profession, while simultaneously reminding them of their humility. The ring serves as a reminder to the engineer and others of the engineer's obligation to live by a high standard of professional conduct.

Many incorrectly believe that the rings are made from the steel of a beam from the first Quebec Bridge, which collapsed during construction in 1907.

[llwhiteoutll]

Originally Posted by Snuffleupagus

Senator Rubio stated the cables were being tightened at the time of the collapse. how this road wasn't closed until the bridge was completed and safety checked is beyond comprehension.

Edit:

update. at least 6 dead now

If a post-tension cable snapped while they were re-tensioning it, that could explain a mid-span collapse. There was mention of tension jacks being visible in some of the pictures and Rubio's tweet about the cables slackening also supports it.

As for leaving the road open with an unfinished bridge in place. It's not abnormal, that's exactly what is going on with the BRT bridge over Deerfoot. The girders are placed on their bearing plates and braced off to the pier and the permanent braces placed between the girders. Deck is poured (partial or full road closure) and then the whole thing will be post-tensioned with Deerfoot open. In the Florida case, with aesthetic cable stays only, the whole span would have been designed to be supported by the piers and would have been fine to leave installed with bracing.