FIU Bridge Disaster

It is a terrible tragedy.  It is very premature to know the reasons for the collapse.   The experts will be examining all the information and this will take time.  Let’s be patient.

The bridge sits in front of the FIU university, which prides itself of its Civil Engineering Department.  Had the bridge been successful, it would have been used to promote the school and the Department.

The bridge traverses 8th Avenue.  I’ve been to FIU numerous times, and considered enrolling there.  There is a light at 107 Ave and 8th St, but it is still hazardous to cross, due to the many lanes of traffic.  The pedestrian bridge was considered after an accident where a pedestrian was killed.

Discussions  from outsiders as to the cause, are pure speculation. Still, questions are appropriate at this point.  Cracks were observed at the north end of the span, where the span attaches to the tower.  From photos of the accident,  it appears  the span completely separated from the tower at this juncture.

The span that collapsed was 174 ft long and weighed 940 tons.  This is 10,000 pounds per foot.   This would be the same as 135 bags of concrete each weighing 80 lbs per ft.  It just seems incredibly heavy.

The span was installed with the canopy.  I am interested to know why as it would add weight to the span and could have been added later.  The tower was a critical element in the structure, as the cable stays would support the bridge in tension.

The bridge might have been designed properly but the sequence of installation made it unsafe.  This is likely to be examined closely. It would seem that the northern span could have been installed first, as this simply would traverse a small lake.

A meeting was held with FDOT officials and the construction firm, on the morning of the disaster.  I am certain this will be part of the review and little is gain from trying to piece together what was discussed.    To avoid the disaster,  8th Avenue would have had to be blocked from traffic, causing an incredible traffic jam.

In the time between now and the review by FDOT, there will be a lot of comparisons to other bridge disasters.   How much of this is really relevant, I can’t say.    This bridge had a number of unique features, including the Accelerated Bridge Construction (ABC) methods, which may make comparisons to more conventional designs difficult.

I won’t go into the legal consequences.  There are hundreds of news stories out there, with excellent information.  Avoiding Monday morning quarter-backing is hard.  I will be patient.

Stay tuned,

Dave

 

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