Miami Bridge Collapse

My wife noted that yesterday’s bridge collapse near Miami, Florida was “horrible.” I think she’s right.

What is certain at this point, Friday afternoon, a bit over 24 hours after the incident, is that a structure collapsed and people died.

Others were injured, but are still alive.

Bridge Down Near Miami


(From BBC News, used w/o permission.)
(A pedestrian bridge at Florida International U. collapsed Thursday, March 15, 2018.)

At least six dead in Florida university bridge collapse
BBC News (March 16, 2018)

At least six people have been killed and nine others hurt after a footbridge collapsed near Florida International University in Miami.

“Police announced the deaths after rescuers spent the night searching for victims trapped beneath the structure.

“The 862-tonne, 174ft (53m) bridge fell over an eight-lane motorway on Thursday afternoon, crushing at least eight vehicles, police said.

“The bridge was erected on Saturday in just six hours….”

Monday morning quarterbacking has started. I’ll get back to that.

We don’t know how many folks died when that bridge fell. Four bodies had been recovered by yesterday evening. Two more bodies have been found since. We’re told that there are almost certainly more still under the wreckage.

Many or most of the fatalities apparently were in cars caught under the bridge. Folks in the cars had stopped for a red light.

Some Killed, Others Injured


(From BBC News, used w/o permission.)
(The bridge spanned Tamiami Trail, U.S. Route 41, west of Miami.)

Names of folks who were killed haven’t been officially released yet. At least one was a student at the university.

At least one person’s last known location was under the bridge. I understand that she was driving one of the crushed cars. She is almost certainly dead. I don’t know how many other folks are missing and possibly under the debris.

Some folks survived the collapse. I’ve seen nine given as the number. As usual in situations like this, priority is given to locating victims and sending survivors to hospitals. I expect we’ll see more exact numbers later, as rescuers and medics have a chance to file reports

Headlines, Assumptions and Memories


(From The Washington Post, via Grand Forks Herald, used w/o permission.)
(The structure would have been a cable-stayed bridge.)

The bridge was still under construction. If the job had gone smoothly, it would have been ready for use next year. Something, obviously, went wrong.

Some news outlets made headlines of safety violations that meant fines at least one of the companies involved. I don’t know what the implication was supposed to be. A history of careless or deliberately sub-spec work, maybe. What the facts are, I have no idea.

Implied ‘shoddy construction’ struck a chord with me. The town I grew up in badly-broken sidewalks for years after what I assume was the lowest bidder’s work got used.

The town’s specs for sidewalks said how deep the concrete should be. The new sidewalks were, in fact, that deep. And they were made of the right sort of concrete. After the job was done, we learned that inspectors had carefully measured depths of the forms: at the edges.

The contractor had cleverly added a slight bulge in the sand between the form edges. After it had been poured and set, the concrete looked fine. It was nicely leveled, and seemed to be ready for use.

The middle of the new sidewalks were mostly sand with a concrete veneer. They held together for several days. Several years later, the city had funds to pay for new sidewalks again. This time, apparently, measuring concrete depth all the way across.

My experience in an upper-Midwest town a half-century back is not proof that someone deliberately botched this construction project. I think it shows that folks can be dishonest, or daft. And that government inspections are only as good as the inspection procedures.

I think every detail of this project will be reviewed. Thoroughly.

As a Northeastern University professor said, this sort of thing isn’t supposed to happen. When it does, folks other than reporters and editors go to work, collecting and analyzing the evidence.

Sometimes they find a problem with a process that had seemed reasonable once, or had worked under other conditions. My experience is that far more often than not, procedures that don’t work as they should get changed. We do learn.1

Old Design, New Technique

The pedestrian walkway would have been a cable-stayed bridge.

The basic design goes back at least to 1595. It’s good for spans too short for cantilever bridges, but not long enough to need a suspension bridge.

Bridges aren’t the only long structures supported with a fan of cables from one or more towers.

The woodcut shows a telescope Johannes Hevelius built in the 1600s.

Quite a few 19th century bridges were cable-stayed. Some of them still stand. The Florida International University pedestrian overpass wouldn’t have been a ’19th century bridge,’ obviously. We’ve changed and refined the tech considerably.

One of the newer construction methods is supposed to reduce traffic congestion while the bridge is being built. It’s called rapid bridge replacement or accelerated bridge construction. A span gets built near where it’ll be used, then moved into position.2

That’s what’s supposed to happen. The newly-installed span is not, obviously, supposed to fall on top of folks waiting at a red light.

I’m quite sure there’s going to be lively discussion about whether that that technique should have been used, and how well it’s been tested. I hope at least some of the discussion is informed, using facts and analysis — not raw emotion.

A point mentioned but not explained in news that I’ve seen got my attention.

Apparently the collapsed span was in place, but not the cables which would have run between it and the support tower. I don’t know enough about the technology and construction methods to have an informed opinion about that.

Not unexpectedly, someone’s started talking about the possibility of legal action against someone in connection with the disaster. Maybe that’ll be justified, maybe not. Bad things happen, and sometimes it isn’t anybody’s fault.

I don’t see a point in playing a blame game. It’s a very human thing to do, though. (November 17, 2017)

It’s now late Friday evening here in central Minnesota. This blog is on UTC time, so it will have a “March 17, 2018” timestamp.

One final thought, and I’m done. Something from Luke:

“‘Or those eighteen people who were killed when the tower at Siloam fell on them—do you think they were more guilty than everyone else who lived in Jerusalem?'”
(Luke 13:4)

I’ve talked about disasters and making sense before:


1 News and views:

2 Background:

About Brian H. Gill

I'm a sixty-something married guy with six kids, four surviving, in a small central Minnesota town. I mostly write and make digital art. I'm only interested in three things: that which exists within the universe; that which exists beyond; and that which might exist.
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