Do you think global warming was a factor in the MN bridge collapse?

Question

Notice that the question says "contributed to", not "caused".

Joseph Romm, for whom I have a lot of respect (former Acting Assistant Secretary of the U.S. Department of Energy and author of 'The Hype About Hydrogen' and 'Hell and High Water') writes:

"the question isn’t whether modern bridges are built to cope with extremes, but whether more extremes than anyone might have designed for contributed to the unusual collapse of a “structurally deficient” bridge. As noted, the NTSB itself has not ruled out the weather as a contributing factor."

http://climateprogress.org/2007/08/06/did-climate-change-contribute-to-the-minneapolis-bridge-collapse/

So I'm curious as to what people think about this. Could the current climate change be significant enough to have contributed to this bridge's collapse, or is this theory a stretch?

Answer 1

Interesting article.

It would definitely be a stretch. But hotter weather can cause buckling of the pavement (the bridge "structure" will have expansion joints so will not be negatively affected by temperature change). I have heard that they were using heavy machines to do maintenance on the road surface and that with the age of that bridge it just isn't built for the traffic and heavy machines that cross it / maintain it.

So increased heat due to GW could have made the asphalt buckle and the equipment to repair that surface damage caused structural damage; but overall it was the design, age and overuse of the bridge that caused it to collapse, not Global Warming.

One thing to be learned from this:

When building strucures, engineers design the strength based on "expected" traffic, use, lifespan, weather, etc. Things change! The changes due to GW are not yet incorporated into the National Building Code (the 100 year storm is now the 10 year storm). California is working on a new construction Standard but it needs to be applied nationally and globally.

I.e. even the Three Little Pigs are smarter than Geo Bush!

Answer 2

No, it's unlikely that global warming had anything to do with it.

Structural Deficiency is actually a pretty good statement of the cause, as the NTSB sees it in their preliminary examination.

Structural deficiency is a scale (0-100) used to rate bridges and other structures. It combines two factors: issues or flaws in the original design, and damage, wear or weathering of the materials. This bridge had a structural deficiency rating of 50. It was in the 47th year of a 50 year design lifetime. In the USA, it was an average bridge.

They will be examining the original design for "we wouldn't do it that way today" type issues, but most of that should already be known and included in it's rating. They'll also look at the past inspections, as a record of how it was aging and being maintained. Some cracks for example, would be expected over time. If and how they were dealt with alters the rating. They are also looking at the weather on a day by day basis since the last inspection. Weather has known effects in terms of expansion and contraction, etc. All this data together should give them a pretty good idea about whether the structural deficiency rating had changed since the last inspection.

Because they have video tape of the collapse as it occurred, they already know where the first failure occurred, and how it progressed from there. I'm sure they'll be focusing on the key points. I heard a report that it may have had more weight than normal on it at the time, due to the construction equipment doing some repaving. They'll have a pretty clear picture once all that data is put together.

I know the usual suspects on here were hee-hawing away when it happened, suggesting people would attribute it to global warming. My heart goes out to anyone in that community reading those posts. It shows their social skills are on par with their science. I haven't heard anyone other than those folks try to bring Global Warming into that tragedy. If some turn up, I'm sure it will be sources on the same level as our pet contrarians.

Answer 3

"NTSB has not ruled out WEATHER as a contributing factor." Weather - NOT climate - how many times does that need to be clarified? BTW, the NTSB is not in the habit of ruling things out until it has had a thorough review of all evidence - the hallmark of prudent and sound investigation.

And, no, a structural engineer could have easily looked at historical temperature values for the Twin Cities area and seen that there has been much higher temperatures and for longer extended periods than what has occurred since the building of the bridge - only four of July's hottest days occurred after 1970. Almost 1/3 of July's record highs (9 days of triple digits - eight in a row) happened in 1936, including the all time high of 108 F. 1936 also holds the August record high of 103 F. http://www.crh.noaa.gov/mpx/Climate/MSPClimate.php

It is more than ridiculous for someone to commit to print such nonsense without the very simple research it takes to see that the idea is totally baseless.

Answer 4

Imo, the bridge collapse was due to the work being done. Somehow the construction weakened the structure in the work area enough to put more stress on the rest of the structure, thus causing the the bridge to collapse.

Imo, Global Warming had nothing to do with the bridge collapse.

Answer 5

It is a minor contributing factor. Mayby 0.001% (so really nothing)

Bigger contributing factors are for example acid pollutions which increase the metal corrosion, especially in steel reinforced concrete.

The design of such bridges uses generally a safety factor of 4 meaning that the bridge could in theory handle a load that is 4 times what the maximum it will have to face will be (static+dynamic load)

The main problem is probably that older materials and design were not built to last since there was no long term experience. Moreover no computer simulations made the design themselves vulnerable to miscalculation. This does not happen anymore nowadays using finished-elements-method to simulate.

Answer 6

No, The problem resulted from ignoring that any building or structure requires maintenance. It doesn't matter if it's a bridge or a house. Ignore it it and it will fail in due time. The people we elect would rather have big new bright shinny pet projects than to focus on the less glamorous things like bridge or building repair. It's not a money issue just where they place their priorities.

Answer 7

It's an insane premise. In the last few years, Minnesota has had unusually warm summers...we're talking in the 90s! If a bridge cannot handle temperatures in the 90s, something is wrong with the construction.

Answer 8

I don't think so but when it's cold outside + then it gets warm things get cracked or weaker(from the expanding and constacting) it could of made it crack and weaken then from then all the weight of the cars/ traffic, so it could of contributed to some point.

Answer 9

No, I do not believe that global warming was a factor. Most definitely theory stretching to new lengths.

Answer 10

As long as the specter of fear is held over the public, politicians will have the ability to extort more money from the public.

To quote H.L. Mencken: "The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary."

Now there's claims that "global warming" is going to cause more volcano's.