This seems like an easy excuse for what happened here. If you can't maintain those 450 bridges, then don't keep 450 bridges. Remove 150 of them and maintain the other 300. You can't just ignore 450 bridges and hope nothing goes wrong because you can't afford to maintain 450 bridges.
Anything is better than people on a collapsing bridge, obviously. But you can only fence it off when you know its too bad. Checking that can be very expensive.
So if you just don't know which of 450 bridges are bad, what do you do? Fence them all of and spark at least outrage? Safest option. Finding out what to do is already expensive
This tragedy shows the importance of inspection and cost of maintenance of infrastructure. In the U.S. there are approximately 600,000 highway bridges. It's estimated that a quarter of them are at their end-of-life mark (that avg being estimated by some at 70). Not counting over 1,700 bridges still in use built before the 19th century, the breakdown is something like this:
This is just bridges. There are also about 84,000 dams and in a decade or two a huge number of both of these will approach their end of life, just as a legion of civil engineers go into retirement.
The problem is that this is done on the OS vendor's terms, not the client's. Maintenance and safety upgrades aren't done to bridges on a whim. They're carefully planned to reduce the impact.
A well-maintained (and well designed, but there's no reason to think the design was at fault here) bridge shouldn't collapse. Ever. "Appropriate maintenance" in this case would have been to periodically unclog the drains so the water can run off in a controlled fashion and not pool and corrode the supports. How expensive can that be? Instead, the bridge collapses (and they were lucky that no one was killed in the collapse), and they have to replace it for millions of dollars. Money saved on maintenance is the very definition of the proverb "penny wise, pound foolish" IMHO.
>56,007 — 9.1% — of the nation’s bridges were structurally deficient in 2016, and on average there were 188 million trips across a structurally deficient bridge each day
This number is kept higher than it needs to be for economic/political reasons. If your bridge is about to fall down at any minute it's easier to get federal dollars (or justify using your existing dollars) to build a new bridge. As a result there's lots of bridges that are past due with shovel ready plans for replacement but the local/state gov is just waiting for it to become a crisis so that they don't have to pay for as much of the fix. If the replacement bridge requires taking private land, disrupting traffic, etc, etc. there's even more reason to wait for a crisis.
There is a catch-22 for such a judgement call. As bridges generally weigh far more than the traffic they carry, there isn't much room between a bridge that is too dangerous for traffic and one that is too dangerous for anything, including repair work.
> 46,154, or 7.5% of the nation’s bridges, are considered structurally deficient, meaning they are in “poor” condition. Unfortunately, 178 million trips are taken across these structurally deficient bridges every day
I don't see how that undermines my point. Everything needs maintenance and upkeep. You have to re-paint the bridge and check it for cracks and do testing on it. But that's measured in days/weeks/months/years vs. a steam engine going off the rails in seconds/minutes/hours.
In my comment I stated:
> a bridge needs some maintenance and upkeep, yes,
Is there a way I could have stated that to emphasize that bridges will fail if they're not maintained?
I have no reason to doubt your facts, you sound knowledgeable, but there is something that you left out, that is important context.
I knew to look for it because of the news article I previously read.
It is this: "Substructure Condition Rating (60) 6 - Satisfactory Condition"
I do not believe this was either the worst rated bridge or the highest priority, and surely there is nobody who deliberately let it happen, so there must be room for improvement in the management of PA bridges.
PA has 3353 bridges in poor condition, according to reports.
FYI: more than half of US bridges are non-redundant. Even the smallest crack from corrosion can propagate and bring it down. And they're all corroding.
Managing structurally deficient bridges is more problematic in places with winter or at least more varied weather (like Pennsylvania).
Just like this bridge, the big problem is that something happens and degradation switches from "slow but manageable" to "Oh, shit, suddenly that beam is gone and this bridge might collapse".
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