[jedrider]

https://www.bbc.com/news/world-latin-america-56977129
Mexico City metro overpass collapse kills 23

I could have been a structural engineer possibly as I like gawking at these manmade disasters.

Somebody tell me that this structure is not just concrete and rebar without the use of steel beams?

How could something like that hold up for it's intended use?

[yellowcanoe]

The collapse in Mexico City is even more amazing when you consider that structures in that area need to be engineered to withstand significant sized earthquakes.

[Outcast_Searcher]

https://www.bbc.com/news/world-latin-america-56977129
Mexico City metro overpass collapse kills 23

I could have been a structural engineer possibly as I like gawking at these manmade disasters.

Somebody tell me that this structure is not just concrete and rebar without the use of steel beams?

How could something like that hold up for it's intended use?

The BBC article you linked to has the mayor saying, "it appeared a girder had given way", which if true, implies the use of beams (and I presume steel for that application).

OTOH, it also says "the line was inaugurated less than a decade ago", and if properly designed, such failures should NOT occur within a decade. Or several decades for that matter, assuming proper inspections and maintenance (like for corrosion) are done.

There will be an investigation. Clearly, engineering error, incompetence in construction, incompetence and/or corruption in materials (like the beam), corruption in construction (were shortcuts taken to lower costs, or deals made to falsify paperwork and siphon off money?) are possibilities until it's proven otherwise. No report of explosions, etc., so I presume no terrorism at this point.

Given that the US has plenty of its OWN serious infrastructure problems, it's not like we should be pointing fingers. It's just tragic that this kind of thing has to occur, which should be entirely preventable if the job is done right (short of a SERIOUSLY massive earthquake that exceeds design specs or some other disaster of similar scale).

[vtsnowedin]

A lot of highway girders are in fact prestressed concrete. Steel cables or strands are stretched through a form and the concrete poured around them. When the jacks are released the strands place the section under tension as if it was being squeezed together at both ends. They are very durable and have the advantage of not rusting or needing to be painted repeatedly.

[vtsnowedin]

How did childcare become infrastructure?
I think Biden's proposal is pie in the sky and should go down in flames.
I do however support a real infrastructure bill that actually is spent on real needed work and not pork barrel ear marks.
To pay for it I would raise the Federal fuel taxes by ten cents a gallon this year and another five cents each year after that. That dime would bring in some 49 million a day or 18 billion a year or 40 million per Congressional district. I would send the money no strings attached to each state and let their legislature and governors decide the priorities cutting Congress and their lobbyist out of the process.
A wise state government (yes there are a few) would only spend the money once it was in hand and avoid all interest and bonding costs.
Of course the states could raise that dime themselves and remove all federal interference and be sure the taxes paid in their state stayed in their coffers.

[jedrider]

How did childcare become infrastructure?

Soft-Infrastructure, like in engineering human-beings.

[Pops]

It's been talked to death but the freeze failures are a good example of a lack of foresigh. I bring it up because I just opened a letter from my local town utility explaining their typical Feb nat. gas bill for generation is about $400k but due to the freeze they wound up getting jammed with a 2 million dollar bill.

This is a little town of 5k who buys electricity from a larger co-op and basically passes thru the cost. Instead of billing customers 5x the normal they tapped the emergency fund and will amortize the cost over 60 months.

Nice they have a little cookie jar, but it isn't bottomless. And... here is the problem with delayed maintenance, lack of planning, etc: the rainy day fund can only cover so many storms. As the climate changes exposing the lack of maintenance and planning, eventually the cushion goes and you haven't the money to cope and things fall apart. Add in population aging and decline, tightening commodities supply, increasing financialization and surplus cash going to the top...

[vtsnowedin]

How did childcare become infrastructure?

Soft-Infrastructure, like in engineering human-beings.

Leaving engineered human beings aside I see child care as an issue that needs to be addressed but having the Federal government get involved would not be helpful and as it is not mentioned in the Constitution it should be left to the states or the people.
A one size fits all Federal program would serve very few well and the costs would be exorbitant.

[Outcast_Searcher]

How did childcare become infrastructure?

Soft-Infrastructure, like in engineering human-beings.

Leaving engineered human beings aside I see child care as an issue that needs to be addressed but having the Federal government get involved would not be helpful and as it is not mentioned in the Constitution it should be left to the states or the people.
A one size fits all Federal program would serve very few well and the costs would be exorbitant.

But that's the kind of thing that buys liberals votes, so you KNOW they'll push hard for it in the current "take care of me" environment.

[vtsnowedin]

But that's the kind of thing that buys liberals votes, so you KNOW they'll push hard for it in the current "take care of me" environment.

The Liberals being for something is not a good reason to follow their lead. My position is based on the merits and likely outcome from such a program.

[Newfie]

It's been talked to death but the freeze failures are a good example of a lack of foresigh. I bring it up because I just opened a letter from my local town utility explaining their typical Feb nat. gas bill for generation is about $400k but due to the freeze they wound up getting jammed with a 2 million dollar bill.

This is a little town of 5k who buys electricity from a larger co-op and basically passes thru the cost. Instead of billing customers 5x the normal they tapped the emergency fund and will amortize the cost over 60 months.

Nice they have a little cookie jar, but it isn't bottomless. And... here is the problem with delayed maintenance, lack of planning, etc: the rainy day fund can only cover so many storms. As the climate changes exposing the lack of maintenance and planning, eventually the cushion goes and you haven't the money to cope and things fall apart. Add in population aging and decline, tightening commodities supply, increasing financialization and surplus cash going to the top...

Pops,

The NE rail lines had decades of “deferred maintenance” before being split up into Amtrak and then the regional rail lines. I spent a good part of my working life involved with that and the consequences. I quite literally saw how career maintenance workers, the front line guys, literally stole and hid spare parts so that the corporate liquidators could not get their hands on it. I was maintaining systems installed in the 1920’s and at time bought spare parts from antique collectors. We had crank magneto phones and party lines through the late 1990’s.

When money did begin to flow it was done haphazardly by different corporate types. There was enormous waste and miss-management. I literally walked into a brand new control room that was absolutely useless. I was able to reconfigure and reuse some of the stuff but a good half was sheer waste. The controls were so bad the dispatchers were getting the train sequence confused and miss routing passenger trains sending them to the wrong destinations. We scrambled to put in place make shift systems using obsolete teletype equipment that lasted for over 10 years until replaced with a modern system that cost millions and did not work as well.

Deferred maintenance is disastrous, the management I saw was blind to it.

[Outcast_Searcher]

When money did begin to flow it was done haphazardly by different corporate types. There was enormous waste and miss-management. I literally walked into a brand new control room that was absolutely useless. I was able to reconfigure and reuse some of the stuff but a good half was sheer waste. The controls were so bad the dispatchers were getting the train sequence confused and miss routing passenger trains sending them to the wrong destinations. We scrambled to put in place make shift systems using obsolete teletype equipment that lasted for over 10 years until replaced with a modern system that cost millions and did not work as well.

Deferred maintenance is disastrous, the management I saw was blind to it.

To me, in the US, it's interesting how, for those with actual technical know-how on a specific real-world subject (be it computers, railroads, etc), corporate incompetence and BS barriers to doing the right thing re rules and paperwork, ARE SO SIMILAR TO the same thing when government (re regulations) is in charge.

No matter how much folks who lean toward, pander to, or are dependent re their jobs, to one side or the other, claim that THEIR side is all good, and the other side is all bad.

[Newfie]

Out,

Not sure I followed you in that.

Decades ago I spent 4 years in the USCG and I thought it was terribly wasteful and incompetent. I could not wait to get into private enterprise to see the difference. Then I went to work on the public side of transit. That was worse.

Then I worked for some contractors. Some of the best experiences in my life. This was tough work but I got more out of it. And we drank a ton if beer.

Then I went into design/consulting and worked for big engineering firms. These were the worse yet. The incompetence was staggering. And I got a larger exposure to many other organizations, sometimes in a high level. Very, very disturbing.

So my career was a mixed bag. The construction part was the best. Latter in my career My company was trying to get involved with construction projects. They could not loose money fast enough. I could not stop them from making stupid mistakes. But the pay was good, the work interesting and challenging, I was part time and set my own hours. But I hated being part of a failed system.

Extremely happy to be retired.

[vtsnowedin]

Extremely happy to be retired.

100% with you there.

[Newfie]

And now a bridge over the Mississippi shut due to a potentially catastrophic crack.

In 1984 SEPTA, the Philly transit agency, had just taken over the regional rail lines on New Years Eve. We were operating the system and new inspectors were doing the inspecting. An inspector was reviewing a bridge when a train went over and he saw several inches of movement in the structure where there should have been none. This piece if the bridge was hard to get to because the space underneath it contained a child care center. He went up on the tracks and stopped all rail traffic, right then and there.

The bridge was ripped out within days and a temporary installed. I lost Thanksgiving because I had to be there to reroute cables around the scene to allow work to progress. So I missed deer season with my Dad, which would be one of our last.

The entire line was then inspected and 7 bridges were found in dire need of replacement. It took a few years to get designs and contracts our and by then I was in construction and spent 2-1/2 years in the replacement project. We shut the railroad down for two 3 month work windows. The old bridges were demolished and new ones rolled in. My job was t replace the electrical systems.

There were 7 prime contracts and my contract had to coordinate with all 6 others. All 7 came in on time with no claims.

[jedrider]

The deadly collapse of Mexico City's 'Golden Line' was a tragedy foretold
https://www.cnn.com/2021/05/10/americas/mexico-city-subway-collapse-romo-analysis-intl-latam/index.html

An engineering/construction failure that no one would want to be associated with. News seems sparse, too.

[jedrider]

Why the Mexico City Metro Collapsed
https://www.nytimes.com/interactive/2021/06/12/world/americas/mexico-city-train-crash.html

It collapsed because of politics and corruption, no doubt. It may not have been the engineering failure that I hoped to enjoy gawking at.

It usually come down to the welds in situations like this. I just broke a steel weld and I'm going to see if crazy glue will hold, but I'm told that I should add epoxy afterwards or I can just buy a new item. I hope they can afford a new metro line in Mexico City.

[Newfie]

What broke?

If you are inclined you may want to try welding it.

[jedrider]

I didn't read through it when I posted as I thought it was blocked, but it unfroze and I was treated to some engineering hubris. It is the type of hubris that says I can make this as cheaply as possible and even get a less than meticulous workforce to construct it without catastrophic problems showing up.

That was a ridiculous design, putting those bolts where no one could reasonably inspect them and skimping out on cross reinforcement.

My towel holder made with reasonably nice gauge twisted stainless steel round stock, but in two pieces had the skimpiest welds that I could only imagine could be examples of other welds serving much more important duty.

[Outcast_Searcher]

What broke?

If you are inclined you may want to try welding it.

To some extent, you might decide based on what it is.

If it's something like a tool that comes under a lot of stress with you around it, it breaking suddenly and potentially causing serious injury probably isn't worth taking the risk on it.

If it would just be annoying if it breaks again, then multiple glues like you mentioned, and perhaps some kind of wraparound support in addition, strongly glued over a large surface area, and perhaps affixed with clamps or something might do the trick. Depends on what it is and how it's shaped, and again, safety considerations.

IMO. Just thinking in terms of common sense. My dad was a depression era first class cheapskate and mechanical engineer and used to jury rig all kinds of stuff to save money. (I have zero knowledge about welding, so can't opine on that).