SkyTrain’s Billion-Dollar Concrete Bill Coming Due

A must read.

As the SkyTrain light metro system is mostly constructed with concrete and what we see is only about 25% of the concrete used, with the rest underground, all with classic rebar construction, it is safe to say;

SkyTrain’s billion dollar concrete bill is coming due sooner than one thinks.

All that concrete!

America’s trillion-dollar concrete bill is coming due

Felix Salmon
Felix Salmon, author of Capital
Illustration of a piece of concrete in the shape of a bag of money.

Illustration: Sarah Grillo/Axios

Concrete construction no longer lasts thousands of years, like the Pantheon in Rome. Instead, its lifespan is roughly 50-100 years, thanks to the way in which modern concrete is reinforced.

Why it matters: That means a multi-trillion-dollar bill is coming due right around now, in the form of concrete construction that needs noisy, dirty, expensive repair.

  • The collapse of a residential tower in Surfside, Florida, is a stark reminder of how catastrophically concrete can fail.
  • Just as the collapse of the Morandi Bridge in Genoa caused Italy to start paying much more attention to remedial infrastructure projects, the Surfside tragedy might help focus America on the urgent need to fix buildings that are nearing the end of their initial lifespan.

The big picture: As Robert Courland explains in “Concrete Planet,” modern concrete is poured around steel rebar, which gives it tensile strength. But tiny cracks — found in all concrete — cause water to start rusting the steel, which then expands, cracking the concrete.

  • Photos of the Surfside basement taken before the collapse show steel rebar breaking all the way through the concrete to the point at which it is fully exposed to the salty and humid Florida air.

By the numbers: One of the most famous concrete buildings in America, Frank Lloyd Wright’s Fallingwater, cost $155,000 to build in 1936 — about $2 million in 2001 dollars. The cost of repairs in 2001 came to $11.5 million.

  • Similarly, repairs to Wright’s concrete Unity Temple are estimated at roughly 20 times the original construction costs, even after adjusting for inflation.

How it works: Once rebar starts corroding, the standard fix involves jackhammering the concrete to expose the steel, brushing the steel to remove the rust, reinforcing the rebar as necessary, and then covering it all back up again with carefully color-matched new concrete.

  • That labor-intensive extreme noise and dust is actually the green, environmentally sensitive solution. The only alternative is demolition and replacement with an entirely new building — something that involves a much greater carbon footprint.

Between the lines: Because concrete fails from the inside out, damage can be hard to detect. And because concrete looks so solid and impregnable, necessary maintenance is often skipped, causing massive bills later on.

  • Local governments are in charge of ensuring building safety, but their willingness and ability to do so varies widely. The owners and residents of concrete buildings often try very hard not to think about corrosion, just because the costs of fixing it are so enormous.

The bottom line: The amount of money needed to fix existing infrastructure (nearly all of which is concrete, in one way or another) stands at roughly $6 trillion, according to the American Society of Civil Engineers. That number does not include homes, offices and other private buildings.

  • If you live in a concrete building that’s more than 40 or 50 years old, it’s an extremely good idea to check carefully on just how well it’s been maintained, lest you find yourself with an unexpected seven-figure repair bill — or worse.

Theories emerge in early stages of investigation into Surfside condo collapse

Comments

4 Responses to “SkyTrain’s Billion-Dollar Concrete Bill Coming Due”
  1. Haveacow says:

    Check concrete carefully at 40 to 50 years, hell in a climate that has as many freeze-thaw cycles as our does, try 30-40 years.

    That lifespan of 50-100 years, assumes many big things, that you got a top dollar mixture, a great pour (not many air bubbles), that your rebar was half decently done and you live in a endlessly stable, really warm-hot climate. More importantly with older concrete, especially really old concrete, is there enough rebar, or any at all?

    One of the engineers I used to work with would endlessly spout that, in more northerly climates (more freeze-thaw cycles), wet climates, jurisdictions that have increased their rebar allowances, both frequently and recently (which is everywhere in the US and Canada) as well as used crappy quality concrete patches when doing far to infrequent small fixes (which is everywhere on Earth), 40 to 60 years is a more accurate lifespan estimation.

    We have learned only recently that “curing” or drying concrete gives off enormous amounts of greenhouse gasses and that anywhere from 10%-20% of the greenhouse gasses in our atmosphere, causing issues for climate change, are because humans use too much concrete. So in many countries we have started shifting to low carbon concrete mixtures. Unfortunately, low carbon concrete mixtures can lower concrete’s lifespan. We are not totally sure by how much.

    Concrete ages geometrically as well as from inside-out, imperfections are slow to start but once you go past a certain point in time, the degree of degradation, amount (volume) and the pace of all this degradation, keeps increasing to a point that entire rebuilds are cheaper than rehabbing the concrete and rebar.

    Remember, the Expo Line may have opened 35 years ago (1986) but it was built between 1981-1986, so some of the structural concrete may have been poured as early as late 1981 that’s 40 years ago!

  2. Haveacow says:

    1. Oh yes, forgot one thing, the price of the concrete mixtures, the recipe for the making of concrete are highly guarded trade secrets and are always going up in price, especially with low carbon concrete mixtures.

    2. Wages are always going up in construction and mixing trucks don’t come cheap. Sometimes it’s just cheaper to make it on site for really large projects.

    3. Many places in the world have very low sand supplies, so the cost of it is increasing (sand is a key ingredient in concrete) and we are destroying nearly all our natural sandy beaches worldwide to get it. Desert sand is useless unfortunately for concrete (it isn’t sticky enough).

    4. Many government jurisdictions want more rebar in concrete and more expensive plastic coated rebar to be used which is a big problem here in Ontario, the cost is now above . The plastic coating makes the rebar waterproof for a much longer period of time.

    The moral of the story, structural concrete has been going up in price 2 to 3 times the rate of inflation since the late 1990’s and shows no signs of ever slowing down, unless we use less of it, stop building with it entirely or stop building things and or have a world wide pandemic to slowdown construction, world wide. The price actually dropped in 2020 but it’s going back up as economies reopen.

  3. Haveacow says:

    Sorry Zwei I goofed, could you add in number 4, here in Ontario, the cost of structural concrete is above $400/cubic metre.

  4. Bill Burgess says:

    Havacow: “We have learned only recently that “curing” or drying concrete gives off enormous amounts of greenhouse gasses”

    Is it really the curing or drying? Or (mainly) the heating to produce cement? See https://www.bbc.com/news/science-environment-46455844

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