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This article has many problems. Most importantly, building techniques such as "steel frame", "traditional bricks and mortar", "mud brick" and "rammed earth" ar
by dkbrk 10y ago
This article has many problems. Most importantly, building techniques such as "steel frame", "traditional bricks and mortar", "mud brick" and "rammed earth" are far less capable than reinforced concrete. The article implies that as these are more "durable" they are superior to reinforced concrete. This is a false equivalence of staggering magnitude. Reinforced concrete is the great enabler of modern high-rise construction and civil engineering; most projects simply would not be able to be built without reinforced concrete. Without reinforced concrete the world would be a very different place.
I take special issue with the article's use of pseudoscientic false analogies.
> This means that concrete structures, for all their stone-like superficial qualities, are actually made of the skeletons of sea creatures ground up with rock. It takes millions upon millions of years for these sea creatures to live, die and form into limestone. This timescale contrasts starkly with the life spans of contemporary buildings.
This is utter drivel.
There is a valid point in that for smaller scale constructions other techniques may be applicable which are otherwise ignored; also that there are alternatives to steel as the reinforcing material, both for prestressed structures and not.
- euroclydon 10y agoI read an engineering guideline on concrete that I wish I could find. It compared the economics of building a steel vs reinforced concrete bridge. Steel came out better when you considered the lifetime and especially the recyclability, but concrete was cheaper to build initially. The steel bridge would last indefinitely, as long as you kept it painted, or even replaced rusted parts. Reinforced concrete is costly to demolish, and nearly impossible to recycle. Crushed concrete can be used as a filler, but in order to be used for fresh concrete it must be free of contaminates, which is rarely the case, and no one wants to risk the integrity of a new structure of any importance. The percentage of all concrete structures even built, that are still standing must be quite large. This will not be a great legacy to leave future generations.
- jessaustin 10y agoWe're not running out of limestone anytime soon, but otherwise this is a bit off-target. All of the alternative construction techniques you mention have advantages over reinforced concrete. Concrete also has its advantages, but TFA is not wrong about the disadvantages. When I traveled to Philippines earlier this year I was struck by how they use masonry in situations that in USA would be reinforced concrete. Granted, the blocks are all CMUs, but the technique is masonry. I think it's because very few roads (at least in the places I traveled) would be suitable for standard 6-yard concrete trucks, whereas you can always throw a few dozen blocks on the back of a motorcycle. Of course labor costs are also a factor. However, concrete in block form is totally recyclable, while as TFA notes when poured it is not.
- gkop 10y agoAren't blocks supposed to be reinforced with rebar and columns poured through? How easy are they to recycle in practice after this? Just curious.
- HillaryBriss 10y agoYes. I believe that's the code in Los Angeles.
- hga 10y agoYeah, if you're in an earthquake zone, like the Pacific Ring of Fire (https://en.wikipedia.org/wiki/Ring_of_Fire https://en.wikipedia.org/wiki/Ring_of_Fire), which most certainly includes California and the Philippines, you're eventually going to be very unhappy if you don't reinforce them.
- jessaustin 10y agoI guess that probably happens some places. I haven't seen it though, and I recently tore down a block building for a friend who has since built a foundation with the blocks. I don't think concrete would be a great material in an earthquake in any configuration. If you have to mix up concrete for pouring anyway, I'm not sure why you'd build a wall first when you could just place some forms instead, which would take much less time.
- Houshalter 10y ago>We're not running out of limestone anytime soon There was an article on HN some time ago on how we are running out of the type of sand necessary for concrete. There is apparently a big black market for sand stolen from rivers and beaches, leading to violence and environmental problems. I was surprised the article didn't mention this.
- schiffern 10y ago>This is utter drivel. It's utter drivel to point out that nonrenewable resources are being squandered at a shocking rate on structures that can't even last a century?