Bridge Falls into Mississippi River

In the SF Bay Area there are plenty of overpasses and bridges. They are constantly being checked and maintained. The Bay Bridge for example Cal Trans starts at one end for regular maintenance, works across to the other end, and immediately starts with the same process all over again. It's constant and never takes a break. The MInneapolis bridge collapsed. There's a failure somewhere. Authorities already admitted there was an official report filed recently stating the bridge was unsafe.

No one's saying the bridge collapsing was intentional. If it wasn't about proper maintenance of the bridge, the only thing left is a design flaw. If I was exploiting this occasion for country versus country rhetoric, I would have grabbed on to a "design flaw."

And neither am I. I was again just trying to make a point that its pointless to make assumptions based on factors that on have a very limited understanding.

Unfortunetly the newsagencies in here have already "pass" that incidence and not much new is released. Some article mentioned that during the maintenance check-ups in 2005 and 2006 there was some sort of structucal unintergenity observed. It didn't elaborate more. That indicates more of design or building flaud rather than poor maintenance.

From the human archetecture history point of view, concrete+steel structure are widely used only after 20th century, although cement was invented by Roman 2000 years ago, but it was used mainly as the glue material in buildings.

The biggest problem with cement is that it will develop the cracks, and eventually break down with the time, the water will accelerate that process significantly. Also the steel bars used in the concrete will get rotten, reduce its strength. This is the problem you can't eliminate, only can slow it down. That's why I said 40-50 years concrete+steel structure is already old, need heavy maintenance.

If you want a building tended to be forever, you choose the stone, esp the granite, it's strong and doesn't have these problems. But the stonework is most expensive that few project can afford. In west the churches built with stone cost hundreds of years' hardwork, today the ground of China's Tiananmen spare, the biggest in the world, is covered with granite chunks, very expensive but last very long.

The second good material for building is bricks, strangely brick structure is better than concrete, it actually lasts longer. But brickwork is very expensive as well. So concrete+steel structure is really a cheap alternative for building, it wont last long except used as the filling material, no matter whatever you do it will have problems.

I believe stones are stronger than concrete, an example is the Angkor Wat temple, I believe you guys have ever heard it. Yeah, one of the seven world wonders, it was made of stones, and just stones, by King Chey Vorroman VII. It was finished in 1181 (recorded by history books). More than 800 years old, and it's still there.

But there's something I don't get your point, do you expect a modern brigde, like the one that collapse, to be build of stones?

Show you an antique picture which was claimed token in 1866: the Angkor Wat, a stone building built in early 12th century.

Eh, you guys do know that the collapse started on one end of the bridge right? Not in the middle on top of the Mississippi, but where it meets land (And I think the connecting bridge)..... So I think I am going to agree with Golly.

BTW, Concrete gets stronger in water. I saw that on TV and I doubt it lies. (Well, when you were paving your yard w/ concrete, didn't you need to spray the yard w/ water every so often before completion? Isn't it said that concrete is better too wet then too dry?)

PS. Bricks are strong and not even bazookas/HEAT round burn through them. (Last I check) But I don't think they are good on large structure because other then the arch, I don't think they are good with lateral forces.

SteelBird said:

But there's something I don't get your point, do you expect a modern brigde, like the one that collapse, to be build of stones?

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It's practical impossible today, given the cost and engineering difficulty(attributed to the cost as well). Concrete is actually a "fast-food" stone, but it will break down not like some natural stone.

The world oldest open-spandrel stone arch bridge - Zhaozhou Bridge, 1500 years already and still in service. But no modern concrete archecture has a design lifespan longer than 200 years.