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Today the Built Environment department's concrete printer starts printing the world's first 3-D printed reinforced, pre-stressed concrete bridge. The cycle bridge will be part of a new section of ring road around Gemert [Netherlands] in which the BAM Infra construction company is using innovative techniques.
[O]ne of the advantages of printing a bridge is that much less concrete is needed than in the conventional technique in which a mold is filled. By contrast, a printer deposits only the concrete where it is needed. This has benefits since in the production of cement a lot of CO2 is released and much less of this is needed for printed concrete. Another benefit lies in freedom of form: the printer can make any desired shape, and no wooden molding frames are needed.
They have managed to not only 3-D print concrete, they have also developed a technique to lay down a cable within the concrete so that it can be 'pre-stressed' — avoiding tensil stress.
The researchers successfully tested a 1:2 scale model under a 2000kg load.
(Score: 3, Interesting) by Dr Spin on Saturday June 24 2017, @09:05AM
A bridge in Shanghai was built with Styrofoam blocks inside it, to reduce the amount of concrete needed.
Many buildings in the ancient Roman world (ie from centuries before the time of Christ) used concrete with tiny clay
vessels embedded to keep the weight down in large dome structures. This is not a new technique, and people who
study construction engineering at reputable universities (or Google), should be fully aware of this technique, as well
as the one of embedding cables or wires and tensioning after the concrete sets, which I saw being done in the 1950's.
It remains the case that 3D printing in concrete gives you abilities never seen before, but these are mostly because
of the combination of speed and complexity of shape. In some cases, clearly, also because "trendiness" means more
effort goes in at the design stage. You can pour a lot of concrete for the cost of a highly skilled design engineer.
Warning: Opening your mouth may invalidate your brain!