Construction 05: Concrete structures (part 1)

19/09/11 | ۩ |

 With this post I officially launch the Errors section.

Once flooring is complete, vertical frame construction must start.
Before that, I need to explain my choice to build a reinforced concrete frame, as this is not really a medieval technique.

The underground cellar, which represents the basement of the house, in the real world would be surrounded by the ground (a rocky ground in many parts of the city) or by the besements of contiguous buildings. It would be thick-walled with bricks and stones. No concrete or metal wire, then.
However, in my case the scale model is not inserted into the ground and I can't take advantage of other existing structures. It stands alone like a high tower.

Moreover, the strains this structure will need to resist (relocations, strokes, etc.) are heavier than a real building have to, unless in case of earthquake or bombing. So, I need an extra-strong structure.
The idea was to build a bearing reinforced concrete structure, with vertical steel pillars at the corners  to guarantee a greater resistance without changing the external appearence of the building.
As you'll see, the idea (carefully prepared) only succeeded partially and after many headaches.

Following the foundation frame on the basement floor, I build a mould with wooden boards. Inside the mould I place the steel bars, just like in a real building site.
I recovered the bars from an old bookshelf support, polished and grooved to improve adhesion with concrete.

Thus far, all good. Then it's time to prepare the concrete to fill the mould...
For the compound to full-fill the narrow mould, I prepare a fluid concrete and I pour it between the boards.

A posteriori I can say that was a fatal mistake. The excess water not prevented the compound to harden (dry climate of Granada helped) but the result was a fragile and poor quality concrete. It crumbles with a simple finger touch.

In these pictures I made after removing the moulds, you can see clearly what I mean. Structure is defective and it's necessary a changing of method, and perhaps a revision of the project itself.
The work stops. For a few days somebody uses the area as a parking lot.
Then I decide for a drastic action and I tear down the whole structure with the exception of a perimeter wall, who looks stronger. 

So, back to square one: concrete base and brick floor.
After an early discouragement I return to work, trying to make a good use of my previous errors.
This time I decide to build walls and pillars in separate moulds to assemble later...

(to be continued)

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