Testing and Prestressing

20150611 - Reciprocal Weighting - 02

We hung 50kg earthbags from the tips of each of the outer reciprocal beams for a few reasons.

Firstly it raised up the back end of outer reciprocal beams, which are connected to the columns with a joint that allows them the see-saw, thus lowering the tips onto the inner reciprocal beams to create the double reciprocal structure. This allows us to put in 12 outer columns from the bottoms of the beams down the the concrete bond beam.

Next, it pre-stresses the structure. We plan to use ferro-cement to cover the roof but the weight of the mortar will compress the structure during application, so we are pre-stressing to achieve the final shape and removing the weights as we lift the mortar.

Finally, it is the first step in testing the strength of the roof. More weights will be added later.

We connected the tips of the outer beams with the inner beams using two 7″ nails in each connection, they will also be tied with thick wire.

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April 9, 2015 Reciprocal Roof