20 Years 20 Buildings: 1.78 Artistic installation, Madrid

In 2018, as part of the events celebrating the fourth centenary of the Plaza Mayor in Madrid, the floating sculpture “1.78”, by the American artista Janet Echelman, was temporarily installed over the statue of Philip III. It is a 44-meter-long and 35-meter-wide piece formed by layers of braided and knotted fiber that stood 21 meters high.

The structural design for the installation of this piece on the Plaza Mayor had to take into consideration several important conditions: firstly, that there is a subway parking lot under the plaza and therefore the loads to be placed on the floor slab should be limited. In addition, given the monumental character and the degree of protection of the buildings surrounding the square, it was not possible to anchor the piece to the facades (which had been the solution generally adopted in other previous locations), but rather a specific auxiliary structure had to be designed. Given the temporary nature of the piece, four masts were designed and analyzed, recycling material commonly used in the assembly of stages (trusses).

The first aspect to be solved was the arrangement of the masts, given the existence of abundant urban furniture in the area. This required an important coordination between the technical and artistic part of the team. The stability of the structure was ensured by means of tie rods to counterweights which, in addition, due to the weight limitations on the square, had to be placed on top of a load distribution substructure.

Did you know that…. the loading of the pre-tensioned structure was monitored by means of load cells both during the assembly process and during the lifespan of the piece, contrasting these data with the wind speeds recorded in an anemometer also located in the vicinity of the installation?