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Around here we love megastructures (and who doesn’t), but there are also curious stories in buildings that do not hold records of any kind and that even seem everyday to us. An example are the Columbus Towersin Madrid (Spain), whose architecture and construction posed certain challenges at the time and which almost made the saying “start the house with the roof” literal. There are 23 floors above and six underground, and its construction was possible thanks to the suspended architecture attributed to its architect Antonio Lamela (died in 2017). Or what is the same, the floors hang from each other, so that the upper floors do not rest on the lower ones. Not one tower, but two, and built from top to bottom This popular saying was already stated by Antonio Lamela, its architect, who maintained that towers could only exist if they were built from top to bottom. The reason: the irregular 1,710 square meter plot on which they were going to settle was too small and the municipal ordinance required many parking spaces, as explained in The Country. For this reason, the foundations would have to occupy a small space, hence Lamela began the construction in the opposite direction, something that in the end would cement (pun intended) an architectural work with a unique building in the entire world. and the decision to do two towers and not a single building as the City Council proposed, it was due to the fact that the architect and his staff confirmed that building a single tower would have deteriorated the urban image “due to the implementation of an element of enormous proportions.” Building them there was by no means a coincidence. The site was in the heart of the city and the City Council established that “the building must be an architectural unit of marked verticality”, as explained on the Estudio Lamela website, and there were numerous changes of criteria regarding a project (as we will see later) that had to adapt to a predictable urban framework, but that could never become a reality because of this. Image: Estudio Lamela And why build them? from the top to the base? As the study itself explains, they found a problem that could not be solved with the usual systems: the adaptation of the needs of the building (residential and with commercial spaces on the ground floor) was incompatible with traditional means, in addition to the irregularity of the site. Hence the idea of ​​”hanging” the towers, so that a double structure could be proposed with the two parts independent and in the end there would be a set of three almost independent buildings: the two towers and the one that acts as a base. Thus, the method consisted of raising a narrow pillar in the center (the core), on which to place the hanging platform (that is, the large concrete head). From there the floors were built downwards, the weight of which falls partly on the central pillar and the rest on the side braces. The pressure of the platform was in turn transmitted by these lateral braces, thanks to the tension of steel cables, thus compressing the soles against the head. “It’s like the building was turned upside down.” Antonio Lamela, architect. A project that was changing in its development The design of the Colón Towers, 116 meters high, was planned from the beginning, differentiating itself from what was usually done in “hanging” buildings, starting from steel structural heads. What was done is a design completely in reinforced concrete, using high-resistance post-tensioned concrete and making the slabs of the typical floors rest on their perimeter on the external tie rods, thus not being in tension but compressed against the post-tensioned concrete structure as we have explained before. In this way, the upper structure (in which the installation machinery would be located) receives the load from the 21 suspended slabs, transmitting it to the core, through which it descends to the ground foundation. For the façade, in principle folded sheet metal was used. anodized aluminum bronze color, although as we will see later this was not what was left in the end. They also count in The Country that this green crown art deco so particular, that it has been popularly known as “the plug”, that the reverse construction of this building baffled those who were watching the progress for years. The Colón Towers began to be built in 1967, but in 1970 the Madrid City Council stopped the works due to “political interests”, according to the architect in numerous interviews. With this (and the lawsuits), the City Council’s compensation allowed the initial use for luxury residences that had been planned to change to house offices, restarting the works and finishing them in 1976. A spectacular ending, but it was not the desired one either. The Colón Towers were considered the “building with the most advanced technology in building construction until 1975” made of prestressed concrete at the World Congress of Architecture and Public Works. It was a pioneering work in its construction, although there were already suspended structures (especially bridges) and over time we have seen more examples of both suspended architecture like this way of building them, like the corporate building of the Nykredit bank by Schmidt Hammer, the Media Tic building by Enrique Ruiz Geli or Hovenring, a suspended platform by ipv Delft that we saw talking about When buildings adapt to bicycles (and not the other way around). The project began being called Torres de Jerez, although it was named after Columbus as its construction took hold and was promoted, in the early seventies and by the construction company Osinalde. After deciding that they would be offices and once built, they were acquired by the family Ruiz Mateosbeing later expropriated to finally be bought by the British group Heron International. The construction company decided to change the aesthetics with a glazed exterior skin to avoid revocation, so that there was a double layer that increased … Read more