Read here about a radio tower designed according to tensegrity priniciples.

Overview


Smiljan Radic, Gabriela Medrano, and Ricardo Serpell have won a competition to design a new landmark for Santiago, Chile: an antenna tower to be placed on the summit of San Cristobal Hill, in the heart of the city. The “Santiago Antenna Tower,” a unique telecommunications tower with panoramic views, should be completed in 2017, in time for the centenary of the Metropolitan Park of Santiago.

Classic 3-strut tensesgrity antiprisms are stacked, separating 11 observation rings, and reaching a total of 140 meters into the air. To be installed 600 meters from the statue of the Virgin Mary, the prisms and rings will encompass antennas installed in five masts and three towers, which currently host the emissions of 10 television channels and 33 radio stations. The design was chosen due to the lightweight nature of tensegrity: the structure's profile will not block the silhouette of the hill or the statue of the Virgin. The design includes a public terrace and pond while also accounting for lighting at night for the main structure as well as different services for visitors, including a café, shop, ticket office, and public restrooms.

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Ringed walkways mark the separation of the 3-strut tensegrity prisms. Santiago Radio Tower design by Smiljan Radic.


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Plans for the Santiago Radio Tower design by Smiljan Radic.


Background

Structural Details


Compressed Elements: 12” tubes, with a thickness between 8 and 12 millimeters. These exist in three standard lengths (11.65 meters, 12.3 meters and 13 meters) that repeat in each level or structural module.

Tensile Elements: rods with 2” of diameter. Doubles may provide structural redundancy.

Architect's Description


===“Tower vs. Antenna” Introduction==]

We propose to build a hybrid object on the top of the hill, so that the hilltop remains whole. The appearance will be between a tower and an antenna, between a stable and recognizable body and one that is unstable and restless.This hybrid is more a ghost than a column. It is the skeleton of a ghost of a column.

Conceptually its form does not propose anything novel for the future, nor does its figure appear graspable in the present. Its message is clearly confusing. Its shape comes from the recovery of certain past architectures that interest us: the formal instability of Buckminster Fuller’s Tensegrity structures and Kenneth Snelson’s sculptures, some of Vhuthemas’ constructivist exercises, the polygonal spirals deployed in space by Aleksandr Rochenko, the craft of the models in the towers of Nieuwenhuys Constant, and even the atmosphere of Cedric Price’s Aviary in London. All of these form the actual memory of this object.

We believe that with this look back – this apparent repetition – the global and diffuse form of this urban object will not be lost in the consumption of a rapid SHOW, and will not compete with formal icons built in other cities, which is something desirable for a Santiago trying to establish its image in the world.

Surroundings


For the scale and size of the proposed project, its urban efficiency must be measured from both a very short and very far distance. All intermediate measures depend on these.

Our antenna will always be read as a transparent non-linear body, subtly changing thanks to its rotating structural modules, but formally ordered through the standard modulation of its components and its rings which float from their vertices, forming a virtual column throughout its height.

At night, each of the elements will be featured with illumination that changes each week in its density and color. This will allow the measure of time, much in the same way ancient bell towers measured the days.

Beneath the antenna, the public space tells the story of San Cristobal Hill’s urbanization, marked by the occupation of its hilltops by the statue of the Virgin Mary in 1908, the Tupahue pool in 1966, the Antilén pool in 1976, and later, in 2009, the Neruda amphitheater.

The public terrace, the mirror of black water, and the public services (cafeteria, shop, ticket office, restrooms) that make up the public space are enclosed by heavy walls that crown the topography. In this way, the circulation within the Park is improved, and the panoramic viewpoint and observatory form one tourist destination, with pedestrian access from Mexico Plaza.

Program


The program is distributed under the tower base scheme, where all the Antenna’s technical services are concentrated in a base that consists of three levels. The antenna tower remains isolated as a technical structure, adjacent to this volume. Both elements are united by some minor adjustments in the terrain and the public terrace.

It is important to clarify that public circulation is always external and topographic; however technical circulation is interior, technicians can access these spaces via parking lots located in the first level of the building’s base.

The antenna is 140 meters high. Its 11 rings are 11.5 meters in diameter to account for the distribution of radio, television and microwave antennas.

One ring for microwaves (at 35 meters high); 6 for radio (between 51.5 to 95 meters); 4 for TV (between 114 and 137 meters).

Each ring has two levels of antennas in its outer perimeter separated by a height of 6 meters. This allows the 16 antennas to be placed in each ring without causing interference. Due to the special geometry of the antenna, some of these rings have slopes of no more than 8%. Tangentially connected to these rings is an 0.6 square meter shaft, which feeds power to the tower and provides an elevator-like platform that will lift the elements necessary for the assembly of the antennas.

Structure


The tower’s structure is based on the principle of tensional integrity, or tensegrity, formed by Buckminster Fuller in the mid-twentieth century. In such structures the compressed elements are embedded in a tensile network, spatially delineating the system and reversing the habitual perception of a cross-linked structure.

The compressed and tensile elements are explicitly distinct, giving dynamic formal possibilities to their rotation and height, despite the fact that these elements are standard in their measurements.
Structural Detail

As in a conventional cross-linked structure, all elements are in compression or pure tension, i.e. they undergo no bending; additionally, all tensile elements are pre-loaded. This produces structures with an exceptionally high ratio of mass to stiffness.

Image Gallery


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Recreación del proyecto de Radic, Medrano y Serpellde en el cerro de San Cristobal, en Santiago de Chile. Photo: Ministerio de Vivienda y Urbanismo de Chile

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Selected Press Reports

El nuevo icono de Santiago de Chile

El nuevo icono de Santiago de Chile by Alfonso F. Reca
Published online by El Pais, 27 October 2014.

La capital chilena pronto contará con un nuevo techo. Santiago, una ciudad que en los últimos tiempos ha visto crecer de manera sustancial su skyline, contará con una gran torre de comunicaciones que coronará su punto más alto, el cerro San Cristóbal, con permiso del edificio Costanera Center, de 300 metros, el más alto de América Latina.

La llamada Torre Antena Santiago lleva la firma de uno de los grandes valores de la arquitectura chilena actual, Smiljan Radic, autor de la 14 edición del pabellón temporal de la Serpetine Gallery, en los Jardines de Kensington, en Londres. El proyecto de Radic, en colaboración con Gabriela Medrano y Ricardo Serpell, consiste en una liviana estructura de 140 metros de altura compuesta por 11 anillos en perfecta comunión con el entorno, ya que no distorsiona la tradicional silueta de la montaña y la estatua de la virgen.

Los autores la definen como una mezcla de torre y antena. “Este hibrido es más un fantasma que una columna. Es el esqueleto del fantasma de una columna”, explican, al tiempo que apuntan a varias fuentes de inspiración como “la inestabilidad formal de las estructuras Tensegrity de Buckminster Fuller o de las esculturas de Kenneth Snelson, algunos ejercicios constructivistas de Vhuthemas, las espirales poligonales desplegadas en el espacio de Aleksandr Rochenko, la manualidad de las maquetas en las torres de Nieuwenhuys Constant o el ambiente del Aviario de Cedric Price en Londres”.

Recreación del proyecto de Radic, Medrano y Serpellde en el cerro de San Cristobal, en Santiago de Chile. / Ministerio de Vivienda y Urbanismo de Chile

La torre cumplirá una doble función: servirá para agrupar en un solo elemento la actual maraña de antenas (cinco mástiles y tres torres) que permiten la emisión de más de una treintena de señales de televisión y radio, y dotará a la ciudad de un nuevo símbolo y referente turístico gracias a un mirador panorámico que ofrecerá espectaculares vistas de Santiago con los Andes de fondo. Además, el proyecto incluye nuevas cafeterías, estanques y zonas de esparcimiento en este tradicional lugar de descanso, al que se llega con el viejo pero entrañable funicular del Parque Metropolitano, una de las zonas verdes urbanas más grandes del mundo. La iluminación cambiante de la nueva construcción será su seña de identidad en la noche andina.

El proyecto de Radic, Medrano y Serpellde, seleccionado entre los presentados al concurso internacional realizado por el Gobierno chileno, tiene prevista su inauguración en 2017, año en el que se celebrará el centenario del Parque Metropolitano.

PHOTO
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Recreación del proyecto de Radic, Medrano y Serpellde en el cerro de San Cristobal, en Santiago de Chile. Photo: Ministerio de Vivienda y Urbanismo de Chile


Links and References


Archdaily announcement: http://www.archdaily.com/478897/first-place-winner-of-santiago-landmark-competition-smiljan-radic-gabriela-medrano-ricardo-serpell/
El Pais article http://elviajero.elpais.com/elviajero/2014/10/23/actualidad/1414021727_732847.html

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