☰ Workshops

Structures in Building Culture

Steel Skeleton (2013)

Visits scheduled in the workshop were organized in two phases: On the first two workshop days, taking advantage of the fact that we were in Barcelona, our visits were mainly focused on the works of architect Antoni Gaudí, in order to analyze the structural component of his architecture projects from a perceptive as well as methodological point of view. One of the objectives was recognizing the relationship between the form of the structure and the thinking process that lead to its conception. This aspect is vital in the work of Gaudí, given the fact that he invented a work system using structural models known as Model Funicular, in order to determine the relationship between form and structure: “Form Finding”.

Halfway through the workshop, we started the second phase of visits. This time, they were more focused on the typical geography and architecture of the “La Garrotxa” region, the location where the workshop took place.  In this second round, we wanted to elaborate on the sensory properties of materials and their expressiveness.

Palau Güell. Barcelona.

Antoni Gaudí Architect

The Palau Güell is one of the first important commissions that Gaudí received at the beginning of his career. The Palau Güell (1886-1890) is a magnificent example of domestic architecture within the Modernisme framework. The palace suggests many of the essential features found in the later production of Gaudí: Fluid sequences of spaces, ingenious structures such as the central dome, the catenary arches, the structural solution for the placement of the stables in the basement, or the complex geometry found in the roof, solved with traditional elements. This roof is where Gaudí started his formal work associated with the architect’s characteristic chimneys, and it is also where he used the famous trencadis solution (broken tile shards) for the first time.

Sagrada Família, Barcelona.

Antoni Gaudí Architect

The Sagrada Família is a catholic basilica designed by architect Antoni Gaudí. Its construction started in 1882 and is still to be completed. Gaudí evolved from his very first neo-gothic project to this particular style, naturalist, organic and adapted to nature which, according to Gaudí, is likely to present ruled geometric forms such as hyperbolic paraboloids, hyperboloids, helicoids and conoids. Ruled surfaces are forms generated by a straight line, known as generatrix. According to Gaudí, these forms are both functional and aesthetic, and his work consisted of adapting the language of nature to the structural forms of architecture.

A key element for Gaudí regarding his method of conceiving structures was the parabolic or catenary arch, which he used as the most suitable element to support weights. By means of the simulation of various experimental polyfuniculars, he determined the optimal form of the structure needed to support the weights of arches and vaults. He developed a scaled model using intertwined strings from which little pellet bags simulating the weights were hung; in  this way, he could determine the funicular of strengths and the form of the structure. Therefore, by observing the status of loads simulated by the little pellet bags, he experimentally determined the ideal form of the structure, which he called “stereostatic”. This reproduced the optimal structure to work in tension , and when inverted, provided the most suitable structure to work in compression.

Gaudí conceived the interior of the Sagrada Família with the structure of a forest in mind, as a set of sub-dividing columns splitting into various branches in order to support a structure of intertwined hyperboloid vaults. He used inclined columns to more efficiently transfer the loads perpendicular to their section, and gave them a double-twist helical shape, as found in tree branches and trunks. He consequently obtained a simple way of supporting the weight of the vaults without having to use external buttresses.

Casa Milà, Barcelona.

Antoni Gaudí Architect

Also known as “La Pedrera” (1906–1912), it was built as two housing blocks with independent entrances, interconnected by two large inner courtyards and sharing a sinuous facade that transmits the rhythm of the interior. The structure of the house is made of pillars, and allows for a free plan with large openings in the façade. The complex is an example of the architect’s  naturalist period, where geometries are straight, forming curvilinear plans. The attic is especially remarkable; Gaudí conceived a space with a form that was independent from the rest of the building. It is an 800m2 plan, holding the laundry room area and, in turn, acting as a thermal regulator, isolating the building from extreme temperatures, for both summer and winter. The space is inspired in the traditional solution of the “Catalan rooftop”, but by using a succession of 270 solid brick parabolic arches instead, which, imitating the inverted structure of a boat, creates a self-supporting structure that neither requires load-bearing walls nor pillars, resulting in a continuous open space along the whole building.

The Colònia Güell Crypt, Sant Boi de Llobregat.

Antoni Gaudí Architect

It was built between 1898 and 1914 and commissioned by the entrepreneur Eusebi Güell as a religious construction for his workers in the Colònia Güell. Intended to be a 40 metre high church, but not complete to this height; only the crypt could be completed by Gaudí. For this construction, Gaudí came up with a new and peculiar method to calculate the structure of the building: In a shed next to the works, he built a four-metre high, large-scale model (1:10) where he placed an installation made of strings from which little pellet bags were hung. He drew the plan of the church in a wooden board fixed on the ceiling, and hung the strings from the load-bearing points, for the funiculars, and the little pellet bags, for the loads. The hanging bags allowed him to obtain the resulting catenary curve, both in arches and vaults. He later took a photograph which, once inverted, resulted in the column and arch structure that Gaudí was looking for. Gaudí then painted the already defined outline of the church over these photos using gouache or pastel, marking every last architectonical, stylistic and ornamental detail of the building.

New Cemetery, Igualada.

Enric Miralles & Carme Pinos

On the way to La Garrotxa, we made a stop at the Cementiri Nou (new cemetery) of Igualada. This cemetery project differs from traditional cemeteries, presenting itself as a park to stroll around and contemplate. The site consists on a cut into the ground and its walls are used to place all the niches, acting as load-bearing walls. Materials are dramatic and austere. Both concrete and steel oxidation processes add to the unfinished look that evolves and matures throughout the years, integrating architecture in its material and natural surroundings.

The site. La Garrotxa

Located not far from the workshop site, still in the Pre-Pyrenees mountain range, La Garrotxa is a very unique area in the Catalan geography, being a self-contained volcanic area with its own microclimate, and above all, with a very particular landscape.  The predominant colors of this landscape are black, red and orange, found in strong contrast with the lush green of its vegetation.


Steel integrates perfectly with this kind of environment. Despite appearing to be an alien and man-made  element in these natural surroundings it also shares the same chemical elements with volcanic soil, which produces their similar colouring. Stone and steel are antagonistic materials with strong personalities which , when placed together compliment each other. (as seen in the Parc de Pedra Tosca or the Croscat volcano),.

Aging process

A common trait of all the experiences we visited is the trace of time as an essential ingredient of the project. Material weathering leaves an even more beautiful patina, enhancing its personality thanks to its texture and an infinite variety of colors. This is the reason why, in this case, working with thicker steel pieces is essential.

“La Lira” theater and public place, Ripoll 2003-2011.

RCR arquitectes

An urban connection ensemble with a covered public square. The whole building is made of steel. It primarily uses untreated steel plate in various formats and surface  textures depending on its eventual use: Pavement, ceiling or vertical siding.

Parc de Pedra Tosca (tuff stone park), Les Preses 2003-2005.

RCR arquitectes

The transformation of a former agricultural area into a park. Surrounded by a magical landscape formed by lava flows over time. The interventions are focused on maintenance, accessibility and path signposting. Everything  is made of untreated steel plate, with a considerable thickness (20-30mm), with purposes ranging from soil and stone retention to sign support.

Athletics stadium and facilities. Olot 1999-2001.

RCR arquitectes   

This complex consists of an athletics track located in a forest glade, as well as two facilities , a small one operating as a bar and the other one as an entrance building containing locker rooms, a gym and management areas. Both buildings mainly use corten steel plates or rolled/folded profiles. Exterior pavements use steel bars laid on the floor, placed every 2-3cm, forming a “rug”.

Bathing Pavilion. Olot 1995-1998.

RCR arquitectes   

A small locker room, bath and bar facility for a relaxation  area in front of the river Fluvià, surrounded by very tall trees in contrast with the horizontal expression of the building. The whole complex is made of steel, both untreated and stainless steel. Both plates and rolled profiles were used.

Restoration of the Croscat volcano. La Garrotxa 1994.

Martirià Figueras and Joan Font

This is an intervention focused on the landscape restoration and consolidation, in order to transform it from a stone quarry into a centre for the interpretation of the volcanic area. Apart from soil movement in order to re-establish a topographical order, corten steel plates were also used, in an advanced state of oxidation. In this particular case, with the purpose of enhancing the red and orange tonalities to respect and sit subtly within the astonishing landscape that surrounds it.


Claudi Aguiló
Raimon Farré
Polytechnic University of Catalonia
School of Architecture of Vallès, Barcelona