Architects: Sabbagh Arquitectos
- Year : 2006
Manufacturers : Arauco, Atika, Bercia, Cintac®, GLASSTECH, Hunter Douglas, Metalcon, Tarkett, Tupemesa
- Collaborators : Hernán Sánchez, Sergio de la Cuadra
- Structures : Ingevsa
- Lighting : Mónica Pérez y Asociados
- Construction : Sitecna
- Floating Hotels : Innovación mar adentro
- Client : Multiexport Foods
- Built Surface : 4 floating hotels 400 m2 each, plus 1 1.000 m2
- Project Architects : Juan Sabbagh, Mariana Sabbagh, Juan Pedro Sabbagh, Felipe Sabbagh
- Country : Chile
The idea of envisioning a hotel floating on the sea is more like an episode of Fantasy Island than the real constructions that sway over the waters of Aysen, in the XI Region of Chile. But the ingenuity of a group of shipyards in Puerto Montt, the design from the architecture office Sabbagh Arquitectos, and the adequate engineering to maintain concrete blocks afloat, allowed to change the face of the southernmost fjords. Dreams come true in the form of floating hotels belonging to the company Multiexport Foods, the world's fifth salmon company.
Although it seems like a simple story, the initial picture did not look very encouraging. This was because the task was to design hotels that met the environmental standards of the company and also offered comfort to the users, who stay up to two weeks at sea. Everything on concrete blocks just 14x9 meters. How to meet the demands of the project? Technological innovation, technical challenges and resourcefulness were key.
After the construction of the Fisheries Building in Puerto Fonk in 2005, Multiexport Foods executives were eager to take on new challenges. So eager, that they decided to hire the services of the office of Juan Sabbagh again, this time to renew the landscape in the fjords of Aysen. "The commission, in terms of architectural design, is similar to the Fisheries building because it was about combining harmony with the landscape and in turn, improving services for the workers," recalls Juan Pedro Sabbagh, partner at Sabbagh Arquitectos.
Thus, the architects set out to design hotels, or dwellings, that as their name implies, delivered optimum operating conditions to people in remote locations. And to ensure the best conditions, the first idea of the project was to develop containers based on prefabricated modules to be located on land. But the ban on construction in environmental areas forced us to move the constructions to the sea. Yes, you read that right, the sea.
With the grant of a maritime area, began the technical and architectural challenges. "In the area there are other fish farms that have houseboats, but these constructions are architecturally and technically very precarious," says Sabbagh. The company raised their demands. "The facility should be able to operate offshore in order to allow optimal control of our production. And it would have to be operable, not only to move but to rotate the growing areas, as required by the strict environmental standards of the company", say representatives of Multiexport Foods.
Faced with such requirements, the architects took advantage of the concrete blocks developed by Sitecna shipyard in Puerto Montt, and on these they proposed what turned into the great architectural and engineering revolution for the area.
But it was not so simple. The architects began by imposing design criteria for construction. Thus, they remember that the first hotel "was done with great sacrifice," but the hard efforts paid off because after the first experience, interesting lessons were acquired.
We talked about a project involving the construction of floating concrete hotels on slabs. But what do these slabs that support hotels consist of? And how do they stay afloat? Let's go step by step.
The slabs, or concrete hulls, which serve as building slabs, consist of rectangular reinforced concrete surfaces of 14x9 m, supported by beams of the same material. The structures that are under water consist of a special material, concrete H30, with higher strength and lower porosity than other types of concrete, that prevents the passage of saline water to the reinforcement bars, avoiding corrosion.
To avoid damage to the building, precautions were increased. "Significant coating was placed, of at least 10 cm of concrete, before the bars. Additionally, special care was placed in areas in contact with the surface, which are more vulnerable to corrosion by the presence of oxygen," explains Eduardo Valenzuela, CEO of Ingevsa. The slabs have a hatch for maintenance.
But the best part of this adventure was building the slabs, because the shipyards assemble them in the bay, waiting for high tide to facilitate the movement of structures, which are concluded at sea. This task has been refined since the fifth element of the project, a farming center of 1.000 m2 currently being developed, will have unique structures instead of recycled structures from old
floating houses, which will give the architects and builders a better control of the space. In fact, it is expected to add another floor to the two that have the rooms already built.
You will wonder how the slabs float, especially since they support hotels 400 m2 each. "It is a system that concentrates weight in the lower part of the construction, in this case in the floating area, and becomes lighter on top", explains Valenzuela.
Indeed, while the concrete is concentrated in the lower area, the upper structure is galvanized metal, with thin 75x75 cm profiles, which can lighten the load towards the seabed. For the same reason, slabs between floors were avoided, which would have forced an additional strengthening of the structure, making the project more expensive. The galvanized metal also imposed conditions. "The grids are made in galvanized pools, which means that the joints must be bolted because a weld would damage the galvanizing," said Valenzuela.
The slenderness had to consider wind in terms of the structural calculation. This is because, unlike solid structures like concrete, which are affected by earthquakes, the lightest elements are vulnerable to wind.
The structure was designed to withstand winds of 180 km / h and was reinforced by diagonal bracing, designed to withstand lateral loads, with slim profiles located behind the walls or hidden in the backs of the hotels.
The structure has high buoyancy due to the fulfillment of a simple rule that is to calculate the force of water caused by the weight of the construction. Thus, considering the submerged volume by the density of water yields a value that indicates displacement. "If the weight of the hotel proves greater than the water it displaces, it sinks," says Valenzuela. Understood. Now let us examine what is on the sea.
It is good to clarify that the slabs transported from Puerto Montt were anchored to the upper structures through a secure and innovative system, so as to avoid any danger of detachment.
Thus, the slabs are joined to the structures through concrete bases or plynths. In turn, bolts are attached to the bases, and on these, pillars every 15 cm, as the teeth of a comb. "A surface was drilled on the base, adhered to a special glue, then a striated column was introduced, the formwork was placed, the concrete was poured and then the formwork removed," lists the engineer. The system was reinforced with a bonding adhesive to secure the joint of the concrete slab with the base. Also, the slab floats 40 cm above the bases, and the hotels are almost 80 cm above the sea level.
For the architects, interior and exterior design of the hotels was crucial. In fact, they maintained the company's corporate color, dark graphite gray, because it allowed them to harmonize with the landscape. This was achieved through sheets specially developed for the project, that allow for continuity between the wall and ceiling.
The company intended to give a comfortable standard for its workers, so a visual environment as comfortable and pleasant as possible was conceived. This was achieved by giving more height to the spaces, using wood for interior finishes to add warmth, and allocating large double-glass windows to provide light and keep the interior temperature, reducing the feeling of confinement.
The architects add that both light and space were essential. "Natural light and ventilation should be elements present in all rooms, so every room has an operable window for ventilation, and a series of bay-windows that illuminate and expand the space," says Sabbagh. Outside, a circulatory surface serves for docking boats and maintenance. Inside the hotels there are two levels, one as operative-dwelling, and the other as leisure-dwelling. Both have rooms for both managers and workers alike, even for some kayakers passing through the area.
In terms of facilities, the company intended to allow "the connectivity and leisure of personnel". For this reason, a TV room, game room, exercise area, and cyber cafe are included.
by Claudia Ramírez F.
BiT Magazine nº57, November 2007