"Jetzt haben wir alle Marken, die das Herz der Swatch Gruppe sind, erstmals unter einem Dach" Nick Hayek
Standing on the top of the hill from an house that my friends and I rented during our period in Switzerland, admiring the beautiful view that the place offers, I was intrigue by a dragon/snake figure down the hill. Going then down the hill, walking along the river Schuss with Marvin Gaye soft music playing on my headphones, my feet felt like floating, pushed by serenity and peace after 20 minutes of walk I have reached to one of my most enjoyable construction site. Yes, right next to the small canal, in tha small fantastic city the swatch group was building something faboulous designed by Shigeru Ban. It is the new headquaters of the Swatch group. Is it a snake or a dragon? Well, it is what it is and I believe it is hard to say but it is a timber construction that the group Blumer Lehman was building up. Since I have happened to be there during the construction process, I'm bringing it to you.
Picture of the swatch headquarter in Biel, Switzerland; Source architecturalrecord.com
I know that such a beauty could hypnotized someone for a short-prolonged time. But let's see what is beneath the beauty.
The old saying " don't change a winning team", well Shigeru Ban collaborated with the group in the construction of the Nicolas G.Hyek Center in Tokyo that opened in 2007. So, in 2011, Shigheru Ban somehow knew how to please his client, matter of fact his proposition won the competition. Although three buildings were built for this competition, our interest is on the headquarter of Swatch.
Although the final complex cladding scheme is the one many people know about, the initial solution was intended to be quite simpler. It was entirely in ETFE cushions. We wanted to make the skin as light as possible," says Shigeru Ban. But once the project was confronted with the issues of integration of radiant heating and cooling ceiling panels, the fire protection with sprinkler, the need for noise control (ETFE is a por acoustic barrier) as well as compliance with Swiss labor regulations that required the inclusion of vision glass, the timber cladding types grew. For an architect like Shigeru Ban who has crafted building out of paper and worked for refugees, challenges are only hidden opportunities. So, he has redesigned the enclosure, trying to take advantage of the full mechanic properties of timber. In this new approach required the help of a parametric designer specialist which they found in Blumer-Lehmann group. The intervention of Blumer-Lehmann group helped defining the structural components, the cladding elements and the extension of structure creating a slimmer assembly.
The result of these first interactions gave a free-form building which is five levels open offices within a reptilian grid shell that extends over a length of 240 meters along the river Schuss until sheltering the entrance plaza and span over the roadway Nicolas G. Hayek Strasse transforming next into the roof of the adjacent conference hall (see illustration in the picture below). It expends in width of 35 meters at its highest point it reaches 27 meters.
Illustration of the different layer of the Swatch heaquarter and Cité des temps;Source architecturalrecord.com
Most of the commentators refers to it as the timber grid shell. It is the result of the composition of 62792 timber pieces for the integration of nearly 2800 uniquely shaped facade panels of which there are three primary types: glass, metal and ETFE cushions to form the grid shell.
Structurally the grid shell consists of double-layer beams in one direction and single-layer beams in the other. The latter do not reach the full height of the grid so they are assisted with beams spanning from one node to another. The timber glulam beams constituting the structure have with heights varying from 760 mm to 920 mm assembled on site, with lengths sometimes going up to 130 meters and were crossing each other’s every 2,30 meters to form the visible grid.
Full display of the timber structure of the roof; source: Maderayconstruction.com When it comes to structural connections, for those who have heard of Shigeru Ban and know about the Tamedia building, Swiss media headquarter in Zurich a seven stories timber building. The architect reduced the steel connectors almost to zero. The same principle was applied as well in this Swatch headquarter. Whether, it was possible the connections of beams were made through wood to wood connections through dovetail joint system and reinforced if necessary, with the least steel plates or screws. As you can see from the pictures below:
Illustration of perforations for dovetail joints and execution; Source: video extraction from Lemman-gruppe.ch
The grid shell was based on the traditional woodworking cross-joint. The lap joint, which cuts away half of the cross section of both beams so they appear to run through each other after assembly, transferring load along both directions. But this type of connections can only be mounted by the direction defined by the vertical faces. In order to overcome that, a "skewed" lap joint was developed for the project, where all vertical faces open towards the assembly direction defined by an angle. This gave place to a cone shaped region. A curved segment could only be assembled if and only if there exists an assembly vector that lies within the assembly cones of all its cross joints.
Illustration of skew lap and vectors through the assembly cones for beams connections; Source: Maderayconstruction.com
In order to have beams going up to 130 meters connections between timber beams segments were necessary as well. In that case the technique of butt joint, where usually a steel plate connects both beams segments via steel dowels. Habitually, the plate is preassembled in one segment and then connected to the other one by inserting the dowels during on-site assembly. But in this project having a steel plate sticking out of the segments would have restricted assembly direction to the plane of the steel plate. In addition, it would have impacted the assembly freedom gained through the skew lap mentioned above. Hence a variation of the joint was developed where steel plates were preassembled in both segments without exceeding the ends of the beams. Once on site, these plates were connected by a third steel plate. This last plate was of conical shape therefore self-positioning after being inserted into the slot.
Despite its shimmering, curved silhouette, the challenge was not in figuring out how to make the free-form enclosure stand up. " in terms of statics, it is a vault or arched bridge, which are forms that are familiar and well understood," says Richard Russel CEO of Leman-Blumer, but the multitude and diversity of the components. Matter of fact, to create such a structure they have started with 2-d solutions as explained by Jan Hampel, 2/3D designer from Lehman. But the complexity and the diversity of the elements forced them to do a 3D parametric design. The vault was then divided in thirteen sections for proper and details study, see illustration below:
Illustration of subdivision of the grid for paramatrezitation; Source: video extration lemman-gruppe.ch
Design-to-Production, was at its best in this project. Once they created the plans for approval by the technical planners and architects. They were given to planning specialists for parameterization in order to generate models. With parameterization, they could create a basis that could be re-implement at any given place in the building. Which had reduced the need of creating same item thousands of times. Given the numerosity of the components and the fact that each had its own shape, one error would have meant thousands of others. The parametrization was the perfect answer for this project by bringing precision and saving time.
The conception here, is not only about structural, it has to take into account the integration of electrical, heating, cooling and the sprinkler. All of this has to be considered already during the production of the single pieces of the roof. That implied about 5000 perforations of the timber components. Timber beams were CNC milled to create precise spaces for services and to enable intersecting beams to tightly interlock. Surprisingly enough, they were all successfully integrated in the grid as shown here below in the picture:
Illustration of the integrations of of districbution of electricity, water, air and sprinkler; Source architecturalrecord.com (modelisation ) & Fabian Scheurer Designtoproduction.com (second picture)
Given the highest level of prefabrication, the execution had to be structured as well. The supply of parts of the structure at the construction site had to be when working on the corresponding stage and in the right order of assembly. The whole building was divided into 13 assembly sectors along the spine in accordance with the parametrization. It was then installed for somewhat over ten months counting during those months 22 days of inclement weather. The beams were delivered on site on the finished state. Although protected in group during the transportation, the single beam was not protected and being a visible beam, it was imperative to avoid any type of damage or soiling during the construction stage.
So, they have to wear gloves to avoid leaving any fingerprints or dirt on the parts.
To build an arch you have to start at the bottom and have a support structure. Here as well, in order to reach the highest point a support structure was necessary. First the scaffolders erected falsework, aligned using a tachymeter to ensure that heights and various axes were absolutely precise. They started at the bottom, placing the individual parts into the structure and working their way up to the highest point, the roof ridge, from two sides in order to place to final element. As soon as the roof ridge was closed, they removed the support structure. With all parts in their designed place the structure stiffened on its own.
The whole structure was assembled within a precision range of five millimeters so constant monitoring was essential in order to quickly noticed anything out the precision. Prefabrication allowed such a complex building to be totally prepared offsite and be simply put together on site. Russel went so far as saying that the workers were only equipped with small hammers and all they had to do, at most, was place a screw with a cordless drill.
Fixations of the beams with cordless drill; Source: video extraction Lemman-gruppe.ch
Remembering that the beams were quite heigh going up to 920 mm, so we could really say that the assembly process was highly simplified. A Simplified assembly meant also less worker required for the assembly process. The picture below is the perfect illustration.
Illustration of the assembly process on-site with the minimum workers necessary; Source: Maderayconstruction.com
Transmutation of prefabrication into reality might be easier for a small project but for the largest timber project of Switzerland and maybe of Europe and given the level of precision required they needed to have a sample model. That is what they did at the exposition of 2015 by bringing a model.
Model presented at the exposition of 2015; Source: Fabian Scheurer Designtoproduction.com
Sustainability was a goal from the start. All the raw materials arrived in form of rounds logs at Erlenhof, it was then cut and dried. For the roof structure the lamellas were then cut to the adequate thickness and successively laminated in curved form in order to form the beam which will be milled and processed on the machine. All the necessary features will be derived with the machines. The flaws are worked out and the beam is treated and packed for delivery on the construction site. "Our vision was to make the building process as environmentally friendly possible" says Nick Hayek, president of the Swatch Executive Group Management Board. Indeed, 1998 cubic meter of timber mostly of spruce from the Swiss forest were used for the construction of the building. Despite the huge amount employed it is important to know that the equivalent amount grows back in Switzerland in just two hours. This quantity of wood used equivalents to a carbon storage of 1848 tons of CO2 stored in the building without mentioning the replaced trees that will be growing henceforth cleaning the environment by absorbing CO2 necessary for the growth. A sustainable building is not only about the material used for the construction but also the energy sources of the building. In this building nine wells were created in order to use groundwater for heat and cooling. 442 curved photovoltaic panels (1770 m2) capable of producing around 212,3MWh energy per year were installed as well. The photovoltaic implementation helps saving 30 tons of CO2 per year based on difference between solar power system and Swiss electricity mix.
Tye Farrow, a LinkedIn contact from Farrow Partners Architects has been having lately a slogan " Build for health". Well, if the exterior of the swatch building has amazed you enough, it is inside that the warms of the timber and skillful use of timber, space, technology of Shigeru Ban await you.
The surface area of the upper floor decreases successfully from floor to floor while galleries with glass balustrades provide view to the lower floors. Besides the regular working places, various common areas are distributed throughout the building, small rest areas in various locations. For some privacy or works that requires concentration, the "alcove cabins" are available. And if the employees need brainstorming space? well they could use the "Reding Stairs" a staircase leading nowhere with steps and views encourage brain creativity.
Illustraction of the inner beauty of the Swatch headquarter; Source:Designboom.com
My main focus was on the Swatch building, it is good to know that in the overall project, Cité des temps was as well designed by Shigeru Ban in the same site. Nestled between the new Swatch headquarter and Omega historic buildings. It is a 80x70x28 meters timber building, an independent architectural unit that complement the Swatch headquarter. It has interesting 14 arcades on the ground floor of 15 meters span and 5 meters wide that support the building. Cité des temps hosts the Omega museum on the first floor as well as the Planet Swatch on the second floor and the Nicolas G. Hayek conference floor (see following picture) on the fourth floor which is topped by the head of the snake.
Nicolas G. Hayek conference hall Cité des temps; Source: Designboom.com
Molded timber posts were used to support timber beams with 15 meters of span. The use of steel connectors was reduced by implementing once more wood to wood dowels connectors as illustrated in the second picture bellow. The cylindrical dowels were made of Beech which is harder than Spruce in order to create rigid connections.
Illustration of timber beams spanning 15 meters, molded posts and detail of connections; Source: architecturalrecord.com
Also in this building 240 m2 of photovoltaics panels were installed and 1618 m3 of Swiss timber were used in the construction process.
" Now, for the first time, we have all the brands at the heart of the Swatch group under one roof", Nick Hayek
Summary:
Building Name: Swatch Headquarters
Client: Swatch AG
Architects: Shigeru Ban Architects; Itten+Brechbuhl AG
Location: Biel/Bienne, Switzerland
Year of conception:
Planning: 213
Construction: 2014
Delivery: 2019
Completion of susbrtucture:
Construction time time:
M3 of timber: 1998 m3
Floor area: 21150 m2
Timber per square meter: 0.93m3/m2
Investment cost: 220 million CHF
Awards: many to come
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