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CONFERENCE "GLASS IN ARCHITECTURE" LA GRANJA JULY 12th 2001

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INTRODUCTION

When I received the invitation to participate in this course about the use of glass in architecture, I remembered one of my teachers of this subject, with whom I had the honour to study during my academic years.

This memory was the reason why, several days later, I decided to read again one of his writings and select certain paragraphs because of their great significance.

"Nowadays and thanks to the great masters, we have indications about how to create good modern architecture (...)"
Braner and Gropius, in a short book containing the works they undertook upon their arrival in the United States of America, explained, for example, the way to suppress the incidence of sun rays on a window glass, in the days when it was more incovenient. In order to achieve this, the authors used a PARSOL glass and located it neatly on the facade at a certain distance and height, so that it could cut the sun rays without breaking or staining them.

It seemed like a simple mechanism, but this idea made me think that such a thing could happen with the whole of the New Architecture and it became for me a reason for joy, some kind of liberation.

This has been corroborated by many of the new masters that have preceded us. It was the beginning of "Physical" architecture. "A wall of (...), a glass (..), a beautiful bearer of (...), placed with (...)".

The master I am referring to is Mr. Alejandro de la Sota, who also used to say: "(...) in Architecture we do not learn about solutions. You have to be yourself and be prepared so that when the moment to look for solutions comes, these come out naturally (...)".

The selection of projects and works that we are now going to show, is a short summary of the solutions that, in the course of our professional career, we have created in order to solve specific situations.

We have chosen the most extraordinary works with the aim of showing the widest possible spectrum of options within the established time limits.

We have selected three projects in which glass is the leading material.

What these three works have in common is the fact of being office buildings that can be used by one or more entities. For this reason, the minimum surface available for rent changes with regard to each of them.

If we analyse these structures from the life span point of view, this kind of buildings have four essential parts that are used at different stages, maintaining the level of confort and performance required at each of these stages.

The structure or framework has to remain constant without losing any of its features during the whole life span of the building. Currently, the experts in this type of studies consider that such period lasts around 50 years.

The facade or skin is an essential element of connection between the external and internal conditions of the building and, as such, it is indispensable in order to achieve the required confort level.

The confort requirements are directly proportional to the standards of living of society. In this case, the estimated period of life span is 20 years.

The reasons stated before, together with others such as recent scientific advances and the growing dynamism and development of the telecommunications sector, have meant that the installations of the buildings, which form the real circulatory and vital system of the functional structure of such buildings, might have to be replaced after an average 20-year period and new technologies should be then incorporated.

The module system and the furniture are elements that give shape to the spaces, and, in this type of buildings, they are one of the aspects with greater mobility.

These considerations bring us to concepts such as module system, versatility, flexibility and accessibility of the different parts of the building.

In the projects we are now going to look at, all these concepts are present as essential elements of the design, although they have been treated with different structures, installations, facades, compartmentalisations, etc.

We have prepared a series of pictures of each of them, including the main floors together with more representative construction details that will surely help us to show them in a more pleasant and precise manner.

OFFICE BUILDING: 8, AVENIDA DE BURGOS

The project for this building was carried out in 1986 and it was finished in 1989.
The plot is located in the northern area of Madrid and, more specifically, in the outskirts of the M-30 ring road. This plot is part of one of the numerous detail studies that were carried out in this area as a result of the new limits brought about by the opening of such road.
The distribution of volumes envisaged three plots surrounding the old church of the demolished Reparadoras Convent.

In these plots, three similar volumes were defined that corresponded to each of them, with 19 floors on the grade line and a surface of 14,000 m2 with development potential.

The access to each of the plots was done through a newly built road surrounding the church with entry and exit from the M-30.

Each volume was defined by two louvered shutters placed on top of each other, the bottom one corresponded to the ground and the first floors with a surface of 1,200 m2 each, and the top one corresponded to the remaining 17 floors on the grade line, with dimensions of 15 m x 45 m and a surface available for rent of 250 m2, which is equivalent to the useable surface of half an average floor.

In order to fulfill modular needs, a horizontal structure of modules of 0,90 m x 0,90 m was planned. According to the wishes of the client, this structure was built in reinforced concrete with lights of 5 m and gantries perpendicular to the longest facade.
The ground plan was designed by locating the group of lifts, the main staircase, the toilets and the installations rooms in the southern facade, opposite to the access of the building.

The emergency stairs were located in the eastern and western facades and at their centre stood the service lifts, fire dry columns and air extraction systems from the basements.

In the roof plan, in the lower level were located the rooms for the boilers and the pumps, the rooms for the lift machinery and the power generator, the cooling plants and the cleaning pod/gondola.

In the upper level were located the heat exchangers, the infrastructure for telecommunications, the cleaning gondola and the lightning conductor.

The planned modules of 0,90 m x 0,90 m in horizontal formed the net on which the following elements were coordinated: structure, facade, installations, compartmentalisations, floors, ceilings, etc.

The floor was fitted with canalisations that could be fully checked, these were placed every 90 cm and matched with the modular net, so that this group of canalisations also matched with the compartmentalisation planned, which included the abovementioned canalisations every 0,90 and, in turn, matched with the distribution and modules of the ceilings.

Regarding the control of the installations, a technical floor of 0,90 x 0,90 m was introduced. The ceilings were made of aluminum sheet and, in order to achieve greater flexibility, given the quantity of elements involved, normal and emergency lights were placed, as well as smoke detectors, PA systems, impulse and return grids, air-conditioning system, automatic sprinklers for fire extinguishing, signs, etc. Likewise, two modules were established: 0,90 x 0,90 in the public areas, and 0,30 x 0,90 inside the offices.

All the elements mentioned above had a relative mobility of 1,20 m with regard to their location in the plan in order to adapt to the different compartiment systems.

In most of the cases, the perimetric fan coils units were situated in the apron walls of the facades. These elements, when located in the space between the framing and the ceiling, increase considerably the useable surface. At the same time, they prevent the grids to be blocked with elements left between the fan coils.

This solution allowed us to to have all the remaining height of the plan available as area of vision.
The fact of choosing a light facade instead of a traditional one is justified because the increase in price of one with regard to the other is compensated for by the increase in useable surface over built surface of one with regard to the other.

At the time of execution of this project, there was not available in the market place, at least to our knowledge, the current wide range of colour reflectors and glasses with features such as noise reduction, thermal insulation, sun factor, etc.

The solution adopted for the facade consisted in a Curtain Wall. Such wall was made up of a structure of aluminum profiles placed vertically at a distance of 0,90 m and multiples of 0,90 m in horizontal position.
The areas of vision are made up of a composition of Reflectasol glass of 10 mm, with a base of Pink-Rosa Parsol glass with an air space of 12 mm and a sheet of 4 + 4 mm. The opaque glazed areas consisted of a tempered Luna Reflectasol glass of 10 mm with Sandwich Panel.

The remaining part of opaque areas was solved by using Sandwich Panels of bronzed-anodised aluminum.
The purpose of this building was to become a reference for current technology through the use of various elements: a building environment predominantly made up of brick, the presence in its centre of the Church of the Old Reparadoras Convent, a brick building of Neobaroque style by Luis Bellido which was finished in 1925, and other structures of this same material such as the old head office of Deutz trucks.

The arrangement of the glazed openings and the aluminum-covered spaces helps stylising the rigid proportions imposed by the distribution of volumes of the building.

The elements that help distinguishing the building, while giving it a uniform image are the following: the coppery and purple colors of panels and glasses, the design of the external emergency stairs as light elements but integrated in the building design, and the finial in the top of the building that integrates the two levels of the roofing.

42, JOSEFA VALCARCEL BUILDING

In the year 1990, the Swedish development company Reinhold announced a tender of projects for the construction of an office building in a plot located in the eastern part of Madrid, in the road leading to Barajas airport.

This plot had a rectangular plan of around 6,000 m2 of surface, with facades opening onto two different streets.

The urban development code established that the setback with regard to the boundaries depended on the height of the building, and the length of the straight span of facade was limited to 70 meters.

The requirements of the tender consisted in an office building that could be used for one or more entities, with a minimum module office surface available for rent of 350 m2 and the possibility to market modules of 700 and 1,400 m2, open-plan stories, flexible distribution, maximum useable surface / built surface, maximum saving of energy and lower maintenance costs.

The maximum built surface on the grade line was established at 10,000 m2 and the number of floors was eight plus a setback attic.
Special attention should be given to the view of the building from the road into Madrid from the airport, in the A-road II.

All these requirements and conditions made the team of Abarrategui choose a solution in which the access to the building was done through an interior road that leaded to the streets corresponding to the facades of the plot.

In order to optimise the distribution of the floors and solve the problem of evacuation and accessibility of the building, two access were planned as well as two centres of communications. Such centres were made up of a group of two lifts and a goods lift, a staircase, toilets, a communications room and installations rooms.
These centres were located in the western facade and they converged in the ground floor level with the access to the building. From this floor, the subterranean car park and the basement of the installations could be accessed through a staircase and a lift.

In the ground floor level, there were two modules of offices and a surveillance and control room for the whole of the construction.

The access routes to the control room were joint by a porch that was created by the volumes located immediately on top. From such porch, the garden area and the pond in the centre of the plot could be easily admired.

Adjacent to the pond, a cylindrical element houses the emergency stairs of the first, second and third floors. In this case, it was necessary to fit out a third centre of evacuation due to the configuration and surface of such floors.

The requirements that consisted in limiting the spans of the facade to 70 m, limiting the volume to be built and establishing a setback distance for the boundaries proportional to the height, were the elements that encouraged us to design a plan in the shape of an omega, with lateral wings tangent to the two main communications nods and with the volume of the emergency staircase located in the central axis.
The first, second and third floors are identical to one another and they consist of four modules of offices.

Due to the urban development requirements mentioned above and to the need of keeping the interior of the office totally open on a structural level with no middle supporting structures, the fourth floor is partly occupied by two big bridge beams that hold the structure of the upper floors and measure 45 m and 27 m respectively, and two brackets of 9 meters.

In this floor, apart from two centres of communications, there are two office modules as well as more balconies.
In the fifth floor are located two modules of offices, two centres of communications and two balconies within a volume of 45 x 14,40 meters resting on the two bridge beams.

The volume of the fifth floor is maintained in the sixth and seventh floors, until the maximum height of cornice is achieved.

At this level, there is a setback attic with two office modules, apart from two balconies in the eastern and western sides of the building and the centres of communications.

The roofing has two centres: in the lower one are located the rooms for the boilers and the pumps, the cooling plants, the enthalpic exhangers, the plant rooms for the lifts and the goods lifts.

In the upper level can be found the lightning conductor, the installations for communication purposes and the cleaning gondolas.

Due to the singularity of the building, in order to clean the facades using conventional pods, thirteen teams had to be distributed in the various balconies located in different parts, leaving some areas with difficult accessibility. To overcome this problem, a new cleaning pod was designed with an arm of 35 m and a flexible telescopic arm that helped gaining access to the areas setback in the facades and, in short, to all the external parts of the building.

With the aim of reducing the vision of such elements from the outside, a central cylinder was located in the vertical spin axis that continued through the cooling plants.

The basic horizontal modulation measures 0,90 X 0,90 m and, in this case, it measures exactly the same in the vertical position, because this figure coincides with the regulations for urban development.

This modulation was the base for the design and the location of the facades, structure, installations, compartmentalisations, ceilings, etc.

In this case, the structure is metallic and takes into account the existing height limitations, so that the design of the floors can be open enough.

The supporting structures are always located in the facades with the web girders placed parallel to these. The bay of the different modules of the building measures 14,40 meters and it is joint by framed girders placed every 1,80 meters and resting on the beams located in the facade.

The framing is made up of concrete over metal sheet, and the installations of each of the floors are placed on the intertices left between the ceiling, the framing and the structure. This optimisation of the space is possible thanks to the modulation of all the elements mentioned above.

The design of the facade was solved by using a curtain wall formed by a reticle of aluminum semiprofiles with thermal bridge failure allowing the execution of three-floor high glazed panels which, in turn, favoured a faster assembling.

The peculiar position of the building against a background in which industrial constructions existed side by side with residential buildings and offices, together with the suburban character of the environment, were the main elements that made us decide to exploit to the most the plastic possibilities of COOL LITE, using a grey, green and pink colour palette to lend the building an individual image, a sort of rainbow in the middle of the storm.

The fact that the glass was of a high performance, allowed us to use all the free space in the facade, such as the joint areas, and it was not necessary to use opaque elements to achieve the global coefficient of heat transfer, as would have happened in the building previously presented.

In the areas of vision, the glazing consisted of COOL LITE of 10 mm plus an air chamber of 12 mm plus a sheet made up of two planilux glasses of 4mm.
In the areas where the vision was not possible, the glass used was COOL LITE of 10 mm plus a sandwich panel in the extrados.

The construction of the curtain wall coincided in Spain with the first manufacture of COOL LITE. The curtain wall system was manufactured in France using panels, for such reason, it was necessary to send the glass to that country for its assembly in the panels, which were later assembled, in turn, at the work site.

Depending on the incidence of the light and due to the special conditions of transparency of the glass, the building is perceived differently throughout the year.

There are other factors that also affect this perception such as the weather conditions, the time of the day, the light, etc. It should also be highlighted that the night vision of the building is radically different because, at this time, the external and the internal lighting systems add multiple variations to the way the building is perceived.

The modulation used in the construction becomes evident in the external side of the building because the glasses are divided following such modulation.

This modularity becomes also evident in the external roofs of the building facade, in the aluminum-covered bridge beams, in the supporting structures, chimneys, crowning elements, etc.

Inside, this modularity is present in the rangers, rails and windows of the curtain wall, in the metal roofs of 0,30 x 0,90 meters, in the distribution of the installations and in the rest of the elements inserted between the plates.

The foreseen compartmentalisations are coordinated with the facades, the installations, roofing, etc. using the same modularity as in the design.

This conception fulfils the need for flexibility and versatility in the use of the office building.

Nowadays, the building is rented to two different companies and is divided vertically in two equal parts.

The first one is occupied by the newspaper La Razón, and the other by the laboratories Roche.

AIR CARGO CENTRE OF MADRID BARAJAS AIRPORT

In the year 1994, the representatives of the Air Cargo Centre of the Madrid-Barajas Airport organised a tender of projects for the construction of the building of the Air Cargo Centre of the airport.

According to the rules of such tender, the building had to include offices for the different air cargo companies, with a list of requirements that covered the construction of offices of 22 m2 to offices of 2,000 m2.

On the other side, the building had to be flexible and versatile enough to allow the renting of a wide range of surfaces.

According to the abovementioned rules, the office building could have a maximum of 9 floors on the grade line and a built surface of 19,000 m2. Another of the requirements consisted in building, in two of the floors, a joint area for business use and another for administration purposes related to air cargo matters of around 2,500 m2 each.

The requirements for the parking area consisted in a total of 1,300 parking spaces with loading and unloading area, divided between general public, clients and business area.

The total height of the building was limited to the upper height established by the airport. Another of the conditions established that the construction of the office building had to be developed in three different stages, so that some of its parts could already be operational from the first stage, such as the administrative, business and parking areas. The surface of the building was fixed at 7,000 m2.

In the second and third phases, while keeping the building operational, it should be possible to enlarge it 6,000 m2 every time.

From the conceptual point of view, the proposal presented has a plan in the shape of a TT. In the first phase, the shape is that of an inverted U and after the two foreseen enlargements it should acquire its definitive TT shape.

In this elemental shape, every stroke represents one of the parts of the building that can be identified according to its function.

For example, the horizontal stroke corresponds to the office building of nine floors in its central part and eight floors in the two external ones.

Each of the vertical strokes represents the Ground Floor of the Business Area and the Administration Services Area, which are developed in two different floors.

The space between the vertical strokes corresponds to a pedestrian gallery partially covered by two glazed vaults, which are reminiscent of the classical shopping arcades of the end of the 19th century and beginning of the 20th that are distributed all around Europe, in places such as Naples, Milan, Brussels, etc.

In this plan are distributed 1,300 parking spaces as well as loading and unloading areas. The vehicular traffic system has been organised in an inverted U shape juxtaposed to the plan of the office building in the enlargement areas corresponding to Phases 2 and 3.

Due to the fact that the building has to be operational during the process of construction of Phases 2 and 3, the central section of phase 1 corresponding to the inverted U, includes the main communications centres of the three phases of the office building.

Each of these centres consists of a staircase, a group of three lifts, a communications room, installations room and toilets.

The office building has two main accesses in the Ground Floor through the indoor gallery, where it is located the control and security unit.

This gallery can be accessed by pedestrians through two routes located in the eastern side, where the client´s parking and the airplane platform can be found.
The northern and southern routes of access, between the nine-floor building and the two-floor one, lead to the gallery from the parking of the business and public services areas and from the public parking.

In the western side, there is another route that allows to access the building from the parkings mentioned above and from the access road to the cargo centre.
In this floor, there is also an access from the pedestrian gallery to the business centre and to the administration services offices.

The emergency stairs located in the east with their respective goods lifts, can be accessed from the porchs of the buildings corresponding to Phases 2 and 3.
Two stairs from the office building and the business building complete the vertical evacuation routes in case of emergency. These are located within the construction and on the grade line.

The electric meter room and the room for control and management of the installations are located adjacent to the routes of access of the office building.

The communications have also been placed in the services and installations basement. This basement occupies only the plan corresponding to the first phase of the Office Building.

In the first floor of the ensemble of the three phases, there is a centre of vertical communications with circular plan that includes an emergency staircase, a goods lift and forced ventilations, as well as the venting system of the premises, which is located throughout the business area and the public services offices.

In this floor, the premises of the business area are directly linked to the lower level through the escalators and through a courtyard with central lighting.
Likewise, some of the rooms of the administration services offices are located in this area.

In the following levels, from the third to the seventh floors, the building keeps the same shape with 5 centres of communications. In the eighth floor, the area corresponding to the first phase is made up of offices. The wings of the Second and Third Phases are balconies.

The roofing plan of Phase 1 has two levels in which are located all the installations that give service to the three phases of the building.

In the lower level are located the rooms for the boilers, pumps, climatisers, cooling towers, power generators, telecommunications infrastructures and PA systems, as well as the rooms for the lift machinery.

The lighting conductor, the aerials and the cleaning pod are located in the upper level. The cleaning pod moves through a rail that runs along the whole length of the First Phase.

In the roofing of the building corresponding to the business area and to the public services offices, there are no installations in any of its two levels, this is due to the fact that they can be seen from the upper floors of the office building.

The parking areas for the restaurants and cafeterias of the business section are located under this roofing.
In order to achieve the highest level of flexibility, Abarrategui designed a screwed metal structure that allowed the construction of open-plan floors in the whole of the office building, with a bay of 13,50 m. The supporting structures and the web girders were located in the facades and, in between them, framed girders were placed every 1,80 meters with a concrete floor slab on steel plate.

In the business and public services areas, only web girders were placed because of the lower density of installations to be located between the ceiling and the framing.

A fundamental principle in order to achieve the desired flexibility and versatility, consists in establishing a modulation as the base for coordinating the different parts of the building: the structure, facades, installations and compartmentalisations. The modulation chosen was 0,90 X 0,90 in horizontal position and 0,85 in vertical position.

The different levels are fitted with canalisations that can be checked every 0,90 m and that are joint by a false ceiling of 1,80 m wide that runs along the longitudinal axis of the floors of the building. Such canalisations form a real fish bone structure.

The removable aluminum roofs measure 0,30 x 0,90 meters in the office areas in order to integrate and place within them all the elements of the installations, since between the roof and the framing are located the installations for air-conditioning, PA, detection, extinguishing and normal and emergency lightning.
All these visible elements have been fitted with mechanisms that allow a relative degree of mobility from their initial position of 1,20 m, in order to facilitate changes in the distribution of the compartmentalisations.

The design of the facades has been solved by using a curtain wall formed by a vertical structure of aluminum sections separated every 0,90 m or multiples of 0,90, so that any compartmentalisation done in the interior of the building and following the modulation of the roofing and the floor canalisations, always finds in the facade an element of division of the curtain wall.

The areas of vision of the office building have been solved by using a combination of COOL LITE SPB glass of 10 mm + air space chamber of 12 mm + sheet of 4+4. One of the glasses is Planterm glass in order to improve the thermic performance.

For this very reason, the curtain wall system has in its sections a device for the rupture of the thermal bridge/heat bridge/for the thermal bridge breakdown.
In the non-vision areas, the materials used have been COOL LITE glasses of 10 mm and a Sandwich Panel of varnished aluminum.

Such coatings model the architectural shapes of the building.

Glass has been one of the main elements used in the design of the panoramic passenger cars of the lifts that run along the eastern facade of the Office Building overlooking directly the airplane platform. The external closure of such cars has been solved using a curved laminar glass in two pieces, plus the cover of the roof.
The skylight designed for the business centre was done with a combination of COOL LITE air space + security sheet.

The abovementioned glasses are placed horizontally and have been dimensioned in order to endure the different climatological conditions and to fulfil the maintenance requirements.

A network of drainage channels in the shape of a grate evacuates the water coming from such skylights.
Due to the fact that the areas of vision of the public services offices and of the business premises did not allowed the use of colour, transparent glasses were used forming a double climalit glazing, with a motor-driven Venetian blind installed between the two glasses to avoid excessive solar radiation.

Another feature of the image of the building are the glazed vaults that cover the gallery that links in the ground level the different parts of the architectural ensemble from east to west.
The vaults are made up of a special structure with steel bars in the shape of tetrahedrons with threaded joints.
By using articulations, this structure rests upon the First Floor and the roofing of the business and public services areas.

Over this structure, and resting on the woodwork knots of aluminum sections, the quadrilaterals of the top side of the spacial structure have been transformed into triangles forming the polygonal surface covered by sheet glass of 10 + 10 mm.

The maintenance of the building facades has been solved by designing a pod/gondola located in the top roof of the central module of the office building.
When extended, the arm pod has a length of 45 meters and in order to keep its stability, it is joint by cables to a mast located in the axis of the trolley that runs through rails. Such rails run alongside the roof.

Due to the maximum height established for the buildings located in the surroundings of the airport, the mast has been designed in order to be able to adopt a resting position. Thanks to an hydraulic system, the pod can come down to the lower level of the roofing in this new position.

The design and modulation of the facades has been done with the following combination of materials: glass, coatings and aluminum jacketings; and with the following elements: the architectural treatment of the external communications centres using singular elements, the integration of the complex systems of installations in the roofing of the building , the design of the crowning elements and of the glazed vaults of the gallery. All these factors help to identify the image of the Air Cargo Centre of Madrid-Barajas airport.