Diagonal ZeroZero Telefonica Tower

Barcelona, Spain

A project by: Estudi Massip-Bosch Arquitectes

About

The position of Diagonal ZeroZero Telefonica Tower is exceptional. It is located next to the sea at the beginning of Diagonal Avenue, Barcelona's main thoroughfare. It is visible from both the city and the coast and it lies on the border between the urban city areas and the new large expanses of public space in the Fòrum area. The project takes this multiple condition as an opportunity to generate a contextual tower which is at the same time a landmark and a public space, taking the urban alignments that form the perimeter of the plot as the generator of the project. It is a trapezoidal prism, sharp andstylized, a clean and serene formshimmeringand light. Its transparency reveals the interior’s dynamic volumes which respond to the different situations of the program, relating the tower to the varying heights of the neighboring buildings. The exterior relates to the city and the view from afar while the interior relates to the program and the close-up vision in response to the two simultaneous scales that such tall buildings must achieve. The ground floor follows the slope of the adjacent streets and it has been developed over three levels which are open to the general public. This situation is quite unique in a corporate building where security is critical, and allows for a direct relationship with the movements of the city in a mutually beneficial result.
The corporate program of the tower has a major public part situated on the ground floor, which actually comprises three interrelated levels, around an atrium 40 meter high that follows the slope of the adjacent Plaça Fòrum. This direct visual and physical continuity with the city connects the building with the urban flows and both helps the tower to benefit from civic activities and facilitates citizens to enjoy and participate in the activities in the building. Within the tower four individual spaces create a dynamic situationand generate a variety of interior experiences: the main lobby atrium facing Diagonal Avenue; an upper atrium, facing the Mediterranean coast; the terrace and the double height of the executive board room located on the 23rd floor; and the lecture hall for 350 people, which occupies two floors and is split into stalls and two amphitheaters that can operate autonomously for smaller groups, so that three different events can take place at the same time. The upper floors are open-plan office spaces, taking advantage of the structural system. This system is a modified tube-in-tube scheme. It consists of a load bearing central concrete core and a perimeter steel structure along the façade, split into two parts: very small and slender vertical interior pillars that only take compression stresses, and external bracing elements that bear the horizontal forces and torque. The floors are concrete slabs that connect the perimeter structure with the central core to form a combined structural device. The bracing elements create an exterior diamond lattice that bears the stresses of each part of the building, with a higher concentration of structural elements in the lower half and a lighter density in the upper parts. This lattice creates a glowing presence further enhancing the tower’s levity and generating four different elevations that also widely change according to light and weather conditions.
The facade is a modular curtain wall made of white aluminum profiles and extra-clear glass with white ceramic paint serigraphy on the outside. The pattern of this serigraphy follows a vertical composition that reinforces the slenderness of the tower and contributes to its changing whitish image. In combination with the inner structure, placed every 1.35 meters, and the exterior structure, this pattern also contributes to the diffusion of solar light and to glare control, generating interiors of great perceptual quality and remarkable visual comfort. 3. TECHNIQUE AND SUSTAINABILITY The development of Diagonal ZeroZero Telefonica Tower project involved several lines of research and innovation conducted during its design and its construction phases. Bearing in mind the double-scale reading that we wanted the building to offer, these lines range from its insert at the urban scale down to its detailing. From the technical point of view we can point out in particular two main innovations carried out in this project: Firstly, its structural system. It is an evolution of the tube-in-tube classical scheme, in which the interior core is a concrete prism housing all vertical shafts and the exterior ring is divided in two: in the inner part of the façade, a series of very slender (16x16 cm from 13th floor 13 up, 16x32 cm under 13th floor) steel pillars 135cm apart carry exclusively vertical loads and generate a screen of sorts that helps diffuse light; whereas an exterior rhomboidal lattice structure made of steel pipes (24x68 cm) supports all torsion and horizontal loads. The concrete core has been built using a very sophisticated climbing formwork that leaves no traces or holes whatsoever on the finished surface, which appears as solid stone. Secondly, its curtain-wall system: while using market-standard elements, it uniquely brings together a series of innovations that add up to both the image of the building and its thermic performance. It is based on a modular frame built with white extruded aluminum with high-performance glass panels formed by a series of layers. From outside in: a pattern of ceramic paint arranged in dotted vertical lines that cover between 25 and 35% of the façade; a magnetron layer on its face 2 for solar control; an air chamber 18mm wide; a laminated 6+6 glass in the interior with a heat-reflective layer. The main sustainable strategy on this building has been its no-frills design approach, propitiated by the necessity to comply with a very tight budget. This condition has prompted us to seek the most efficient solution for every design problem, which often has meant to choose systems and materials for their capability to double their function: for instance, the inner concrete core is not paneled and doubles as a beautifully textured finishing material; the exterior lattice is not only a key structural element but casts deep shadows on the façade thus reducing solar radiation; serigraphy on the curtain wall helps control sunlight and reduces maintenance needs due to its pattern alike to the salted spray coming from the nearby sea; normal artificial lighting is used also as spectacular lighting by the simple device of changing color temperatures of the lamps differentiating the atriums from the other spaces of the tower. And so on. This approach has meant not only a substantial reduction of the number of materials used in the building, but has also allowed us to focus on the most important aspects of its construction and the clear and austere definition of its spaces. Further sustainable strategies include: connection of the building to the recently established network of District Heating and Cooling of the Forum area, which drastically reduces CO2 emissions to almost zero and greatly lowers electrical consumption; reuse of grey waters, by the implementation of double piping funneling water from washroom sinks into toilets through a depuration system, greatly reducing water consumption; or regulation of artificial lighting by photocells that automatically adjust interior illumination to exterior light conditions. collapse