Wednesday 25 December 2013

Traces of Peter Rice (Arup, 2012)


As Peter Rice took on his professional career in Arup, the outstanding engineering firm produced the documentary ¨Traces of Peter Rice¨ on occasion of the 20th anniversary of his death in 2012.

The documentary goes through his professional career including interviews with his colleagues, partners and people who had the opportunity to meet him.


Through this interesting documentary, the great Irish engineer is brought closer to those who only had the chance to read his books and visit his projects.


Monday 5 August 2013

Hotel Me in Barcelona (Dominique Perrault, 2008)

Summary--The specifications of the Hotel Me project required a particularly innovative facade design. This article describes and explains the unusual solution developed by the façade designers, in answering the specification’s requirements.

1. Introduction

One of the Engineer’s tasks is to execute the Architect’s design. Such a statement depicts the work done for the façade of the Hotel Me designed by Dominique Perrault and his design team. It is located at the junction of the Avinguda Diagonal and Pere IV Street in Barcelona. The building is a skyscraper of 117 metres in height (Photograph 1). The geometry is reminiscent of a number four, inspired by the stone heads of Easter Islands, with and adjacent 25 metres tall cube shaped building.

2. The Façade

2.1. Architecture

The façade is a unitized curtain wall system formed by several differing modules, combining heights of 2.6 and 4.6m, forming a saw tooth shape. Once installed, each unit incorporates the waterproofing, the fire, thermal and acoustic insulation, and moreover the internal architectural design for the room.

Each of the rooms is formed by four panel types (Photograph 2 and 3). Two of them are ‘opaque’ type being a triple skin 4.6 m high formed by an external laminated glass, a stainless steel metal shaped sheet sited in the air gap and a inner insulation sandwich panel with stainless steel bright polished as per design for the room.


Photograph 1. View from Avinguda Diagonal

Another type of panel is named the ‘filter’ being 2.6m high and allowing solar radiation to pass through a triple skin formed by two panes of glass with a stainless steel perforated shaped sheet fitted between the glass. The inner skin is accessible for maintenance.

The last panel is named ‘transparent’; being a window 2.6m high.

There is a fourth type of panel placed at the emergency stairs providing ventilation. This module is clad with vertical louvers of bright polished stainless steel.

Photograph 2.
The fitting of the unitized curtain wall modules in saw tooth orientation. Note the three types of panels, being the opaque 4.6m high, filter and transparent 2.6m high panels. This is the mountain-facing elevation and it can be seen how each module bridges two floors.
Photograph 3.
View from a standard room of inner side of unitized modules. The opaque modules can be seen with stainless steel bright polished finish, the filter with the perforated metal sheet and the transparent window. 

2.2. Engineering

The frame of the unitized curtain wall panel is formed by two layers of aluminium joined through a low conductivity material that breaks the thermal bridge.

The waterproofing of the union between the transom and mullion is resolved through a waterproofing sealant.

Each curtain wall module is formed by two panels including hooks to be hung on the brackets fixed to the concrete slab (Photograph 4).

Photograph 4.
Typical module clad with unitized curtain wall 7.2m high and 1.2m wide, covering two rooms. The panel above is transparent and the panel below is opaque.

One of the specification’s requirements was to provide the fire insulation at the gap between the curtain wall and the slab, including the fire insulation in the curtain wall module. In order to achieve this a rock wool panel was added in the module in front of the slab, and the joints were sealed with fire rated materials. Once the solution was designed, it was tested in a European notified laboratory, achieving 92 minutes of fire resistance.

The acoustic performance of the whole room with the curtain wall panels attached was also tested. The acoustic insulation achieved was 39 dB, being higher than the 30 dB required by the standard.

The waterproofing is achieved through the contact between the bubble gaskets fixed continuously through the aluminium frame (Photograph 5).

The filter and opaque panels include an air gap, where the stainless steel bright polished bent sheet is inserted. The particular design of the bent sheet required them to be bent through a manual process.

The opaque modules are cladded with the bright polished stainless steel as the finish for the room in the inner skin. This is fixed through an aluminium cover cap.

The external glass is laminated transparent float, structurally bonded to the aluminium frame. Due to the requirements of the Quality Control team, additionally a cover cap was used for fixing the glass mechanically onto the frame.

The internal glass, an insulated low emissivity unit, is present in the transparent and filter modules.

The façade is resolved and interfaced with the perimeter elements such as vertical dividers, ceilings and finished floors. The acoustic insulation (Photograph 7) and fire insulation elements (Photograph 6) are executed in situ. Subsequently, the finishing trims are installed.

Photograph 5. View of the union of two modules. Note the broken thermal bridge, the bubble gaskets, the waterproofing sealant at the union between transom and mullion, and the cover cap as a mechanical fixing component.

Photograph 6. The technical design for the composition at the dividing line between rooms that achieves 45 dB of acoustic insulation.


Photograph 7. The technical design for the horizontal fire insulation composition covering the gap between module and slab.


2.3. Execution

The main activities for the assembly, brackets and modules, were carried out from the outside the building due to the particularities of the project, as described below:

The limited thickness of the floor, did not allow the bracket installation on the slab surface. It was consequently installed on the slab edge from the outside of the building.

The design of the main structure of the building, with concrete walls as divisions at the façade facing the sea and the metallic structure at the façade facing the mountains, did not enable the use of any kind of equipment for horizontally shifting the modules along the floor plan after unloading the prefabricated units. The panels had to be individually lifted up to each storey in order to be installed. Hence, a free surface on the slab was needed, in order to move, erect and install these panels.

Therefore, a customized auxiliary system was designed to resolve the conflict with the elements in the interior of the building to allow installation from the outside, optimising safety, convenience and performance.

This kind of track running continuously through the full perimeter of the building, as it was not feasible to work from inside due to the interference with the structure of the building. This rail supported two cradles and a mini-crane (Photograph 8).

The cradles were allowed to move horizontally and vertically throughout the entire façade. The cradle included all the elements to carry out the works efficiently. The mini-crane could hoist and install the curtain wall modules (Photograph 9). It was designed to allow a maximum load of 1100kg. It was possible to hoist a curtain wall panel from the ground floor to the 32nd storey, and then it could be horizontally moved to the final position, aligned and installed (Photograph 10).


The vertical displacement of the module was guided by a tensile cable system the same height as the building.

The method statement for the assembly was based on the shifting of the modules to the package, the dismantling of the package to the individual modules, the hoisting by the mini-crane and the guidance of the tensile cable system. Once the module reached the respective storey, it was horizontally moved to its position, where it was aligned by the jacking bolts at the hook bracket, ensuring the contact between the bracket and module.

The daily average performance was 70 square metres, with the wind being the main issue. The daily performance, considering only the net days worked, was 90 square metres.

The quality control plan was rigorous, inspecting the welding and torque settings of the brackets, module tolerances to meet the requirements of the project and to achieve the environmental performance designed.

With regard to the dimensional control, a survey of main structure was periodically carried before analyzing and making the decisions on the position of the façade, whilst absorbing the misalignments of the structure.
Photograph 8. The customized auxiliary system to install the modules. The system was installed on the 32nd storey through a cantilever beam. Note the vertical displacement of the module.
Photograph 9. Mini crane, lane system and cantilever beams as a structural system.

Photograph 10. Unitized curtain wall module during horizontal displacement at 31st storey.

3. Conclusions

Without any doubt, the unitized curtain wall system, minimized the installation works on site, improving the delivery times and the quality of the final product, in comparison to an in situ façade system (Photograph 11).

The success of such a particular façade was based on the façade being defined four months prior to being erected onto the building, rigorous planning and successful cooperation among the staff of the façade company and main contractor, obtaining the approvals of the consultants and architects to carry out the façade works properly coordinated with the rest of subcontractors.

 
Photograph 11. View of the building from Pere IV Street.


Note 1: This article has been already published in journals of architecture (Revista Hueco Arquitectura; AFL Arquitectura de Fachadas Ligeras; Infodomus; L´Informatiu del CAATB). The original version is posted in this blog in the following  link .


Note 2: The building was named as Hotel Sky during the project execution.





Friday 7 June 2013

Mejora de la eficiencia energética a través del diseño en fachadas (AFL, 2013)


Este artículo pretende contribuir en la mejora de la eficiencia energética de los edificios a través de las fachadas, exponiendo una de las soluciones constructivas que diseñaron nuestros antepasados y mostrando como ésta ha evolucionado hasta nuestros días.

En los últimos años, es perceptible un intento de concienciar la sociedad en el ahorro energético y todo lo que supone para las futuras generaciones.

Esto afecta de manera muy importante a la industria de la fachada y del muro cortina. La fachada es uno de los componentes más influyentes en el consumo energético del edificio durante su vida útil. Por este motivo, en fase de proyecto, se debe determinar con precisión el rendimiento energético en valores como la conductividad térmica y el factor solar. De esta manera, se asegura el cumplimiento de los valores mínimos que indican normativas y códigos locales.

Las prestaciones energéticas de las fachadas están íntimamente relacionadas con el diseño de las instalaciones de climatización. La relación del grado de aislamiento de la fachada con la energía necesaria para climatizar el edificio posiblemente no siga un modelo lineal. De todos modos, la mejora del aislamiento de fachada reduce hasta cierto punto la demanda de energía del equipamiento de climatización. Por tanto, el diseño del envolvente tiene una incidencia muy importante en cuanto al consumo energético y al coste económico se refiere.

Existe la percepción de que hay que crear nuevos diseños y encontrar nuevos materiales para mejorar las prestaciones energéticas de las fachadas. Aunque pueda parecer paradójico, se pueden encontrar soluciones eficientes sólo con observar y entender qué hicieron nuestros antepasados para conseguir los mismos objetivos.

Por tanto, si queremos mejorar la eficiencia energética, se podría investigar las soluciones constructivas llevadas a cabo a lo largo de la historia, en las zonas más calurosas del planeta. Este ejercicio ya ha sido realizado por  varios arquitectos e ingenieros, los cuales se han desplazado hasta Oriente Medio para aprovechar las prestaciones de la Mashrabiya, lo que muchos consideran, uno de los elementos de protección solar más eficientes diseñados hasta ahora.

La Mashrabiya es un elemento de arquitectura tradicional arábica formada por una celosía de madera para las ventanas, que cumple las funciones de seguridad, privacidad y protección contra la radiación solar. Fue diseñada para permitir la entrada de aire y luz en espacios interiores, y evitar la entrada de la radiación solar (Figura 1).

 
Figura 1. Mashrabiya
La firma de arquitectos Aedas, en colaboración con los ingenieros de Arup, evolucionaron esta solución arquitectónica tradicional. A través de los recursos tecnológicos que se disponen en la actualidad, se diseñaron y se construyeron las fachadas de las torres Al Bahar en Abu Dhabi, en los Emiratos Árabes Unidos (Figura 2).

Figura 2. Al Bahar Towers, Abu Dhabi, UAE
Cada una de las dos torres presenta una fachada de doble piel, donde la piel exterior está formada por aproximadamente mil paneles triangulares que forman un modulado hexagonal. Su apertura está regulada en función de la radiación solar. El envolvente está sujetado por marcos independientes que están fijados a dos metros de distancia desde la fachada interior (Figura 3 y 4).

El equipo de ingeniería programó cada triángulo para simular su operación en respuesta a la radiación solar durante los diferentes días del año.

Figura 3. La fachada durante su instalación
Desde el punto de vista estético, la apariencia del edifico está cambiando continuamente, mientras el consumo del aire acondicionado se reduce. El factor solar y la conductividad térmica se adaptan en función de las condiciones atmosféricas externas.

La revista Time premió el proyecto como una de la mejores innovaciones en el año 2012.

Figura 4. Detalle de la solución de la piel exterior de fachada
Otro exponente de evolución en este sentido  es la fachada del edificio del Burj Doha, diseñado por Jean Nouvel y sus colaboradores, que está ubicado en Al Corniche Street en West Bay, en la ciudad de Doha en Qatar. El edificio es un rascacielos de 238 metros de altura, que presenta una geometría helicoidal y que está coronado por una cúpula con una antena muy estrecha en la parte superior (Figura 5).
Figura 5. Burj Doha (Doha, Qatar)
La solución de fachada está formada por una piel interior de muro cortina acristalado y una piel exterior formada por una malla de aluminio inspirada en la Mashrabiya. Contiene diseños tradicionales locales, que al mismo tiempo, combina diferentes intensidades de malla según la orientación. De este modo, la fachada actúa como un elemento regulador eficiente de intercambio de energía entre el edificio y la atmósfera (Figura 6 y 7).

Además, la fachada está considerada como una bella expresión de la cultura local, conseguiendo que un edificio moderno sea un icono de la arquitectura tradicional Árabe.

Figura 6. Detalle del diseño de la malla de aluminio

Figura 7. Vista des del interior del edificio
Conclusiones

El diseño es uno de los recursos más importantes para obtener construcciones energéticamente eficientes. Es la base para poder utilizar de manera adecuada y óptima nuevos diseños de fachada y la aplicación de nuevos materiales.

Al mismo tiempo, a través de estos diseños, el Arquitecto pretende respetar la cultura y la tradición local, dejando un legado para las futuras generaciones, las cuales puedan sentirse identificadas con su cultura y su país a través de estas contrucciones actuales.




Thursday 24 January 2013

Al Bahar Towers (Abu Dhabi, 2012)



Al Bahar Towers

I was born in a small country adjoining the Mediterranean Sea, where the weather is specially sunny during the year, but warm during summer.

As a facade engineer, we need to improve the environmental performance such as the U-value and solar shading through an efficient design, improving the comfort indoor and reducing the amount of air conditioning spent in summer.

From my point of view, the facade industry will continue to develop new technical solutions, because the industry is aware that there is an important marketplace with this regard.

For instance, the envelope for the Al Bahar Towers in Abu Dhabi, designed by Aedas from London studio in collaborations with the engineering firm Arup, meets my previous statement. 

Both 145 meters towers were completed during summer 2012, being erected in three years.

Inspired in the traditional Arabic architectural element Mashrabiya, the perforated lattice screens used in the Arabic houses through the Middle East, the screen for each tower is made by approximately  1,000 triangular fabric panels in a hexagonal pattern that opens or closes in response to the sun radiation. The screen is supported in an independent frame sited two meters outside from the inner skin.


The engineering team programmed every triangle to simulate their operation in response to sun radiation and incident angles during the different days of the year. All the screens are closed during evenings.

From the aesthetic point of view, the appearance of the building is continuously changing, whereas the air-conditioning consumption is reduced, the solar control and the U-value is performed according to the external environmental conditions. 

It is deemed as an active facade, modifying their performance in line with the weather conditions, mitigating the air condition load by reducing the U-value.

The magazine Time has named the project as one of the top innovations in 2012.

This technical solution makes the most of a traditional architectural element, at the same time innovating through the use of the technology at our disposal nowadays.

By the way, I have found out that Abu Dhabi citizens use a warm and affectionate tone when naming emblematic buildings, this is the Corn cob.


The facade during the installation



Technological rain screen