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ESAComp is software for analysis and design of composites. Its scope ranges from conceptual and preliminary design of layered composite structures to analyses of details.

Modern organic architecture with ESAComp

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What is organic architecture?

First coined by Frank Lloyd Wright (1867 - 1959), it describes his environmentally-integrated approach to architectural design. His philosophy, where structure and appearance of a building is based on organic forms and harmonizes with its natural environment [1], was then embraced by architects across the world and evolved further by using new materials to create structures often without visible means of support. Modern organic buildings tend to avoid linear or rigidly geometric shapes by using wavy lines and curved shapes to suggest organic forms, often coupled with natural materials.

Examples include works of Gaudí; "The Sydney Opera House" by Jørn Utzon; "Dulles International Airport" and other works by Finnish architects Eero Saarinen and by Alvar Aalto; "The World Trade Center Transportation Hub", also known as the PATH station with the associated transit and retail complex, by Spanish architect Santiago Calatrava which opened on March 3, 2016.

Varna Regional Library: An approach for an interactive space for 21st century

Varna Library ProposalWhen Varna, Bulgaria, wanted to consolidate their libraries to create the "Varna Regional Library", a new and active public space in the centre of the city, they launched an open international architectural competition and invited architects across the world to participate.

Digital Architects (Vienna, Austria) and Archicoplex Ltd (Tokyo, Japan) proposed an innovative wooden composite façade that acts as both an external support structure for the building and louver system allowing a comfortable natural light into the library.

"To achieve this, we use new and innovative simulation technology to engineer strong, lightweight wooden composite sections capable of withstanding all the necessary load cases", says architect Atanas Zhelev, from Digital Architects, "We used ESAComp software for the preliminary laminate analysis, to evaluate the structural component behaviour along with the development of the joint system".

In all cases, the economics of the material and processes (how much adhesive and wood is used, ease of manufacturing, etc) were considered along with the structural advantages and disadvantages.

Wood composite material development

varna 2The wood-carbon composite comprises thin sheets of birch wood, with layers of carbon fibre interspersed between them, all adhesively-bonded together: a classic plywood type construction, but with a modern twist provided by an advanced composite reinforcement to enhance structural performance.

Atanas explains, "First, we needed to understand the wood laminate construction before adding in the carbon plies. Here, we examined using different thicknesses of wood, either on the external faces or in the middle, within one laminate to determine how much structural strength changes compared with a laminate having equal thickness plies."

varna 3"We then moved on to determine the behaviour with different orientation of the carbon layers", says Atanas. "We focused on comparing the effects of carbon fiber in +45/-45 and in 0/90 degree to the main structural load. Although predictable, we wanted to know the exact difference and how the shear response changes. Since the wood grain is orientated in the load direction, we estimated that reinforcing the composite in +45/-45 degree would benefit the structure. However, considering the relatively narrow beam width, the benefit of the increase in shear strength cannot compensate for the loss of tensile strength, meaning that a combination of both orientations is a better solution."

"We had two setups for testing: for parts of the façade where the material experiences the structural load along the grain and the wind load as an out-of-plane force; where the structural load is out-of-plane and the wind load is in-plane."

"Here, we determined the ratio between +45/-45 and 0/90 oriented carbon plies. The aim being to achieve a more isotropic behaviour with well-distributed elastic responses in all directions."

Structural component behaviour

varna 5The structure was divided into 3 simplified main façade elements (vertically-oriented; horizontally-oriented; transition between those elements with different radius of curvature) having the correct dimensions and, using the optimised wood-composite laminate developed, examined for their exact structural and wind load cases.

Atanas explains "An important point of the design of the façade is the wooden lamellas, splitting and joining in different points of the overall structure. The analysis at this stage gave us very good input to the design, helping us understand how thick each part of the structure needed to be depending on the vertical or horizontal orientation of the structural element".

"Overall, it showed that the more horizontally-oriented elements have to get thicker compared with the more vertically-oriented elements owing to the structural load being bigger than the wind load and to the decrease in performance of the composite to out-of-plane shear."

Joint system development

varna 6To join the façade to the concrete slabs of the building, two types of joints were evaluated: simple bolted joints with a steel member bolted to the concrete slab on one side and to the wooden façade on the other; bonded joint where a full carbon composite beam member is bonded to the wooden façade by a structural adhesive and on the other to the concrete slab using epoxy concrete adhesive.

"Holes drilled for bolts effectively damage the wooden façade and require the structure to be supported by big, heavy steel members that spoil the elegant, fluid design of the façade. Whereas a bonded joint gives the possibility to use a thinner carbon fiber beam than the steel counterpart," said Atanas. "The question in this case is how to join this wood-carbon composite element to the concrete slab. Bolting it to the concrete was not an option, so the solution was a newly-developed epoxy concrete. This material is both a structural adhesive, which makes it easier to bond with the wood, and being a concrete makes it easy to bond with the concrete slab."

varna 7The joint analysis performed in ESAComp determined the thickness of the joining member required to make this process possible. Two different lay-ups for the carbon beam were evaluated to see the different responses and how we can minimize the thickness of the beam and make the façade retain its elegance".

Full details of the proposed structure can be found here: http://varnalibrary.bg/entries/306/

What next for wood-carbon composites?

Digital Architects are continuing their experiments with wood–carbon composites. In January 2017, they structurally-certified a wood-carbon composite material for architectural use, along with the "Active Grid Monocoque" construction method required to manufacture ultra-thin lightweight, long-span roof structures using this wood-carbon hybrid.

 

About Digital Architects

Digital Architects was founded in Vienna Austria in 2016 by architects Atanas Zhelev and Mariya Korolova after completion of their studies at Zaha Hadid Studio in Vienna. The office focusses on architectural and structural design, with its own product and prototype development workshop.

Continued development of their wood-carbon range of composites is currently supported by the University of Innsbruck, Institute of Experimental Architecture, Hochbau Department, under the supervision of Prof. Rames Najjar, along with Altair Engineering and Bodo Mueller Chemicals. Together with Architect Martino Hutz, they also developed a wood-carbon bicycle frame. This technology demonstrator further highlights the potential of the material.

For more details: https://www.facebook.com/DigitalArchitectsStudio/ ; https://issuu.com/digitalarchitects/docs/digital_architects_ltd ; This e-mail address is being protected from spambots. You need JavaScript enabled to view it

About ARCHICOMPLEX Ltd.

In 2003, Architect Daisuke Hirose established his design office Archicomplex in Tokyo, Japan, on completion of his studies at Tokyo University of Science, then worked with Kengo Kuma and completed further studies at the prestigious GSAPP, Columbia University.

He has since consulted for major industries, such as SUBARU Motors and Fuji Heavy Industries Ltd., for their global design strategy of motor show stands worldwide. He has also won numerous domestic and international awards for his acclaimed designs and is currently engaged in architectural designs and Sustainable Culture Programs in Japan and Taiwan.

For more details: www.archicomplex.com

 

Ref [1] Dictionary of Architecture and Construction edited by Cyril M Harris, McGraw-Hill, 1975

 

© 2017 Jo Hussey - Altair Engineering Finland Oy