Vincent Callebaut's Agora Garden

An International Competition First Prize Winner in November 2010, also known as the Tao Zhu Yin Yuan is a 20 storied Carbon-absorbing green tower in Taipei, Taiwan. This structure is interesting because it not only catches the eyes of everybody but it deals with some of the grave issues of the world like deforestation, global warming and depletion of resources. It does so without hampering the comfort, luxuries and maintenance issues.

Four main ecological objectives the building will accomplish:

• The reduction of the climatic global warming. 

• The protection of nature and biodiversity.

• The protection of the environment and the quality of life.

• The management of natural resources and waste. 

The Twist

The twisting tower is not only aesthetically appealing, but it serves certain purposes, which are as follows:

• The first objective is to be perfectly integrated in the North / South pyramidal profile of the Building Volume. Actually, the morphology of the project changes according to its orientation. Its East/West elevations draw a rhomboidal pyramid whereas the North-South ones represent a reverse pyramid. 

• The second objective is to generate a maximum of cascades of suspended open-air gardens, not part of the F.A.R. (floor area ratio). Thus, the planted balcony surface area can easily exceed the limit of the required 10 percents. The global framework of 40 percents of building coverage ratio, i.e. 3,264 sq. m. is thus totally respected. 

• The third objective is to offer to the inhabitants exceptional panoramic views on the skyline of Taipei by multiplying the transversal views, especially towards the very close Taipei 101 tower and the Central Business District in full emergence. 

• The fourth objective is to generate from a flexible standardized level a progressive geometry with corbels which assures the intimacy and the confidentiality of each apartment by avoiding the indiscreet vision axes.

The Structure

Floorplans of the units follow two typical layouts on alternating floors, so to best fit into the Vierendeel beam structure.

:- The Vierendeel beam structure is a form of arrangement of trusses in squares placed one after the other, instead of the alternating inverted triangles. You can see an example of it in the 16th slide attached at the end of the article.

:- It is uneconomical and has very complex load calculations and so it is not used in bridges.

:- But Vincent Callebaut has used it to create spaced that are completely column free. Had her used the conventional trusses, the diagonal members would have made it impossible to divide spaces efficiently. The square cavities makes the accessibility easy.

:- Please check the research paper I have quoted in the references as well. "The Vierendeel" by David J. Wickersheimer

• It uses the Outrigger system

:- In short, it an exoskeleton structure that supports members externally.

:- In this structure, it is the curved member you see that circumscribe all the levels. "The spiral mega column" as Vincent calls it.

:- Best explained in the American Journal of Engineering Research “Optimum Position of Outrigger System for High-Rise Reinforced Concrete Buildings Under Wind And Earthquake Loadings” -P.M.B. Raj Kiran Nanduri -B.Suresh -MD. Ihtesham Hussain

• Each unit contains 550 square meters of column free floorspace, allowing for maximum flexibility of the interior layouts.
• Two huge rooftop clubhouses under the pergola are surrounded by sky gardens that will naturally filter and purify rainwater with the action of the plants. The purified rainwater is injected into the building’s water distribution system by gravity.
• The technical flexibility is obtained by the integration of the double deck and double wall concepts
• The network of the flows (rain water, used water, hot water, electricity, under floor-heating, cool air, hot air, optic fibre, etc.) crossing the central core can thus irrigate without any difficulty on the horizontal way all the surface area of each storey.

:- The network of flows refers to the MEP lines that run through the central core and the Outrigger system and thus it is easy to irrigate the 26000 shrubs all along the different levels by passing the water from the central core outwards to the end of the floor level.

• In order to protect the organic substrate tanks from the heating coming from the solar radiation, the planting beds will be covered by a layer of Bethel white granite on honeycomb slab.

:- I read a little bit about Bethel White Granite, and found out that it was not used for tiles because it was porous. But Vincent used exactly that characteristic of the granite to his advantage, because that porosity drained excess water and provided air circulation to the vegetation which are very necessary for the structure as well. The Honey comb slab allows room to accommodate the soil and roots of the shrubs and also the MEP lines.

Interesting Features

The building will integrate the recycling of organic waste and used water, BIPV solar photovoltaic energy, rainwater recycling, and composting into its plans.

The building will include car parks, a swimming pool, a fitness center, and lobbies that will connect the indoor spaces with the surrounding outdoor spaces.

The central core of the building will be a vertical twisted garden surrounded by sky entry foyers.

The core itself does not pivot but is surrounded by a naturally lightened horizontal circulation loop welcoming the entry foyer dedicated to each unit.

This “buffer loop” enables the main entrance to always be in the axis of each apartment despite the 4.5 degrees rotation story by story.

Hope you enjoyed the article

The attachment below has the references and the complete presentation made by myself