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Programme | 26 April 2022

Keynote: Võ Trọng Nghĩa
VTN Architects | Vietnam

Lecture: Save Our Earth

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Keynote: Alberto Veiga
Barozzi Veiga | Spain

Lecture: Tanzhaus Zürich

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ACO On Site: Sponge Cities for Trees
Daniel Zimmermann & Christopher Peiritsch | Austria

Lecture: Sponge City for Trees

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VTN Architects
Vietnam | Ho Chi Minh City

Võ Trọng Nghĩa was born in Vietnam and became famous at a very early age. After receiving his architecture degree from Nagoya Institute of Technology in 2002, for which he was awarded the 2004 Furuichi Kimitake Prize for the best master's thesis of the year, he first joined the University of Tokyo Design Laboratory's Landscape and Urban Planning Laboratory in the Department of Civil Engineering. He also received the President's Award of the University of Tokyo for his academic achievement during his doctoral work. In 2006, however, he discontinued his dissertation to return to Vietnam and establish his own firm, VTN Architects. Since then, VTN Architects has become a world-leading architecture firm, honored with 147 international awards and 23 Vietnamese awards for its pioneering work in green building. Among the many awards are prestigious prizes such as the Prince Claus Award from the Netherlands in 2016. He received gold medals from ARCASIA, The Architects Regional Council Asia seven times in 2019, 2017, 2016, 2014, 2011, and 2007.

He was named Architect of The Year by Deezen in 2019 and received the Building of the Year 2014 Award for the Dailai Bamboo Complex by ARCASIA for the best building of the year in 2014. He won seven awards at the World Architecture Festival in different years.

Nghia has lectured internationally at prestigious institutions. He has been a visiting professor at the Singapore University of Technology and Design (SUTD). His achievements have been featured by international media such as CNN, NHK, BBC, etc. The office has been published widely: A+U from Japan or Arquitectura Viva from Spain dedicated entire issues to VTN Architects' projects. His works are published as in three monographs in the US on bamboo architecture architecture, green architecture and houses.

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Project impressions

Barozzi Veiga
Spain | Barcelona

Italian-born Alberto Veiga, grew up in Santiago de Compostela, Spain. He studied architecture at the Escuela Técnica Superior de Arquitectura de Navarra in Pamplona.

Together with Fabrizio Barozzi, he founded the office Barozzi Veiga in Barcelona in 2004. Barozzi Veiga is dedicated to architecture and urban planning. It has won numerous awards in national and international competitions. Currently, the firm is developing projects in Belgium, China, Germany, Spain, the United Kingdom and the United Arab Emirates, as well as in the United States, where it has been commissioned to create a new master plan for the redevelopment of the Art Institute of Chicago. Among the buildings realized by Barozzi Veiga are the Ribera del Duero Headquarters (2011), the Infanta Elena Auditorium in Águilas (2011), the Szczecin Philharmonic Hall (2014) or the Bündner Kunstmuseum Chur (2016), as well as some office and residential buildings in Bergamo and a single-family house in Barcelona.

Barozzi Veiga has received numerous awards over the years, such as the Mies van der Rohe Award for European Architecture in 2015 for the Szczecin Philharmonic Hall.

Alberto Veiga taught at the Universitat Internacional de Catalunya in Barcelona (2007-10) and was a visiting professor at the Instituto Universitario di Architettura in Venice (2014) and at the Escuela Técnica Superior de Arquitectura de Navarra (2021).

Fabrizio and Alberto regularly lecture on their theoretical background and design approach and participate in academic activities worldwide. They have been invited to present their work at MIT, Cornell University, Yale School of Architecture, IIT Chicago, Royal Academy of Arts in London, Berlage Institute, ETH Zurich, IUAV Venezia, University of Hong Kong and FAUP Oporto, among many other important universities and institutions around the world. In 2020, both were appointed foreign members of the Académie d'Architecture.

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Project impressions

ACO on site
Sponge Cities for Trees


Urban trees have a positive influence on the microclimate. They reduce wind speeds and provide shade. Through evaporation, they extract sensible heat from their surroundings and increase humidity. The perceived ambient temperatures are reduced. This is why vital trees are among the most effective means of combating local summer overheating - the so-called “urban heat-island effect”.

The sponge city principle for trees is an innovative system that enables the healthy development of large-crowned trees in paved areas and creates underground retention space for rainwater, thus ensuring the survival of urban trees in the street space.

If the root zone of trees is located under paved surfaces (sidewalks, parking lots, roads), the road substructure must have a suitable structure that meets both the technical requirements of road construction and the biological demands of trees. Creating retention space for precipitation water relieves the burden on the sewer system and provides trees with water even during dry periods.


Climate change is taking place. Hot, dry summers increase and will bring many more heat days and tropical nights. Locally occurring heavy rain events will more frequently overload sewer systems and cause flooding. Local governments must develop strategies for these consequences of climate change.

Climate forecasts for the next decades indicate that the climate crisis will worsen. To keep our settlement areas livable, administrative and planning bodies must respond. Actions that are to have an effect in the future must be set today.


Trees reach their full capacity against the effects of climate change only after about 30 years, when they have developed a large crown. However, crown size is directly related to root volume. In practice, we find in cities and towns too small tree pads, unsuitable substrate, soil compaction and polluted street water. The trees get stuck in their development after a few years, cause increased maintenance effort and often die. In addition, the roots often cause considerable damage to municipal infrastructure (broken road surfaces, ingrown pipes).

Most street trees currently only reach an age of 20 to 30 years and remain small. They cannot come close to fulfilling their potential for mitigating the effects of climate change! With the sponge city principle, the tree discs can be kept smaller on the surface, as water and air are provided for the trees under the paved surfaces. Precipitation is directed into the underground retention space of the sponge city, bound to soil particles and stored until it is evaporated by the trees. Excess water infiltrates or is drained away. This creates more scope for the design of public space.

The exciting topic will be presented in more detail both in theory and by means of two practical examples: Urban development using the example of the "Quartier am Seebogen" and the implementation in existing surroundings using the example of the city of Graz.

Our speakers

Daniel Zimmermann

3:0 Landschaftsarchitektur

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Christopher Peiritsch

ACO Group

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