Aggregate Structure

The chapter extends their multi-disciplinary research at the forefront of architecture, engineering, and materials science. The chapter appears in “Digital Fabrication in Interior Design” by Routeledge, which expands dialogue about digital fabrication at the scale of interiors to inform design theory and practice.

Designed granular materials establish a radically new paradigm in architectural design and construction: Departing from the notion that the geometry of a spatial structure can be predefined by its designer, they embark on the unknown territory of self-organizational and emergent behaviour as design drivers. This shift in design thinking is embedded in the nature of these material systems: Granular materials, which are by definition consisting of large numbers of particles in loose contact, can assume both solid and liquid states.

By virtue of this property, designed granular materials can be discussed with respect to self-organization as well as emergence. In a designed granular material, the particles are defined in their materiality and geometry which additionally allows affecting the behaviour of the overall granular material and thus its self-organizational or emergent behaviour . Projects conducted in research and teaching point the way in the deployment and exploration of these two aspects. While novel design methods of observation, interaction and approximation need to be established, the core challenge is a shift in design thinking towards an architecture of emergent enclosures which ultimately allow the spontaneous formation of spatial structures either by its inhabitants or by a computationally driven machine.

Chapter overview (Routledge)

“In a designed granular system the individual particle is custom designed to exhibit a specific behavior, and in this case we were aiming to develop designed granules which allow for building vertical structures that do not need additional formwork,” explains Karola Dierichs, researcher at the ICD and project author.

These synthetic granular systems are an emerging area of architectural design research. Designed granulates are particle systems with large numbers in which the individual granules are synthetically made and geometrically defined. Defining the geometry of the individual grains makes the aggregate a programmable matter, which has properties that cannot be found in naturally-occurring granulates such as sand or gravel. This physical property enables structures built from these granulates to be fully recyclable, and during construction can be rapidly poured into multiple spatial formations and adapted to almost any site constraints.

The focus of the ICD Aggregate Pavilion 2015 has been the exploration of programmed verticality (staking), a feature that transcends the natural granular angle of repose. Furthermore, the structure is functionally graded using three different types of aggregates that can be deployed in difference zones of vertical structures to accommodate load transfer that increases from top to bottom.

The ICD has investigated the structures and also a range of possible construction and grading techniques using scale models and 1:1 prototyping in a factory environment. Distinct-Element Modeling (DEM) simulations that allow both for predictive and analytic modeling of particle systems with very high numbers have complemented testing. To build the towers that form the pavilion, the team programmed a cable robot to drop small clusters of the granules in specific areas based on their research into possible construction and grading techniques.

The cable robot was custom-designed as a large-scale robotic system that can be adjusted according to site conditions and dimensions, with a maximum range of 30 meters. The system was adjusted to the site and fixed to four surrounding trees after initial testing within a confined framework. Onsite calibration allowed for precise placement of the granular material by the robot within the construction area. The structures could be constructed and re-constructed in situ.

A total of 30,000 particles were injection molded using recycled plastics sourced from local industry. Two or three variations of a geometric granule type based on a single parametric model were used in construction to accommodate different structural requirements.

The entire structure was constructed without formwork in a few hours, and reconstructed multiple times during the exhibition period. The cable robot achieved accuracy within the range of a few centimeters across the construction space of a seven-meter square, with a payload of one kilogram.

Institute for Computational Design (ICD)

Karola Dierichs, Achim Menges

Design Team

Giulio Brugnaro, Matthias Helmreich, Ondrej Kyjanek, Gergana Rusenova, Emily Scoones, Leyla Yunis

Cable Robotics

Martin Loucka, Ondrej Kyjanek

Manufacturing

Wilhelm Weber GmbH & Co. KG

Funding

Holcim Awards for Sustainable Construction, ITASCA Consulting Inc.

The individual grains of these aggregates are geometrically defined to interlock and consequently require no additional binding agent. Aggregate Structure is thus fully recyclable and can be rapidly poured into multiple spatial formations and adapt to almost any site constraints from urban to rural.

Progress: Aggregate architecture made from designed, self-solidifying granulates is an innovation in terms of approaches regarding construction technology and processes. The methodology is very simple and thus transferable: no expert training is needed. Both the design of granulates and the pouring itself can be replicated using both manual and digital aggregation methods.

People: The granulates will be locally produced in Baden-Württemberg, Germany. This ensures a very high quality of working conditions in compliance with German law including regulations for compensation, safety, basic needs and gender issues. The project will be constructed at the University of Stuttgart in cooperation with students and student assistants as part of an educational program at the Institute for Computational Design (ICD).

Planet: Aggregate structures made from designed, binder-free granules are fully recyclable. Once the aggregate system is produced, it can be used over and over again. If ice or snow are used as a formwork, which the designed granulates solidify upon, water as a renewable energy makes 90% of the construction system. Additionally the use of either bio- or recycled plastics or naturally-grown wood as the base material of the designed granulates is investigated.

Prosperity: The main financial investment lies in the design and fabrication of the grains themselves. After production these can be reused multiple times to produce a vast amount of non-repetitive architectural structures with only very limited production costs. If naturally occurring materials like sand or snow are deployed as a formwork for the designed granules, cost per structure is even reduced by an average of 80-90%.

Place: Being moldable, an aggregate structure can adapt to almost any site constraints from urban to rural. If embedded into a naturally erosive environment, such as sand or snow, designed and natural aggregate systems can become one synesthetic system, using natural materials and energetic processes as part of the construction cycle.