Deep Surface Morphologies

Hannah Kramer Design Build Spring 2012 Universität Stuttgart – ICD + ITKE Sean Ahlquist + Julian Lienhard Prof. Achim Menges + Prof. Jan Knippers Study Abroad in Stuttgart, Germany – Academic Year 2011/2012

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DEEP SURFACE MORPHOLOGIES

The goal: to design a structure for a client adjacent to the site of a medieval stone tower in Monthoiron, France. This tower is potentially the only realized architectural design by DaVinci.

For unknown reasons of French bureaucracy, we could not and cannot yet refer to the tower as such and were implored to call it "La Tour de l'Architecte". Dubbed M1, the building at La Tour de l'Architect showcases the combined research on the subject of integrated material behaviors and a lightweight hybrid of bending-active and tensile structures from the Institute for Computational Design (ICD) and the Insitute for Building Structure and Structural Design (ITKE), developed with the students at Universit채t Stuttgart. The innovative structural concepts of M1 are spatially and technically oriented to situate a canopy with a minimal exertion of force, but with a maximally articulated spatial presence on the site. This was accomplished, at multiple scales, through a macro-system of interwoven bending rods that form leaf-like shapes, and an internal differentiated cell system installation. The minimally invasive, force-active, articulated material system was a necessity given the closely neighboring and currently unstable context of the crumbling stone tower.

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BENDING ACTIVE TENSILE FORCES

The morphology of the integrated material system is accomplished with glass-fiber reinforced polymer (GFRP) rods of diameters ranging from 3mm-20mm in combinations with textile membranes as both continuous surfaces and open-weave meshes. The actively bent rods produce stiffness in their curvature while their position is stabilized through the introduction of membrane surfaces. The arrangement of the membranes allows them to act in pure tension, further stabilizing the entire system and producing a structural equilibrium. The M1 building is comprised of 110m of GFRP rods, approximately 50 square meters of membrane material, and three foundations each consisting of 0.1m続 of concrete. The morphology stands as a true hybrid lightweight structural system, where the organization of bending-active beams and tensile surface elements creates moments of long-span arches, overlapping grid-shell conditions, and doubly-curved pure tensile surfaces.

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MATERIAL BEHAVIOR COMPUTATION

A critical step in accomplishing such complex integrated force-active morphologies is the calibration of design and analytical studies done through both physical experiments and computational methods. The M1 project was developed through computational means which were continually advanced and calibrated via studies of physical behaviors at a model scale and building scale. The design methodology spanned various computational environments and degrees of specificity.

For generative studies, a behavior-based modelling environment, developed in Processing through the research of Sean Ahlquist, was engaged. The open (Java-based) programming environment allowed for custom objects to be developed and altered with consideration for the elasticity and strength of known materials, quickly registering feedback from physical studies. As both a design avenue and method for material specification, advanced simulation in Sofistik was simultaneously utilized. Through methods developed by Julian Lienhard, different topological arrangements of macro-level rod and membrane elements could be studied and parameters specified to determine structural viability. Programmed methods in Sofistik allowed for great degrees of displacement in form-finding the rod positions to be robustly and efficiently accomplished. Thus both simulation of approximated means and highly material specific means could be pursued in consequence and in correlation with physical material studies.

ITERATIONS

TEXTILE STRUCTURE

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The tectonic strategy for the structure inherits a textile logic across scales and details, while the spatial strategy focuses on conditions of differentiation and orientation. At the macro-scale, the leaf-like geometries of the rods are interwoven relying upon various lashing and lacing techniques to lock the topology into a rigid frame. The global form that is realized orients the structure toward an existing arched wall which once deďŹ ned a large domed space. The tectonic methods are continued at the base of the structure where the rods are aggregated into lashed bundles and laced into GFRP posts. In combination with the membranes, the structure advantageously accumulates multiple layers and a structural elasticity. Such features enable the system to withstand varying stresses of wind, rain, and snow, yet rebound to its initial form-found state, while also mediating spatially the same forces via multiple differential layers. The internal cells provide a similar structural functionality at a smaller, localized scale, but are more oriented towards offering an integrated strategy for spatial differentiation. Working to disintegrate the homogeneous nature of the textile membrane, the cells are constant in their topology, yet differentiated in their form. Utilising Polyamid textile for tensile stiffening in the cells and variation of light transmittance, the cell surfaces were articulated at more minute scales in comparison to textile membranes.

CONNECTIONS: LACING + LASHING

ASSEMBLY

CELLS

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Overall, the material system of the M1 building explores the structural capacity and formal variability of a lightweight structure comprised of highly elastic rod elements and stiff membrane surfaces.

The very nature of the system demanded simultaneous study of how structural equilibrium is formed and determination of the spatial performative capacity of the result. As such, the design methodology was formed to track both articulation of material properties and differentiation of spatial consequences. The M1 building serves La Tour de l'Architecte as a demonstror, an exempliďŹ cation of innovative structures generated of experimental means, as well as providing fundamental function for meeting and workspace within the complex of buildings as the site undergoes redevelopment.

For ongoing research, the building serves as a demonstrative prototype for hybrid force-active structures in their realization, as well as computational design methodologies for their generation.