Tensile Configurations

Kenneth Tracy¹, Sachin Sean Gupta¹, Loo Yi Ning Stella¹, So Jing Wen, Abhipsa Pal¹, Thomas Wortmann², Robert Bamford³

¹Singapore University of Technology & Design (SUTD)

²Xi’an Jiaotong – Liverpool University

³Web Structures

Structural membranes exhibit advantages over slab and frame structures, accommodating large deformations while still elegantly combining spatial enclosure with material efficiency.

One of the most promising types of membrane structures are membrane tensegrity structures, which are composed of discontinuous struts embedded in a tensile membrane.

To date, membrane tensegrity structures are limited to completely closed formations or require extensive tethering, hindering their applicability for diverse architectural contexts.

Here, a design framework is presented for creating self-supporting membrane tensegrity shell structures with spatial openings, enabled by novel reciprocally tessellated strut configurations.

Through a combination of heuristic physical prototyping and digital formfinding tools, a library of membrane tensegrity forms has been developed that serves as tangible data for an expanded morphospace.

To test the effectiveness of the established methods, a 10 m2 membrane tensegrity shell pavilion was built as a first large-scale demonstrator.

Feedback from this demonstrator led to the development of computational strut tessellation tools that enable the search for informed, performance-driven design space.

Textile membrane structures are renowned for their ability to span wide spaces while remaining incredibly thin, offering lightness of weight and distribution of load solely through tension.

However, one recurring challenge to their implementation is that these structural typologies typically require a substantial external support system to tether the membrane, resolve its live loads, and continuously apply sufficient amounts of pretension to maintain its stiffness.

Creating decomplexified textile membrane structures that do not require such extraneous support can potentially mobilize their widespread adoption.

One approach to achieve a self-supporting tensile structure is by instilling tensegritic design principles. Tensegrity (tensile-integrity) structures, as the root of the name suggests, are tension-dominant structures that consist of minimal, discontinuous (non-touching) compression elements connected by an array of continuous tensile elements.

Tensegrity structures are a provocation to the status quo of reliance on mass and thickness: the compressive elements are diminished in size and mass to such an extent that they serve solely as a means of pretensioning and transferring loads to thin, ubiquitous tensile elements, which serve as the primary structure.

The compression elements were materialized as struts in the tensegrity structures that were envisioned by Fuller in the 1960s, whereas cables offered tensile capacity. With this choice to use such one-dimensional tension elements came an inherent problem of adding enclosure as a separate layer to the system.

The design space search was conducted in the context of the Tensile Configurations undergraduate design studio at the Singapore University of Technology & Design (SUTD), which focused on investigating membrane tensegrity morphologies that invoke optimal air flow conditions in tropical climates.

The combination of physical modeling and digital form-finding tools was used to generate a promising pool of shell designs, one of which was selected, scaled, and constructed as a 10 m2 membrane tensegrity shell demonstrator.

This demonstrator provided valuable feedback that led to development of machine learning-based computational design tools for performative strut tessellation. This paper will detail the formulation of these membrane tensegrity shells design methods, highlighting their successes, limitations, and opportunities for further development.