Title: Asymptotic Building Envelope – Simplifying the fabrication and assembly of free-form construction
Principal Investigator: Eike Schling
Type: General Research Fund and Early Career Scheme 2021
Received by: Research Grant Council, Hong Kong
Start Date: 01.01.2022
Scheduled Completion: 31.12.2023
Sum Awarded: 787,940 HK$
Office: The University of Hong Kong, Department of Architecture
This proposal aims to enhance a new, sustainable approach to design lightweight freeform structures whilst embracing simple, repetitive fabrication and assembly.
Doubly curved structures, such as shells or membranes, carry loads through tension and compression using substantially less material than bending-active plate or beam systems. Nonetheless, their application in architecture remains rare, as their free-form
geometry often lacks to integrate with the built environment, and creates high costs in the fabrication, logistics and assembly of individual and spatially complex parts. In 2017, a geometric design method was developed by the PI, using asymptotic curve
networks to enable a simple fabrication from straight and flat lamellas and repetitive orthogonal joints. The use of slender lamellas facilitates a self-forming erection process and offers structural resilience as both gridshell and grillage, thus allowing for a smooth
transition from curved to flat design.
Initial built examples of asymptotic structures have verified the advantages for fabrication, assembly and load-bearing behavior. However, so far the technology has only been used for free-standing sculptures of up to 6 m span without cladding system
and thus remains in an experimental stage of design. We aim to develop a low-cost, low-skill construction system for doubly curved building envelopes. For this purpose, two full-scale prototypes, a vertical curtain-wall module and a horizontal self-supporting roof segment, will be constructed and tested in close collaboration with the building industry (GOMORE) and the Department of Civil Engineering, HKU.
Furthermore, the design process is currently still complex and time-intensive. In order to open up this approach to the architectural community, we propose to develop a computational workflow that integrates the topological grid definition, structural formfinding
and analysis, and fabrication planning within one digital environment (Rhinoceros 3D) using Iso-geometric Analysis (IGA) for seamless NURBS modelling.
Finally, we develop architectural design scenarios, that illustrate the geometric performance and functional integration into the built environment. These scenarios pave the way for further research beyond the scope of this proposal. In the future, we aim to procure an urban site and implement a case study in order to evaluate the performance, exhibit the system to the public and collect user feedback.
By creating the constructive and computational method to design low-cost, light-weight asymptotic building envelopes, this study will become a building block for sustainable and affordable architectural applications for the twenty-first century. It thus offers an
alternative to the extravagant and bespoke design solutions currently used for free-form construction.