A method for the realization of complex concrete gridshell structures in pre-cast concrete

This paper describes a method for the design and fabrication of complex funicular structures from discrete precast concrete elements. The research proposes that through the integration of digital form finding techniques, computational file-to-fabrication workflows and innovative sustainable concrete casting techniques, complex funicular structures can be constructed using prefabricated elements in a practical, affordable and materially efficient manner. A recent case study is examined, in which the methodology has been used to construct a pavilion. Custom written dynamic relaxation software was used to define the overall form and successive algorithms then defined each component’s unique geometry, unrolled into flat shapes, and nested all parts into cut-files. PETG Plastic sheets were 2-Dimensionally laser cut and folded to produce the unique casting molds. The case study was carried out in collaboration between the Aarhus School of Architecture and the University of Technology, Sydney (UTS). Basic research in casting techniques defined the framework for the design process, and a custom written dynamic relaxation software application became the primary form-generating tool in the design process of a constructed pavilion. Fabrication and construction constraints were embedded within the design of both the overall structure and its components. Finite Element Analysis [FEA] was completed in order to verify the form-finding results, to ensure structural stability, and to direct adjustments of the structure during the design process.
The constructed pavilion case study, constructed in a very short time, for low cost and with relatively unskilled labor demonstrates that the integration of algorithmic form-finding techniques, CNC fabrication workflows and the use of innovative PETG folded mold techniques enables the practical realisation of freeform funicular structures in pre-cast concrete.