Parametric model for generation and analysis of modular, freeform floating island networks, constructed using flexibly formed Buoycrete
dr.sc. ir. Diederik Veenendaal (Summum Engineering)
Marco Bovio MSc Eng (LeadingEDGE Marine Engineering)
ing. Guido Visch (Boskalis Research and Development)
The growing world population coupled with sea level rise due to climate change, has generated interest in land creation at sea. Modular floating islands could create such space in an affordable and sustainable manner.
This paper presents a robust parametric model that is able to generate different network configurations of shape-optimized modular islands. The model is further developed, by using it to study a single module in more detail.
The complex, freeform geometry of each module is made possible by using Buoycrete: a neutrally buoyant, non-dissolvable concrete mix. Buoycrete enables underwater concrete operations without high slurry pressures. Thus, flexible fabrics can be used as formwork for predefined (complex) concrete shapes, instead of needing expensive rigid moulds.
The overall geometry is created by the parametric model in four steps: an initial plan network, with a regular tiling or irregular Voronoi pattern; the immersed body of each module; the internal compartmentation; and the exterior texture. Each island has a doubly curved body, designed to optimize stability, stresses and weight distribution under static conditions, thus reducing material demand. In addition, an open porous Buoycrete reef structure is added to the underwater body, to dissipate wave energy and potentially accommodate marine life.
A single module, generated by the parametric model, is studied in more detail. A lower centre of buoyancy together with the optimized underwater volume results in reduced wave motion response, and coupling forces between the island modules. A comparison using diffraction analysis between the module and a conventional box-shaped underwater volume demonstrates these benefits. The parametric model is also coupled to a RANSE CFD solver, in order to evaluate drag and viscous damping effects for the investigated module. The resulting metrics can be fed back into the parametric model, to improve the design of the overall floating network.
Keywords – parametric modelling, fabric formwork, Buoycrete, CFD, floating island
Diederik is a structural engineer, engaged in innovative and complex structural designs, as well as parametric modeling and computational optimization. He studied Civil Engineering at TU Delft, specializing in building engineering. He was a visiting student in 2006 at the LSU Hurricane Center after hurricane Katrina, developing floating structures and buoyant foundations for historical buildings. He completed his Master’s thesis on evolutionary optimization of fabric formed beams, and started his professional career at Witteveen+Bos engineering consultants, working on the North/South subway line in Amsterdam and the largest tensioned membrane roof in the Netherlands, ice skating arena De Scheg in Deventer. He then obtained a doctorate at the Block Research Group at the Institute of Technology in Architecture at ETH Zurich, Switzerland, researching flexibly formed concrete shells. In 2017, he started his private consultancy, Summum Engineering in Rotterdam, continuing professional work, teaching and lecturing on parametric modelling and lightweight structures.
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