This research was carried out to develop a novel composite material consisting of a thread reinforcement and a clay matrix, as well as to develop a method of shaping this material into hollow spatial structures. Ceramic elements in the building industry are currently created by applying extruding, pressing and casting methods. The approach of spraying clay onto predefined knitted meshes increases the usability of digitally fabricated lightweight ceramic elements, while eliminating the need for scaffolding. In this approach, multiple layers of a fluid clay mass are sprayed onto the tensioned mesh using an industrial, six-axis robotic arm. This allows the precise application of the material and results in varying material thicknesses. Due to the complementary qualities of clay which absorbs compressive forces and threads which absorb tensile forces, lightweight structures can be created. The research involved experimenting with clay mixtures, several thread types, knitting methods and spraying techniques, as well as fabricating a 1:1 lightweight module as an architectural prototype.

In this paper, we will demonstrate a new method of using knitted meshes to act as a formwork and to reinforce thin and hollow spatial clay structures. Currently, ceramic elements in the building industry are formed using extruding, pressing, or casting methods. This new approach can increase the usability of digitally fabricated lightweight elements, by spraying clay onto mass customised knitted meshes. Compared to fabrics that are used to shape concrete as a stay-in-place formwork, knitted meshes are available in various densities and changing patterns. They also offer the possibility to use a non-flexible thread as an elastic mesh. Knitted meshes are formed in a predefined shape by stretching them without the use of elaborate scaffolding. A specific liquid clay mixture is applied by spraying multiple layers onto the mesh by an industrial, six-axis robotic arm to precisely achieve variable wall thicknesses. Due to the complementary qualities of clay, which absorbs compressive forces and the threads, which absorb tensile forces, structures can be designed with a material optimisation scheme. To demonstrate the potential of such composite materials and the building process itself, a 1:1 lightweight module was constructed as an architectural prototype.

SažetakUkratko su prikazane osnovne karakteristike membranskih konstrukcija te su opisani koraci u postupku projektiranja i izgradnje membranskih konstrukcija s njihovim specifičnostima. Posebna je pozornost posvećena postupku proračuna membranskih konstrukcija. Istaknuto je temeljno obilježje po kojem se te konstrukcije razlikuju od konvencionalnih tipova konstrukcija -nalaženje oblika, te su navedeni neki djelomice neriješeni problemi koji postoje u proračunu zbog nedostatka europskih norma za taj tip konstrukcija. Proveden je proračun membranske konstrukcije po uzoru na postojeću konstrukciju u sklopu zgrade zračne luke Zadar u kompjutorskom programu IxCube. Prikazani su pomaci membrane za djelovanje vjetra te je konstrukcija provjerena na gomilanje padalina. Ključne riječi: membranska konstrukcija, proračun laganih konstrukcija, nalaženje oblika Particularities in the structural design of membrane structures AbstractMain characteristics of membrane structures are briefly presented with overview of design and construction process particularities. Particular attention is given to the structural design of tensile membrane structures. Form-finding, i.e. the main aspect by which they differ from more conventional structural types, is emphasized and some partly unsolved problems in structural design due to lack of European standard are outlined. Design of membrane structure, inspired by existing structure within the Zadar airport, is conducted with computer software IxCube. Membrane displacements for wind load are presented and the structure is verified for rain and snow accumulation.

Sažetak U radu su prikazana tri primjera optimizacije kôda u realizaciji iteriranoga Ritzova postupka (IRM) i njegove inačice istovrijedne metodi konjugiranih gradijenata (IRM-CG) u programskom jeziku C++. Nakon opisa osnovnih shema pohranjivanja rijetko popunjenih matrica, uključujući posebnosti simetričnih matrica, prikazano je izračunavanje umnoška rijetko popunjene matrice i vektora, izračunavanje umnoška rijetko popunjene i pune matrice te ispitivanje zadovoljenja uvjeta za prekid iteracije. Optimizacije su provedene radi ublažavanja "uskih grla" u algoritmima IRM-a i IRM-CG-a.

The embodied carbon emissions from building materials and construction are today responsible for 38% of annual global GHG emissions in the current global environment. If we are to reach the European energy plan with net-zero emissions by 2050, now is the time to rethink our construction principles, as well as building elements and materials. One of the possible steps to achieve this goal is to explore new solutions using regional sources and sustainable raw materials. In our research, we use alginate to see if we can substitute conventional structural elements with others based on this sustainable material, whose potential in architecture is so far unrevealed. Alginate, which is found in brown algae cell walls, is an irreversibly hardening elastic moldable material, i.e. once hardened, its form can neither be changed nor converted back into an original state. In this paper, we present a series of experiments with different natural additives. By respecting the natural behaviour tendencies of macroalgae, but also by experimenting with chitosan to increase the rigidity and glycerin to increase the elasticity of the alginate, various shapes of elements are obtained, ranging from linear ones, towards membranes and shells. An initial tensile test is made for the linear elements and the results are commented in comparison to similar natural fibres. The created models demonstrate promising outcomes while also opening some new research questions, confirming the potential of this innovative application.