Experimental and numerical investigation of an interlocking system out of osteomorphic cast glass components


  • Faidra Oikonomopoulou TU Delft, Architecture and the Built Environment




The previous chapter concluded that blocks following an osteomorphic geometry are the most promising in respect to the principles of interlocking and glass casting. Moreover, interlayers of the polyurethane (PU) family are considered the most suitable for a building application, without compromising the transparency of the resulting structure. Based on these findings, this chapter aims at investigating the structural behaviour of an interlocking assembly employing osteomorphic blocks and PU as an interlayer. Initially, experimental research is conducted in different PU interlayers available in the market, aiming on finding one that fulfils the established design criteria and mechanical properties, as discussed in chapter 7.6. Different readily available two-component PU interlayers, with a Shore Hardness ranging between 60A – 80A, are cast to follow the osteomorphic interlocking geometry and are tested under static compressive load between two half osteomorphic kiln-cast glass blocks in series of 3 specimens and in 2 different thicknesses (3mm and 6mm). The results suggest that the tearing strength of the interlayer is as important as its Shore Hardness; whereas the geometry of the interlocking form can further influence the overall resistance of the assembly against tearing. They also highlight that insufficient contact (mismatch) of the interlayer with the glass blocks, due to dimensional deviations, can lead to the eventual failure of the assembly even under static load due to peak stresses that are further increased by the lateral stresses occurring due to the creep of the interlayer. From the examined interlayers, PU with a shore hardness between 70A – 80A, are considered as the most suitable for the further experimental validation of the assembly. Following, to investigate the influence of the interlocking mechanism to the structural behaviour of the proposed Thus, to further explore the influence of the most crucial geometrical aspects of the interlocking mechanism, namely the height and amplitude of the glass components, to the overall structural performance under shear a numerical model65 is made. In accordance with the output of the experimental validation, here an osteomorphic block with multiple locks is tested, considering a 4 mm thick 70A PU interlayer. The results of the numerical model indicate that bricks of reduced height are more susceptible to failure by bending, whereas with taller brick variants shear lock failure is more critical. It is also confirmed that an increased amplitude of the interlock can be beneficial as it leads to an increased shear capacity and lower uplifting effects. It is also shown that specimens with increased height reach the failure stress limit with considerably smaller deformations, thus, requiring a higher manufacturing precision.

Author Biography

Faidra Oikonomopoulou, TU Delft, Architecture and the Built Environment

Faidra (Phaedra) Oikonomopoulou was born on 1984 in Athens, Greece. In 2009 she graduated with a diploma (MSc) of Architect Engineer from the Faculty of Architecture at the National Technical University of Athens [NTUA], ranking among the top students in her class. For the coming one year she worked both as an architect engineer in Athens and as a travel article contributor. In 2010 she followed a second master degree in Building Technology at the Delft University of Technology. It was her MSc thesis initiative that introduced her to glass as a structural material: "The design of a fully glass pavilion for the Temple of Apollo Epikourios in Peloponnese". She proudly presented the findings of her thesis in Challenging Glass 3 Conference. Following her graduation in 2012, Faidra embarked on an adventure in Namelok, a Maasai village in Kenya, to work on the use of mud bricks for construction and pursue her other big passions: travelling and wildlife spotting. Many elephants and lions later she returned to Delft as a researcher for a project on innovative glass joints, followed by a six-month internship in an engineering office specializing in structural glass applications in Athens.