Exploring the possibilities of structural cast glass in the consolidation of historic buildings

Abstract

The search for a transparent, reusable, innovative, architecturally aesthetical, structural material that could be used as consolidation system for decayed historic buildings led to the ambition to test a topological interlocking (osteomorphic) design by using numerical calculations. In the last decennia glass has evolved to be a structural material that could be implemented in diverse structural elements. The mechanical properties of glass, in particular the high compressive strength, offer today a competitive solution that can be used for the purpose of restoration, allied to its transparency and aesthetics. The use of glass as a material is also aligned with the recommendations laid down by the international agreements for restoration. Due to its transparency it allows the ruin (Schaesberg Castle) to be perceived in its damaged state keeping the identity and at the same time being distinguishable from the original material in a subtle and immaterial way.
A literature research gave the technical background necessary related to glass, and how by choosing cast glass in the form of topological interlocking (osteomorphic) this would improve its strength and stiffness by introducing a 3d dimension and optimizing the use of compression. The case study’s main purpose was to give a context for the architectural and structural design and evaluate the technical consequences of applying a topological interlocking structural assembly to replace the missing parts of the existing castle. A design was proposed based on the topological interlocking osteomorphic stability system. The design criteria obtained by the literature and case study were then combined to obtain a model to be tested using numerical calculations.
A global model in Finite Element Analysis, with Diana FEA was chosen to test the whole structural integrity and performance by looking at the stresses and the maximum capacity of the system to check if it fulfilled the strength and stability requirements and to test the influence of two types of connections between the materials.
The results suggested that the system performed well and was strong enough but are based on the assumption of a monolithic system which resulted in a less accurate outcome, unable to predict the failure mode by delamination. According to the results, this system can be implemented to replace the missing parts of a monument but a more detailed model is needed to study more accurately the local failure behaviour.
This can serve as a starting point for future research in similar situations. The study of the connections, although conceptual, can support decisions for detailed design proposals.