Safety assessment of the South Oculus of Canterbury Cathedral

Abstract

The South Oculus of the Canterbury Cathedral is a structure composed of two layers, the ferramenta that supports the glass and the grille, which are connected together by pins. Despite the fact that this wrought iron space frame is almost 850 years old, it can be stated that the structure is in good condition, based on a visual inspection. Deterioration is localized in a few points and in the pins, which are the most damage elements. In order to perform the structural assessment, firstly, dynamic identification tests were carried out to estimate the dynamic properties. Then, a numerical model of the current structure was created to evaluate its the performance when subjected to the wind load. The model was calibrated based on the dynamic properties measured on site. The results of the non-linear analysis permitted the conclusion that the structure presents a very large safety. Furthermore, a parametric analysis showed the importance of the grille and how the decay of the pins can affect the load bearing capacity of the structure.