07/10/2020

UIC Barcelona researchers analyse the plans of Tortosa Cathedral’s spiral staircase

The results of this study, conducted by members of the research group in Architectural Heritage Research, were presented at the eighth Euro-American Congress REHABEND 

Between 28 and 30 September, researchers from the research group in Architectural Heritage Research at UIC Barcelona School of Architecture took part in the eighth Euro-American Congress on Construction Pathology, Rehabilitation Technology and Heritage Management (REHABEND). 

Josep Lluis Ginovart, the group’s director, presented the study titled Traza gótica del caragol sobiranes de la Torre de Santa Caterina de la Catedral de Tortosa (“Gothic plans of the upper spiral staircase in Tortosa Cathedral’s Santa Caterina Tower”) alongside research assistant, Cinta Lluis i Teruel. The study analyses the geometric design of the spiral staircase (caracol de husillo in Spanish or caragol de botó rodó in Catalan) that forms part of the Gothic temple and was built between 1412 and 1424. “Building spiral staircases requires arithmetic expertise to determine the total number of steps, calculate the amount of strides a person would make and ascertain the necessary height within the staircase. The circumference of the Santa Caterina staircase is divided into 13 sections, which coincides with its 13 steps. This polygonal shape does not appear in mathematical studies or practical geometry from that period", the researchers pointed out, highlighting therefore the architectural value of this Gothic structure. 

The study also looks at how plans of spiral staircases built in the Medieval Period feature a support template used to help build the spiral structure, with a set square that was rotated along its edges. “There are around 200 plans of staircases similar to those in Tortosa Cathedral, such as the staircases in Strasbourg Cathedral and Vienna Cathedral”, they stated.  

The Euro-American Congress REHABEND is organised by 20 organisations from ten European and American countries and is co-chaired by the University of Cantabria through its Building Technology R&D&I Group (GTED-UC), and the University of Granada. This year’s conference was held online due to restrictive measures put in place for COVID-19.