Dr. Eng. Ahmed Elyamani

Citation:

Elyamani, A., Wind and earthquake analysis of spire of cimborio of Barcelona cathedral, , Barcelona, Spain, Technical university of Catalonia, 2009.

Thesis Type:

Abstract:

Barcelona Cathedral is one of the most important monuments not only in Spain but also all over the world. The construction of the Gothic cathedral started in 1298 under King Jaume II and in 1460 the main building was completed. The two architects Josep Oriol Mestres and August Font i Carreras completed the construction of the gothic façade in 1889 and the central spire in 1913, following the same design previously proposed by the French architect Charles Galters in 1408. The central spire reaches a height of 90 m over ground level which makes it very vulnerable when subjected to lateral loads like wind and earthquakes. Being finished at the beginning of the 20th century (when the concept of reinforced concrete was being widely spread) gave the builders the chance to centrally reinforce all masonry beams of the spire with steel ties and nowadays these steel ties are facing very severe problems due to corrosion. A complete project for restoration of the spire is being executed nowadays in which a complete dismantling and reconstruction will be carried out. The steel ties will be replaced with titanium ones in order to eliminate the corrosion problem. In order to understand wind and seismic performance of the spire and the role and strength contributions of the steel ties, the different applied loads on the spire which are self weight, wind loads and earthquake loads have been estimated ,then a numerical model of the spire has been created and analyzed using the finite element program DIANA. First a linear elastic analysis under the effect of spire self weight then a combination of spire self weight and wind loads and finally a combination of spire self weight and earthquake loads. The high tensile stresses in masonry beams under the effect of the combination of spire self weight and wind loads and the combination of spire self weight and earthquake loads meant that linear elastic analysis wasn't enough to describe the structure behavior and a nonlinear analysis was essential. A nonlinear analysis under the effect of spire self weight (using three different constitutive models to describe masonry nonlinear behavior) was investigated and it revealed an elevated safety margin as the spire can carry more than ten times its self weight. Then to investigate the seismic performance of the spire a nonlinear static pushover analysis (using two different constitutive models) has been carried out.As a conclusion of this study the steel ties are highly needed to carry the tensile stresses resulted from seismic actions and the spire would be able to resist a maximum base shear of 420 KN (16% of the spire self weight).

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