Experimental and numerical studies on the belltower of Santa Justa y Rufina (Orihuela-Spain)

Abstract

The bell-tower of Santa Justa y Rufina is located in the historical city of Orihuela (Alicante-Spain). Its construction dates from the XV century, having suffered several changes later. The monumental group was declared National Monument by the Spanish government in 1971. For the study of the structural behaviour of the tower it becomes necessary to know its dynamic response influenced by two important aspects: a) the construction is located in a high seismic risk area, and b) the tower is endowed with six bells that rotate on their axis according to the Spanish characteristic system at a speed between 20 cycles/min and 40 cycles/min. With the purpose of studying its dynamic response a monitoring program has been carried out using accelerometers with the aim of determining the bending and torsional natural frequencies of the tower as well as approaching the value of the structural damping ratio of the construction. Once the experimental results were analyzed, a numerical model of the tower was carried out. This model has been calibrated using the experimental results to assess the seismic vulnerability of the structure to earthquakes that currently the Spanish Standard states for this area, as well as to evaluate the effect of the swinging of the bells after the future restoration planned. The overall elastic modulus and joint rigidity of the tower and the nave of the church have been considered as control parameters. A foundation of 1.5 m height was considered; the connection between the tower and the foundation has not been considered rigid.