Assessment of Seismic Load Capacity of a Slender Masonry Clock Tower

Abstract

The paper presents the seismic vulnerability assessment of a historical masonry clock tower by means of the finite element method. The mechanical behavior and failure mechanism of these structures must be well understood in order to evaluate their performance and select an appropriate retrofit approach when needed. Stone towers, which sometimes have complex geometries and irregularities and are often designed for vertical loads, are vulnerable to lateral loads, especially earthquake loads, due to the slenderness of the tower and the limited ductility of the stone. This study aims to determine the horizontal load capacity of a magnificent clock tower by investigating its structural behavior using the finite element method. The analyzes carried out considering the seismicity of the region showed that the clock tower would be severely damaged or completely collapsed in case of an earthquake with an exceedance probability of 10% in 50 years. In non-linear time history analyses, the maximum base shear force to weight ratio was calculated as 0.27. The maximum drift ratio at the top of the clock tower reveals that the tower exceeds the collapse prevention performance level. The residual displacements obtained from non-linear time history analysis prove that plastic deformations occur on the tower body. In the light of this data, it is considered that the clock tower needs to be retrofitted with acceptable restoration procedures against possible earthquakes in the region.