Seismic Risk Assessment of a Medieval Tower: The Case Study of Craco

Abstract

In the present paper the risk assessment of the medieval Norman tower of Craco (Matera, Italy) is discussed. Craco is a totally abandoned little town because of the activation of landslide motions of its soil depth. The medieval tower is one of the few buildings still standing as it is built on a fixed stiff foundation ground. Nevertheless, the tower is, indirectly, subjected to the movements of the close landslide. The tower is located in the highest and more stable part of the hill where the old town was built in the XII century for protection from enemy attacks. It is 20 m tall and has a (11 x 11) m 2 square plan. The basement has a truncated pyramid shape; originally it had two masonry vaults, one barrel on the first floor, which no longer exists, and a still visible cruise at the second order, connected by a now destroyed internal staircase. In 1949 a reinforced concrete cistern was placed inside the tower. Craco is classified as a town with a medium level seismic hazard. The main aim of the present study is to evaluate the seismic risk by means of a Finite Element model, calibrated through dynamic tests performed on the tower and considering the historical value of the structure and the context in which it stands. In fact, the structure is characterized by several peculiarities: the presence of a reinforced concrete cistern, the interaction with the surrounding buildings, the closeness to the landslide, the topographical exposition, etc. Moreover, the structure has a great impact on the society due to its touristic interest, as it is an emblem of the, so-called, "ghost town" of the Appennino mountains. A new approach is proposed to evaluate the effects of all the previously cited features on the evaluation of the seismic risk of the tower, introducing also economical and sociological parameters.

A Conceptual Design Approach for Archaeological Structures, a Challenging Issue between Innovation and Conservation: A Studied Case in Ancient Pompeii

“…For buildings located in seismically active zones, seismic isolation systems could be a very effective solution for improving the earthquake resistance of these structures. The main advantage of a seismic isolation system is that no structural elements should be added to the structure in order to strengthen it [25][26][27], while the traditional techniques, oriented to increase strength and ductility, are not always useful in the seismic rehabilitation of complex masonry structures. The aim to reduce seismic actions, thus avoiding significant damages to the structure and its contents even under strong earthquakes, yields successful results, since the devices can interfere moderately with the structure itself.…”

“…In the literature, most authors have focused their attention on the testing and monitoring of the structural properties of buildings and monuments [14][15][16][17][18][19][20] in order to understand the rehabilitation needs of the structures. A few authors [21][22][23][24][25], interested in assessing the structural challenges at archaeological sites, have investigated the aspects related to the challenge of considering both the seismic requirements and conservation of the authenticity of the material fabric.…”

Probabilistic seismic assessment of a high-rise URM building

“…The evolution of the different null and non-null damage states according to the requested spectral displacement is presented in Fig. (1)(2)(3)(4)(5). The specific and mean damage ratio for the damage states is also presented in Fig.…”

“…In order to assess the seismic vulnerability of the structures, different methods have been developed in which the seismic action and the response capacity of the constructions are defined based on different approaches [4][5][6]. The vulnerability index method (VI) defines the seismic action from the macroseismic intensities detailed in the EMS-98 scale, while the structural behaviour is described by a vulnerability index [7].…”

Determining the Dynamic Characteristics of a Multi-Story RC Building Located in Chile: A Comparison of the Results between the Nonparametric Spectral Analysis Method and the Parametric Stochastic Subspace Identification Method

“…These methods can be grouped into two main categories: parametric identification, which establishes a simplified mathematical model with which the measured and calculated responses can be compared, and nonparametric identification, which identifies the system by means of transformations, functions, and mathematical processes [20,21]. Some interesting works determining the dynamic response of heritage and modern structures with irregularities using system identification techniques can be consulted in the references [22][23][24][25]. In these works, different approaches are used to identify the main dynamic characteristics using accelerometers installed in the studied buildings.…”