Francesco Clementi

Seismic Assessment of a Monumental Building through Nonlinear Analyses of a 3D Solid Model

ABSTRACT The paper analyzes the static behavior and the seismic vulnerability of the “San Francesco ad Alto” building in Ancona (Italy), which is currently used as a Regional Headquarter of the Marche Region by the Italian Army and was formerly a monastery. The global static structural behavior and the dynamic properties have been evaluated using the Finite Element modeling technique, in which the nonlinear behavior of masonry has been taken into account by proper constitutive laws. The concepts of homogenized material and smeared cracking are used to evaluate the capacity of the monastery to withstand lateral loads together with the expected demands resulting from seismic actions (N2 method), using a nonlinear static analysis (pushover). The comparison of seismic demand and capacity confirms the susceptibility of these types of buildings to extensive damage and collapse, as frequently observed in similar buildings. This paper aims to point out that advanced numerical analyses can offer significant information on the understanding of the actual structural behavior of historical buildings. It is believed that the methodology and the overall conclusions of this case study are valid for many historical monasteries in Europe.

Vibration-Based SHM of Ordinary Buildings: Detection and Quantification of Structural Damage

One of the most important issues in civil and in mechanical engineering is the detection of structural damages, which are defined as changes of material properties, of boundary conditions and of system connectivity, which adversely affect the system’s performances. The damage identification process generally requires establishing existence, localization, type and intensity of the damage.During its service life, a structure, besides his natural aging, can be subjected to earthquakes. These events may have a deep impact on building safety and a continuous monitoring of the structure health conditions, through Structural Health Monitoring (SHM) techniques, is necessary in many cases.Within this a background, the purpose of this work is to propose an integrated novel approach for the diagnosis of structures after a seismic event. The proposed monitoring system is based on recording the accelerations of the real structure during a seismic input, and the reintroduction of them into a numerical model, suitably tuned, in order to outline a possible post-earthquake scenario.This approach provides an estimation of the health of the building and of its residual life, and to detect and quantify the damage, some of the crucial aspects of SHM. Actually, we also get both online and self-diagnosis of the structural health.The technique is applied to a real structure, an industrial building liable of some seismic vulnerabilities. It it did not undergo an earthquake, so we have not recordered accelerations, and get them from a different numerical models subjected to the ground acceleration of a realistic earthquake.Copyright

Seismic behavior of an Italian Renaissance Sanctuary: Damage assessment by numerical modelling

The paper deals with modelling and analysis of architectural heritage through the discussion of an illustrative case study: the Medieval Sanctuary of Sant’Agostino (Offida, Italy). Using the finite element technique, a 3D numerical model of the sanctuary is built, and then used to identify the main sources of the damages. The work shows that advanced numerical analyses could offer significant information for the understanding of the causes of existing damage and, more generally, on the seismic vulnerability.

Preliminary study of the influence of different modelling choices and materials properties uncertainties on the seismic assessment of an existing RC school building

This paper studies the influence of some aleatory and epistemic uncertainties on the seismic behaviour of an existing RC school building through a codified sensitivity analysis that uses pushover analyses and a logic tree approach. The considered epistemic uncertainties, i.e. diaphragm stiffness and modelling of stairs, seem not influencing the final assessment in term of index of seismic risk. Vice versa, aleatory ones, i.e. concrete and steel mechanical properties, strongly affect the Index. For this reason, investigations and tests should focus on the study of the mechanical properties, and, in particular, on the study of columns’ concrete mechanical properties, which have the largest impact on the building seismic response.

Seismic assessment of existing precast concrete buildings: Influence of deformable connections

The paper is focused on the key role of the connections between precast elements in determining the seismic performance of industrial Precast Structures (PS). The work critically investigates the influence of different variables on the connection behaviour, as well as the results of the different safety assessment approaches. Referring to a case study based on an industrial PS located in Italy, one highlights the importance of the connection in the seismic upgrade of existing PS, and the minor role of the mechanical slenderness of the column when considering weak connections.The paper is focused on the key role of the connections between precast elements in determining the seismic performance of industrial Precast Structures (PS). The work critically investigates the influence of different variables on the connection behaviour, as well as the results of the different safety assessment approaches. Referring to a case study based on an industrial PS located in Italy, one highlights the importance of the connection in the seismic upgrade of existing PS, and the minor role of the mechanical slenderness of the column when considering weak connections.

SEISMIC ASSESSMENT OF CULTURAL HERITAGE: NONLINEAR 3D ANALYSES OF “SANTA MARIA DELLA CARITÀ” IN ASCOLI PICENO

In this paper a masonry church is analysed in order to assess its seismic vulnerability with respect to the actual state of conservation, including past retrofitting. The case study is the “Santa Maria della Carità” church, located in Ascoli Piceno, a small town of Marche region, in the Centre of Italy, where two major earthquakes occurred in August and in October 2016, causing widespread damage. The church has a large historical, architectural value because is one of the most important example of the Barocco age in the region, and contains a lot of precious paintings of local artists. Moreover it has also a social value for the city of Ascoli Piceno, because it is the only one that is opened to the devotees for every moment of day and night. Stroked also by the L’Aquila earthquakes (2009) the church was subjected to a retrofit intervention (2010), in order to obtain a better “box-like behaviour”. Churches are usually characterised by a high seismic vulnerability due to their structural and geometric configurations, heterogeneous and deteriorated materials. These structures have very large and high external walls without internal orthogonal walls: the space thus created is often covered by some thin vaults or thrusting arches. In this work using an advanced FEM approach (a 3D nonlinear solid numerical model has been used to evaluate the seismic capacity) the structure has been studied to establish its significant deficiencies, in order to obtain a clear understanding of the structural behavior. The results should be useful to design a reliable strengthening intervention, but they could be also extrapolated to the wide variety of historical churches, and generalized for a wide masonry building category. 2533 Available online at www.eccomasproceedia.org Eccomas Proceedia COMPDYN (2017) 2533-2541