Explorando por Autor "Spacone, Enrico"

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Acceso Abierto
Alternative approach for reproducing the in-plane behaviour of rubble stone walls
(2017) Tarque, Nicola; Camata, Guido; Benedetti, Andrea; Spacone, Enrico
Stone masonry is one of the oldest construction types due to the natural and free availability of stones and the relatively easy construction. Since stone masonry is brittle, it is also very vulnerable and in the case of earthquakes damage, collapses and causalities are very likely to occur, as it has been seen during the last Italian earthquake in Amatrice in 2016. In the recent years, some researchers have performed experimental tests to improve the knowledge of the behaviour of stone masonry. Concurrently, there is the need to reproduce the seismic behaviour of these structures by numerical approaches, also in consideration of the high cost of experimental tests. In this work, an alternative simplified procedure to numerically reproduce the diagonal compression and shear compression tests on a rubble stone masonry is proposed within the finite element method. The proposed procedure represents the stone units as rigid bodies and the mortar as a plastic material with compression and tension inelastic behaviour calibrated based on parametric studies. The validation of the proposed model was verified by comparison with experimental data. The advantage of this simplified methodology is the use of a limited number of degrees of freedom which allows the reduction of the computational time, which leaves the possibility to carry out parametric studies that consider different wall configurations.
Acceso Abierto
Masonry infilled frame structures: state-of-the-art review of numerical modelling
(2015) Tarque, Nicola; Candido, Leandro; Camata, Guido; Spacone, Enrico
This paper presents a state-of-the-art review of the nonlinear modelling techniques available today for describing the structural behaviour of masonry infills and their interaction with frame structures subjected to in-plane loads. Following brief overviews on the behaviour of masonry-infilled frames and on the results of salient experimental tests, three modelling approaches are discussed in more detail: the micro, the meso and the macro approaches. The first model considers each of the infilled frame elements as separate: brick units, mortar, concrete and steel reinforcement; while the second approach treats the masonry infill as a continuum. The paper focuses on the third approach, which combines frame elements for the beams and columns with one or more equivalent struts for the infill panel. Due to its relative simplicity and computational speed, the macro model technique is more widely used today, though not all proposed models capture the main effects of the frame-infill interaction.
Acceso Abierto
Nonlinear Dynamic Analysis of a Full-Scale Unreinforced Adobe Model
(2014) Tarque, Nicola; Camata, Guido; Spacone, Enrico; Varum, Humberto; Blondet, Marcial
This paper describes the results of a numerical study of a full-scale adobe building model tested on a shaking table. Material properties of adobe masonry were calibrated to represent the wall in-plane seismic behavior, based on a prior numerical analysis of an adobe wall carried out by the authors. The inelastic part of the constitutive model was represented by a softening curve in tension and by a hardening/softening behavior in compression; thus, the fracture energy is a key issue in the modeling process. A finite element model that relies on a homogenous continuum approach was developed in Abaqus/Explicit software. The damage evolution in the numerical simulation represented fairly well the experimental crack pattern, for in-plane and out-of-plane seismic effects. Overall, the calibrated material properties and the explicit solution scheme proved to be appropriate for simulating the seismic behavior and predicting capacity of unreinforced adobe structures subjected to seismic loading.
Acceso Abierto
Numerical simulation of an adobe wall under in-plane loading
(2014) Tarque, Nicola; Camata, Guido; Varum, Humberto; Spacone, Enrico; Blondet, Marcial
Adobe is one of the oldest construction materials that is still used in many seismic countries, and different construction techniques are found around the world. The adobe material is characterized as a brittle material; it has acceptable compression strength but it has poor performance under tensile and shear loading conditions. Numerical modelling is an alternative approach for studying the nonlinear behaviour of masonry structures such as adobe. The lack of a comprehensive experimental database on the adobe material properties motivated the study developed here. A set of a reference material parameters for the adobe were obtained from a calibration of numerical models based on a quasi-static cyclic in-plane test on full-scale adobe wall representative of the typical Peruvian adobe constructions. The numerical modelling, within the micro and macro modelling approach, lead to a good prediction of the in-plane seismic capacity and of the damage evolution in the adobe wall considered.
Texto completo enlazado
Seismic response of hospitals at different scales
(Pontificia Universidad Católica del Perú, 2019-03-21) Liguori, Nicola; Tarque, Nicola; Spacone, Enrico
Nowadays, natural disasters are more frequents and destructives compared to the past, causing many deaths and injuries. Existing hospitals are defined essential structures that have the goal to protect the public health of citizen. They are called to resist not only to the impact of a disaster, but also to be operational in that case. Operational means that all the components of a health facility such as structures, architectural elements, contents, lifelines, key staff and the whole organizational system have to be functional. That objective is a challenge for the existing structures, especially for those built with obsolete seismic codes and in high seismic hazard areas like Lima. Furthermore, in case of an emergency, health facilities are called to response as a network in order to be more efficient and resilient. It implies that hospitals have to be managed not only at small-scale referring to the single hospital, but also at large-scale referring to the whole health system composed by all the health facilities involved in a determined area. Transfer of patients, staffs, water and medicines, can be moved under the coordination of a headquarters in this way. Starting from a developed health sector contingency plan in case of earthquakes for Lima metropolitan area, an assessment of the seismic performance of health facilities at large and small scale was carried out. At large-scale, two exploratory models were developed. The first one adapts to evaluate the basic seismic response capacity of hospitals, while the second one useful to assess the hospital treatment capacity of health facilities in the aftermath of a seismic event. Both models were carried out considering structural and nonstructural building damages using fragility curves provided by international standards, given the lack of Peruvian curves. Both models were proposed for a case study of 41 hospitals in Lima metropolitan. Given the lack of data about Peruvian building fragility curves, for a high rise infilled reinforced concrete hospital building, fragility curves were developed through the capacity spectrum approach including record-to-record variability. The method also allowed to to assess at small-scale the seismic structural performance of the investigate hospital building using the capacity analysis method.