On the Structural Analysis and Seismic Protection of Historical Masonry Structures (original) (raw)
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Seismic vulnerability assessment of historical masonry structural systems
Engineering Structures, 2014
The Masonry structures are complicated systems that require a thorough and detailed knowledge and information regarding their behavior under seismic loading. Appropriate modeling of a masonry structure is a prerequisite for robust earthquake resistant design. However, modeling a real structure to a robust quantitative (mathematical) representation is a very difficult and complicated task. This paper presents an approach toward a solution of the problem. A novel methodology for earthquake resistant design of masonry structural systems, either before or after their repair and/or strengthening, is presented. The entire process is illustrated in the case study of a 4-storey historical masonry structure located in the city of Patras, in Greece.
Seismic vulnerability and preservation of historical masonry monumental structures
Earthquakes and Structures, 2012
Seismic damage and vulnerability of five historical masonry structures surveyed after the 1999 Kocaeli and Duzce, Turkey earthquakes are discussed in this paper. The structures are located in two neighboring cities that have been struck by five very large (M s ≥ 7.0) earthquakes during the 20 th century alone. Older masonry mosques with arches and domes and their masonry minarets (slender towers) were among the most affected structures in this highly seismic region. While some of the religious and historical structures had virtually no damage, most structures suffered significant damage or collapsed. In the city of Bolu, for example, approximately 600-year-old Imaret, 500-year-old Kadi, 250-year-old Sarachane, and 100-year-old Yildirim Bayezid mosques suffered substantial structural damage after the 1999 earthquakes. Another historical mosque surveyed in Duzce partially collapsed. Most common factors contributing to deterioration of historical structures are also presented. Furthermore, a brief overview of issues associated with analysis and modeling of historical masonry structures is provided.
Seismic and Restoration Assessment of Monumental Masonry Structures
Materials
Masonry structures are complex systems that require detailed knowledge and information regarding their response under seismic excitations. Appropriate modelling of a masonry structure is a prerequisite for a reliable earthquake-resistant design and/or assessment. However, modelling a real structure with a robust quantitative (mathematical) representation is a very difficult, complex and computationally-demanding task. The paper herein presents a new stochastic computational framework for earthquake-resistant design of masonry structural systems. The proposed framework is based on the probabilistic behavior of crucial parameters, such as material strength and seismic characteristics, and utilizes fragility analysis based on different failure criteria for the masonry material. The application of the proposed methodology is illustrated in the case of a historical and monumental masonry structure, namely the assessment of the seismic vulnerability of the Kaisariani Monastery, a byzantine church that was built in Athens, Greece, at the end of the 11th to the beginning of the 12th century. Useful conclusions are drawn regarding the effectiveness of the intervention techniques used for the reduction of the vulnerability of the case-study structure, by means of comparison of the results obtained.
A Methodology for Evaluating the Structural Safety of Historical Monuments in Seismic Areas
This paper outlines the methodology followed for evaluating the structural safety of the important historical Islamic monument Hala Sultan Tekke located in high seismic area in Cyprus. The adopted method involved, performing in-situ investigation, laboratory tests and conducting rigorous analytical analyses. In-situ investigations included carrying out geometrical and constructional surveys to the monument, visual inspection to building structural elements, monitoring propagation of recorded cracks, excavating open pits and drilling boreholes for exploring foundation and sub-soil conditions and conducting in-situ non-destructive tests on monument walls. Laboratory tests included determining chemical and mechanical properties for materials utilized for monument construction and Geotechnical conditions. Analytical studies included performing both static and dynamic structural analyses on mathematical models accurately simulating the monument geometrical configuration taking into consi...
Seismic Vulnerability Assessment of a Monumental Masonry Building
Infrastructures
Recent seismic events that hit the central part of Italy have highlighted again the high vulnerability of the historical and architectonical heritage of Italy and the importance of preserving it. However, the seismic assessment of monumental buildings is particularly complex because each historical construction is a singular case realized by specific techniques. Therefore, the first step should be the knowledge of the building even if it is a difficult task. In the present paper, the seismic behavior of an important nineteenth century astronomical observatory, constructed between 1816 and 1819, was investigated. The building, located in Naples, in the southern part of Italy, and classified by the Italian code as an area of medium seismic hazard, was analyzed in the elastic and inelastic range under seismic actions. In this study, the results of two different models were proposed and critically compared. The first one was implemented by shell elements for walls and vaults developing ...
ISCARSAH Symposium "Assessment and strengthening of historical stone masonry constructions subjected to seismic action", 2009
The acknowledgment of the scientific community that the structural safety aspects of constructions belong-ing to the cultural heritage can not be treated according to standard procedures that are fitted for new constructions, is leading to new, specific approaches for assessing their actual structural performances and then for developing new, more appropriate methodologies and design criteria for their repair and strengthen-ing. The basic idea is that the usual, even the most sophisticated, structural design approaches naturally imply a certain level of “over-design”, and this can lead to unacceptable solutions when dealing with “existing structures” (ISO 13822). Over-designing interventions on existing structures could in fact imply in general unacceptable costs and, in the case of the historical heritage, unacceptable losses of cultural (historic, artistic) values. On this respect, the “seismic condition” presents the most delicate implications, as the very extreme resources of the structure , i.e. those connected with resistance mechanisms that are normally neglected and in any case almost impossible to include in structural models, are mobilized. Attempts to offer comprehensive methodologies to tackle such difficulties have been recently made at an international level by the ISCARSAH committee of ICOMOS and, for constructions in seismic areas, by the Italian standardisation bodies (Ministry of Culture and Ministry of Public Works). The consciousness that any calculation imply over-design has as relevant consequence that the formal match between “code requirements” and “formally demonstrated structural performances” can be misleading, and not necessarily required. Assessment is no more considered a more or less sophisticated exercise of analytical/numerical structural models, but an articulated and combined use of structural models, historical informations, surveys and investigations, personal, qualitative judgments (based on past experiences, specific training, comparisons, evaluations of past performances of a constructions) that in a “multidisciplinary” context , ensuring that all the values (economical, social, historic, artistic) of the constructions are taken into account, leads to a final decisions on if and how to intervene. Moreover, safeguarding “cultural values” implies also appropriated selection and design of the intervention materials and technologies. Attention is than paid to the possibilities offered by the traditional solutions and to their possible combinations with innovative ones. The general aspects of the Italian approach that have been outlined, together with some case studies are pre-sented to exemplify these guiding principles and to introduce researches on traditional and innovative tech-niques and methodologies, employed in historical structures, carried out at the University of Padua.
Assessment of Seismic Vulnerability of a Historical Masonry Building
Buildings, 2012
A multidisciplinary approach for assessing the seismic vulnerability of heritage masonry buildings is described throughout the paper. The procedure is applied to a specific case study that represents a very common typology of masonry building in Italy. The seismic vulnerability of the examined building was assessed after the following: (a) historical investigation about the building and the surrounding area, (b) detailed geometrical relieves, (c) identification of materials by means of surveys and literature indications, (d) dynamic in-situ tests, (e) foundation soil characterization, (f) dynamic identification of the structure by means of a refined Finite Element (FE) model. After these steps, the FE model was used to assess the safety level of the building by means of non-linear static analyses according to the provisions of Eurocode 8 and estimate of the q-factor. Some parametric studies were also carried out by means of both linear dynamic and non-linear static analyses.
Aspects of Seismic Assessment and Redesign of Traditional Masonry Buildings
Most of the traditional greek buildings (new-classic ones or not, small or large), with an age of more than 75 up to 250 yrs, are made of rubble stone masonry with a large volume of low strength lime mortars, while their floors/roofs are mainly made of timber. Their seismic assessment and redesign, based on recent conceptions and normative or informative code principles and criteria, is a challenging problem for the Structural Engineer, not to mention restrictions imposed due to the monumental character of almost all of these old buildings. To this end, the new “frame” of Euro-Codes, and especially of EC 6 and EC 8, is applied in general, as recently completed by the new Greek Codes on (Structural) Assessment and Interventions (nGCSI, 2012), fully harmonized with this “frame” of ECs but far beyond them and more detailed, with a lot of relative application rules. Several aspects are involved in structural assessment and redesign of such old buildings, as covered by the Codes and shortly presented/discussed in this paper, such as : Investigation and documentation of the geometrical and the mechanical data of the existing building, together with their reliability levels (DRLs), i.e. the so-called “knowledge levels”, influencing almost all phases and steps of the design; Quantitative assessment and documentation of any wear, deterioration or damage, of any kind, together with a practical but reliable and safe assessment of the residual mechanical characteristics, based on damage levels (DLs); Decision regarding the performance level (PL), i.e. the foreseen or expected degree of damage during the earthquake itself, probably different for the assessment or the redesign of the structural interventions; Aspects of mechanical behaviour of the masonry (and other) elements, out-of-plane and in-plane response, macro-models etc., before and after repair or/and strengthening, as well as Methods of analysis and dimensioning or redimensioning, linear and non-linear, checks in terms of force or of displacement, depending on PLs and based on skeleton curves. In this paper, most of the related issues are shortly covered, as faced during the structural design, while certain characteristic examples and applications are presented.
Seismic vulnerability of ancient masonry buildings: The case study of low-rise towers
CENTRAL EUROPEAN SYMPOSIUM ON THERMOPHYSICS 2019 (CEST)
The aim of this paper is the seismic vulnerability assessment of different types of low-rise towers. These buildings are typical of the Calabrian region, and have various purposes. The most common are watchtowers located along the coasts, and had a defensive role. In other cases, the low-rise towers are ruins of religious complexes located in strategic and historical areas. In particular, in this paper two structures will be investigated: the castle of "San Fili" in Stignano (RC) and the ruins of the ancient church of St Francis of Assisi in Amantea (CS). The result of this preliminary study was the creation of a simplified geometric model used for the definition of the numerical model with the FE code Abaqus CAE. In order to obtain the natural frequency of these structures, two modal shapes analysis are carried out. The last step was the execution of non-linear static analysis in order to evaluate the seismic response.