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- A vulnerability index formulation for the seismic vulnerability assessment of vernacular architecturePublication . Ortega, Javier; Vasconcelos, Graça; Rodrigues, Hugo; Correia, MarianaThe valorization and preservation of vernacular architecture, as well as traditional construction techniques and materials, is a key-element for cultural identity. Conservation efforts are often mainly focused on historical constructions and monuments. Furthermore, more detailed and sophisticated seismic vulnerability assessment approaches typically used for monumental buildings require time, cost and resources that are not commonly assigned to the study of vernacular architecture. Earthquakes come unexpectedly, endangering in-use vernacular architecture and the population who inhabits it. That is why simplified methods for the seismic vulnerability assessment of vernacular architecture are of paramount importance. The present paper presents a new formulation for the vulnerability index method particularly adapted to the characteristics of vernacular architecture: Seismic Vulnerability Index for Vernacular Architecture (SVIVA). The vulnerability index method has been used extensively in the literature using different formulations that were always defined based on empirical knowledge acquired through post-earthquake damage observation and expert judgment. The SVIVA formulation is developed by means of an analytical process instead of the traditional empirical approach. The process included an extensive numerical modeling campaign that allows adapting the method to the characteristics of vernacular architecture by gaining a deeper quantitative knowledge on their seismic behavior.
- Use of post-earthquake damage data to calibrate, validate and compare two seismic vulnerability assessment methods for vernacular architecturePublication . Ortega, Javier; Vasconcelos, Graça; Rodrigues, Hugo; Correia, Mariana; Ferreira, Tiago Miguel; Vicente, RomeuThe paper presents and discusses the application of two large scale seismic vulnerability assessment methods on the island of Faial in Azores (Portugal). The two methods are specifically conceived to assess the seismic vulnerability of vernacular architecture. The first method follows a classical seismic vulnerability index approach and is referred as SVIVA (Seismic Vulnerability Index for Vernacular Architecture). The second method is referred as SAVVAS (Seismic Assessment of the Vulnerability of Vernacular Architecture Structures) and it is a numerical tool intended to estimate the seismic capacity of vernacular buildings in terms of seismic load factors associated with different structural damage limit states. The main reason behind the selection of Faial Island as a case study was the availability of post-earthquake reports of the building stock after the 1998 Azores earthquake, which allowed comparing the damage scenarios obtained using both methods with the post-earthquake damage data and thus helped for the calibration and validation of the two methods. The application of both methods led to a good fit between estimated versus observed damage grades, which validated their applicability as large-scale first level approaches. Moreover, as the main outcome, the paper presents the novelties of the SAVVAS method, which had not been applied before, and discusses its main advantages, namely: no need for calibration with previous post-earthquake damage data, an enhancement of the prediction capabilities, a more individualized evaluation of the buildings and the possibility to assess the seismic performance of the building in different loading directions.
- Assessment of the influence of horizontal diaphragms on the seismic performance of vernacular buildingsPublication . Ortega, Javier; Vasconcelos, Graça; Rodrigues, Hugo; Correia, MarianaThe awareness and preservation of the vernacular heritage and traditional construction techniques and materials is crucial as a key element of cultural identity. However, vernacular architecture located in earthquake prone areas can show a particularly poor seismic performance because of inadequate construction practices resulting from economic restraints and lack of resources. The horizontal diaphragms are one of the key aspects influencing the seismic behavior of buildings because of their major role transmitting the seismic actions to the vertical resisting elements of the structure. This paper presents a numerical parametric study adopted to understand the seismic behavior and resisting mechanisms of vernacular buildings according to the type of horizontal diaphragm considered. Detailed finite element modeling and nonlinear static (pushover) analyses were used to perform the thorough parametric study aimed at the evaluation and quantification of the influence of the type of diaphragm in the seismic behavior of vernacular buildings. The reference models used for this study simulate representative rammed earth and stone masonry vernacular buildings commonly found in the South of Portugal. Therefore, this paper also contributes for a better insight of the structural behavior of vernacular earthen and stone masonry typologies under seismic loading.
- Assessment of the efficiency of traditional earthquake resistant techniques for vernacular architecturePublication . Ortega, Javier; Vasconcelos, Graça; Rodrigues, Hugo; Correia, MarianaSpecific architectural elements can be identified in constructions located in regions frequently exposed to earthquakes. These earthquake resistant features were developed empirically by local communities to protect their built-up environment. Research in these traditional practices, resulting from a local seismic culture, is a relevant and positive approach, since it focuses on the strength of the system rather than on its weaknesses. Its integration into current vernacular building practices can help to preserve and retrofit surviving in-use examples while respecting their authenticity. The main goal of the present work is to assess numerically the efficiency of traditional earthquake resistant solutions to mitigate the seismic vulnerability of vernacular architecture. The paper thus presents the results of a detailed numerical study based on finite element modeling and nonlinear static (pushover) analysis intended to quantitatively evaluate the influence of each technique on the seismic behavior of vernacular constructions and to better understand their structural role under seismic loading.
- Seismic Vulnerability and Loss Assessment of Vila Real de Santo António, Portugal: Application of a Novel MethodPublication . Ortega, Javier; Vasconcelos, Graça; Rodrigues, Hugo; Correia, MarianaThe city of Vila Real de Santo António (VRSA) was erected after the 1755 Lisbon earthquake following a Pombaline development similar to the well-known reconstruction of Lisbon downtown. It included seismic-resistant measures at an urban and architectural level, but most original buildings have nowadays been replaced or are highly altered. A research question arises whether or not and to what extent these alterations have compromised the seismic vulnerability of the historical city center. The paper presents the seismic vulnerability assessment of the historic city center of VRSA using a newly developed method: Seismic Assessment of the Vulnerability of Vernacular Architecture Structures (SAVVAS). The method proposes a numerical tool intended to estimate the seismic capacity of vernacular buildings using qualitative and simple quantitative data that can be rapidly obtained from visual inspections. The seismic vulnerability and loss assessment consider different scenarios, including the historical condition, and studies different retrofitting strategies.
- Development of a Numerical Tool for the Seismic Vulnerability Assessment of Vernacular ArchitecturePublication . Ortega, Javier; Vasconcelos, Graça; Rodrigues, Hugo; Correia, Mariana; Miranda, Tiago Filipe da SilvaAiming at protecting the vernacular heritage located in earthquake prone areas, the paper presents the development and validation of the numerical tool that constitutes the core of a novel seismic vulnerability assessment method: Seismic Assessment of the Vulnerability of Vernacular Architecture Structures (SAVVAS). An extensive numerical modeling campaign was carried out to evaluate and quantify the influence of several parameters on the seismic response of vernacular buildings. The results were compiled into a database on which regression analysis could be performed to extract correlations between seismic capacity and qualitative and simple quantitative data that can be obtained from visual inspection.
- Seismic Analysis of a Portuguese Vernacular BuildingPublication . Barros, Ricardo; Rodrigues, Hugo; Varum, Humberto; Costa, Aníbal; Correia, MarianaRammed-earth constructions are present all over the world and are common in Portugal, especially in the southern part of the country. In recent years, several research works published on this topic focused on characterizing the mechanical properties and understanding the structural behavior of buildings through experimental and numerical works. Much of the work focused on the characterization of the seismic vulnerability of rammed-earth construction. The research presented in this paper offers another contribution on this topic, particularly in understanding the influence of construction elements in a vernacular seismic culture. On the basis of a simplified case study, derived from a real building, a set of numerical analyses was carried out to assess the influence of the geometry, layout, and different retrofitting solutions typical of vernacular rammed-earth constructions on behavior and seismic performance.