Tiago Miguel Ferreira

Seismic vulnerability assessment of historical urban centres: case study of the old city centre in Seixal, Portugal

The seismic vulnerability assessment of old masonry buildings is essential not only to buildings with recognised historical and heritage value but also to ordinary residential masonry buildings. This paper approaches the seismic vulnerability assessment of masonry buildings by applying a simplified methodology to the old city centre of Seixal in Portugal. The methodology adopted in this study was based on a vulnerability index used for the evaluation of damage and the study of loss scenarios on a large scale. Over 500 buildings were assessed using this methodology, and the results were analysed using an integrated Geographical Information System tool. The integration of the vulnerability and loss results could allow city councils or regional authorities to plan interventions based on a global view of the site under analysis, leading to more accurate and comprehensive risk mitigation strategies that support the requirements of safety and emergency planning.

Analysis of the Out-Of-Plane Seismic Behavior of Unreinforced Masonry: A Literature Review

Although the issue of the out-of-plane response of unreinforced masonry structures under earthquake excitation is well known with consensus among the research community, this issue is simultaneously one of the more complex and most neglected areas on the seismic assessment of existing buildings. Nonetheless, its characterization should be found on the solid knowledge of the phenomenon and on the complete understanding of methodologies currently used to describe it. Based on this assumption, this article presents a general framework on the issue of the out-of-plane performance of unreinforced masonry structures, beginning with a brief introduction to the topic, followed by a compact state of art in which the principal methodologies proposed to assess the out-of-plane behavior of unreinforced masonry structures are presented. Different analytical approaches are presented, namely force and displacement-based, complemented with the presentation of existing numerical tools for the purpose presented above. Moreover, the most relevant experimental campaigns carried out in order to reproduce the phenomenon are reviewed and briefly discussed.

Seismic vulnerability assessment of historical urban centres: case study of the old city centre of Faro, Portugal

The necessity of implementing seismic vulnerability assessment procedures to the Portuguese building stock has become urgent as recent predictions indicate the possibility of the occurrence of an earthquake similar to the well-known 1755 Lisbon earthquake within the next 50 years. Obviously, at first instance, large-scale procedures should be used rather than more extensive and accurate methodologies suited for individual buildings assessment. Moreover, it is fundamental to operate in the most vulnerable areas in our built environment, typically, the historical urban centres. As it is recognised, it is within these areas, that old masonry buildings are generally concentrated, being both the most representative and vulnerable constructive typology. Comprising 354 buildings, the case study of the old city centre of Faro is herein presented aiming at analysing and evaluating the seismic vulnerability of its old masonry building stock. In order to achieve these objectives, a vulnerability-index-based methodology was used for the assessment of the seismic vulnerability of the old masonry buildings belonging to the historical centre of Faro (Ribeirinha area) carried out through detailed inspection and survey. The results obtained were analysed using a geographical information system tool. The integration of such vulnerability and loss results represents a valuable tool for city councils and/or regional authorities to plan interventions, on the basis of a global view of the site under analysis, leading this way to more accurate and comprehensive risk mitigation strategies which comply with the requirements of safety and emergency planning. The application of this large-scale scoring methodology has confirmed moderate-to-high values for the vulnerability of this particular area, which combined with its high seismicity, may be quite alarming.

Seismic vulnerability assessment of the old city centre of Horta, Azores: calibration and application of a seismic vulnerability index method

The seismic vulnerability assessment of old masonry buildings is essential not only to buildings with recognised historical and heritage value but also to ordinary residential masonry buildings. Thus, and resorting a wide set of damage data collected after the 1998 Azores earthquake, this paper addresses the topic of the seismic vulnerability assessment of traditional masonry buildings through the calibration and application of a simplified vulnerability assessment method to the old city centre of Horta (Faial Island), in Portugal. In this case study, 192 buildings were assessed using this methodology, and vulnerability and loss scenarios were analysed using an integrated Geographical Information System tool. As is discussed in this paper, such procedure could allow city councils or regional authorities to plan interventions based on a global view of the site under analysis, leading to more accurate and comprehensive risk mitigation strategies, which can than support the requirements of safety and emergency planning.

Analysis of the impact of large scale seismic retrofitting strategies through the application of a vulnerability-based approach on traditional masonry buildings

The buildings’ capacity to maintain minimum structural safety levels during natural disasters, such as earthquakes, is recognisably one of the aspects that most influence urban resilience. Moreover, the public investment in risk mitigation strategies is fundamental, not only to promote social and urban and resilience, but also to limit consequent material, human and environmental losses. Despite the growing awareness of this issue, there is still a vast number of traditional masonry buildings spread throughout many European old city centres that lacks of adequate seismic resistance, requiring therefore urgent retrofitting interventions in order to both reduce their seismic vulnerability and to cope with the increased seismic requirements of recent code standards. Thus, this paper aims at contributing to mitigate the social and economic impacts of earthquake damage scenarios through the development of vulnerability-based comparative analysis of some of the most popular retrofitting techniques applied after the 1998 Azores earthquake. The influence of each technique individually and globally studied resorting to a seismic vulnerability index methodology integrated into a GIS tool and damage and loss scenarios are constructed and critically discussed. Finally, the economic balance resulting from the implementation of that techniques are also examined.

Urban Fire Risk: Evaluation and Emergency Planning

Abstract The management, prevention and mitigation of urban risks are assumed as priority actions within the framework of any rehabilitation and requalification process at the urban scale, particularly in the case of the rehabilitation and refurbishment of old city centres. In the most specific domain of urban safety, seismic and fire risk, which can cause serious consequences, are part of the collective memory of several communities and must be inevitably highlighted. The severity of the resulting damages is a more than valid reason to strongly value prevention, planning and mitigation strategies, limiting their consequences and guaranteeing permanent improvement actions. In the view of the abovementioned, and in the scope of a research project carried out, a new urban fire risk assessment methodology was developed and applied to the old city centre of Seixal. This simplified methodology is based on a preestablished method designated ARICA. Over 500 buildings were assessed using this methodology, and the results were spatially analysed using an integrated geographical information system tool (GIS). It is worth noting that the integration of the risk results into a GIS platform is a valuable step towards the risk mitigation at a urban scale, allowing city councils or regional authorities to plan interventions on the basis of a global spatial view of the site under analysis leading to more accurate and comprehensive risk mitigation strategies that support the requirements of safety and emergency planning in case of urban fire.

Seismic Risk at the Urban Scale: Assessment, Mapping and Planning☆

Abstract In the last decades the evaluation of the seismic risk is of rising concern, considered essential in the activity and definition of strategy planning and urban management. The evaluation of the seismic vulnerability of the existent building stock in the perspective of seismic risk mitigation should not be placed only in relation to the isolated buildings of relevant historical and cultural importance, but also, in relation to residential buildings within old urban centers. When assessing the seismic vulnerability of buildings it is essential to first establish the project objectives, before subsequently choosing the most appropriate strategy and tools necessary for building assessment and fulfillment of these objectives. It is also extremely important to understand the difference between the detailed approaches used for individual building assessment and those methods most efficient for larger scale analysis, pursued for city center assessment. In this work, the results attained from the vulnerability assessment of the old city center of Faro, in Portugal, allowed the estimation of physical damage scenarios, economical and human losses. The methodology applied herein and results are presented resourcing to a GIS application and database management system, enabling the storage of building features and survey, seismic vulnerability and risk mapping, as well as the continued upgrading and improvement of the collected data.

In situ Out-of-Plane Cyclic Testing of Original and Strengthened Traditional Stone Masonry Walls Using Airbags

This article presents a field experimental campaign carried out on an existing one-story stone masonry building, aiming at characterizing the out-of-plane behavior of its walls. A bidirectional test set-up based on a self-equilibrated airbag system was developed and used on three similar masonry walls under distinct conditions: original, retrofitted, and strengthened. The results obtained and the main advantages and shortcomings found in the test set-up are discussed. Finally, some of the most popular retrofitting and/or strengthening techniques applied during the 1998 Azores reconstruction process are critically analyzed, aiming at suggesting quantifications for future interventions on existing unreinforced masonry buildings.

In Situ Flat-Jack Testing of Traditional Masonry Walls: Case Study of the Old City Center of Coimbra, Portugal

Single and double flat-jack tests are presently used widely for assessing the mechanical characteristics of stone masonry. This technique remains as one of the most versatile in situ test procedure for the estimation of the main mechanical properties of masonry walls. Nevertheless their application is still controversial due to the difficulty of accepting in some cases the results as reliable. This article presents and discusses the results of an experimental campaign resorting to flat-jack technique carried out with the scope of the rehabilitation process of the historical city center of Coimbra.

Seismic vulnerability assessment of historical masonry buildings located in Annaba city (Algeria) using non ad-hoc data survey

Seismic vulnerability analysis of historical masonry buildings, addressed to earthquake emergency management and protection strategy planning, requires large-scale vulnerability and damage assessment. In this sense, two seismic vulnerability index methods and damage estimation have been adapted and applied to a pilot-scale urban area located in Annaba city (Algeria). The first method is based on the EMS-98 building typologies, and the second is based on the Italian GNDT approach. To accomplish this task, the authors employed an existing data survey, which, however, was not originally developed for seismic purposes. It was used herein to provide input to the vulnerability methods. The main goal of this research is not only to assess the seismic vulnerability and expected damage within Annaba, but also to adapt the two mentioned approaches to the existing data survey, aiming to use such nonspecific building database and to study the possibility of its application for seismic risk estimation in similar regions. The results obtained from the application of these two methods were integrated and compared using a geographic information system, proving that the vulnerability of the buildings surveyed in Annaba is significant, and therefore risk mitigation efforts and public awareness are required.