J. A. R. Mendes da Silva

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.

Evaluation of Strengthening Techniques of Traditional Masonry Buildings: Case Study of a Four-Building Aggregate

Increasing appraisal of the durability, conservation state, and changeable use and function of old buildings in urban centers relies a great deal on the structural safety evaluation of vertical load capacity and the ability to resist horizontal forces. The need to assess seismic vulnerability, particularly of traditional masonry buildings, is a key issue. Evaluation of the seismic vulnerability of old buildings is essential in the definition of strengthening needs and minimization of damage from seismic actions in the safeguarding of built heritage. A three-dimensional model was developed for an aggregate of four traditional masonry buildings located in the old city center of Coimbra, in Portugal. The finite element modeling of these buildings has aimed to identify structural fragility, understand the damages detected, and evaluate the global structural safety of these types of buildings. The primary results obtained in this case study helped to interpret the structural damage and stress distribution, and...

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 and Risk Assessment of Historic Masonry Buildings

Seismic risk evaluation of built-up areas involves analysis of the level of earthquake hazard of the region, building vulnerability and exposure. Within this approach that defines seismic risk, building vulnerability assessment assumes great importance, not only because of the obvious physical consequences in the eventual occurrence of a seismic event, but also because it is the one of the few potential aspects in which engineering research can intervene. In fact, rigorous vulnerability assessment of existing buildings and the implementation of appropriate retrofitting solutions can help to reduce the levels of physical damage, loss of life and the economic impact of future seismic events. Vulnerability studies of urban centres should be developed with the aim of identifying building fragilities and reducing seismic risk. As part of the rehabilitation of the historic city centre of Coimbra, a complete identification and inspection survey of old masonry buildings has been carried out. The main purpose of this research is to discuss vulnerability assessment methodologies, particularly those of the first level, through the proposal and development of a method previously used to determine the level of vulnerability, in the assessment of physical damage and its relationship with seismic intensity.

Directives towards a sustainable urban rehabilitation process in old cities

The main goal of this work is to support, scientifically, the urban rehabilitation decisions to Coimbras historic downtown (a traditional Portuguese city) under a sustainable construction perspective. This paper presents the ten main issues to find a solution on sustainable urban rehabilitation, according to the existing experiences and concepts. The main aspects of sustainability were analysed on two levels: the urban and the building. Furthermore, they were compared with the guidelines of several urban interventions and it was possible to outline a general structure of intervention. This case study is supported by a local research program on inspection and appraisal, concerning construction technology, building defects, architectural and social characterisation, of about 800 buildings. It contributes to define intervention strategies in old areas of Portuguese cities, with a constant concern to tailor solutions and proposals to the existing reality in terms of physical, social and cultural characteristics.

Buildings in the old town of Coimbra: knowledge and action to promote their rehabilitation

Purpose – The purpose of this paper is to report on the behaviour of the different types of facades used in the old town of Coimbra in Portugal when they are exposed to seismic activity.Design/methodology/approach – Over 400 facades in the uptown, and 700 in the downtown of Coimbra were surveyed to determine their material and their current state of decay. Further investigations on two specific sites were undertaken to determine the effects of seismic activity on the facades.Findings – The paper reports on the classification of the results from the different surveys into a web‐based database. In order to achieve this classification a geographic information system (GIS) tool was used to locate the different sites under investigation.Originality/value – This paper combines the results of an investigation into the inspection of facades in Coimbra, Portugal, with a GIS tool and database to document the results of the different surveys for seismic activity.

Cultural Heritage Monuments and Historical Buildings: Conservation Works and Structural Retrofitting

The preservation and strengthening of historical constructions over time is highly to be supported due to their cultural and heritage value and the potential economic exploitation related to tourism. Old masonry buildings are subjected to slow aging processes, which must be monitored in order to prevent irreversible deterioration of materials and structural damage, as well as reduce vulnerability to natural hazards, in particular earthquakes. Conservation requirements may be summarized with the principle of “minimum intervention”, which is based on the idea of maintaining, as much as possible, the original characteristics of the buildings, avoiding the use of invasive strengthening techniques that would compromise their authenticity. However, the daily use of this building stock, which is very important to avoid abandonment, raises the problem of complying not only building conservation but also safety principles. Within this scope, the selection and use of correct structural modelling tools to assess the present state and to support the design of the necessary strengthening interventions is a challenging issue. Thus, this chapter presents, by means of case studies, examples of methodological approaches for the diagnosis and seismic assessment of historical structures, as well as for the design of retrofitting and strengthening works.

Structural and architectural characterisation of old building stocks: case study of the old city centre of Seixal, Portugal, rebuilt after the Great 1755 Lisbon earthquake

AbstractThis paper addresses the issue of historical urban centres from the perspective of the analysis and inventory of building features. The cataloguing process of the building typologies is presented herein as a synthesis of the main construction forms, using as a case study the old city centre of Seixal, Portugal, rebuilt in its present form after the great 1755 Lisbon earthquake. As marks of an historical and architectural heritage, old urban centres should be protected, safeguarded and potentialised. Therefore, it is essential to have a complete understanding of the diachronic process of both buildings and urban mesh, in order to support qualified, conscientious and sustainable interventions.

Strategies to assess the sustainability in the rehabilitation process - a tool for interventions in old centres

In order to reduce the pace of new constructions, it is necessary to rethink the city and act upon the built environment taking into account the impact of the urban expansion. These interventions must be conditioned by the need to guide human activity towards the sustainability principles. This paper presents a sustainability assessment model for buildings located in old city centres which have historical characteristics and are shaped by a built fabric of high cultural value but are often characterised by vacant houses and constructive degradation. The model was based on the analysis of other assessment systems used across the world and also on the study and characterisation of these specific urban areas. The main objective was to create a decision support tool to guide designers and technicians involved in interventions in the built environment, as well as the user in terms of occupation and building maintenance, particularly regarding resource consumption and waste generation.