Historical city buildings are an integral part of the built heritage to be preserved, and their safety is a primary requirement in seismic areas. Collapse of ancient masonry buildings due to seismic actions occur mostly due to overturning of the perimeter walls. This paper addresses the issue of seismic analysis and vulnerability of historical city centers, with a specific case study: the 18th century downtown part of Lisbon, Portugal. The finite element method was adopted for a number of different analyses, introducing non-linear behavior of the materials. From the analysis, the following issues have been addressed: (a) seismic vulnerability of this type of constructions; (b) influence of the group of buildings on the seismic behavior of the individual buildings that compose a single compound; and (c) methodology for action. It is believed that the conclusions obtained with respect to the seismic assessment of masonry buildings can be extrapolated for the wide variety of historical city centers.
This paper presents a review of the methods for seismic vulnerability assessment, together with an experimental method based on shaking table testing. This method is applied to a Portuguese masonry building typology with stone walls and timber floors, subjected to increasing earthquake damage. Traditional-like materials and techniques are used in the building. The vulnerability curves are presented and the damage indicator is correlated with the crack patterns and EMS 98.
Outlining the best strategies for seismic risk mitigation requires that both benefits and costs of retrofitting are
known in advance. The assessment of the vulnerability of building typologies is a first step of a more extensive
effort, concerning the analysis of the viability of seismic risk mitigation and taking into account retrofitting
The methodology adopted to obtain the seismic vulnerability of some classes of residential buildings existing in
mainland Portugal is presented. This methodology is based on a structural analysis of individual buildings
belonging to the same typology. An application example is presented to illustrate the methodology.
Fragility curves of “boxed” building typology are also presented and broken down into three height classes:
low-rise, medium-rise and high-rise. These curves are based on average capacity spectra derived from several
individual buildings belonging to the same typology.
Uma das principais missões de um engenheiro civil é a garantia da segurança e
protecção de pessoas e bens. Ora, é do conhecimento geral que Portugal Continental possui
um historial de ocorrência de sismos de elevada intensidade e que, sempre que estes
ocorrem, os danos observados são extremamente elevados. Ao mesmo tempo, verifica-se
que parte do parque habitacional existente apresenta características que lhe conferem
grande vulnerabilidade sísmica e que se tratam de edifícios já com alguma idade,
necessitando de intervenção, tanto ao nível estrutural como ao não estrutural. Assim, surge
a motivação para estudar a viabilidade da intervenção estrutural para a redução da
vulnerabilidade sísmica deste edificado. Este trabalho constitui então um contributo para
resolução do problema atrás mencionado, demonstrando-se de forma clara a necessidade de
intervenção estrutural nas três tipologias construtivas analisadas, com a análise e
verificação da vulnerabilidade sísmica dos edifícios e procedendo-se também a estudos de
viabilidade económica e de desempenho do edificado. Simultaneamente, pretende-se que o
mesmo seja entendido como uma ferramenta de auxílio aos técnicos especialistas na tomada
A análise da vulnerabilidade sísmica do edificado existente é realizada para cada uma
das tipologias construtivas em estudo: edifícios com paredes em alvenaria de pedra e
pavimentos em madeira...
This paper discusses a mechanical model for the vulnerability assessment of old masonry building aggregates that takes into account the uncertainties inherent to the building parameters, to the seismic demand and to the model error. The structural capacity is represented as an analytical function of a selected number of geometrical and mechanical parameters. Applying a suitable procedure for the uncertainty propagation, the statistical moments of the capacity curve are obtained as a function of the statistical moments of the input parameters, showing the role of each one in the overall capacity definition. The seismic demand is represented by response spectra; vulnerability analysis is carried out with respect to a certain number of random limit states. Fragility curves are derived taking into account the uncertainties of each quantity involved.
The earthquake of the 9th of July 1998 that hit in the central group of the Azores
archipelago greatly affected the islands of Faial, Pico and São Jorge, reaching a magnitude of
Mw 6.2 with the epicentre located about 15km northeast of the Faial Island. This earthquake
allowed the collection of an unprecedented quantity of data concerning the characterisation
of the building stock and the damage suffered by construction. This is the main purpose
of this research, consisting essentially of three main aspects: (i) A detailed characterisation
of the building stock, assigning a five category classification, from old traditional rubble
stone masonry to reinforced concrete moment framed buildings; (ii) A detailed damage
grade classification based on the different damage mechanisms observed; and, (iii) A seismic
vulnerability assessment of the building stock. The results of the vulnerability assessment
together with the building stock database and damage classification were integrated into a
GIS tool, allowing the spatial visualation of damage scenarios, which is potentially useful
for the planning of emergency response strategies and retrofitting priorities to mitigate and
manage seismic risk.
This paper approaches the issue of seismic vulnerability assessment strategies for facade walls of traditional
masonry buildings through the development of a methodology and its subsequent application to the old building
stock of the historical city centre of Coimbra. Over 600 building facades were evaluated in accordance to the
methodology developed. From the post-earthquake damage assessment of masonry buildings in Aquila, Italy, it
was developed and calibrated an analytical function to estimate the mean damage grade for masonry facade
walls. Once defined the vulnerability function for facade walls, the calculation of damage scenarios was carried
out and was subsequently used in the development of an emergency planning tool and in the elaboration of an
accessibility routing proposal for the case study – Old city centre of Coimbra.
The seismic vulnerability associated to existing reinforced concrete buildings, constructed until the late 1970’s, in urban areas of many European countries with moderate to high seismic hazard, is of
extreme importance. In that period, reinforced concrete buildings were designed and constructed
without considering adequately earthquake provisions, constituting therefore a significant source of risk for our cities. Recent major earthquakes around the world have evidenced that this type of existing buildings lacking appropriate seismic resisting characteristics are very vulnerable.
The present paper focus in four important subjects regarding the seismic behaviour of reinforced concrete buildings, first the importance of the experimental studies on full-scale buildings in
particular with two full-scale four-storey reinforced concrete frames tested, in these tests two problems were under study the presence on infill masonry panels in the structure and the use of
smooth reinforcement bars, that induces a sudden loss of concrete-steel bond is one of the sources
of brittle failure in RC elements. For the presence infill masonry panels it’s presented a simplified
macro-model that is able of represents the global behaviour of infill masonry panels and its
interaction with RC elements and its application to a case study. Regarding the study of RC buildings smooth reinforcement bars it’s presented the experimental campaign ongoing and the first
results and conclusions.
Another identified problem in the seismic behaviour of RC buildings is the behaviour of axially loaded reinforced concrete members under biaxial bending moment. It’s presented the actual lack of experimental studies and the nonexistence of simplified models able to represent these effects and the experimental study of RC columns under uniaxial and biaxial bending.
The evaluation of the seismic risk of built-up areas is associated to the level of earthquake hazard, building
vulnerability and level of exposure. Within this holistic approach that defines seismic risk, building
vulnerability is from all three variables, the one that assumes great importance not only because of its obvious
physical consequences in the occurrence of a seismic event, but because it is the potential aspect, for which the
engineering research can intervene, improve and even control seismic behaviour of existing buildings, reducing
the level of vulnerability and consequently the level of physical damage, life loss and economical loss.
Development of vulnerability studies in urban centres can be conducted aiming to identify building fragilities
and reduce the seismic risk, therefore in the scope of the rehabilitation process of the old city centre of
Coimbra, a complete identification and inspection survey of the old masonry buildings has been carried out.
The main purpose of this paper is to discuss the vulnerability assessment methodologies, particularly the first
level approaches, by presenting a proposed method which determines previously the level of vulnerability, only
then assessing physical damage and its relationship to seismic intensity. It is presented and discussed the
strategy and proposed methodology adopted for the vulnerability assessment...
The increasing concern and consequent appraisal on durability, conservation state
and changeable use and function of old buildings in urban centres relies a great deal on the
structural safety evaluation of vertical load capacity but also the capable resistance to
horizontal forces. The need to assess seismic vulnerability, particularly of the traditional
masonry buildings is a key issue. Particular attention has been put upon the building stock of
the old city centre of Coimbra, mainly constituted by old masonry load-bearing buildings of
significant architectural value.
The evaluation of the seismic vulnerability of old buildings is essential in the definition of the
strengthening needs and minimization of possible damages due to seismic actions, in
safeguarding of built heritage or in the identification of critical buildings. This paper intends
to contribute for the assessment of old buildings considering the local seismic risk.
A three dimensional model was developed for an aggregate of four buildings. The finite
element modelling of these buildings has intended to identify structural fragilities, help
understand the damages detected in the existing structures (crack opening) and evaluate the
global structural safety of this type of buildings.
It will be presented the main results obtained in this study...
The concern and need to assess seismic vulnerability, particularly of the traditional
masonry buildings under seismic actions is a key issue, that should be a priority in
the mitigation of the seismic risk, definition of strengthening requirements needs and
minimization of possible damages due to seismic actions, in the identification of
critical buildings and safeguarding of built heritage.
This paper provides information on the constructive and structural details of the
traditional buildings in Coimbra, Portugal, and interprets the potential structural
damage and discusses its seismic behaviour, identifying structural fragilities and
consequently their vulnerability. It also presents the main results obtained in the
numerical studies, and verifies the global stability and dynamic response to seismic
actions. Three different strengthening techniques to improve the global behaviour of
these buildings were modelled and analysed. Efficiency of the strengthening
strategies is also discussed in terms of deformation demands and cost-benefit
Earthquakes represent one of the main cause of serious damage and loss of historic and architectural heritage. Interventions to preserve these building should start with a careful knowledge and assessment of their seismic vulnerability, in order to support any needed retrofitting and strengthening measures.
This paper proposes a procedure to register and diagnose of the level of damage on churches after the occurrence of an earthquake, and also to assess the seismic vulnerability of this type of construction. This procedure was applied to sixteen churches in the Azores islands which were hit by the July 9th 1998 earthquake.
Belfries of church towers are elements with a particular seismic vulnerability. For this reason, and based on the Italian methodology proposed by the Linee Guida (2006), it is applied to belfries of two churches from Pico (Azores), a simplified mechanical model for assessment of seismic vulnerability of this type of structures.
The seismic vulnerability assessment of old traditional masonry building stocks, in a seismic risk mitigation perspective, is truly essential not only for buildings with recognized historical and patrimonial value, but also, in relation to regular buildings. In this sense, this paper approaches the issue of the seismic vulnerability assessment of masonry buildings through the application of a simplified methodology to building stock of the old city centre of Seixal, Portugal. This methodology is based on a vulnerability index, suitable in the evaluation of damage and in the creation of large scale loss scenarios (economical and human). Over 500 buildings were evaluated in accordance with the referred methodology and the results obtained were then integrated into a Geographical Information System tool. The integration of this kind of vulnerability and loss results into a GIS tool allows that city councils or regional authorities make their decisions based on a global view of the site under analysis, which led to more accurate and faster decisions either in terms of risk mitigation strategies or rehabilitation plans. This tool can also assumes great importance in the construction of safety and rescue plans.
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.
Slender masonry structures are distributed all over the world and constitute a
relevant part of the architectural and cultural heritage of humanity. Their
protection against earthquakes is a topic of great concern among the scientific
community. This concern mainly arises from the strong damage or complete
loss suffered by this group of structures due to catastrophic events and the
need and interest to preserve them. Although the great progress in technology,
and in the knowledge of seismology and earthquake engineering, the
preservation of these brittle and massive structures still represents a major
challenge. Based on the research developed in this work it is proposed a
methodology for the seismic risk assessment of slender masonry structures.
The proposed methodology was applied for the vulnerability assessment of
Nepalese Pagoda temples which follow very simple construction procedure and
construction detailing in relation to seismic resistance requirements.
The work is divided in three main parts. Firstly, particular structural fragilities
and building characteristics of the important UNESCO classified Nepalese
Pagoda temples which affect their seismic performance and dynamic properties
are discussed. In the second part the simplified method proposed for seismic
vulnerability assessment of slender masonry structures is presented. Finally...
Considering that vernacular architecture may bear important lessons on hazard mitigation and that well-constructed examples showing traditional seismic resistant features can present far less vulnerability than expected, this study aims at understanding the resisting mechanisms and seismic behavior of vernacular buildings through detailed finite element modeling and nonlinear static (pushover) analysis.
This paper focuses specifically on a type of vernacular rammed earth constructions found in the Portuguese region of Alentejo. Several rammed earth constructions found in the region were selected and studied in terms of dimensions, architectural layout, structural solutions, construction materials and detailing and, as a result, a reference model was built, which intends to be a simplified representative example of these constructions, gathering the most common characteristics.
Different parameters that may affect the seismic response of this type of vernacular constructions have been identified and a numerical parametric study was defined aiming at evaluating and quantifying their influence in the seismic behavior of this type of vernacular buildings. This paper is part of an ongoing research which includes the development of a simplified methodology for assessing the seismic vulnerability of vernacular buildings...
The present dissertation approaches the assessment of the seismic
vulnerability of old stone masonry building aggregates. With this topic it
is presented a review on the most recent methods and tools used for the
seismic vulnerability assessment of masonry buildings, focusing the research
developed both in Italy and Portugal. Moreover, a case study of an old
stone masonry building aggregate was assessed, which is located in San
Pio delle Camere (Abruzzo, Italy), slightly a ected by the 6th April 2009
L'Aquila earthquake. This building aggregate was modelled using the STA
DATA software 3muri®. On one hand, static non-linear numerical analysis
was performed to obtain capacity curves and a prediction of the damage
distribution in the structure, caused by the input seismic action (hybrid
method), on the other hand indirect methods were used, based on di erent
vulnerability index formulations.; A presente dissertação insere-se no estudo da avaliação da vulnerabilidade
sísmica de agregados de edifícios antigos de alvenaria de pedra. É feita uma
revisão geral da literatura sobre os mais recentes estudos e ferramentas para
a avaliação da vulnerabilidade sísmica de agregados de edifícios de alvenaria
de pedra, enfatizando o trabalho de investigação desenvolvido em Itália e em
Portugal nesta temática. É avaliada a vulnerabilidade sísmica de um caso de
estudo de um agregado de edifícios...
Following detailed studies of Portuguese vernacular building typologies, this paper deals with
buildings located in historical urban centres. An analysis of the history of the urban centre and, in particular, of
some vernacular buildings is enhanced. Additionally, a discussion on the influence of changes of the geometry,
and on added built volumes to original buildings in the seismic vulnerability of the buildings is also provided.
Given the fact that using timber frame structures has proven to improve the seismic behavior of
vernacular architecture, as has been reported in past earthquakes in many countries, its
preservation as a traditional earthquake resistant practice is important. This paper firstly intends
to evaluate whether the use of timber frames as a traditional seismic resistant technique for
vernacular architecture in the South of Portugal, traditionally a seismic region, is still active.
Secondly, the city of Vila Real de Santo António was selected as a case study because it also
followed a Pombaline development contemporary to the reconstruction of Lisbon. The plan
included the provision of timber frame partition walls for some of the buildings and, thus, an
overview of the type of constructions originally conceived is provided. Finally, the alterations
done in the original constructions and the current state of the city center are described and the
effect of these changes on the seismic vulnerability of the city is discussed.