Downtown Lisbon Research Articles

PGAA, INAA and luminescence to trace the “history” of “The Panoramic View of Lisbon”: Lisbon before the earthquake of 1755 in painted tiles (Portugal)

“The Panoramic View of Lisbon” is a unique masterpiece of Portuguese glazed tiles which depicts the city before the earthquake of 1755. Compositional analysis was done by PGAA, INAA and XRD. The first absolute dating by luminescence was done, including a reconstruction of the history of radiation exposure of the pieces. Compositional patterns of the tiles suggest the use of carbonated clays from downtown Lisbon to manufacture the ceramic bodies at high firing temperatures (900–1100 °C). Luminescence dating results point to the manufacture of “The Panoramic View of Lisbon” in the late 17th–early 18th centuries.

Experimental behavior of masonry wall-to-timber elements connections strengthened with injection anchors

Out-of-plane failure mechanisms observed in stone masonry buildings subjected to seismic action are often a direct result of poor connections between structural elements. During a seismic event these weak connections become incapable of assuring proper load transmission. Therefore, the need to prevent these phenomena is of critical importance in understanding the behavior of unstrengthened masonry buildings along with the necessity of developing effective strengthening solutions. This paper presents injection anchors as a viable option to improve anchorage between masonry and timber elements on historical buildings, as for example wall-to-timber framed wall or wall-to-timber diaphragm connections. The experimental campaign consisted of quasi-static monotonic and cyclic pullout tests performed on real scale specimens, representative of wall-to-timber framed wall connections found in late 19th century buildings of downtown Lisbon, Portugal. Combined cone-bond failure was obtained in all 7 tests. Boundary conditions of the specimens greatly affected the results in terms of maximum pullout force, dissipated energy, and strength degradation. Displacement ductility of the strengthened connections is high. The force–displacement curves clearly pointed out the influence on the results of the wall’s compressive stress state and the contribution of friction in the grout/masonry interface.

The 1531 Lisbon Earthquake: A Tsunami in the Tagus Estuary?

Abstract On 26 January 1531, a strong‐magnitude earthquake heavily impacted Lisbon downtown. Immediately after the earthquake, the eyewitnesses reported large waves in the Tagus estuary, mainly north of the city and along the northern bank of the river. Descriptions include large impacts on ships anchored in the estuary and even morphological changes in the riverbed. We present a synthesis of the available information concerning both the earthquake and the water disturbance as a basis for the discussion of the probable tectonic source and the magnitude of the associated river oscillations. We hypothesize that the initial disturbance of the water can be attributed to the coseismic deformation of the estuary riverbed, and we use a nonlinear shallow water model to simulate the tsunami propagation and inundation. We show that the Vila Franca de Xira fault is the most probable source of the 1531 event. The largest inundation effects of the model correlate well with the historical descriptions: the impact is relevant in the inner Tagus estuary, but inundation in downtown Lisbon is small.

Geotechnical characterization and seismic response of shallow geological formations in downtown Lisbon

<p> </p><p>The geological and geotechnical characterization of shallow formations is one of the main steps in performing a microzonation study. This paper presents an example of the usefulness of the information compiled in a geological and geotechnical database for the estimation of the seismic response of the shallower formations of the Lisbon downtown area of Baixa. The geotechnical characterization of this area was performed based on the analysis of Standard Penetration Test (SPT) data compiled in the geological and geotechnical database. This database, connected to a geoscientific information system (CGIS), allows, also, the definition of 2D geological profiles used for estimating the thickness of the shallower layers. The shear-wave velocities (V<span><sub>S </sub></span>) for each layer were estimated from empirical correlations using mean SPT values computed from the statistical evaluation of the compiled data. These V<span><sub>S</sub></span> values were further calibrated with ambient vibration recording analysis. The seismic response of Baixa’s superficial deposits was estimated by applying a 1D equivalent linear method to a set of soil profiles, regularly distributed across the area, and using synthetic accelerograms to simulate input motions associated with probable earthquake occurrences in Lisbon. The results are presented in terms of maps of predominant frequencies, with the corresponding amplification level, as well as spectral amplification factors for 1 Hz and 2.5 Hz. The results show that the fundamental frequency of the Baixa area is between 1.2 Hz and 2 Hz, for the whole central valley, reaching 3 Hz near the edges where anthroprogenic and alluvial deposits have less expression. Amplification factors up to 5 were obtained. These results were achieved regardless of the considered input motion. The similarity of the obtained fundamental frequency with the natural frequency of Baixa’s old building stock increases the probability of resonance effects in future earthquakes.</p><p><span style="font-size: medium;"><br /></span></p>

Seismic assessment and retrofitting of Pombalino buildings by pushover analyses

The heritage value of the mixed wood-masonry 18th century Pombalino buildings of downtown Lisbon is recognized both nationally and internationally. The present paper focuses on the seismic assessment of global response and retrofitting of a typical Pombalino building by nonlinear static analyses, performed by the research software Tremuri, which is able to model 3D configurations. The structure is modelled using nonlinear beams for masonry panels, while in case of the internal walls (frontal walls) an original formulation has been developed in order to take into account their specific seismic behaviour. Floors are modelled as orthotropic membrane finite elements: this feature allows to simulate the presence of both flexible and rigid diaphragms, being the first ones more representative of the original state while the second ones of retrofitted configurations. Seismic assessment has been evaluated by applying nonlinear static procedure and comparing the performance of different configurations (by considering various retrofitting strategies). Finally, assuming a lognormal cumulative distribution, fragility curves are obtained to be representative of Pombalino buildings: the most important application of such curves is for seismic risk and loss estimation analyses.

A First Approach for Displacement Analysis in Lisbon Downtown Using PS-InSAR

Lisbon Downtown presents unique geomorphologic properties which makes it an area prone to terrain instability. Serious accidents have occurred there, namely, during the 1755 earthquake and a flooding event at the extension of a subway line, demanding a frequent monitorization for safety reasons and expense minimization. In this study, Permanent Scatterers technique is applied. The calculated displacement velocities are compared to those obtained from levelling operations. Possible causes for the discrepancy are presented in the paper. Besides a subsidence trend, a seasonal behaviour is also detected, probably related to aquifer recharge or tides.

Energy recovery in SUDS towards smart water grids: A case study

The development of a methodology for urban flood adaptation and energy recovery solutions is resting on the concept of Sustainable Urban Drainage Systems (SUDS) as a measure to reduce risks of urban flooding while fully utilizing the available resources. Flood drainage systems are infrastructures essential in urban areas, which include retention ponds that can be used as water storage volumes to damp floods and simultaneously to produce energy, constituting innovative solutions to be integrated in future smart water grid′s designs.The consideration of urban flooding as a problem caused by excess water that can be harvested and re-used is expected to provide a comprehensive representation of a water-energy nexus for future urban areas. The study comprises an optimization of energy recovery in SUDS of a small district area of Lisbon down-town through the use of a low-head hydropower converter.The status-quo solution based on a basin catchment for the average expected runoff is analysed, with influence of the tidal backwater effect of the Atlantic Ocean which causes difficulties to the drainage of excess flow. The methodology used to reach the flow damping and the optimized solution for energy production is presented.

In-plane shear behaviour of traditional timber walls

The reconstruction of Downtown Lisbon after the 1755 earthquake was based on a novel constructive system of masonry buildings with an internal three-dimensional timber-framed structure named “gaiola pombalina”. This internal structure aimed at improving the global stability of masonry buildings, enhancing their capacity to dissipate energy under seismic loadings. But this structural system is not only typical of Portugal, but constitutes part of the built heritage of various countries. This paper aims at getting experimental insight on the mechanical behaviour of timber-framed walls subjected to in-plane loading, as only scarce information is available in literature, in order to assess their effective performance to seismic actions. To do this, the experimental results of cyclic tests carried out on traditional timber-framed walls with distinct typologies will be analysed, namely (1) unreinforced timber-framed walls without infill; (2) timber-framed walls without infill with Glass Fibre-Reinforced Polymer sheets (GFRP) placed at the connections; (3) timber-framed walls with brick masonry infill.

Relações entre múltiplas redes no Bairro Alto (Lisboa)

Having sprung up in the 16th century, Bairro Alto is a neighborhood located in Lisbon's downtown area and can be considered a typical popular neighborhood, with a predominantly elderly population, which is historically characterized by various forms of bohemian life. In the 1980's, the rise of increased nightlife activities,followed by some changes that occurred in the neighborhood, attracted a growing number of goers from several social networks. The article presents some outcomes from an ethnographical research initiated in 2007, with emphasis on three dimensions: the methodological consequences of the anthropologist's interactions with Portuguese, Brazilian and African persons who frequent the area; the emphasis on observations of a specific street and its sociability dynamics; the reconstitution of some specific networks articulating Bairro Alto night goers.

"Vintage Nightlife": Gentrifying Lisbon downtown

Over last two decades, culture has played a very important role in large-scale urban transformations. In that sense, nightlife promotion has become one of the most important strategies for urban regeneration in post-industrial cities. This paper explores the newly emerged vintage-style nightlife in the former harbour quarter of Cais do Sodre (Lisbon downtown). To do this, I focus on a recently renewed hostel building called Pensao Amor – formerly frequented by sailors and prostitutes, and today considered the coolest nightlife venue in the Portuguese Capital. After presenting an updated state of the art exploration of gentrification and nightlife, I argue in the second part of my paper that Pensao Amor is currently playing a key role in the gentrification of the urban nightscape in the Cais do Sodre neighbourhood, where its traditional nightlife is today being supplanted by a vintage-style nightlife. Furthermore, I argue that the consumption of this recently promoted vintage nightlife as a new form of social distinction can be also seen as the (re)production strategy of a socially and morally sanitized nightlife which marginalizes everyone who is seen as inappropriate, or in other words, socially perilous to the city branding of Lisbon.

Strategically robust urban planning? A demonstration of concept

Planning for the future is inherently risky. In most systems, exogenous driving forces affect any strategy�s performance. Uncertainty about the state of those driving forces requires strategies that perform well in the face of a range of possible, even improbable, future conditions. This study formalizes the relationship between different methods proposed in the literature for rigorously exploring possible futures and then develops and applies the computational technique of scenario discovery to the policy option of a subsidy for low-income households in downtown Lisbon. The work demonstrates one way in which urban models can be applied to identify robust urban development strategies. Using the UrbanSim model, we offer the first known example of applying computational scenario-discovery techniques to the urban realm. We construct scenarios from combinations of values for presumed exogenous variables�population growth rate, employment growth rate, gas prices, and construction costs�using a Latin-hypercube-sample experimental design. We then data mine the resulting alternative futures to identify scenarios in which an example policy fails to achieve its goals. This demonstration of concept aims to lead to a new practical application of integrated urban models in a way that quantitatively tests the strategic robustness of urban interventions.

A hysteretic model for “frontal” walls in Pombalino buildings

The heritage value of the mixed wood-masonry 18th century Pombalino buildings of downtown Lisbon is recognized both nationally and internationally. These buildings have a three-dimensional timber structure composed of wooden floors, stairs and walls intended to provide better seismic resistance and are enclosed by masonry walls. These interior wooden walls are called “frontal” walls and their behaviour under cyclic loading has scarcely been studied. This report describes an experimental programme to determine the hysteretic behaviour of these “frontal” walls, using static cyclic shear testing with imposed displacements. Two tests were conducted on two identical real-size walls. A new hysteretic model for the cyclic behaviour of these “frontal” walls in Pombalino buildings is presented and calibrated based on the experimental results. The hysteresis model was developed based on a minimum number of path following rules that can reproduce the response of the wall tested under general monotonic or cyclic loading. The model is constructed using a series of exponential functions and linear functions. The nine parameters in this model capture the nonlinear hysteretic response of the wall. The hysteretic behaviour of such walls subjected to cyclic loading exhibit high nonlinear force-displacement responses and high ductility.

Fernão and Fernando: Two Great Travelers

This paper attempts to draw a parallel between Fernão Mendes Pinto, the sixteenth-century adventurer, explorer and writer who spent twenty-one years travelling in the Middle and Far East, and Fernando Pessoa, the twentieth-century poet who spent his working life at the desks of commercial firms in downtown Lisbon. In Pinto’s case, the voyage was the actual physical movement from one place to another, through dangers and adventures, while in Pessoa the voyage was an immobile journey through the inner self. It is argued that Pinto’s book Peregrinação and Pessoa’s book Livro do desassossego can be read as entering a dialogue with each other.

Potential inundation of Lisbon downtown by a 1755-like tsunami

Abstract. In this study, we present 10 m resolution tsunami flooding maps for Lisbon downtown and the Tagus estuary. To compute these maps we use the present bathymetry and topographic maps and a reasonable estimate for the maximum credible tsunami scenario. Tsunami modeling was made with a non-linear shallow water model using four levels of nested grids. The tsunami flood is discussed in terms of flow depth, run-up height and maximum inundation area. The results show that, even today, in spite of the significant morphologic changes in the city river front after the 1755 earthquake, a similar event would cause tsunami flow depths larger than one meter in a large area along the Tagus estuary and Lisbon downtown. Other areas along the estuary with a high population density would also be strongly affected. The impact of the tide on the extent of tsunami inundation is discussed, due to the large amplitude range of the tide in Lisbon, and compared with the historical descriptions of the 1755 event. The results presented here can be used to identify the potential tsunami inundation areas in Lisbon; this identification comprises a key element of the Portuguese tsunami emergency management system.

Rubble stone masonry walls in Portugal strengthened with reinforced micro-concrete layers

This paper describes and analyses the performance of two structural strengthening solutions for rubble stone masonry walls. The strengthening solutions are characterised by: sprayed micro-concrete steel reinforced layers on both lateral faces of the walls, with transversal steel ties through the thickness of the specimens, not in contact with the base of the loading systems; sprayed micro-concrete steel reinforced layers on lateral faces of the specimens, without transversal steel ties but in contact with the base of the loading systems. For the first solution three specimens were tested under axial compression load and three under compression-shear load, and for the second solution three specimens were tested under axial compression load. The results are compared with unstrengthened (reference) specimens. Strengthening solutions of this nature have been used in the rehabilitation of old masonry walls in Portugal, particularly in Lisbon downtown, and in the rehabilitation of some Azores buildings after the 1998 earthquake.

URBAN REGENERATION ECONOMICS: THE CASE OF LISBON'S OLD DOWNTOWN

Buildings are one of the biggest assets of Lisbon's central downtown accumulated over a period of several centuries. The efficient use and optimization of the value of these assets are a challenge for both the owners of individual buildings and for society as a whole. Recently, a new regeneration initiative was announced for old urban Lisbon's downtown, covering three fields of intervention: the economic, social and physical fields. This paper presents a case study of the regeneration program for the Lisbon's old downtown including an analysis of the framework used to assess the costs and benefits. Santrauka Pastatai – tai vienas pagrindinių Lisabonos centrinio komercinio rajono turtų, sukauptų per keletą amžių. Efektyvus šio turto naudojimas ir vertės optimizavimas – tai iššūkis ir atskirų pastatų savininkams, ir visai visuomenei. Neseniai paskelbta nauja senojo Lisabonos komercinio rajono atgaivinimo iniciatyva, apimanti tris intervencijos sritis: ekonominę, socialinę ir fi zinę. Šiame darbe pristatomas senojo Lisabonos komercinio rajono atgaivinimo programos atvejo tyrimas, pateikiama sąnaudų bei naudingumo įvertinimo sistemos analizė.

Management of the built heritage in the Lisbon's central downtown

PurposeBuilt heritage is one of the biggest assets that Lisbon's central downtown has accumulated since eighteenth century. The efficient use of these assets is a challenge for both the owners of individual buildings and society as a whole. Recently, a new regeneration initiative was announced for Lisbon's historic district. This paper aims to address the urban problems of old Lisbon's downtown, to discuss the existing public intervention framework and to present an integrated information management system aimed at providing technical and economic information needed to improve co‐ordination between public sector and private agents.Design/methodology/approachThe research methodology of the study is an interpretative case study method. The case study approach is one of the most commonly used research designs in qualitative research. The contents and conclusions from the research were obtained by means of: a review of publications and current practices related to urban regeneration; a review of data and information on urban regeneration studies; a survey conducted throughout the duration of the study; and a case study.FindingsThe integrated information management system presented in this paper is a tool that allows the management agency of the Lisbon's historic district to the take full advantage of the potentialities of the area, namely the strategic location and the historic and architectonic heritage.Research limitations/implicationsA great number of buildings in the historic district are classified as buildings of “public heritage”. The findings suggest that property and economic activity can be the driving forces for revitalising Lisbon's historic district.Originality/valueThis paper is aim to understand the key features of old Lisbon's downtown and to analyse existing practice in managing built heritage on the historic district. It also seek to identify how an information management system could improve the current intervention practices, in the area, that agency follows.

Design of repair measures of a damaged shield driven tunnel

Due to a construction incident a shield driven tunnel in downtown Lisbon, part of an extension in progress of the existing metro system, was flooded. After this tunnel had been pumped dry the tunnel turned out to be severely deformed and damaged due to this flooding incident. After assessment of the post-accident strength of the tunnel it was concluded that remedial measures were necessary. In order to guarantee the stability and integrity of the tunnel a secondary tunnel inside the existing primary tunnel has been designed. During construction the deformations of the primary and secondary tunnel are monitored automatically and made accessible by GIS. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

Archaeology of Lisbon Old City: ceramic crucibles from pre-XVIIIth century metallurgical foundries

During an emergency archaeological intervention conducted in downtown Lisbon (the Old City), ceramic foundry crucibles were collected in a layer of embankment debris used after the earthquake that destroyed the city in 1755. A chemical and phase-constitution study was undertaken to complement the dating and to ascertain the kind of foundries (metallurgical or glass-working) concerning two intact cup-shaped crucibles and a fragment displaying glassy outflows. Non-destructive methodologies were used – namely, laboratory techniques (X-ray fluorescence spectrometry and X-ray diffraction) combined with synchrotron-radiation-induced micro-fluorescence (SRXRF). Analytical results are presented and discussed. SRXRF analysis of the glassy outflow on the larger crucible revealed the presence of mercury and traces of gold, along with copper, suggesting that it might have been used to manipulate gold amalgams. A possible Islamic origin was disclosed for the smaller crucible as only tin was detected in the external outflow and further confirmed by minute cassiterite (SnO2) grains.