Project

SafEarth - Seismic protection of earthen construction heritage

Goal: Identification and assessment of the importance of building details associated with the seismic culture of adobe and rammed earth constructions;

Material characterization of adobe and rammed earth;
Experimental characterization of the seismic behaviour of adobe and rammed earth structures;

Development of numerical models for the simulation of adobe and rammed earth structures, unstrengthened and strengthened with coatings reinforced with geo-mesh;

Development of recommendations for End-users on the safety assessment and strengthening of adobe and rammed earth structures.

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Project log

Antonio Romanazzi
added a research item
Rammed earth structures are worldwide spread, both as architectural heritage and new constructions. Yet, rammed earth buildings present, in general, high seismic vulnerability. Despite the several studies conducted on the mechanical characterisation of rammed earth and on the numerical modelling of structural elements built with this material, further in-plane cyclic tests on rammed earth sub-assemblies are required to characterise their hysteretic behaviour. In this framework, an experimental program was conducted where cyclic in-plane tests were performed on a large-scale rammed earth wall. The geometry of the wall was defined to represent a sub-assembly commonly found in rammed earth dwellings from Alentejo (Southern Portugal). The wall was subjected to cyclic shear displacements with increasing amplitude, imposed in both positive and negative directions. To detect the dynamic properties of the wall and to assess the development of the structural damage, dynamic identification tests were conducted along the experimental programme. The results are analysed in terms of crack pattern, dynamic properties, displacement capacity, base shear performance and stiffness degradation. Further discussion is led on the dissipated energy, while a bi-linear and linear equivalent systems are proposed as simplified modelling approach. In conclusion, degradation of structural capacity was observed due to cyclic loads, while adequate energy dissipation and base shear coefficient were obtained.
Antonio Romanazzi
added a research item
Rammed earth constructions, beyond being largely spread in the built heritage, are known for their high seismic vulnerability, which results from high self-weight, lack of box behavior and low mechanical properties of the material. Hence, to mitigate this seismic vulnerability, a compatible textile reinforced mortar (TRM) is here proposed as a strengthening solution, because of its reduced mass and high ductility. The few research about the structural behavior of TRM-strengthened rammed earth elements addresses the global behavior, overlooking the local behavior of the system. An analytical approach to infer the bond stress-slip relationship following the direct boundary problem is proposed. Based on a previous series of pull-out tests, an adhesion-friction constitutive law is portrayed considering also a damage model that considers the degradation of the reinforcing fibers due to friction.
Antonio Romanazzi
added 3 research items
Despite the current awareness of the high seismic risk of earthen structures, little has been done so far to develop proper strengthening solutions for the rammed earth heritage. Based on the effectiveness of TRM for masonry buildings, the strengthening of rammed earth walls with externally bonded fibers using earth-based mortar is being proposed as a compatible solution. In this context, the investigation of bond behavior was conducted by means of direct tensile tests, pull-out tests and single lap-shear tests. The specimens were prepared using earth-based mortars and two different types of meshes (glass and nylon) while considering different-bonded lengths. The direct tensile tests on TRM coupons showed the high capacity of the nylon mesh in transferring stresses after cracking of the mortar. The pull-out tests highlighted that in the case of glass fiber mesh, the bond was granted by friction, while the mechanical anchorage promoted by the transversal yarns granted the bond of the nylon mesh. Finally, the single lap-shear tests showed that the adopted earth-based mortar seems to limit the performance of the strengthening.
Earthen constructions are spread worldwide, not only as architectural heritage but also as new buildings, in which a total of around one fourth of the global population is estimated to live in. Among the different raw earth techniques, rammed earth was widely used to build vernacular dwellings in different regions. Despite the raising awareness for the high seismic hazard, recognized seismic vulnerability and high seismic exposure associated with earthen structures, the reduction of their seismic risk has been a topic insufficiently addressed. In general, the seismic vulnerability of rammed earth structures is due to poor connections between structural elements (walls and floors), high self-weight and low strength of the material. Hence, a TRM-based strengthening technique is proposed to improve their seismic capacity. To estimate the enhancement of the in-plane performance achieved with the TRM, an experimental program was conducted. Rammed earth wallets were tested under diagonal compression considering their unstrengthened and strengthened condition. The TRM strengthening was performed by embedding a glass fibre mesh ( GRE ) or a nylon mesh ( NRE ) in a compatible earth-based mortar. In general, the proposed TRM-based strengthening seems to improve the shear behaviour of rammed earth by enhancing the shear strength and promoting stress distribution after cracking, while no significant influence on the shear modulus of rammed earth seems to occur.
A textile reinforced mortar (TRM) compatible with rammed earth structures is proposed to mitigate their seismic vulnerability. Being TRM a composite material, defining the matrix-fibre interface relationship is fundamental to predict the performance of strengthened structures. In this framework, an existing analytical approach with a newly damage model was adapted to a specific TRM composite system that is not yet addressed in literature. Hence, an adhesion-friction law was calibrated with basis on recent experimental observations. In conclusion, the proposed algorithm reproduces adequately the elastic and nonlinear response of the matrix-fibre interface and predicts with accuracy the pull-out strength of the composite.
Antonio Romanazzi
added 2 research items
Rammed earth technique is spread worldwide, representing the local identity of many cultures for which they must be preserved. Yet, rammed earth heritage is also well known for its high seismic vulnerability and despite the increasing concern for this aspect, few investigations were conducted on dynamic response of such structures. In this framework, an experimental program was undertaken on a rammed earth mock-up by means of shake table tests carried out at the National Laboratory of Civil Engineering (LNEC) in Lisbon. To investigate the out-of-plane behaviour of rammed earth walls, a mock-up was built in real scale with a U-shape and then subjected to a series of increasing seismic inputs. The results are here discussed in terms of damage, displacements and base shear coefficient. In conclusion, the model behaved as a rigid block to earthquake excitations.
Daniel V. Oliveira
added 4 research items
Due to the availability of the earthen material and its regular use to build traditional dwellings, earthen architecture is often associated with vernacular architecture. Among several earthen architecture techniques, the most common found worldwide is adobe. Most of the adobe architecture has pitched or flat roofs, but in some hot and dried regions, due to the lack of wood, earthen vernacular architecture was built with adobe curved roofs (i.e. vaults and domes). Adobe curved roof is composed by adobe masonry of earthen bricks dried in the sun and earthen mortar, which is a sophisticated adobe building roof type. This paper focuses on the vaulted adobe roof as a kind of adobe curved roof. Around the world, where adobe architecture was developed, adobe arches can be found over doors and windows. However, adobe vaults cover adobe construction, and were originated and developed in the Middle East, more than 3000 years ago. A vast number of vaulted adobe buildings remain intact in Iran, in particular in historic cities. The city of Yazd in Iran, with a large number of adobe monuments and vernacular architecture, possesses a great built heritage that arises from various historical periods, ancient cultures and civilizations. Yazd has a vast number of vernacular adobe houses with vaulted adobe roofs. A considerable number of those buildings still exist nowadays, in good condition. When reviewing the body of literature, it can be stated that vaulted adobe architecture that resulted from thousands of years of refinement is outside the scope of the majority of available research. The present research addresses the history of adobe vault, its construction methods and structural behavior. Furthermore, to better understand this type of earthen architecture culture, the vaulted adobe architecture from Yazd has been studied in more detail.
Masonry construction built with compressed earth blocks (CEBs) is one of the most significant examples of sustainable buildings based on the earth construction technology. Nevertheless, despite the economic and environmental advantages, the seismic vulnerability of these construction is object of concern. The aim of the present paper is to numerically investigate the response of a one-story CEB masonry building subjected to horizontal forces simulating seismic actions. Both modal and non-linear static analyses are performed through the commercial Finite Element (FE) code TNO-DIANA by using a 3D FE macro-modelling approach. During the analyses, particular attention has been devoted to the influence of some structural elements such as interior partition walls and ring beams.
Earth has always been widely used as building material all around the world, as a solution to the needs of poor and rural lifestyle of population. Over the years, earthen materials have been revalued as a good economic and sustainable choice for developing countries. One of the most important improvement in the earthen construction technologies field is represented by compressed earth blocks (CEBs). Nevertheless, even if it is an improvement of traditional building techniques, the seismic vulnerability of these constructions still requires further understanding. The aim of the present paper is to numerically investigate the seismic response of one-story CEB masonry buildings by performing incremental dynamic analyses (IDA). In particular, three different models are examined in order to consider the influence of structural elements, such as internal partition walls and a ring beam. The obtained results are compared in the paper with the ones carried out by using static pushover analyses.
Rui André Silva
added a research item
The high seismic vulnerability of earth constructions has been evidenced by several recent earthquakes that occurred around the World with moderate to high magnitudes, namely Bam 2003, Pisco 2007 and Maule 2010. The seismic risk associated to earth constructions is further amplified by the fact that a great percentage of these constructions is built on regions with important seismic hazard. Thus, the preservation of the immense earthen built heritage and of the life of their inhabitants demands adopting innovative strengthening interventions. However, the success of such solutions requires fulfilling compatibility requirements, while its general use requires adopting affordable materials and low complexity technical solutions. In the last years, textile reinforced mortars (TRM) have been increasingly used to strengthen masonry structures due to their high structural effectiveness and compatibility. In the case of earth constructions, these composite materials are also expected to provide efficient strengthening, though specific component materials should be adopted. This paper presents an experimental program dedicated to the characterization of the composite behavior of two TRM composites proposed for strengthening rammed earth walls. The composites differ on the mesh used, namely a low cost glass fiber mesh and a nylon mesh acquired locally, while the same earth-based mortar was used in both cases. The experimental program involved testing the mortar under compression and composite coupons under tension. In general, the glass TRM presents higher strength and stiffness in tension, while the nylon TRM presents considerably higher deformation capacity. Finally, stress-strain relationships describing the composite behavior are presented for numerical modelling purposes.
Reza Allahvirdizadeh
added a research item
The large availability of raw earth around the World led to its extensive use as a building material through history. Thus, earthen materials integrate several historical monuments, but their main use was to build living and working environments for billions of people. On the other hand, past earthquakes revealed their inadequate seismic behavior, which is a matter of concern as a significant percentage of earthen buildings are located in regions with medium to high seismic hazard. Nevertheless, their seismic behavior and the development of efficient strengthening solutions are topics that are not yet sufficiently investigated in the literature. In this context, this study investigates numerically the in-plane seismic behavior of a rammed earth component by means of advanced nonlinear finite element modeling, which included performing nonlinear static (pushover) and nonlinear dynamic analyses. Moreover, the strengthening effectiveness of a low-cost textile-reinforced mortar on such component was also evaluated. The strengthening was observed to increase the load and displacement capacities, to preserve the integrity for higher lateral load levels and to postpone failure without adding significant mass to the system. Furthermore, the pushover analysis was shown to predict reliably the capacities of the models with respect to the incremental dynamic analysis.
Rui André Silva
added an update
O seminário SafEarth tem como objetivo principal apresentar os resultados do projeto à comunidade e promover uma troca de ideias sobre a proteção sísmica das construções em terra.
 
Reza Allahvirdizadeh
added a research item
Raw earth is one of the most widely used building materials and is employed in different techniques, among which adobe and rammed earth are the most common. The respective structural systems, like in masonry buildings, acceptably withstand against gravity loads, though they are significantly vulnerable to earthquakes. Moreover, a great percentage of the World's population is still inhabited in such environments, which are endangered by future earthquakes. The current article investigates the seismic in-plane performance of an I-shaped rammed earth component by means of advanced nonlinear finite element modelling. In this regard, conventional pushover analyses were conducted to evaluate load/displacement capacities and to assess probable failure modes. It was observed that the component fails mainly due to detachment of the wing walls from the web wall and due to occurrence of diagonal shear cracks at the web. Subsequently, the application of Textile Reinforced Mortar (TRM) strengthening solution to the component was studied and shown to be able to maintain the integrity of the component for larger lateral load levels. Finally, the reliability of the pushover analyses to predict the seismic response was evaluated by comparison with outcomes from incremental nonlinear dynamic analysis.
Reza Allahvirdizadeh
added a research item
The importance of raw earth is highlighted by the millions of persons living in earthen buildings around the World and by numerous historical monuments made of this material. Its widely availability led to the development of a variety of building techniques, including rammed earth, which is the main focus of this study. Similarly to unreinforced masonry structures, rammed earth buildings acceptably withstand gravity loads, but are significantly vulnerable to earthquakes. In this regard, great attention has been put on the proposal of efficient, compatible, affordable and reversible strengthening solutions. However, very limited studies address either the experimental testing or modeling of the seismic response of such buildings. The current study investigates the seismic out-of-plane performance of a plain and subsequently strengthened rammed earth sub-assembly (U-shape) using an advanced finite element modeling approach calibrated based on previously conducted small-scale experiments. Here, failure mechanisms, corresponding capacity and efficiency of the adopted strengthening solution (low-cost textile-reinforced mortar) are evaluated by means of pushover analyses. Then, the reliability of the pushover analyses is assessed by comparing its outcomes with that of the incremental dynamic analyses. In general, the failure was found to be governed by overturning of the web wall due to its detachment from the wing walls, while the strengthening was found to increase the capacity and delay the damage development.
Rui André Silva
added 3 research items
The aim of this paper is to implement a numerical model to reproduce the non-linear behaviour of cob walls under shear loading. Axial compression, pull-off and diagonal compression tests, were carried out to derive the mechanical parameters. In addition, the stress-strain relationships, the non-linear behaviour and the failure modes were defined. The experimental results were then used to calibrate a finite element model. The material behaviour was simulated through a macro-modelling approach adopting the total strain rotating crack model. A sensitivity analysis was conducted to assess the effects of varying the parameters with higher uncertainty on the structural behaviour. The numerical model achieved good correspondence with the experimental results, namely in terms of simulation of the shear stress-shear strain relationship and of damage pattern.
An important rammed earth built heritage can still be found in Alentejo, despite its use became marginal during the last decades. This traditional heritage rises some level of awareness with regard to its seismic safety since this region is characterised by moderate seismic hazard and earth constructions are often associated with a high seismic vulnerability. Nevertheless, the existing knowledge is insufficient to correctly assess the seismic performance of traditional rammed earth constructions from Alentejo and conclude about their structural stability. This work contributes for a better comprehension of the seismic vulnerability of rammed earth constructions from Alentejo by means of a simplified methodology for assessment of the in-plane and out-of-plane behaviour of walls from twenty selected buildings. This methodology included the computation of geometry-based indexes and a simple linear kinematic analysis. The conducted study indicates that the seismic behaviour of these constructions benefits from their traditional architectonic features. | O Alentejo possui um vasto património construído em taipa, apesar de o recurso a esta técnica construtiva terse tornado residual nas últimas décadas. Este património tradicional gera alguma preocupação relativamente à sua segurança sísmica, uma vez que esta região apresenta uma perigosidade sísmica moderada e as construções em terra são geralmente associadas a uma vulnerabilidade sísmica elevada. Contudo, existe uma falta acentuada de conhecimento sobre o desempenho sísmico das construções tradicionais de taipa do Alentejo, não permitindo concluir sobre a sua estabilidade estrutural. Este trabalho pretende contribuir para uma melhor compreensão da vulnerabilidade sísmica das construções tradicionais de taipa do Alentejo através da aplicação de uma metodologia de avaliação simplificada do comportamento no plano e fora do plano das paredes de uma amostra de vinte edifícios. Esta metodologia incluiu o cálculo de índices geométricos e uma análise cinemática linear simples. O estudo realizado sugere que o comportamento sísmico destas construções beneficia das suas caraterísticas arquitetónicas tradicionais.
Earthen constructions constitute a considerable part of the existing heritage and a large percentage of the World population is still living or working in buildings built with this structural material. Rammed earth constructions are acceptably stable under gravity loads, but are significantly vulnerable to earthquakes. Strengthening methods used to enhance the load capacity and ductility of the building should also satisfy a variety of principles, such as compatibility with the substrate, affordability and reversibility. In this study, the seismic performance of both unstrengthened and strengthened rammed earth structural components is investigated. In particular, the out-of-plane behaviour is studied by means of different nonlinear finite element models. At first, pushover analysis is conducted on unstrengthened walls to evaluate their capacity and understand possible failure mechanisms. Afterwards, pushover analyses are conducted on strengthened walls to choose between different strengthening materials and assess the effectiveness of the adopted strengthening technique. Finally, an artificially generated ground motion record is applied to both unstrengthened and strengthened structural components to perform nonlinear time-history analyses. The outcomes were used to compare the dynamic behaviour of the structure against the results of the pushover analyses.
Rui André Silva
added a research item
Earth constructions constitute an important part of the built heritage and are spread worldwide. Rammed earth is among the most used earth construction techniques, though it exhibits a high seismic vulnerability. Nevertheless, the structural behaviour of rammed earth structures is still insufficiently comprehended. Thus, the preservation of this built heritage requires exhaustive characterisation of its mechanical and structural behaviours, as well as the development and validation of adequate intervention solutions. In this context, this paper presents an experimental program aimed at evaluating the effectiveness of grout injection to repair cracks and at further characterising the in-plane shear behaviour of rammed earth walls. The experimental program included the testing of rammed earth wallets under diagonal compression, which were subsequently repaired with injection of a clay-based or a hydraulic lime-based grout, and retested. Furthermore, sonic tests were conducted on the wallets before the destructive tests. The obtained results allowed to highlight that both grouts led to similar repairing performances , though the interlocking contribution promoted by the coarse particles of the rammed earth to the shear behaviour was found to be irrecoverable.
Rui André Silva
added 2 research items
Raw earth is among the most ancient building materials and the related building techniques are found widespread around the world. Currently, it is estimated that about 25% of the global population lives in earthen buildings and about 10% of the UNESCO World Heritage is built with earth. Nevertheless , an important overlap can be observed when the geographical distribution of raw earth constructions is compared with that of the seismic hazard. This circumstance , combined with the seismic vulnerability of earthen buildings, results in a high seismic risk, as demonstrated by recent moderate earthquakes. Despite the current awareness for this problem, little has been done so far to develop proper strengthening solutions for the rammed earth heritage. Based on the effectiveness of externally bonded fibers for masonry buildings, the strengthening of rammed earth walls with an earth mortar coating reinforced with a geomesh is here adopted as a compatible solution. The objective of this work is to investigate and characterize the bond behavior of the above mentioned strengthening solution to further describe the response of the interaction mortar-mesh. To this purpose, an experimental program was undertaken based on a series of pull-out tests. Specimens were prepared using earth mortar, two different types of meshes (glass fiber and nylon) and considering different bonded lengths. The results highlighted distinct bond behaviors. In the case of the glass fiber mesh, the bond was granted by friction and mechanical interlocking, while the mechanical anchorage promoted by the transversal yarns granted the bond of the nylon mesh.
In the framework of this study, a 1:2 scaled replica of a traditional single-storey adobe building was constructed and tested at the laboratories of the University of Cyprus. The main objectives of the experimental program were to evaluate the structural performance of adobe buildings under horizontal loads (simulating seismic action) and to investigate the effectiveness of cracking repair by means of injection with a compatible grout. The model was initially subjected to a series of monotonic static lateral loading cycles that led to the development of extensive cracking damage and to significant reduction of the load-bearing capacity and overall stiffness. A compatible clay-based grout was then developed using the same soil as the one composing the model's adobes. This material was injected into the cracked sections of the masonry and the repaired model was re-tested. The clay-based grout successfully restored structural continuity, precluding the reopening of injected cracks during subsequent loading cycles. The recorded load-deformation response revealed that the grout repair reinstated the original stiffness of the structure and recovered more than 90% of the initial lateral strength. The results indicate that clay-based grouts can be used for re-establishing the stability of adobe constructions under static loads.
Daniel V. Oliveira
added a research item
Raw earth constitutes a significant and worldwide spread built heritage, continuously endangered by the occurrence of earthquakes, since earthen structures are acknowledged by their high seismic vulnerability. Thus, the protection of this heritage and of its inhabitants requires adopting efficient and compatible seismic strengthening solutions. The strengthening of rammed earth walls with textile reinforced mortars (TRMs) is a solution being recently investigated, where the incorporation of earth based mortars and low-cost strengthening meshes fulfils compatibility requirements. Nevertheless, the role of the mortar in TRM strengthening is yet insufficiently investigated, namely with respect to the shrinkage and bond behaviours. This paper intends to contribute for filling this gap by presenting an experimental program that included Alcock's tests, pull-off tests and a novel 2D-shrinkage test based on digital image correlation (DIC) monitoring. As main conclusions, it can be referred that the clay content of earth mortars must be controlled to minimize shrinkage and that the shrinkage of earth mortar coatings is a very fast process.
Rui André Silva
added 2 research items
Rammed earth constructions represent a valuable cultural heritage of vernacular architecture, whose significance has acquired even more importance in the last years with the renovated interest for this sustainable building technique. The aim of this work is to develop a FEM model typologically representative of a Portuguese vernacular rammed earth construction in order to characterize numerically its seismic performance and raise awareness about the level of improvement introduced by two compatible strengthening techniques: textile reinforced mortar (TRM) and a ring beam applied at the top of the walls.
Due to the vulnerability of vaulted adobe buildings during the past earthquakes, it is crucial for such building typology to be evaluated in terms of seismic capacity. This paper deals with the seismic performance of historic vaulted adobe construction in adobe houses, typical from the city of Yazd, Iran. To this end, six 1:3 scaled adobe vaults were analyzed experimentally aiming at estimating their structural performance. The tests were performed in loading-unloading steps of increasing amplitude of an imposed vertical displacement at 30% of span. The tests were carried out in two unstrengthened and four strengthened adobe vaults. Vaults were strengthened with a low cost textile reinforced mortar (LC-TRM), where a low cost fiberglass mesh is covered with an earth-based mortar. Two adobe vaults were strengthened at intrados and the other two at extrados. The experimental results show that the vaults behavior is enhanced due to the LC-TRM application, with respect to the unstrengthened vaults. A significant increase of the load carrying capacity and also an important improvement in ductility was evident. In addition, new failure mechanisms were observed for the strengthened vaults when compared with the formation of the typical four-hinge mechanism of unstrengthened vaults.
Rui André Silva
added 9 research items
Rammed earth constructions are known for their high seismic vulnerability, which menaces their preservation and puts in risk the life of millions of people living in regions with important seismic hazard. The poor conservation condition of many of these constructions largely contributes for the aforementioned situation. The presence of cracks is one common type of damage occurring in the walls, which debilitates their structural behaviour both for in-plane and out-of-plane loading. The injection of grouts has been studied recently as a solution to repair this type of damage. However, the repair effectiveness of this technique needs further research. This paper presents an experimental program, where the effectiveness of the injection of a mud and a commercial grout base on hydraulic lime for repairing cracks in rammed earth is compared. Diagonal compression test were carried out on wallets before and after repair, where the response was monitored with Digital Image Correlation (DIC). Furthermore, sonic tests were used as a technique to assess the repair efficiency by non-destructive means. In general, both types of grouts presented similar performance.
Este artigo apresenta um programa experimental dedicado à avaliação do desempenho de uma calda de terra e de uma calda comercial, à base de cal hidráulica, na reparação de fendas em paredes de taipa. Foram executados ensaios de compressão diagonal em muretes de taipa, que foram reensaiados após reparação com a injeção das caldas. As caldas apresentaram uma eficiência de reparação semelhante.
The paper presents a comparison between two different numerical modelling approaches aimed to simulate the in-plain behaviour of rammed earth walls, namely under axial, diagonal and cyclic shear-compression loading. Axial, diagonal compression tests and cyclic shear-compression experimental tests were carried out for this purpose, which allowed determining important mechanical parameters, such as compressive strength, Young’s modulus, Poisson’s ratio, shear strength, shear modulus and horizontal load capacity. Furthermore, it allowed assessing the level of non-linear behaviour of the respective stress–strain relationships as well as the failure modes. The experimental results were then used in the calibration of numerical models (based on the finite element method) for simulating the non-linear behaviour of rammed earth under shear and cyclic shear-compression loading. Both macro- and micro modelling approaches were considered for this purpose. The procedures adopted for model calibration established the reliability of various modeling strategies for the different loading conditions.
Daniel V. Oliveira
added a research item
Past earthquakes have demonstrated that historical vaulted adobe buildings are highly vulnerable to seismic actions. Hence, it is crucial for such building typologies to be evaluated in terms of seismic capacity. To this end, this paper deals with the seismic performance of historical vaulted adobe houses from the city of Yazd, Iran, as one of the seismically active areas of the world and possessing a very rich adobe heritage. Thus and based on a detailed geometrical survey, a representative sample of adobe houses from Yazd was studied using a simplified in-plane analysis based on three geometric indexes. Concerning the out-of-plane behavior, a deeper assessment was conducted by performing a numerical study, where the main influential parameters on the seismic behavior of vaulted adobe buildings were considered. The numerical analyses were carried out by adopting the limit analysis theory implemented in the Block2D software. The results obtained indicate the safe in-plane behavior of most of the houses and the safe out-of-plane response of the sample under gravitational loads. However, the sample out-of-plane safety under earthquake-induced loads seems to be a matter of concern.
A. Costa
added 2 research items
A qualidade de vida nos núcleos urbanos constitui uma meta dinâmica, fortemente influenciada pelos processos sociais e económicos, pela evolução das suas exigências e expectativas e pela evolução do próprio tecido urbano, do parque edificado e das infraestruturas. Nos núcleos urbanos antigos, são peças fundamentais deste desafio a garantia do conforto e de salubridade, num equilíbrio que se quer, sustentado e sustentável, com a preservação das memórias e da cultura local. Para além da inadequada resistência à ação sísmica, a grande maioria deste edificado encontra-se em avançado estado de degradação, situação que, aliada a outros fenómenos de índole social, tem levado ao abandono massivo destes espaços de elevado valor histórico e patrimonial. De facto, muitos destes edifícios necessitam de intervenções estruturais urgentes, nomeadamente de intervenções de reforço que visem reduzir a sua elevada vulnerabilidade sísmica, particularmente nas zonas do território onde a perigosidade sísmica é mais importante. É nesta base que surge a presente publicação, elaborada no âmbito do projeto de investigação "URBSIS - avaliação da vulnerabilidade e gestão do risco sísmico à escala urbana", e cujo conteúdo vem sublinhar a necessidade de ser elaborado um plano nacional de redução da vulnerabilidade sísmica, particularmente do património histórico e dos núcleos urbanos antigos, para que as situações de risco sejam devidamente identificadas, hierarquizadas e acauteladas. PTDC/ECM-URB/2564/2012
A Capela dos Ossos é um dos locais mais visitados em Portugal e faz parte da Igreja de São Francisco em Évora, Portugal, sendo este um dos mais importantes monumentos Portugueses. A Capela dos Ossos, foi construída no século XVII, estando as suas paredes e pilares revestidos com ossos e crânios ligados por cimento pardo. As abóbadas são de tijolo rebocado a branco, pintadas com motivos alegóricos à morte. O ensaio de carga estático sobre as abobadas da Capela dos Ossos teve como objetivo a avaliação da resposta estrutural de um conjunto de abobadas da Capela dos Ossos ao longo de um carregamento gradual, até se atingirem os 350kg/m 2. A Igreja de São Francisco está em obras e no projeto estava prevista a utilização da parte superior da Capela dos Ossos para um museu, havendo uma imposição em caderno de encargos de que antes de se efetuar a obra seria necessário realizar um ensaio de carga que demonstrasse a capacidade da estrutura abobadada para receber uma carga de 300kg/m 2. Foi feito o registo dos deslocamentos verticais em vários pontos e avaliada a eventual formação de fissuras. Após o carregamento foi retirada toda a carga, para avaliação da recuperação das deformações. A aplicação da carga foi feita recorrendo a sacos de cimento. O ensaio permitiu observar que a estrutura em estudo tem uma rigidez considerável e da análise dos resultados pode concluir-se que a estrutura manteve um comportamento perfeitamente aceitável para os níveis de carga a que foi submetida. Ao longo do ensaio e no final deste não foram detetadas quaisquer alterações de índole estrutural nem foi observado o aparecimento de fendas ou fissurações. ABSTRACT The Bones Chapel is one of the most visited places in Portugal and is part of the São Francisco Church in Évora, Portugal. The Bones Chapel was built in the XVII century, with its interior walls and columns coated with bones and skulls. The domes were constructed with of clay bricks. The static load test was performed to evaluate the structural response of a set of domes of the Bone Chapel along a gradual loading, aiming the total load of 350kg/m 2. During the rehabilitationworks in the São Francisco, was included to change the top of the Bone Chapel to be used has a museum, with an imposition on contract that prior to the construction of the museum it would be necessary to perform a load test to evaluate the ability of the domed structure of the Bones Chapel to receive a dead load of
Rui André Silva
added a project goal
Identification and assessment of the importance of building details associated with the seismic culture of adobe and rammed earth constructions;
Material characterization of adobe and rammed earth;
Experimental characterization of the seismic behaviour of adobe and rammed earth structures;
Development of numerical models for the simulation of adobe and rammed earth structures, unstrengthened and strengthened with coatings reinforced with geo-mesh;
Development of recommendations for End-users on the safety assessment and strengthening of adobe and rammed earth structures.