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To make the territory more usable for farming, rural populations used and perfected masonry walls for centuries to help organize the landscape, to establish boundaries between different landowners and to protect crops and property from animals and other external threats. In recent decades, the rural territory of Northwest Portugal undertook an irreversible transformation from a purely rural into a low-density urban land. In this process, traditional farm walls were faced with contemporary needs and population demands, which in most cases ended with demolition of the walls and their replacement by new ones. In this context, the landscape heritage value and rural identity preservation depend to a large extent on the rebuilding solutions chosen to replace the demolished wall heritage.This paper addresses the analysis of traditional schist farm walls from Northwest Portugal. The study starts by focusing on their authenticity and by identifying characteristic features, as well as analysing the existing wall typologies, morphologies and main constructive features. The schist stone used for centuries as a building raw material is characterized from the physical and mechanical points of view. A rebuilding methodology was then applied to a case study, for which different local contemporary rebuilding solutions were identified and characterized. A decision-making process was established according to specific intervention guidelines, with implementation of the chosen solution presented in detail.Finally, this paper aims also to enlighten researchers, technicians and builders to the importance and need of protecting the endangered vernacular masonry walls' heritage, and to contribute to the development of suitable rehabilitation and rebuilding solutions for similar types of interventions., This work was partially financed by FEDER funds through the Competitivity Factors Operational Programme (COMPETE) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project POCI-01-0145-FEDER-007633. Authors wish to express their gratitude to the Barqueiros parish council and to the companies Construjouve, for their support during the construction of the wall, and Artecanter for their support with the specimens' preparation. The first author expresses his gratitude to the Portuguese Science and Technology Foundation for the scholarships granted (SFRH/BD/86704/2012)., info:eu-repo/semantics/publishedVersion

Textile Reinforced Mortar (TRM), also known as Fabric Reinforced Mortar or Fabric Reinforced Cementitious Matrix, composites are an emerging technology for the external repair and strengthening of existing structures. For most applications, the effectiveness of the TRM reinforcement relies on its bond performance. This recommendation identifies the best practice to characterize the bond behaviour of TRM. A shear bond test method is proposed to determine the peak axial stress (associated with the maximum load that can be transferred from the structural member to the externally bonded TRM reinforcement), the stress-slip relationship and the failure mode that controls the TRM-to-substrate load transfer capacity. Guidelines on specimen manufacturing, experimental setup, test execution, and determination of test results are provided., info:eu-repo/semantics/publishedVersion

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 article 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., FCT - Fundação para a Ciência e a Tecnologia(POCI-01-0145-FEDER-007633), info:eu-repo/semantics/publishedVersion

The acoustic emission (AE) technique is used for investigating the interfacial fracture and damage propagation in GFRP- and SRG-strengthened bricks during debonding tests. The bond behavior is investigated through single-lap shear bond tests and the fracture progress during the tests is recorded by means of AE sensors. The effect of hygrothermal conditions on the debonding characteristics and failure mode is also investigated by performing accelerated ageing tests. Accelerated ageing tests resulted in a change of failure mode in GFRP-strengthened specimens which helped in assessment of AE output in different failure modes, but no conclusive strength degradation was observed in the specimens. The results show that the average and cumulative AE energy are correlated to the FRP slip and debonding fracture energy in GFRPstrengthened specimens, respectively. The fracture progress and active debonding mechanisms are characterized using results from the AE technique. Moreover, a clear distinction between the AE outputs of specimens with different failure modes, in both SRG- and GFRP-strengthened specimens, is found which allows characterizing the debonding failure mode based on acoustic emission data. The tests performed in this study are also a contribution towards the application of AE techniques for on-site health monitoring of strengthened masonry structures., Fundação para a Ciência e Tecnologia

Full characterization of the bond behavior between Fiber Reinforced Polymers (FRPs) and masonry in externally bonded reinforcement (EBR) technique is crucial at the design stage or structural performance prediction. In this regard, a full-field assessment technique seems to be valuable for an adequate characterization of the bond behavior. The digital image correlation (DIC) and feature tracking techniques have been used in this study for investigating the evolution of strains and deformation during uniaxial tensile tests and shear debonding tests in FRP-masonry systems. The results show that the DIC is a valuable technique for characterization of the bond behavior and investigating its three-dimensional aspects. The DIC was also found applicable for following the matrix crack development in Steel Reinforced Grout (SRG) specimens. Feature tracking method was used for monitoring the strains development on the steel fibers in SRG specimens during tensile tests.

Fiber reinforced polymers are being extensively used for external strengthening of masonry structures. However, durability of this strengthening technique under environmental conditions is still under inves- tigation. Previous studies indicate that moisture plays an important role in the durability of bond between FRP and substrate. Moisture can cause degradation in the bond behavior and also in the mechan- ical properties of the constituent materials. This paper presents and discusses the results of an experi- mental investigation on the effects of moisture on the bond behavior in FRP-strengthened masonry bricks. The degradation in the bond performance has been investigated by performing pull-off and pull-out tests on the conditioned specimens. The change in the mechanical properties of the materials has also been investigated. Comparative analysis has been performed and the results are presented and critically discussed., This work was partly funded by project FP7-ENV-2009-1-244123-NIKER of the 7th Framework Program of the European Commission, which is gratefully acknowledged. The first author also acknowledges the financial support of the Portuguese Science Foundation (Fundacao de Ciencia e Tecnologia, FCT), through grant SFRH/BD/80697/2011.

Contemporary world is facing numerous bomb explosion attacks on public and civil buildings causing huge loss of property and human lives. As a consequence, the society needs more safety and protection for the existing structures against blast loads. Among the various strategies, one effective way to enhance the blast resistance of reinforced concrete and masonry structures is through retrofitting using various types and forms of fibrous and composite materials. This work presents an up to date review of available literature and publications on the fibrous and composite materials utilized for blast protection of structural elements and highlights the lacking areas where further research is required.

The paper discusses the behavior of a typical masonry building in Bosnia and Herzegovina built in the 1950s without any seismic guidelines. A global numerical model of the building has been built and masonry material has been simulated as nonlinear. Additionally, calculations done with a “less” sophisticated model are in a good correlation with the finite element method (FEM) calculations. It was able to “grasp” the damage pattern; not as detailed as in the FEM calculations, but still quite good. On the basis of this it may be concluded that in this case calculation with Frame by Macro Elements (FME) program could be recommended for future analysis of this type of structures, having quite good results with a less computation time. However, in the need for more precise results FEM should be utilized.

Considering the safety assessment requirements of masonry arch bridges, different levels of reliability, based on uncertainty, may be distinguished, whose core objectives are to accurately analyse the ultimate load-carrying capacity and the serviceability structural response. Within this framework, a simplified full-probabilistic methodology for the safety assessment of existing masonry arch bridges is proposed, which combines both structural analysis and Bayesian inference procedures. The proposed framework aims to determine the ultimate load-carrying capacity (Ultimate Limit State) of masonry arch bridges, by using probabilistic procedures and Limit States principles. Geometric, material and load characterization, as well as inherent uncertainties will be also considered. In order to determine the ultimate loadcarrying capacity, a limit analysis approach, based on the mechanism method, will be employed. Due to the high computational costs required by a probabilistic safety assessment framework, a sensitivity analysis will then be introduced. The incorporation of new information from monitoring and/or testing will be performed by the application of Bayesian inference methodologies. Based on the information collected, two reliability indexes will be computed and compared, one with data collected from design documentation and literature and the other with data collected from testing, emphasizing the importance of testing and the advantages of Bayesian inference procedures. The probabilistic framework developed is tested and validated in a Portuguese railway masonry arch bridge from the 19th century., This work was partly financed by FEDER funds through the Competitivity and Internationalization Operational Programme COMPETE and by national funds through FCT - Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007633. Also, the collaboration and information provided by the Portuguese railway network (REFER) is gratefully acknowledged. Finally, the information made available by Dr. Cristina Costa is kindly acknowledged.

Rammed earth constructions are widely found worldwide, but they are endangered by their recognised high seismic vulnerability. As compatible and affordable reinforcement approaches are important requirements for these constructions, a strengthening solution based on low cost textile reinforced mortars (LC-TRM) is proposed here, within the framework of a large research project. This paper presents the results of an experimental program aimed at characterising low cost meshes available in the market (glass fibre, plastic, metallic and nylon) and at assessing possible mortars (unstabilised earth, stabilised earth, commercial earth and cement-based) capable of integrating the LC-TRM strengthening system. In general, the results obtained seem to indicate that the glass fibre meshes and the earth mortar are good options., This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of projects POCI-01-0145-FEDER-007633 and POCI-01-0145FEDER-016737 (PTDC/ECM-EST/2777/2014). The support from grant SFRH/BPD/97082/2013 is also acknowledged., info:eu-repo/semantics/publishedVersion

Fibre-reinforced composite materials have gained an increasing success, mostly for strengthening, retrofitting, and repairing existing structures. However some problems may arise with the use of traditional FRP (Fiber Reinforced Polymer), particularly when the compatibility with the substrate and the reversibility of the intervention are required, as in case of cultural heritage buildings, or specific exposition conditions may compromise the long term effectiveness of the reinforcement, as in presence of high temperature and humidity. Starting from these considerations new composite materials are emerging as a more effective solution in certain fields of application and under specific service conditions; in this context, mortar-based composite systems, consisting of one or more layers of uni- or bi-directional fibre nets embedded in cement/lime-based matrix layers, can be used as reinforcement of both concrete and masonry structures. However, the research work dealing with these emerging materials and their performances when used as a strengthening system for existing structures is still limited. Both experimental and theoretical investigations are needed in order to deliver reliable design methodologies. In this work, a Round Robin Test aimed to the characterization of both bond with the existing substrate and tensile performance of glass fabric (in the form of grids) coupled with inorganic mortar matrices is presented. The investigation was conducted at fifteen laboratories involved in the RILEM Technical Committee 250-CSM (Composites for the Sustainable Strengthening of Masonry). With the aim of studying the bond behaviour between Fabric Reinforced Cementitious Matrix (FRCM) composites and masonry substrate, single and double lap shear tests were carried out on brick-masonry prisms. Results provide useful informations about the mechanical properties, the bond capacity and the failure mechanisms of different commercially available glass FRCM systems. Finally, critical aspects are underlined to address the progress of research work., info:eu-repo/semantics/publishedVersion

The compatible strengthening of historical constructions is a critical issue in modern restoration practice. Among others, numerical modelling became a powerful instrument in the practice of checking the suitability and effectiveness of a given structural strengthening solution. In particular, the topic of numerical modelling of masonry arches and vaults was developed by many researchers for several years. This paper is focused on the numerical representation of a traditional strengthening technique, based on the use of transversal masonry diaphragms applied to arches and vaults. Macro and micromodelling approaches were considered in this work as to discuss the adequacy and efficiency of the strengthened method and also compare results between the two approaches. To further define the properties and effectiveness of the strengthening solution, a parametric study was conducted by means of geometrical and mechanical modifications applied to the diaphragms.

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., This research work was partly financed by FEDER funds through the Competitivity Factors Operational Programme (COMPETE) and by Portuguese national funds through FCT(Foundation for Science and Technology) within the scope of projects POCI-01-0145-FEDER-007633 and POCI-01-0145-FEDER-016737 (PTDC/ECM-EST/2777/2014). The support from grant SFRH/BPD/97082/2013 is also gratefully acknowledged.

The paper presents a comparison between different numerical modelling approaches aiming to simulate the in-plain behaviour of three types of earthen materials, namely adobe masonry, rammed earth and cob. For this purpose, uniaxial and diagonal compression tests were carried out, which allowed determining important mechanical parameters, such as compressive strength, Young's modulus, Poisson's ratio, shear strength and shear modulus. Furthermore, the tests 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 for the calibration of numerical models (based on the finite element method) for simulating the non-linear behaviour of the earth materials under in-plane shear loading. Both macro- and micro-modelling approaches were considered for this purpose. The procedures adopted for model calibration established the reliability of various modelling strategies for the different loading conditions. The simplified approach based on macro-modelling shows a satisfactory accuracy and low computational costs. The results reproducing the uniaxial compression are in good correspondence with the post-elastic behaviour observed in the experimental campaign. The micro-modelling approach adopted to reproduce the shear behaviour, even with higher computational cost, represents a suitable tool to predict the adobe masonry and rammed earth collapse mechanisms., This study was partially funded by European Commission within the framework of the project NIKER (grant number 244123) dealing with improving immovable Cultural Heritage assets against the risk of earthquakes. The study was also partly financed by FEDER funds through the Competitivity Factors Operational Programme (project POCI-01-0145-FEDER007633) and by national funds through Portuguese Foundation for Science and Technology (project PTDC/ECM-EST/2777/2014 and grant SFRH/BPD/97082/2013). The authors wish to acknowledge Mr. André Gardei and Mr. Jürgen Kuhn for their support in samples preparation and tests setup., info:eu-repo/semantics/publishedVersion

Textile Reinforced Mortars (TRMs) have found extensive attention for externally bonded reinforcement of masonry and historical structures. However, only few information is available regarding their mechanical properties and effectiveness in improving the seismic performance of strengthened structures. This paper presents an extensive numerical investigation on the effect of TRM composites on the nonlinear response and failure modes of masonry walls. The effect of boundary conditions and the TRM type on the performance of strengthened walls are critically discussed and presented. It is shown that the performance and failure mode of the walls can significantly change after strengthening, an important issue that should be considered at the design stage. Finally, the effect of TRM application on the nonlinear response of a large historical masonry facade in Macau is investigated and presented., The first author is grateful to the SAHC Master Programme for the grant awarded. The second author acknowledges the financial support of the Ministerio da Ciencia, Tecnologia e Ensino Superior, FCT, Portugal, under the grant SFRH/BPD/92614/2013 as well as the financial support of the European Union's Marie Curie Individual Fellowship program under REA grant agreement No. 701531., info:eu-repo/semantics/publishedVersion

Key Engineering Materials, vol. 747., Tensile Reinforced Mortars (TRMs) are promising composites that address the compatibility demands required for strengthening of masonry and historical constructions. Although many recent studies have been devoted to the use of these materials for strengthening purposes, several issues such as efficiency for improving the structural performance are clearly open. The aim of this paper is to numerically investigate the effectiveness of TRM systems on the in-plane and out-of-plane response of masonry walls. Numerical models are adopted to describe the nonlinear behaviour and the failure mechanisms of unreinforced and strengthened walls. It is shown that the implementation of TRM layers improve largely the performance of the masonry walls both in terms of strength and displacement capacity., (undefined), info:eu-repo/semantics/publishedVersion

The demand for building materials and techniques with reduced environmental impact has been increasing in the last few years. Thus, efforts have been taken to include alternative raw materials with reduced extraction impacts and low embodied energy in their production, namely natural materials and industrial by-products with low or no processing needs. Nevertheless, the lack of technical knowledge about this type of materials leads to issues related with its safety, quality and durability. The work presented in this paper intends to be a contribution on this topic. Thus, an experimental program was carried out to evaluate the mechanical performance of interlocking compressed earth blocks (ICEBs) stabilised with activated alkali fly ash. The main objective of the experimental program was to assess the possibility of further exploiting the mechanical performance of the original dry-stack masonry system, by means of the use of mortared joints. Two alkali-activated binder based earth mortars were used for this purpose, and the results showed that a substantial mechanical improvement is obtained in terms of compression and shear behaviour of the respective masonry., This work is financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by Portuguese funds through FCT - Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007633. The support from grant SFRH/BPD/97082/2013 is also acknowledged. The authors wish to express their gratitude to Eng. Jorge Henriques, on behalf of the company PEGOP - Energia Electrica SA, for providing the fly ash, and to Eng. Miguel Rodrigues, on behalf of the company CJR GROUP, for providing the soil.

In the past decades, structural robustness has gained major interest due to the collapse of remarkable structures, such as the Ronan Point tower and the World Trade Center. In both situations, a local damage lead to structural collapse, triggering research to restrain progressive collapse in structures. Masonry arch bridges are important historical structures, with many of them still in service. Over their long lifetime, deterioration and damage have affected their ultimate load-carrying capacity, which must be considered when evaluating the safety condition of these structures. This paper presents a methodology for robustness-based assessment of masonry arch railway bridges, by computation of the ultimate loadcarrying capacity resorting to the limit analysis method. The main damage scenarios, namely their location and extension, will be presented and discussed. The influence of such damage is discussed in detail, as well as the most influencing structural parameters, being justified the robustness capacity in such cases. The developed methodology is then applied to a Portuguese railway masonry arch bridge., (undefined), info:eu-repo/semantics/publishedVersion

Nowadays, there is an increasing interest in using fibre reinforced polymers (FRP) for strengthening masonry elements. It has been observed that these materials, when used for externally bonded reinforcement (EBR), improve the performance of masonry components. However, issues such as durability and longterm performance of strengthened elements are still open. The bond between composite material and masonry substrate is a critical mechanism in EBR strengthening techniques, and therefore its durability and long-term performance should be deeply investigated and characterized. In the present study, the influence of hygrothermal conditions (combined effect of moisture and temperature) on the bond performance is investigated by performing single-lap shear bond tests on two sets of GFRP-strengthened specimens. Different surface preparation techniques are used for each set of specimens to study their effects on the bond degradation. The effect of boundary conditions on FRP delamination is also investigated through visual inspection. The results showed surface grinding significantly improves the bond durability. Extreme FRP delamination was observed in specimens prepared with original brick’s surfaces, being mainly due to thermal incompatibility., (undefined)

The absence of appropriate structural connections is known to be one of the main factors contributing to the activation of out-of-plane mechanisms of masonry walls that can compromise the entire stability of a building. The high vulnerability of historical unreinforced masonry buildings to these types of mechanisms imposes the necessity to develop engineered strengthening solutions capable of ensuring positivewall-diaphragm anchorage to work in tension.A design methodology was developed covering aspects related to the estimation of the seismic demand and the design of a retrofit solution studied experimentally. The procedure proposed relies on the assessment of the resistant capacity associated with several possible failure modes and the estimation of the seismic demand considering the existing recommendations found on Eurocode 8 (CEN/TC 250 2010), ASCE/SEI 41-13, and NZSEE (2006)., The authors would like to acknowledge Professor Jason Ingham for providing essential information and technical expertise concerning the NZSEE (2006) application. This work was partially funded by project FP7-ENV-2009-1-244123-NIKER of the 7th Framework Program of the European Commission, and by FCT, within ISISE, project UID/ECI/04029/2013, which are gratefully acknowledged.

Publicado em "Brick and block masonry : trends, innovations and challenges : proceedings of the 16th International Brick and Block Masonry Conference (IBMAC 2016)...", ISBN 978-1-138-02999-6, Although earthen construction has been practiced for millennia, its advantages associated to current environmental concerns are giving new opportunities to earth as a modern building material. The paper presents and discusses the first results of an experimental campaign carried out at University of Minho on the characterization of masonry components made of stabilized compressed earth blocks, produced with granitic residual soils, typically from Northern Portugal, and considering both dry-stack and mortared joints. The use of mortar joints modifies significantly the mechanical behaviour of masonry, both in terms of stiffness and strength., FCT, within ISISE, project UID/ECI/04029/2013, Fundação para a Ciência e Tecnologia (FCT) - SFRH/BPD/97082/2013

This paper reports the first attempt of developing macro-scale auxetic structures based on re-entrant hexagon design from braided composite materials for civil engineering applications. Braided composite rods (BCRs) were produced and arranged as longitudinal and horizontal elements to produce three types of auxetic structures: (1) basic re-entrant hexagon structure, (2) basic structure modified by adding straight longitudinal elements and (3): structure-2 modified by changing structural angle. The influence of various material and structural parameters as well as structure type on Poisson's ratio and tensile properties was thoroughly investigated. The auxetic behaviour was found to strongly depend on the structural angle and straight elements, resulting in lower auxeticity with lower angles and in presence of straight elements. Material parameters influenced the auxetic behaviour to a lesser extent and a decrease in auxetic behaviour was noticed with increase in core fibre linear density and using stiffer fibres such as carbon. The reverse effect was observed in case of tensile strength and work of rupture. Among these structures, structure-3 exhibited good auxetic behaviour, balanced tensile properties, and high energy absorption capacity and their auxetic behaviour could be well predicted with the developed analytical model. Therefore, these novel structures present good potential for strengthening of civil structures., The authors gratefully acknowledge the financial support for carrying out this research work from University of Minho, under the scheme of "Strategic plan of school of engineering - Agenda 2020: Multidisciplinary projects."

Summary The transcriptional regulator CITED2 is essential for heart development. Here, we investigated the role of CITED2 in the specification of cardiac cell fate from mouse embryonic stem cells (ESC). The overexpression of CITED2 in undifferentiated ESC was sufficient to promote cardiac cell emergence upon differentiation. Conversely, the depletion of Cited2 at the onset of differentiation resulted in a decline of ESC ability to generate cardiac cells. Moreover, loss of Cited2 expression impairs the expression of early mesoderm markers and cardiogenic transcription factors (Isl1, Gata4, Tbx5). The cardiogenic defects in Cited2-depleted cells were rescued by treatment with recombinant CITED2 protein. We showed that Cited2 expression is enriched in cardiac progenitors either derived from ESC or mouse embryonic hearts. Finally, we demonstrated that CITED2 and ISL1 proteins interact physically and cooperate to promote ESC differentiation toward cardiomyocytes. Collectively, our results show that Cited2 plays a pivotal role in cardiac commitment of ESC., Graphical Abstract, Highlights • Overexpression of CITED2 in ESC promotes cardiogenesis upon differentiation • Cited2 depletion reduces ESC ability to generate cardiac cells • Cited2 expression is enriched in cardiac progenitors • CITED2 and ISL1 cooperate to promote ESC differentiation toward cardiomyocytes, In this article, Bragança and colleagues show that the transcriptional regulator Cited2 is essential for cardiac commitment of mouse embryonic stem cells (ESC), and its depletion in ESC impairs the expression of early mesoderm markers and cardiogenic transcription factors. In addition, they demonstrate that CITED2 and ISL1 proteins interact and cooperate to promote ESC differentiation toward cardiomyocytes.

Fiber Reinforced Polymers have become a popular material for external strengthening of masonry structures. The performance of this strengthening technique is strongly dependent on the bond between FRP and substrate. This paper presents numerical modeling of the bond behavior in FRP-strengthened masonry components using interface elements, based on a recent testing program at the University of Minho. A trilinear bond-slip model is proposed for the interface elements based on observed experimental behavior of strengthened components. The comparison between numerical and experimental results shows that the proposed model is suitable for numerical simulation of the bond behavior and allows a better understanding of the mechanisms involved in the failure process., This work was partly funded by project FP7-ENV-2009-1-244123-NIKER of the 7th Framework Programme of the European Commission, which is gratefully acknowledged. The experimental results mentioned in the paper were obtained within the framework of the RILEM TC 223-MSC activities, for which the authors are grateful.

The conservation and rehabilitation of several sites of cultural heritage and of the large housing stock built from earth requires the development of techniques and materials compatible with this kind of construction. Grout injection is one repair solution which has been put forward over the last few years, whereas there is preference for employing grouts that incorporate earth in their composition. However, knowledge of such grouts is still very limited and requires further research. The experimental program discussed in this paper contributes to the comprehension of the influence of the composition of an unmodified mud grout, namely regarding its fresh-state rheology, hardened-state strength and adhesion. In general, the results obtained showed that the rheological behaviour of a mud grout greatly depends on the colloid behaviour of the clay fraction, and that the addition of a deflocculant and modification of the clay content (with a silt size material) is required to obtain grouts with adequate solid fractions., The authors wish to express their gratitude to the Portuguese Science and Technology Foundation for the scholarship granted to the first author (SFRH/BD/39145/2007) and to the companyWienerberger (Belgium) for kindly providing the kaolin.

Assessment of the seismic performance of structures is still a challenge. Historic masonry structures exhibit peculiar properties (low tensile strength and lack of box behavior) that make the task of the analyst even more difficult. It seems that traditional design and assessment methods, similar to the ones currently used for reinforced concrete structures, are not applicable. This article provides a review of the seismic analysis of masonry structures without box behavior. Different methods of structural analysis are discussed and a comparison is made between pushover methods and non-linear dynamic analysis with time integration. Three cases studies (San Torcato church, Qutb Minar and “Gaioleiro” buildings) were used and the results show that traditional, adaptive or modal pushover analyses are not totally in agreement with non-linear dynamic analysis or experimental observations.

The present paper describes the seismic assessment of the Qutb Minar in Delhi, India. Three models with different levels of complexity and simplifications were developed. The use of these models allows to overcome the complexity on the study of the seismic behavior of ancient masonry structures; by combining the results of the different models it is possible to obtain a better and more comprehensive interpretation of the seismic behavior. The models were used for non-linear static (pushover) and non-linear dynamic analyses. The static and dynamic analyses give different behaviors, indicating that push-over analysis should be used carefully in the seismic assessment of masonry structures. For the static analysis, the base of the tower is the most vulnerable part; while according to the dynamic analysis, it is the upper part of the tower. This last behavior is according to the historical damage suffered by the tower due to earthquakes. The different behaviors can be explained by the influence of the higher modes of vibration., This research was part of the activities of the EU-India Economic Cross Cultural Programme "Improving the Seismic Resistance of Cultural Heritage Buildings", Contract ALA-95-23-2003-077-122. F. Pefia acknowledges funding from the FCT grant contract SFRH/BPD/17449/2004, as well as the partial support of the project PAPIIT IN105409.

Textile Reinforced Mortars (TRMs) have received extensive attention for externally bonded reinforcement of historical and masonry structures. Despite this recent attention, the available information on the test methods and mechanical performance of TRMs at different scales are limited. Extensive experimental results are still necessary for development of design formulas and application guidelines. This paper presents a multi-level experimental investigation on the performance of Steel Reinforced Grouts (SRGs) as a common TRM type. The focus is not only on the mechanical characterization but also the test methods and practical challenges. The tests include materials characterization, fiber-to-mortar bond characterization, tensile tests on TRM composite, and TRM-to-masonry bond characterization tests. The tests are performed on three different SRG systems made of pozzolanic lime-based and geopolymeric-based mortars as sustainable matrices for strengthening and restoration applications., The first author acknowledges the financial support of the Ministerio da Ciencia, Tecnologia e Ensino Superior, FCT, Portugal, under the grant SFRH/BPD/92614/2013., info:eu-repo/semantics/publishedVersion

Proper structural connections play an important role in ensuring seismic loads distribution and developing global damage mechanisms of structures. In historical unreinforced masonry buildings, effective connections between masonry walls and timber floors or walls through the use of anchors can prevent the occurrence of out-of-plane mechanisms and promote box-like behavior. Particularly for historic structures, injection anchors can comply with requirements as decreased architectural impact and minimum intervention. Therefore, this paper aims at developing structural design parameters and recommendations that allow the design of connections retrofitted with injection anchors, found in historical unreinforced masonry buildings, built during the 19th century, in Portugal. Existing strength prediction formulae based on behavior models, and idealized force-displacement curves were developed to better fit the results obtained from a series of quasi-static monotonic and cyclic pullout tests carried out on pairs of injection anchors. Behavior models were able to approximate the experimental results, if adapted to the specificities of historical masonry. Further validation is needed, particularly for the combined cone-bond model. From the idealized curves, displacement acceptance criteria, expected forces, and behavior factors were proposed, according to the performance-based approaches recommended by EC8-Part 3 and ASCE/SEI 41-13. Finally, retrofit design recommendations were addressed., This work was partially funded by project FP7-ENV-2009-1-244123-NIKER of the 7th Framework Program of the European Commission, which is gratefully acknowledged. Authors would like to thank the technical staff of the Structures Lab. of University of Minho for the assistance provided preparing and carrying out the tests and also, Monumenta, Ltd. for the construction of the specimens and Cintec® for the installation of the injection anchors.

Externally bonded reinforcement (EBR) of masonry structures with Fiber Reinforced Polymers (FRPs) has received extensive attention during the last years. Despite the vast literature on mechanics and short-term performance, the durability and long-term performance of these systems still remain insufficiently studied. Structures are subjected to harsh environments such as coupled temperature and moisture variations (hygrothermal conditions) during their service life. A clear understanding on the performance of the strengthening system under these conditions is critical at the design stage.This paper presents an experimental investigation on the effect of long-term hygrothermal conditions on FRP-strengthened masonry components. The focus is on the interfacial bond behavior and materials mechanical properties. The effect of mechanical surface treatment on the bond durability is also investigated., The second author acknowledges the financial support of the Ministerio da Ciencia, Tecnologia e Ensino Superior, FCT, Portugal, under the grant SFRH/BPD/92614/2013., info:eu-repo/semantics/publishedVersion

The paper presents an experimental investigation on an innovative repair method, in which composite reinforcements, after debonding, are re-bonded to the substrate using a highly deformable polymer. In order to assess the effectiveness of this solution, shear bond tests were carried out on brick and masonry substrates within two Round Robin Test series organized by the RILEM TC 250-CSM: Composites for the Sustainable strengthening of Masonry. Five laboratories from Italy, Poland and Portugal were involved. The shear bond performance of the reinforcement systems before and after repair were compared in terms of ultimate loads, load–displacement curves and strain distributions. The results showed that the proposed repair method may provide higher strength and ductility than stiff epoxy resins, making it an effective and cost efficient technique for several perspective structural applications.

Innovative composite materials made of continuous fibers embedded in mortar matrices have been recently received attention for externally bonded reinforcement of masonry structures. In this regards, application of natural fibers for strengthening of the repair mortars is attractive due to their low specific weight, sustainability and recyclability. This paper presents experimental characterization of tensile and pull-out behavior of natural fibers embedded in two different mortar-based matrices. A lime-based and a geopolymeric-based mortar are used as sustainable and innovative matrices. The obtained experimental results and observations are presented and discussed.

Stone masonrywalls are the most relevant structural element in the seismic response of a masonry building. Once the out-of-plane mechanism are adequately prevented, the seismic response of a building depends on the in-plane strength capacity of its walls. This paper presents a discussion on the in-plane behaviour of masonry panels with different slenderness ratios and distinct levels of compression load, subjected to shear loading, using advanced numerical simulations. The numerical study is based on an experimental campaign performed at the University of Pavia on stone masonry piers. The calibrated models were also used to carry out parametric analysis varying the geometric wall configuration and the pre-compression level. Distinct walls subjected to different stress levelswere assessed and the influence of these parameters on the in-plane behaviour is discussed., The second author would like to express her gratitude to the National Foundation for Science and Technology (FCT) for the PhD grant SFRH/BD/71599/2010. This work was supported by FCT, within ISISE, project UID/ECI/04029/2013.

A great number of masonry arch bridges dates back to past centuries, being preserved by society due to their historical and still economic importance. Thereby, adequate preservation measures are required. Regarding masonry arch bridge’s structural condition, it is relevant to consider its age, and consequently deterioration, and the fact that these bridges are submitted to loads higher than those for which they were conceived, being imperative to assess their structural performance. Regarding safety assessment requirements, there are different reliability levels, whose objectives are to analyse the ultimate load-carrying capacity and the serviceability performance. This paper presents and discusses a framework that allows to determine the ultimate load-carrying capacity (Ultimate Limit State) of masonry arch bridges, using limit analysis and probabilistic approaches. Geometric and material data and load characterization, as well as inherent uncertainties will be also introduced. In order to determine the ultimate load-carrying capacity, the plastic theory will be employed, namely the limit analysis theorem, which is based on kinematic mechanisms. Since one of the main drawbacks of a probabilistic analysis is the required high computational resources, a sensitivity analysis is incorporated in order to reduce the analysis time. The presented framework is validated with an application to a set of existing Portuguese railway masonry arch bridges., This research was funded by project PEst-C/ECI/UI4029/2011 (FCOM-01-0124-FEDER-022681) and by the Portuguese Science and Technology Foundation through project UID/ECI/04029/2013. Also, the collaboration and information provided by the Portuguese railway network (REFER) is gratefully acknowledged.

In this chapter, a review on the mechanical behaviour of masonry is presented. The aim is to establish a base of knowledge and understanding of masonry that will underpin its mechanical characteristics and will inform the decisions towards the selection of the computational tool used which are going to be described in the following chapters. Initially, a brief description of the factors that influence the mechanical response of masonry and the variation of the material properties are discussed. The review then considers the possible causes of cracking in masonry and the different failure modes that may occur during loading. Principal findings from the review are summarised at the end of the chapter.

The bond behavior between Fiber Reinforced Polymers (FRPs) and masonry substrates has been the subject of many studies during the last years. Recent accelerated aging tests have shown that bond degradation and FRP delamination are likely to occur in FRP-strengthened masonry components under hygrothermal conditions. While an investigation on the possible methods to improve the durability of these systems is necessary, the applicability of different bond repair methods should also be studied. This paper aims at investigating the debonding mechanisms after repairing delaminated FRP-strengthened masonry components. FRP-strengthened brick specimens, after being delaminated, are repaired with two different adhesives: a conventional epoxy resin and a highly flexible polymer. The latter is used as an innovative adhesive in structural applications. The bond behavior in the repaired specimens is investigated by performing single-lap shear bond tests. Digital image correlation (DIC) is used for deeper investigation of the surface deformation and strains development. The effectiveness of the repair methods is discussed and compared with the strengthened specimens., The first author acknowledges the financial support of the Portuguese Science Foundation (Fundacao de Ciencia e Tecnologia, FCT), through grant SFRH/BPD/92614/2013. Additional acknowledgement goes to Sika Poland for providing the PS polymer to the laboratory of the Minho University in Portugal.

This paper describes the procedure adopted in the analysis and design of repair measures of a historical masonry arch bridge, carried out at Universidade do Minho. The bridge under study crosses over Vizela River, near Guimaraes. A detailed survey carried out allowed concluding that remedial measures were necessary in order to restore safety. The bridge load capacity was also assessed by means of a simple computational tool based on the limit analysis theory. To assure the safety use of the bridge, by light traffic and people, repair measures were proposed in accordance with the modern principles of intervention in historical structures.

The growing concerns regarding the environmental impact generated by the use of inorganic materials in different fields of application increased the interest towards products based on materials with low environmental impact. In recent years, researchers have turned their attention towards the development of materials obtained from renewable sources, easily recoverable or biodegradable at the end of use. In the field of civil structures, a few attempts have been done to replace the most common composites (e.g. carbon and glass fibers) by materials less harmful to the environment, as natural fibers. This work presents a comprehensive experimental research on the mechanical performance of natural fibers for the strengthening of masonry constructions. Flax, hemp, jute, sisal and coir fibers have been investigated both from physical and mechanical points of view. The fibers with better performance were tested together with three different matrices (two of organic nature) in order to produce composites. These experimental results represent a useful database for understanding the potentialities of natural fibers as strengthening systems., The first author would like to thank the Civil Engineering Laboratory and Fibrous Materials Laboratory at University of Minho and the Fibrenamics group, which have contributed greatly to this work.

The paper presents the results of experimental research on the structural behavior of dry joint masonry. The most relevant experimental results concern the strength response of stone dry joint masonry walls subjected to in-plane combined compressive and shear loading. Significant features of the structural behavior shown by the walls are discussed and conclusions on their ultimate capacity and observed failure mechanisms are addressed. Complementarily, the application of an existing numerical model, stemming from plasticity and based on a micromodeling strategy, is also presented and discussed with regard to its capacity to simulate the obtained experimental results. The model was calibrated with data collected from complementary tests carried out on specimens and prisms made of the same type of stone. Finally, the usage of a simplified method of analysis based on a continuum of diagonal struts is also addressed.

A constitutive model developed for the simulation of the cyclic behaviour of interface elements is proposed. Its theoretical framework is fully based on the plasticity theory. Starting from an existing monotonic model, two new yield surfaces are introduced in order to include non-linear unloading/reloading behaviour in an accurate fashion. The motion of the unloading surfaces is controlled by a mixed hardening law and, by adopting appropriate evolution rules, it is possible to reproduce non-linear behaviour during unloading. Numerical results concerning the analysis of both uniaxial tests and masonry walls are presented and discussed as application and validation examples of the constitutive model.

This paper addresses the results of accelerated hygrothermal (coupled temperature and moisture) tests on FRP-strengthened clay bricks aimed at investigating bond degradation mechanisms. The exposures are selected to simulate different environmental conditions and the bond degradation is periodically investigated by visual inspection and by conventional single-lap shear bond tests. The changes in the properties of material constituents have also been monitored and the results are presented and critically discussed. A decay model is then adopted for simulating the observed degradation in the specimens. The model, once validated, is used for long-term performance prediction of FRP-masonry systems and the results are compared with the environmental reduction factors proposed by available design guidelines., The first author acknowledges the financial support of the Portuguese Science Foundation (Fundacao de Ciencia e Tecnologia, FCT), through grant SFRH/BD/80697/2011.

The increasing interest on earth construction as a sustainable building solution led to the development of modern earth construction techniques, in particular of masonry made of compressed earth blocks (CEBs). The traditional chemical stabilisation of the soil is a frequently used improvement process. However, such process increases significantly the embodied energy of the CEBs. This paper presents an alternative technique for the stabilisation of CEBs, based on alkali activation of fly ash. The mechanical behaviour of the CEBs and of the respective dry stack masonry is comprehensively investigated through an experimental program, during which this technique proved to be highly effective., The authors wish to express their gratitude to Mr. Pedro Esteves for his support in the experimental work and to Eng. Jorge Henriques, on behalf of the company PEGOP – Energia Eléctrica SA, for providing the fly ash. The financial support provided by the Portuguese Science and Technology Foundation through the project FCOMP-01-0124-FEDER-028864 (FCT-PTDC/ECM-EST/2396/2012) is also gratefully acknowledged., Fundação para a Ciência e a Tecnologia (FCT)

The paper presents an experimental program aiming at assessing the mechanical performance of rammed earth walls, namely under compression and shear loading. Axial compression and diagonal compression 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 and shear modulus. 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 (finite element method) for simulating the non-linear behaviour of rammed earth under shear loading. Both macro- and micro modelling approaches were considered for this purpose. The total strain rotating crack model was used to simulate the behaviour of the rammed earth material, while the Mohr–Coulomb failure criterion was used to simulate the behaviour of interfaces between layers. In general, the numerical models achieved good agreement with the experimental results, but uncertainties related to the definition of the input parameters required to perform a sensitivity analysis. The compressive strength, the Poisson’s ratio, the tensile strength and the tensile fracture energy revealed to be the most important parameters in the analyses., Fundação para a Ciência e a Tecnologia (FCT)

The acoustic emission (AE) technique is used for investigating the interfacial fracture and damage propagation in GFRP-and SRG-strengthened bricks during debonding tests. The bond behavior is investigated through single-lap shear bond tests and the fracture progress during the tests is recorded by means of AE sensors. The fracture progress and active debonding mechanisms are characterized in both specimen types with the aim of AE outputs. Moreover, a clear distinction between the AE outputs of specimens with different failure modes, in both SRG-and GFRP-strengthened specimens, is found which allows characterizing the debonding failure mode based on acoustic emission data., (undefined)

Most of masonry arch bridges dates from ancient times, having an important historical value to society, thus requiring appropriate conservation approaches. Regarding masonry arch bridge’s structural condition, considering its age, and consequently deterioration, and the fact that they are submitted to loads much higher than those existing at their construction period, it is imperative to evaluate the structural performance of these structures. This paper will expose a methodology for safety assessment of masonry arch bridges, namely in terms of ultimate load-carrying capacity, determined by limit analysis. Monitoring and material characterization are standard procedures in safety assessment and, will be shown that Bayesian techniques are a useful tool to incorporate new gathered information in structural analysis model. Safety assessment procedures described in the article will be applied to a Portuguese stone masonry arch bridge from the 19th century., (undefined)

Recent research has proved the potential of alkaline activated fly-ash for soil stabilisation. However, such studies have not focused on the link between financial, mechanical and environmental aspects of this solution, but only on their absolute mechanical properties. The present paper characterises the mechanical behaviour of a large spectrum of activator-ash-soil combinations used to build jet mixing columns, analysing also the cost and CO2 (eq) emissions. The concern with these two vectors forced a decrease in the quantity of stabilising agent added to the soil, relatively to previous research, and the effects of such low quantities have not yet been published. However, the results clearly showed a significant improve in strength, still well above the average values expected when improving the stressstrain behaviour of a weak soil. Uniaxial compressive strength tests were used to assess the effects of the fly-ash percentage, the alkalieash ratio and the water content. The carbon calculator recently developed by the European Federation of Foundation Contractors and the Deep Foundations Institute was used to quantify the CO2 (eq) emissions associated with this technique. The financial cost was estimated based on the experience of a major Portuguese contractor. For comparison purposes, soil cement mixtures were also analysed, using similar conditions and tools used for the soil-ash analysis. Results showed that the cement and ash solutions are very similar in terms of overall performance, with some advantage of the former regarding financial cost, and a significant advantage of the latter regarding the CO2 (eq) emissions. This new grout, although it is in an embryonic stage, it has the potential for broader developments in the field., Teixeira Duarte S.A., Pegop e Energia Electrica S.A.

The safety evaluation of structures comprises several factors to assess their condition state. However, the global safety of structures cannot be reached at all because there are many uncertainties sources. Due to all these uncertainties, the wisest way to deal with this problem is to assume all of these uncertainties as random variables and perform a reliability analysis, which is a probabilistic analysis, in order to obtain a reliability index that can give the structure condition. This paper presents the nonlinear analysis of an existent reinforced concrete railway bridge, with DIANA software. The developed model will be used in a probabilistic based approach in order to obtain a global reliability index, which is then compared with a threshold value in order to evaluate the bridge condition., (undefined)

Auxetic materials are a class of materials that expand transversely when stretched longitudinally. Recently, auxetic materials are gaining special interest in the technical sectors mainly due to their attractive mechanical behavior. This paper reports, for the first time, the development of auxetic structures from composite materials and the characterization of their auxetic as well as mechanical properties. Five different auxetic structures were developed varying their structural angle using core reinforced braided composite rods, containing glass fibers for axial reinforcement, polyester filaments for braided structure and epoxy resin as the matrix. Auxetic behavior of these structures was studied in a tensile testing machine using an image-based tracking method. Additionally, an analytical model was used to calculate Poisson’s ratio of these structures. According to experimental and analytical results, auxetic behavior and tensile characteristics of these structures were strongly dependant on their initial geometric configuration (i.e. structural angle). These novel auxetic structures exhibited Poisson’s ratio in the range of 0.30 to 5.20., The authors gratefully acknowledge the financial support for carrying out this research work from University of Minho, under the scheme of "Strategic plan of school of engineering - Agenda 2020: Multidisciplinary projects."

Identifying novel players of the pluripotency gene regulatory network centered on Oct4, Sox2, and Nanog as well as delineating the interactions within the complex network is key to understanding self-renewal and early cell fate commitment of embryonic stem cells (ESC). While overexpression of the transcriptional regulator Cited2 sustains ESC pluripotency, its role in ESC functions remains unclear. Here, we show that Cited2 is important for proliferation, survival, and self-renewal of mouse ESC. We position Cited2 within the pluripotency gene regulatory network by defining Nanog, Tbx3, and Klf4 as its direct targets. We also demonstrate that the defects caused by Cited2 depletion are, at least in part, rescued by Nanog constitutive expression. Finally, we demonstrate that Cited2 is required for and enhances reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells. Stem Cells 2015;33:699–712

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., This work was partially funded by project FP7-ENV-2009-1-244123-NIKER of the 7th Framework Program of the European Commission, which is gratefully acknowledged. Authors would like to thank the technical staff of the Structures Lab. of University of Minho for the assistance provided preparing and carrying out the tests and also, Monumenta, Ltd. for the construction of the masonry walls and Cintec (R) for the installation of the injection anchors.