Schist constructions represent an important cultural, architectural and historical legacy in Europe, and particularly in Portugal, that urges to preserve. Included among the traditional Portuguese architectural heritage, there are many traditional buildings in schist masonry, distributed from North to South, varying the types of buildings, the constructive methodologies and even the material schist, which may vary in properties and characteristics, depending on the region where it is extracted. Over the years, this traditional architecture has implemented a sustainable construction through the use of natural materials available in the region, as today it is desired to implement in the contemporary construction practice. The constructive techniques and solutions of these traditional structures have been developed in direct relation with various factors as economic, environmental and social, adapting to different requirements over the time, originating a wide diversity of construction typologies that today exist in Portugal. The present study intends to describe and characterize the different building typologies of the traditional schist construction in Portugal mainland. Examples of more prominent constructions, considering its dimensions and/or patrimonial importance are presented and analyzed.

Em intervenções sobre edifícios existentes, é da maior importância dispor de informação que represente, de forma fiável, tanto o sistema estrutural como as propriedades dos materiais. Tal é ainda mais relevante no caso dos edifícios cujos elementos resistentes verticais consistem em paredes de alvenaria de pedra, situação predominante nos núcleos urbanos antigos portugueses, devido quer à variabilidade das propriedades mecânicas desta tecnologia construtiva (devida não apenas às características dos seus componentes, mas também à forma como os mesmos são dispostos), quer à degradação que porventura tenham sofrido ao longo do tempo. No caso de edifícios inseridos em conjuntos urbanos de valor patrimonial, a realização de ensaios destrutivos é normalmente desaconselhável, impondo-se a realização de procedimentos semi- ou não-destrutivos que permitam obter, com o mínimo de dano possível, os dados a utilizar nos modelos de análise estrutural para aferição da segurança.No caso particular da cidade de Viseu, verifica-se a falta de informação relativa às propriedades mecânicas das paredes de alvenaria de pedra de granito presentes no seu núcleo antigo. Assim, com vista a informar intervenções de reabilitação estrutural que privilegiem a manutenção do sistema resistente original do edificado antigo corrente nesta zona, este trabalho pretende apresentar um primeiro contributo para a caracterização das propriedades mecânicas destes elementos estruturais.A campanha desenvolvida compreendeu a observação visual do alçado, a realização de ensaios de macacos planos, a observação da secção transversal e a caracterização mecânica da pedra empregue.Numa fase posterior, procede-se a uma recolha crítica da informação disponível na literatura relativa à caracterização mecânica de alvenarias de pedra, de diferentes tipologias, para a realidade portuguesa. Pretende-se assim apresentar uma primeira proposta de valores de referência a considerar, como primeira aproximação, na modelação numérica, avaliação da segurança ou projeto de reforço de construções antigas de alvenaria de pedra, para a realidade nacional.

A evolução das técnicas de projeto e execução de obra permitiu, regra geral, melhorias nas construções. Apesar disto, trouxe também o aparecimento de algumas patologias que provocam desgaste e redução de desempenho dos edifícios. As paredes de alvenaria sem função estrutural são aquelas onde mais se evidencia esta problemática. O esquecimento sucessivo, em fase de projeto, da relevância que as paredes possuem nos edifícios provoca o aparecimento de diferentes patologias ao longo da vida útil dos mesmos. Os movimentos de expansão e contração dos materiais constituintes das paredes de alvenaria, em particular os movimentos das argamassas de assentamento e dos tijolos cerâmicos, conduzem, com frequência a situações de grave fissuração. Estas surgem muitas vezes de forma inesperada e a sua reabilitação apresenta elevados custos e grandes dificuldades tecnológicas, para além das repercussões arquitetónicas. Nesta dissertação, pretendeu-se, numa primeira fase, sistematizar a informação mais relevante neste domínio, na perspetiva do apoio ao projeto de paredes de alvenaria não estruturais. De seguida procedeu-se à caracterização de uma parede específica em tijolo face à vista, em termos de movimentos naturais, e à avaliação, com recurso a ferramentas numéricas elementares, do seu efeito, em termos de tensões e potencial risco de fissuração. Isto foi conseguido através da simulação de modelos de paredes de alvenaria, com recurso ao programa Autodesk Robot Structural Analysis, com diferentes disposições de juntas de dilatação e com variações geométricas pontuais. Estes modelos foram sujeitos a variações de temperatura e de humidade. Foi ainda adotado um caso de estudo de um edifício que evidenciou alguns problemas de fissuração em fase de construção.

The use of lime as a binder in masonry lining mortars plays an important role in its conservation and durability. Knowledge of the mechanical characteristics of pre-existing and restoration mortars is essential in order to guarantee the compatibility between them and for avoiding the appearance of pathologies. The paper mainly focuses on the study of the mechanical performance of lime-based mortars to be applied in rehabilitation works in old buildings. Four types of mortars were tested with very similar workability, based on lime putty, aerial lime, and hydraulic lime. Sand and crushed rock powder were used as aggregates. Compressive and flexural strengths of the mortars were determined, as well as their ultrasonic pulse velocity. Furthermore, specific tests were carried out to characterize the performance of the mortar when used as a binder for plasters and coatings, such as the development of cracking, superficial water absorption under low pressure, and pull-off strength. According to the results obtained, mortars with lime putty showed better mechanical properties, while those with aerial lime had better behavior regarding water absorption under pressure. Despite that, it was generally possible to verify the adequacy of the studied mortars to be used in the rehabilitation of masonry elements.

Coatings and plasters are an integral part of masonry cladding, having a fundamental protective and aesthetic function. They are exposed to numerous aggressive actions, which produce their degradation over time. The utilization of lime, as a binder in masonry lining mortars, plays an important role in their durability and conservation. The objective of this work is to analyze the fresh and durability properties of lime-based mortars for their application in the restoration of old buildings. Four different kinds of mortars were studied with similar workability, using as binders lime putty, aerial lime, and hydraulic lime. The aggregates used consisted of sand and crushed rock powder. As fresh properties, the consistency (by using the flow table) and water retentivity were determined. With respect to durability-related properties, water absorption by capillarity and by immersion, drying kinetics, and carbonation depth were studied. Bulk density and porosity of the mortars were also obtained. Mortars with lime putty showed higher global porosity and water absorption by immersion, while aerial lime mortars presented lower porosity and higher water absorption by capillarity. Finally, the durability performance of all the studied lime mortars was overall adequate for being applied as masonry coatings in the restoration of old buildings.

The methodology presented in this work combines the theoretical framework developed for the dynamics of coupled rigid elements with the characteristics of rocking motion, in order to reproduce the behaviour of blocky masonry structures un der seismic actions. As an application, a closed kinematic chain structure is analysed for the case of harmonic forcing.

Although many experimental tests and numerical models are available in the literature, the numerical simulation of the seismic response of existing masonry buildings is still a challenging problem. While the nonlinear behavior of masonry structures is reasonably predictable when the out-of-plane behavior can be considered inhibited, when the in-plane and out-of-plane responses coexist and interact, simplified models seem unable to provide reliable numerical predictions. In this article, taking advantage of the experimental tests carried out in a shaking table on two masonry prototypes at LNEC, a macro-element approach is applied for the numerical simulations of their nonlinear response. The adopted approach allows simulating the nonlinear behavior of masonry structures considering the in-plane and out-of-plane responses. Since it is based on a simple mechanical scheme, explicitly oriented to representing the main failure mechanisms of masonry, its computational cost is greatly reduced with respect to rigorous solutions, namely nonlinear FEM approaches. Two modeling strategies are adopted, namely a regular mesh independent from the real texture of the prototypes and a detailed one coherent with the units disposal. The numerical results are discussed and the correlation between the nonlinear static analyses and the dynamic response is provided.

Flat-jack testing is a widely used non-destructive test method to determine mechanical properties of historical masonry during inspection and diagnosis. This method can give valuable quantitative results for the local stress within a masonry element and deformability of the masonry; however, several issues arise when testing irregular and multi-leaf masonry elements leading to inaccurate or unusable results. A previous study by the authors discussed the limitations of flat-jack testing and proposed a new enhanced test system consisting of tube-jacks instead of flat-jacks in order to overcome the difficulties related to the flat-jack method. FE models used to simulate the difference between the conventional flat-jack method and the new tube-jack method revealed the simulated tube-jack tests provided reliable measurements for the stress state within the masonry and a more even stress distribution, reducing possible damage to the structure. The development of the tube-jack prototype system and its preliminary laboratory testing are presented in this paper. Tube-jack tests were performed in mortar joints of simple masonry specimens loaded in compression. Finally, further research steps and improvements to the method are presented.