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Abstract(s)
Os muros de suporte em alvenaria de pedra em junta seca são das mais antigas estruturas de engenharia civil, adequadas para aplicações que vão desde simples muros de vedação a grandes estruturas de suporte do solo com vários metros de altura. Por exemplo, os socalcos realizados para cultivar terrenos nas encostas, de que a região do Alto Douro é paradigma, exigiram desde tempos muito remotos a construção de muros de suporte em alvenaria de junta seca. A técnica depende da habilidade do pedreiro em selecionar e posicionar cada pedra apropriadamente.
A integridade estrutural é mantida por meio do peso próprio e do atrito nas interligações dos blocos de rocha, definindo um comportamento diferente do das estruturas de betão. Outra especificidade reside na falta de regulamentação para o projeto dos muros de suporte em alvenaria de junta seca.
Neste contexto, a presente dissertação pretende contribuir para melhorar o conhecimento sobre o comportamento estrutural dos muros de alvenaria de junta seca, em particular dos muros de suporte em alvenaria de granito em junta seca. Para concretizar este objetivo, foi realizado um ensaio em modelo reduzido, recriando os modos de rotura frequentemente observados em muros gravidade. A análise da estabilidade, no âmbito do dimensionamento estrutural segundo o método dos estados limites previstos nas normas europeias, foi realizada tendo por base os modelos de cálculo para os muros gravidade e com recurso a uma metodologia baseada no conceito de linha de pressões.
O presente estudo evidencia uma das principais causas de danos e deformação dos muros de alvenaria de junta seca, que é o carregamento excêntrico da fundação da própria estrutura geotécnica, seja devido à distribuição desuniforme da carga (muro e aterro) ou a sobrecarga no tardoz do muro. Da análise da estabilidade verifica-se que existe segurança dos muros de suporte em alvenaria de granito de junta seca, concebidos segundo orientações gerais decorrentes da experiência aprimorada de geração em geração. Porém, a análise não considera a interação entre o peso da estrutura geotécnica e o impulso nas diversas secções do muro, a qual é determinante para um melhor dimensionamento.
Dry-stone retaining walls are amongst the oldest civil engineering structures which are suitable for applications ranging from simple field walls to large earth-retaining structures with several meters in height. It’s example, the terraces built to cultivate terrain on the slopes which are paradigm of the Alto Douro region, have required since the earliest times the construction of dry-stone retaining walls. This technique relies upon the skill of the mason’s skill in selecting and positioning each stone appropriately. The structural integrity is maintained by the self-weight and interblock friction between stone blocks, defining a different behaviour compared to the concrete structures. Other spec lies in the lack of regulation for their design. In this context, the present thesis intends to contribute to improve the knowledge about the structural behavior of dry-stone masonry walls, particular the granite ones. To achieve this objective, a small-scale model test was carried out, recreating the failure modes frequently observed in gravity walls. The stability analysis, in the context of the structural design according to the limit states method established in the European codes, was carried out based on calculation models for the gravity walls and using a methodology based on the concept of thrust line. The current research highlights one of the main causes of damage and deformation within dry-stone walls, which is the eccentric loading of the foundation of the geotechnical structure itself, either from the non-uniform distribution of the load (wall and the embankment) or the surcharge behind the wall. From the stability analysis, it is verified that there is safety of the granite dry-stone walls, designed according to general orientations arising from the improved experience generation after generation. However, the analysis does not consider the interaction between the geotechnical structure’s weight and the earth pressure in the various wall’s sections, which is determinant for a better design.
Dry-stone retaining walls are amongst the oldest civil engineering structures which are suitable for applications ranging from simple field walls to large earth-retaining structures with several meters in height. It’s example, the terraces built to cultivate terrain on the slopes which are paradigm of the Alto Douro region, have required since the earliest times the construction of dry-stone retaining walls. This technique relies upon the skill of the mason’s skill in selecting and positioning each stone appropriately. The structural integrity is maintained by the self-weight and interblock friction between stone blocks, defining a different behaviour compared to the concrete structures. Other spec lies in the lack of regulation for their design. In this context, the present thesis intends to contribute to improve the knowledge about the structural behavior of dry-stone masonry walls, particular the granite ones. To achieve this objective, a small-scale model test was carried out, recreating the failure modes frequently observed in gravity walls. The stability analysis, in the context of the structural design according to the limit states method established in the European codes, was carried out based on calculation models for the gravity walls and using a methodology based on the concept of thrust line. The current research highlights one of the main causes of damage and deformation within dry-stone walls, which is the eccentric loading of the foundation of the geotechnical structure itself, either from the non-uniform distribution of the load (wall and the embankment) or the surcharge behind the wall. From the stability analysis, it is verified that there is safety of the granite dry-stone walls, designed according to general orientations arising from the improved experience generation after generation. However, the analysis does not consider the interaction between the geotechnical structure’s weight and the earth pressure in the various wall’s sections, which is determinant for a better design.
Description
Keywords
Alvenaria de Junta Seca Análise da Estabilidade Dimensionamento Ensaios Experimentais Linha de Pressões Modelo Reduzido 2d Muros de Suporte