Artigos de Revista

Depois de uma apresentação geral do estudo, em desenvolvimento no LNEC, intitulado

No artigo desenvolve-se uma reflexão introdutória ao que se julga ser a oportunidade atual de se repensarem os espaços exteriores privados numa perspetiva que alia a estimulante relação do espaço exterior privado com o restante espaço doméstico à igualmente estimulante e afirmada integração da natureza nos edifícios. Numa segunda parte do artigo avança-se em tipologias habitacionais marcadas por espaços exteriores privados, desenvolvendo-se um pouco, em seguida, e sequencialmente, a relação entre acessos e espaços exteriores privados, a importante relação entre exterior privado, adequação climática e sustentabilidade ambiental doméstica e as associações preferenciais entre espaços domésticos interiores e exteriores.

No artigo aborda-se o objetivo

Cities face unprecedented demographic, environmental, economic, social, and spatial challenges. In recent years, the implementation of nature-based solutions (NBS) is becoming more relevant in cities to improve urban resilience and to cope with climate change. NBS represent cost effective solutions that simultaneously provide environmental, social, and economic benefits and help build resilience.

As construções antigas fazem parte do tecido histórico das cidades, pelo que é importante proceder a intervenções de reabilitação eficientes, mas não destruidoras da sua identidade e valor cultural intrínseco. A utilização de rebocos armados apresenta-se como uma solução simples e eficaz no reforço sísmico deste tipo de construções, nos casos em que não é possível ou exigível a preservação dos revestimentos de paredes. Neste artigo, são analisadas várias composições de rebocos armados, constituídos por ligantes à base de cal aérea, cal hidráulica ou cimento, com um traço usual e com armaduras constituídas por redes metálicas, redes de fibra de vidro e uma rede de fibra natural. É analisada a capacidade resistente à tração dessesrevestimentos armados, assim como aspetos que podem influenciar a compatibilidade com os materiais existentes, apresentando-se as principais vantagens e desvantagens dos vários tipos de revestimentos.

Shallow geothermal energy systems (SGES) may take different forms and have recently taken considerable attention due to energy geo-structures (EGS) resulting from the integration of heat exchange elements in geotechnical structures. Still, there is a lack of systematic design guidelines of SGES. Hence, in order to contribute towards that direction, the current study aims at reviewing the available SGES modeling options along with their various aspects and practices. This is done by first presenting the main analytical and numerical models and methods related to the thermal behavior of SGES. Then, the most important supplementary factors affecting such modeling are discussed. These include: (i) the boundary conditions, in the form of temperature variation or heat flow, that majorly affect the predicted thermal behavior of SGES; (ii) the spatial dimensions that may be crucial when relaxing the infinite length assumption for short heat exchangers such as energy piles (EP); (iii) the determination of SGES parameters that may need employing specific techniques to overcome practical difficulties; (iv) a short-term vs. long-term analysis depending on the thermal storage characteristics of GHE of different sizes; (v) the influence of groundwater that can have a moderating effect on fluid temperatures in both heating and cooling modes. Subsequently, thermo-mechanical interactions modeling issues are addressed that may be crucial in EGS that exhibit a dual functioning of heat exchangers and structural elements. Finally, a quite lengthy overview of the main software tools related to thermal and thermo-hydro-mechanical analysis of SGES that may be useful for practical applications is given. A unified software package incorporating all related features of all SGES may be a future aim.

The collapse of bridges inevitably leads to economical losses and may also be responsible for human fatalities. A bridge may fail due to several reasons, with local scouring around its foundation being the most common. Despite decades of scouring research, there are still many uncertainties affecting the design process of bridge piers. The most critical and least explored are the hydrological and hydraulic variables. The recent intensification of floods may also increase the vulnerability of bridges to scour effects. Therefore, the present work aims to propose a risk-based methodology for considering scour at bridge foundations. It is composed of three main steps: (i) assessing extreme hydrological events (hazards); (ii) modeling river behavior through the computation of flow characteristics and bridge scour depths; and (iii) assessing bridge scour risk by associating its scour depth to foundation depth ratio with the priority factor (vulnerability) and assigning a qualitative evaluation of the scour risk rating (level of risk). The hydrological modeling incorporates uncertainty with an averaging approach in the design floods definition. The flow characteristics are simulated with the HEC-RAS model, which also contains a scour module for bridge scour assessment. However, other empirical estimates are considered for simple and pile-supported foundations. This study ends with a qualitative assessment of how the scouring phenomenon affects bridge vulnerability and its safety. The proposed risk-based methodology - validated through a case study, the new Hintze Ribeiro bridge in Portugal - can be potentially incorporated into regular bridge inspection schedules as a useful tool for risk management measures, assisting in catastrophic events

Nowadays, the management and safety control of large dams is generally based on automatic monitoring, including the socalledseismic and structural health monitoring systems (SSHM), using the latest technology for automatic data measurement,acquisition and transmission. These systems should include software for automatic management and analysis of continuousmonitoring data and software for numerical simulation of the dam dynamic behavior using 3D finite element models. Thissoftware should be designed to provide useful and reliable information to meet the needs and expectations of stakeholders,and to support the studies of researchers and engineers responsible for structural health monitoring. This paper is focusedon the experience gathered from the SSHM system of Cabril dam, a 132 m high-arch dam, in Portugal, that has been undercontinuous dynamic monitoring since 2008. The importance of the software specifically developed for automatic modalidentification, automatic detection of seismic vibrations (distinct from vibrations due to the operation of discharge gates andpower groups), and automatic comparison between experimental data and computed results from a reference finite elementmodel of the dam-reservoir-foundation system, is highlighted. This software includes: (1) the generation of graphics withthe evolution of the identified natural frequencies over time and the comparison with calculated frequencies using differenthypothesis for concrete damage evolution; and (2) a service to automatically send emails summarizing key dynamic monitoringresults to stakeholders to provide the necessary support for informed management and engineering decision making.The main results from SSHM of Cabril dam are presented, namely regarding the evolution of modal parameter over time,considering the influence of water level variations, and the measured response during an earthquake event.

Sewer asset management gained momentum and importance in recent years due to economic considerations, since infrastructure maintenance and rehabilitation directly represent major investments. Because physical urban water infrastructure has life expectancies of up to 100 years or more, contemporary urban drainage systems are strongly influenced by historical decisions and implementations. The current decisions taken in sewer asset management will, therefore, have a long-lasting impact on the functionality and quality of future services provided by these networks. These decisions can be supported by different approaches ranging from various inspection techniques, deterioration models to assess the probability of failure or the technical service life, to sophisticated decision support systems crossing boundaries to other urban infrastructure. This paper presents the state of the art in sewer asset management in its manifold facets spanning a wide field of research and highlights existing research gaps while giving an outlook on future developments and research areas.