Papers

This paper is focused on the study of an earthquake protection system, the tuned liquid damper (TLD), which can, if adequately designed, reduce earthquake demands on buildings. This positive effect is accomplished taking into account the oscillation of the free surface of a fluid inside a tank (sloshing). The behaviour of an isolated TLD, subjected to a sinusoidal excitation at its base, with different displacement amplitudes, was studied by finite element analysis. The efficiency of the TLD in improving the seismic response of an existing building, representative of modern architecture buildings in southern European countries was also evaluated based on linear dynamic analyses.

In railway lines, transition zones between different track support conditions normally evidence higher degradation rates,thus requiring additional maintenance to ensure safety and service quality. Studies based on numerical simulations indicatethat under sleeper pads (USP) can minimise those degradation rates. The study presented herein focuses on the in

The employment of non-traditional materials such as soil

The employment of nontraditional materials such as soil-rock mixtures, for economic and environmental reasons, in the construction of earthworks poses some new challenges for compaction techniques and their control, and for the determination of the embankment characteristics that result from the compaction method. Those characteristics experience important changes according to the relative percentages of the existing fractions. Usually, this kind of material results from bulky rock extraction without explosives, and it can include some large-size particles (greater than 0.5 m). In addition, the measured deformations associated with these materials have been larger than expected. For the execution control of the soil-rock mixtures from the Odelouca dam borrow areas, a series of vibratory and standard compactation tests was performed to estimate reference values for the maximum dry density and optimum water content of these materials, and a new methodology was proposed. The Odelouca dam is a zoned embankment dam, 76-m high, with clayey soil in the core and weathered shist with a significant fraction of oversized particles in the shells. This paper presents the results of the compaction control in addition to the dam performance during the construction and first filling phases as a validation of implemented construction procedures. DOI: 10.1061/(ASCE)C0.1943-7862.0000864. O 2014 American Society of Civil Engineers.

This paper presents a thermal simulation validation study of the typical precision that a trained thermal simulation engineer can expect to obtain for the simulation of a room connected to a naturally ventilated double skin facade. The open source building thermal simulation tool EnergyPlus is used to predict air and surface temperatures in a free running weather exposed test cell. The validation approach used does not allow for fine tuning the simulation model by trial and error and includes a sensitivity analysis on the impact of different simulation options such as: number of thermal zones, ground heat transfer and accuracy of solar radiation data. The analysis of the results is consistent with the engineering application goal by focusing on standard indicators: average error, bias and difference between predicted and measured daily maximums. The results show good agreement between simulation and experiment, with an average simulation error in air and radiant temperature of1.4"C and an average daily maximum error of 2.5oC,

The variation of wood density and mechanical properties with site, tree and within tree (longitudinal and radial) were studied for blackwood (Acacia melanoxylon R. Br.) grown in four sites in Portugal. Twenty trees were randomly selected (40 cm dbh class, 33

Vehicle trajectory descriptions are required for the development of driving behaviour models and in the calibration of several traffic simulation applications. In recent years, the progress in aerial sensing technologies and image processing algorithms allowed for easier collection of such detailed traffic datasets and multiple-object tracking based on constrained flow optimization has been shown to produce very satisfactory results, even in high density traffic situations. This method uses individual image features collected for each candidate vehicle as criteria in the optimization process. When dealing with poor image quality or low ground sampling distances, feature-based optimization may produce unreal trajectories.In this paper we extend the application of the k-shortest paths algorithm for multiple-object tracking to the motion-based optimization. A graph of possible connections between successive candidate positions was built using a first level criteria based on speeds. Dual graphs were built to account for acceleration-based and acceleration variation-based criteria. With this framework both longitudinal and lateral motion-based criteria are contemplated in the optimization process. The k-shortest disjoints paths algorithm was then used to determine the optimal set of trajectories (paths) on the constructed graph.The proposed algorithm was successfully applied to a vehicle positions dataset, collected through aerial remote sensing on a Portuguese suburban motorway. Besides the importance of a new trajectory dataset that will allow for the estimation of new behavioural models and the validation of existing ones, the motion-based multiple-vehicle tracking algorithm allowed for a fast and effective processing using a simple optimization formulation.

Faz cerca de um ano que publicamos um texto sobre os princípios da ventilação e da qualidade do ar nas habitações. Neste texto apresenta-se um resumo sobre o enquadramento regulamentar da ventilação nos edifícios de comércio e serviços, que segue os princípios de: i) prevenção das emissões, ii) extrações locais quando aplicável e hierarquia de pressões para evitar a dispersão de poluentes, iii) remoção dos poluentes pela renovação do ar. 0 princípio da prevenção das emissões encontra-se consubstanciado por legislação diversa, nomeadamente pela lei do tabaco, dos aparelhos de combustão e do regulamento dos produtos da construção. Foi mantido o incentivo para a utilização de materiais de construção com baixas emissões para o ar interior. Para limitar problemas de qualidade do ar interior, nesta versão do regulamento foi introduzida a necessidade de extração mecânica de ar em locais com fortes odores ou de geração de vapor de água, nomeadamente nas instalações sanitárias. Encontra-se preconizado o princípio de uma hierarquia de pressões dos espaços, através de exaustão de ar nos locais mais poluídos.

Uma das grandes opções de viver o habitar