Artigos de Revista

A set of scale-model tests carried out to enlarge the range of wave steepness values analysed in run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a gentler slope breakwater’s trunk armour and roundhead, is presented in this paper. A stretch of a rubble mound breakwater (head and part of the adjoining trunk, with a slope of 1(V):2(H)) was built in a wave basin at the Leibniz University Hannover to assess, under extreme wave conditions (wave steepness of 0.055) with different incident wave angles (from 40º to 90º), the structure behaviour in what concerns wave run-up, wave overtopping and damage progression of the armour layer. Two types of armour elements (rock and Antifer cubes) were tested. Non-intrusive methodologies including a new application of laser scanning technique for the assessment of both armour layer damage and wave run-up and overtopping were used. It is expected that such work will contribute also with data to improve empirical formulas as well as to validate complex numerical model for wave-structure interaction.

Masonry arch bridges form a significant portion of the European transport infrastructure network. Many of these bridges are relatively old but still in service. Increasing vehicle loads and speeds have highlighted the need for reliable estimates of their service condition. Past research demonstrated that load-carrying capacity of a masonry arch bridge is a function of the soil response. However, today, the approaches used for the simulation of soil in masonry arch bridges are over-simplistic and most of them do not take into account the soil-structure interaction phenomena. This paper presents a novel modelling approach, based on the discrete element method, for the simulation of backfill material in masonry arch bridges. According to the method, bricks in the barrel vault are simulated as an assembly of distinct blocks separated by zero thickness interfaces at each mortar joint. Backfill is represented as an assemblage of densely packed discrete irregular deformable particles, here called ‘‘inner-backfill particles”. A series of computational models were developed and their results are compared against full-scale experimental test results. A good agreement between the experimental and the numerical results was obtained which demonstrates the huge potential of this novel modelling approach. One of the major advantages of the proposed approach is its ability to simulate the initiation and propagation of cracking in the backfill and arch ring with the application of the external load. It is envisaged that the current modelling approach can be used by bridge assessment engineers for understanding soil pressures and load distribution on the backfill and arch ring and thus develop serviceability criteria for masonry arch bridges of their care.

Mechanical constraints have a non-negligible influence in the motion of oscillating wave surge converter (OWSC) devices. The key novelty of this paper is a numerical simulation tool for OWSCs that does not neglect or significantly compromise mechanical constraints such as hydraulic power take-off (PTO) system, revolute joints and frictional contacts among components. The paper is aimed at presenting the key components of the numerical simulation tool and at validating it with laboratory data featuring an OWSC with mechanical constraints under regular and irregular waves. It is based on the implementation of the multibody solver of Project Chrono under the Smoothed Particle Hydrodynamics (SPH) model of DualSPHysics, where the SPH solver resolves the interaction between wave and flap and the multibody solver resolves the interaction between flap and mechanical constraints. Comparison between numerical results and experimental data show that the numerical simulation tool properly predicts the dynamics of the OWSC. Furthermore, in what concerns hydrodynamics of the near-flap flow, the computed and measured free-surface elevations and phase-averaged flow field show reasonable agreement. Once properly validated, the numerical simulation tool is then applied to study the influence of several mechanical constraints, PTO damping characteristics and flap inertia on the hydrodynamic of the OWSC. The viability of OWSC design solutions based on the developed numerical simulation tool is emphasised, in view of its performance in the test cases to which it was subjected.

Knowledge of forces due to the action of waves on submarine outfalls composed by a pipe and stabilizing concrete weights, considering the wave propagation direction to the outfalls, is essential to their design. 3D numerical models based on RANS-VoF (Reynolds-Average-Navier-Stokes Volume-of-Fluid) are able to estimate forces on the pipe and weights. The present study aims to simulate a submarine outfall with stabilizing concrete weights at 1:15 scale which was previously tested in the 3D Shallow Water Basin at the Danish Hydraulics Institute (DHI) to analyse the influence of the direction of the incident wave and the distance from the pipe to the bottom on the outfall forces. In this study, numerical results are compared with experimental ones for waves with four different amplitudes and with wave incidence perpendicular to the outfall. The use of k-? SST turbulence model led to good agreement between numerical drag and lift forces and experimental ones, with a mean difference of 8.9 and 7.6%, respectively.

No presente artigo aborda-se a relação entre o interior doméstico e os respectivos vãos de janela, considerados estes vãos como importantes elementos de construção, acabamento, e qualidade arquitectónica do interior doméstico. Inicia-se a reflexão com a consideração das janelas como elementos de composição dos alçados/volumetrias, mas também como elementos multifuncionais e de composição do interior doméstico; desenvolve-se, depois, a temática das janelas domésticas como elementos de composição dos alçados/volumetrias; seguem-se alguns comentários sobre a multifuncionalidade das janelas domésticas; e conclui-se com uma reflexão sobre as janelas como elementos específicos de composição do interior doméstico.

This paper is built around a research project developed with the support of the Regional Planning Authority of the Algarve Region in Portugal which assessed mobility patterns covering all modes of transport using heterogeneous data sources (time-series data). Data mining techniques helped to identify limitations in some data sets. The econometric analysis showed that integrated autoregressive models and moving averages for series with seasonality were successful in the prediction of passenger flows using time-series data gathered by the regional authority from transport operators and other entities. Results from the analysis are useful to support a strategy to reverse current trends on continued car growth (along with public transport decrease) and to devise policy measures to enable a sustainable mobility path towards decarbonisation and social equity goals until 2030.

O risco refere-se à probabilidade de ocorrerem danos causados pela manifestação de um determinado perigo, sendo função da perigosidade, da exposição (de pessoas e bens) e da vulnerabilidade dos elementos expostos face a esse perigo.Um componente essencial da avaliação do risco è a análise da perigosidade associada aos perigos identificados num dado território, sejam de origem natural ou decorrentes da ação humana. Outro componente essencial é a análise dos elementos (pessoas e bens) expostos aos perigos, bem como as características que contribuem para a suavulnerabilidade - ou a sua resiliência em situação de acidente grave ou de catástrofe. Nesta comunicação dá-se conta de alguns estudos desenvolvidos pelo LNEC nos domínios da avaliação da perigosidade e da vulnerabilidade sísmica das construções, da perigosidade de agitação costeira e risco de galgamentos costeiros e da avaliação da vulnerabilidade de edifícios aos incêndios florestais.

A reflexão discute e propõe uma abordagem do ato de caminhar como método integrado e interdisciplinar para captar a experiência territorial das pessoas e, no campo do urbanismo, perspetivar a cidade. Atenta aos amplos benefícios do uso caminhado da cidade, às virtualidades do incrementar espaços caminháveis, ao caminhar como ato de resistência e assimilação estético-sensorial da cidade, o objetivo aqui é, todavia, abordar o caminhar como recurso metodológico de apreensão compreensiva, cocriativa e mais responsiva da cidade. A acuidade do caminhar advém aqui, por um lado, de um percurso etnográfico de investigação que, por outro lado, tem colaborado para insinuar sobre o interesse de uma maior ingerência didático-pedagógico que, em defesa de que se caminhe mais antes de intervir na cidade, assuma efetivamente o caminhar como um potencial método cocriativo do captar e fazer o espaço urbano.

Abstract: Controlling air quality is of the utmost importance within today's buildings. Vertical air curtains are often used to separate two different climatic zones in order to reduce heat transfer. This research work proposes an air curtain aimed to ensure a proper separation between two zones, a clean one and a contaminated one, which is to be used together with an air extraction from the ?contaminated? compartment. A CFD parametric study was carried out in order to assess the optimal parameters for achieving the aerodynamic sealing of the air curtain. The software OpenFOAM was used to carry out the simulations. This paper presents the numerical validation of the computational fluid dynamics model for contaminant control applications and the final simulation results. Furthermore, it refers to the test results obtained in the framework of previous research, which were obtained in both small scale and full size testing, and demonstrates that the simulation results are coherent with the experiments. This research work shows that, when properly implemented, the air curtains provide the adequate aerodynamic sealing to maintain the air contaminants within the ?contaminated? compartment. The appropriate performance can be obtained for nozzle speeds as low as 1 m/s and for a nozzle thickness of 10 mm. The best performance is obtained when the extraction flowrate of the ?contaminated? compartment corresponds to the total flowrate entrained by the air curtain from the ?non-contaminated? side.