Papers
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Papers
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Evaluation of Energy efficient Refurbishment of Residential Buildings in Southern Europe Based on the Cost-optimal Methodology
In line with the European Energy Performance of Building Directive (EPBD), this paper aims to calculate thecost-optimal energy performance of a residential building in southern Europe, more precisely in Portugal,taking into consideration thermal and lighting (daylighting and artificial lighting) refurbishment solutions. Theeconomic calculation method used considers the initial investment costs, the running costs (including annualmaintenance costs, operational costs, energy costs and periodic replacement costs), greenhouse gas emissionscosts and disposal costs. The results obtained for the energy needs allow choosing the cost-optimal package ofrefurbishment measures. It is shown in this paper the relevance of daylighting and artificial lighting solutionsfor the users
Year: 2024
Number Pages:
66023-66031pp..
Author(s): Brandão de Vasconcelos, A; Santos, A.; Cabaço, A.
: International Journal of Development Research
Editor: IJDR
Volume:
Volume 14, assunto 6.
Keywords: Artificial lighting; Daylighting; Energy efficiency; Cost-optimal; Refurbishment
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Experimental investigation of wave severity and mooring pretension on the operability of a moored tanker in a port terminal
This paper investigates the influence of sea severity and mooring line pretension configuration on the operabilityof a moored vessel at a modified berthing site inside a port. A physical model was constructed to replicate thenew layout of the port of Leix
Year: 2024
Author(s): Abdelwahab, H.S.; Pinheiro, L.; Santos, J. A.; Fortes, C. J. E. M.; Guedes Soares, C.
: Ocean Engineering
Editor: Elsevier
Volume:
291 (2024) 116243.
Keywords: Mooring pretension; Moored ship; Ship motions; Port downtime; Ship operability; Physical modelling
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Experimental study of an onshore dual chamber oscillating water column device
A wave flume is used to study a scaled model of a stepped bottom dual-chamber Oscillating Water Column (OWC) installed onshore. Compared to traditional single-chamber OWCs, the use of dual-chambers is expected to widen the range of sea states in which the OWC is more efficient, and the step, in front of the first chamber, boosts the capturing energy capacity of the device. The Power Take-Off (PTO) system is modelled as an air opening in the pneumatic chambers. Several experiments combining regular incident waves and PTO damping conditions are performed. Results of the amplitudes of the free surface elevations inside the chambers show that the device can amplify the incident wave amplitude up to 1.57 times in chamber 2. Results of the primary efficiency show that the device is highly dependent on the PTO damping characteristics and can reach around 40% for a wide range of wave periods. Results of the reflection analysis show that the reflection coefficient is also dependent on the PTO damping characteristics but remain lower than 0.6 for all the studied cases. Sloshing phenomenon (mostly in the cross-section direction) was observed for a wavelength close to the cross-section dimension, impacting negatively on the device pneumatic performance.
Year: 2024
Number Pages:
16p..
Author(s): Gadelho, J.; REZANEJAD, K.; Guedes Soares, C.; Santos, J. A.; Anastas, G.; Fortes, C. J. E. M.
: Ocean Engineering
Editor: Elsevier
Volume:
Volume 300 (117240).
Keywords: Reflection coefficients; Efficiency improvement; Breakwater; Experiments; Oscillating water column
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Experimental study on drag coefficient of flexible vegetation under non-breaking waves
Laboratory experiments of wave propagation over rigid and flexible vegetation fields, with the same configurations, were conducted to understand the effect of vegetation flexibility on the drag coefficient (CD). The direct method and the least squares method (LSM), based on force and flow measurements, are applied to calculate the CD in the experimental conditions. The formulations of both methods are extended to estimate the CD for flexible vegetation cases. A video analysis was performed to account for the swaying motion. Typically, wave dissipation is lower for flexible than for rigid vegetation of the same configuration, under the same flow condition. Therefore, a proportional effect in the corresponding CD results, obtained from common CD calibration to wave dissipation without considering vegetation motion, is usually observed. However, the present results show that although the wave dissipation was 34% lower for flexible relative to rigid vegetation, the respective CD values were close. CD estimations considering vegetation motion and inertia suggest that CD of flexible vegetation was up to 13% higher relative to rigid vegetation. Accounting for inertia reduced the CD for rigid vegetation up to 7%, while raised the CD for flexible vegetation up to 13%.
Year: 2024
Number Pages:
14p..
Author(s): Reis, R.; Fortes, C. J. E. M.; Rodrigues, J.; HU, Z.; Suzuki , T.
: Ocean Engineering
Editor: Elsevier
Volume:
Volume 296.
Keywords: Wave dissipation; Inertia; Vegetation motion; Flexible vegetation; Drag coefficient
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Exploring the Cyclic Behaviour of URM Walls with and without Damp-Proof Course (DPC) Membranes through Discrete Element Method
The unreinforced masonry (URM) walls are the common load-bearing structural elements in most existing buildings, consisting of masonry units (bricks) and mortar joints. They indicate a highly nonlinear and complex behaviour when subjected to combined compression-shear load-ing influenced by different factors, such as pre-compression load and boundary conditions, among many others, which makes predicting their structural response challenging. To this end, the present study offers a discontinuum-based modelling strategy based on the discrete element method (DEM) to investigate the in-plane cyclic response of URM panels under different vertical pressures with and without a damp-proof course (DPC) membrane. The adopted modelling strategy represents URM walls as a group of discrete rigid block systems interacting along their boundaries through the contact points. A novel contact constitutive model addressing the elasto-softening stress-displacement behaviour of unit-mortar interfaces and the associated stiffness degradation in tension-compression regimes is adopted within the implemented discontinuum-based modelling framework. The proposed modelling strategy is validated by comparing a re-cent experimental campaign where the essential data regarding geometrical features, material properties and loading histories are obtained. The results show that while the proposed compu-tational modelling strategy can accurately capture the hysteric response of URM walls without the DPC membrane, it may underestimate the load-carrying capacity for URM walls with the DPC membrane.
Year: 2024
Author(s): Pulatsu, B.; Wilson, R.; Lemos, J. V.; Mojsilovic. N.
: Infrastructures
Editor: MDPI
Volume:
9(1), 11.
Keywords: Unreinforced masonry
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Exploring Wave
Aquatic vegetation in the littoral zone plays a crucial role in attenuating wave energy andprotecting coastal communities from hazardous events. This study contributes to the developmentof numerical models aimed at designing nature-based coastal defense systems. Specifically, a novelnumerical application for simulating wave
Year: 2024
Author(s): El Rahi, J.; Martinez-Estevez, I.; Reis, R.; Tagliafierro, B.; Dominguez, J.M.; Crespo, A.J.C.; Stratigaki, V.; Suzuki, T.; Troch, P.
Editor: MDPI
Keywords: Project chrono; DualSPHysics; SPH-FEA coupling; Fluid
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Fichas de rendimento e preços de soluções de reforço estrutural de elementos de betão armado
As fichas de rendimento de operações de construção, contendo informação sobre os recursos, os rendimentos e os preços unitários das atividades, assumem um papel importante no planeamento económico da construção. No caso particular das soluções de reforço de elementos de betão armado, não existem, até à data, fichas de rendimento para esse tipo de operações. Neste sentido, foi realizado um estágio profissional para a Ordem dos Engenheiros, no Laboratório Nacional de Engenharia Civil (LNEC), tendo em vista a elaboração de fichas de rendimento para diferentes soluções de reforço de elementos de betão armado: chapas de aço coladas, chapas de aço aparafusadas, laminados de compósitos reforçados com fibras de carbono colados e betão projetado. Foi utilizada, para o efeito, a estrutura de informação das fichas de rendimento do LNEC
Year: 2024
Author(s): Folgado Santos, C.; Cabaço, A.; Brandão de Vasconcelos, A
: Brazilian Journal of Development
Editor: Brazilian Journal of Development
Volume:
Volume 10, n 6.
Keywords: betão armado; preços; reforço estrutural; fichas de rendimento
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Fire-retardant and fire-resistant coatings: From industry to the potential use on cultural heritage
Fire is one of the most damaging deterioration agents in a short time of action. It can cause considerable damage, leading to the loss of lives and possessions. Concerning fire safety recommendations, buildings must be protected by an integrated system of passive and active measures. Two passive measures widely used in many industries are fire-retardant and fire-resistant coatings. These systems provide a fire-protective layer to the surfaces of flammable and non-flammable materials, delaying or preventing their ignition, reducing the heat transfer from the source to the substrate and decreasing the flame spread and the release of smoke and toxic gases. When exposed to fire, according to the different mechanisms of action, fire-protective coatings (FPC) can be classified as non-intumescent and intumescent. Despite being widely mentioned in heritage fire safety guidelines, studies on their application in the field are still scarce. Namely, research on the safety and efficacy of their application near collections (in support materials) and systematic studies comparing different formulations. Therefore, this research assembles interdisciplinary studies on the use of FPC to deepen knowledge and theoretically identify the feasibility of their application in collection support/storage materials or exhibition furniture (bookshelves, cabinets, plinths) in heritage environments.
Year: 2024
Author(s): Soares, I.; Ferreira, J.; Silva, H. M.; Rodrigues, M. P.
: Journal of Cultural Heritage
Editor: Elsevier
Volume:
Volume 68.
Keywords: Heritage; Fire-retardant; Fire-resistant; Intumescent; Non-intumescent; Coatings
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Freeze-thaw durability of vacuum infused glass fibre composites with unsaturated polyester and vinyl ester matrices
This paper presents an experimental study about the effects of freeze-thaw cycles (FTC) on the mechanical and thermomechanical properties of glass-fibre reinforced polymer composite laminates produced by vacuum infusion using two different polymer resins: unsaturated polyester (UP) and vinyl ester (VE). Following preconditioning in distilled water for 30 days at 20
Year: 2024
Author(s): Hasan, T.; Correia, J. R.; Garrido, M.; Soares, F.; Cabral-Fonseca, S.; Jorge, M.; J. SENA-CRUZ
: Construction and Building Materials
Editor: Elsevier
Volume:
455.
Keywords: durability; freeze-thaw cycles; vacuum infusion; vinyk ester; unsaturated polyester; Glass-fibre reinforced polymer
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Global and local geometrical imperfections of pultruded GFRP profiles based on a modal approach
ABSTRACT - The ultimate capacity of pultruded glass fibre reinforced polymer (pGFRP) profiles depends significantly on geometrical imperfections (GIs), given their sensitivity to buckling phenomena arising from both thin walls and low elastic moduli. However, GIs are not yet comprehensively addressed in design guidance. This paper proposes a new approach to characterize the initial GIs of pGFRP profiles based on a modal approach. Given the lack of comprehensive knowledge in this area, this study presents a highly accurate and robust methodology to measure GIs and dimensional deviations (DDs) in pGFRP profiles using a 3D contact coordinate measurement machine (CMM). The modal approach encompasses the measurement of dimensional parameters and a point cloud transformation that enables the assessment of GIs associated with pure buckling modes of pGFRP profiles. This procedure allows the quantification of three types of global GIs associated to (i) minor-axis (weak axis), (ii) major-axis (strong axis) bending, and (iii) twist. Additionally, the procedure also includes the assessment of local GIs, considering the wall (plate-like) imperfections. The separation of GIs into these four types (shape and amplitude) is of major relevance as its paves the way to the development of analytical design formulas for the strength prediction of pGFRP members. The approach described in this paper also serves two important purposes: (i) the statistical analysis of DDs and GIs of pGFRP members, and (ii) the identification of distinct shapes and amplitudes of GIs that form the basis for reliable design considerations of pGFRP members.
Year: 2024
Number Pages:
18p..
Author(s): Silvestre, N.; Correia, J.; Pinheiro, A.; Ribeiro, A.; Lages Martins, L.; Lazzari, J.
: Construction and Building Materials
Editor: ELSEVIER
Volume:
412 (2024) 134813.
Keywords: Modal decomposition; Geometrical imperfections; Dimensional deviation; 3D contact measurements; Pultruded profiles; Glass fibre reinforced polymer (GFRP)
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