• Condition-Based Maintenance Models for Stone Claddings

  C. Ferreira, A. Silva, J. Brito, L. Neves

  Example of a collection (2020). 12

  
  

  Abstract

  Most of the maintenance actions in the construction sector are still reactive and sporadic, based on subjective criteria. Usually, maintenance actions are performed when the building already presents unacceptable degradation levels, and the reactive maintenance actions carried out only correct the anomalies observed, not dealing with the causes, thus leading to additional costs and risks for owners. This study establishes a condition-based maintenance model applied to natural stone claddings. This model has a stochastic nature, in order to deal with the complexity of the degradation phenomena. For that purpose, Petri nets are used, providing an efficient tool to model the deterioration process and the maintenance decisions considered for stone claddings. The maintenance model is a full life-cycle model that encompasses: (i) the stochastic assessment of the degradation condition of the stone claddings, and their expected service life; (ii) and the inspections, maintenance and renewal processes. In this study, three maintenance strategies are considered: (i) major intervention only; (ii) combination of minor and major interventions; and (iii) combination of cleaning operations, minor and major interventions. The impact of the different maintenance strategies in the future performance and remaining service life of stone claddings is analysed, also evaluating the economic impact of each maintenance plan.

  Abstract
  Most of the maintenance actions in the construction sector are still reactive and sporadic, based on subjective criteria. Usually, maintenance actions are performed when the [...]

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• Condition-Based Maintenance Models for Stone Claddings

  C. Ferreira(1), A. Silva(1), J. Brito(1), L. Neves

  Example of a collection (2020). 10

  
  

  Abstract

  ''Most of the maintenance actions in the construction sector are still reactive and sporadic, based on subjective criteria. Usually, maintenance actions are performed when the building already presents unacceptable degradation levels, and the reactive maintenance actions carried out only correct the anomalies observed, not dealing with the causes, thus leading to additional costs and risks for owners. This study establishes a condition-based maintenance model applied to natural stone claddings. This model has a stochastic nature, in order to deal with the complexity of the degradation phenomena. For that purpose, Petri nets are used, providing an efficient tool to model the deterioration process and the maintenance decisions considered for stone claddings. The maintenance model is a full life-cycle model that encompasses: (i) the stochastic assessment of the degradation condition of the stone claddings, and their expected service life; (ii) and the inspections, maintenance and renewal processes. In this study, three maintenance strategies are considered: (i) major intervention only; (ii) combination of minor and major interventions; and (iii) combination of cleaning operations, minor and major interventions. The impact of the different maintenance strategies in the future performance and remaining service life of stone claddings is analysed, also evaluating the economic impact of each maintenance plan.''

  Abstract
  ''Most of the maintenance actions in the construction sector are still reactive and sporadic, based on subjective criteria. Usually, maintenance actions are performed when [...]

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• Financial Management of Construction Companies

  J. Kusák, E. Vítková

  Example of a collection (2020). 8

  
  

  Abstract
  Financial Management of Construction Companies

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• Probabilistic approach to the service life prediction of timber claddings

  A. Silva, A. Prieto

  Example of a collection (2020). 6

  
  

  Abstract
  Probabilistic approach to the service life prediction of timber claddings

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• Influence of casting conditions on pullout behaviour of short post-installed expansion anchors

  F. Delhomme, C. Hervé, T. Roure

  Example of a collection (2020). 4

  
  

  Abstract
  Influence of casting conditions on pullout behaviour of short post-installed expansion anchors

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• Evaluation of the Influence of the Contact Area in the Adherence of Mortar by Mixed Mode Flexure (MMF)

  A. Melo, Â. Silva, S. Torres, J. Delgado, A. Azevedo

  Example of a collection (2020). 2

  
  

  Abstract

  ''The detachment of ceramic tiles in buildings is a problem that still persists in several modern constructions, despite various advances achieved in the sector of façade technology and an increasingly demanding consumer public. Studies have shown that most ceramic failures in façades occur between the interface mortar and ceramic tile. '' This work intends to contribute to the study and understanding of the influence of the contact area on the interface bonding between the adhesive mortar and ceramic tile by means of the adhesion resistance evaluation from the crack propagation test in mixed mode of stress (MMF) which simulates tensile and shear forces simultaneously. A punctual progressive load was applied to a considerable number of specimens in order to promote internal tensile and shear forces. The variables incorporated into the experiment were the type of mortar employed and the mortar thickness in the specimen. The experimental results show that the bonding strength values found by the direct drive test were 60.8% (AC II) and 58.1% (AC III) higher than the results obtained by the mechanical test in mixed mode, indicating an overestimated system result of the façade covering when the direct tensile bonding strength was verified exclusively.

  Abstract
  ''The detachment of ceramic tiles in buildings is a problem that still persists in several modern constructions, despite various advances achieved in the sector of façade [...]

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• A study of the impact of environmental loads that penetrate a passive skylight roofing system in Malaysian buildings

  K. Al-Obaidi, M. Ismail, A. Rahman

  Test journal 33 (2017).

  
  

  Abstract

  A passive skylight system is a significant building design element that provides an ideal condition for interior spaces. However, the use of this system is limited to specific climatic regions because of its considerable effect on the indoor environment. Malaysia is a tropical country that has favorable natural benefits, such as solar geometry and natural light, which can brighten building interiors throughout the year. However, harnessing this benefit affects spaces, especially those in single-story buildings, because of excessive natural loads. This study reviews a concept to understand the passive behavior of solar radiation in the form of light and heat that falls on, interacts with, and is emitted from a skylight system in a single-story building. The study method is theoretically based on descriptive analysis to assess design requirements. The review shows that designs grounded on the physical aspects of climate (influenced variables), materials (design variables), and human comfort (affected variables) in one process (ESI) can develop the architectural way of thinking rather than estimate the condition based on a limited perspective. This assumption indicates that the adoption of this concept in the preliminary design stage will enable designers to balance the building environment effectively.

  Abstract
  A passive skylight system is a significant building design element that provides an ideal condition for interior spaces. However, the use of this system is limited to specific [...]

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• Passive cooling techniques through reflective and radiative roofs in tropical houses in Southeast Asia: A literature review

  K. Al-Obaidi, M. Ismail, A. Rahman

  Test journal 33 (2017).

  
  

  Abstract

  Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The passive cooling technique is one of the innovative practices and technologies that provide buildings with comfortable conditions through natural means. Reflective and radiative processes are the methods used to decrease heat gain by facilitating the elimination of excess heat in a building׳s interior to maintain a comfortable environment. Given that the potential of these techniques vary from region to region, their application in the tropics should be examined. Exploring these approaches in detail allows us to rethink how to effectively adapt these techniques to overcome the build-up of heat in modern tropical houses in Southeast Asia. This study reviews the physical characteristics of these approaches to guide architects and building designers. Results indicate a great reduction in operational cost. However, the significant differences in the performance of colour and material properties should be considered, given that the selected approach strongly affects the required thermal conditions of a building.

  Abstract
  Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The [...]

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• A FEM fluid-structure interaction algorithm for analysis of the seal dynamics of a Surface-Effect Ship

  J. García-Espinosa, B. Serván-Camas, P. Ubach, E. Oñate, D. Di-Capua, J. Espinosa

  Example of a collection (2017).

  
  

  Abstract

  This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of the seal dynamics of a surface effect ship. The fluid solver developed for this purpose, uses a potential flow approach along with a stream-line integration of the free surface. The paper focuses on the free surface-structure algorithm that has been developed to allow the simulation of the complex and highly dynamic behavior of the seals in the interface between the air cushion, and the water.The developed fluid-structure interaction solver is based, on one side, on an implicit iteration algorithm, communicating pressure forces and displacements of the seals at memory level and, on the other side, on an innovative wetting and drying scheme able to predict the water action on the seals. The stability of the iterative scheme is improved by means of relaxation, and the convergence is accelerated using Aitken^s method.Several validations against experimental results have been carried out to demonstrate the developed algorithm.

  Abstract
  This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of the seal dynamics of a surface effect ship. The fluid solver [...]

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• Particle methods in Computational Fluid Dynamics

  I. S.R., O. E., B. P.

  Example of a collection (2017).

  
  

  Abstract

  Particle methods in Computational Fluid Dynamics (CFD) are numerical tools for the solution of the equations of f luid dynamics obtained by replacing the fluuid continuum with a finite set of particles. For mathematicians, particles are just points from which properties of the uid can be interpolated. For physicists the particles are material points, which can be treated like any other particle system. Either way, particle methods have a number of attractive features. One of the key attributes is that pure advection is treated exactly. For example, if the particles are given a determined colour and the velocity is specified, the transport of colours by the particle system is exact. The convection of properties also eases the solution of multi material problems, simplifying the detection of interfaces. The use of particles also allows to bridge the gap between the continuum and fragmentation in a natural way, for example in fracture or droplets problems. Since the computation domain, the particles, matches exactly the material domain of interest, the computational resources are optimized with the corresponding reduction in storage and calculation time compared to other methods. Finally, because of the close similarity between particle methods and the physics of the problems to be solved, it is often possible to account for complex physics more easily than with other methods.

  Abstract
  Particle methods in Computational Fluid Dynamics (CFD) are numerical tools for the solution of the equations of f luid dynamics obtained by replacing the fluuid continuum [...]

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• PROPUESTA DE REFORZAMIENTO PARA EDIFICACION EDUCATIVA TIPO ANTIGUO II-MOP VENEZUELA

  J. Yépez, M. Dikdan, L. Andrade, R. Rojas

  Example of a collection (2017).

  
  

  Abstract

  This article presents the study of structural reinforcement for a building of educational use, known as "Old Type II". The school was built before the creation of the Venezuelan SeismoresistantCovenin 1756. The results of the structural analysis showed insufficient responsiveness to service requests, high vulnerability to seismic action and deficiencies in the quantity and distribution of reinforcing steel. For this reason, the reinforcement of the superstructure was proposed by the construction of panel walls, verifying their action on the existing piloting system. For the modeling, the values of resistance of the concrete obtained in the destructive tests made by the materials laboratory of the School of Civil Engineering of the Universidad Centroccidental Lisandro Alvarado and the soil parameters from the geotechnical study were used.

  Abstract
  This article presents the study of structural reinforcement for a building of educational use, known as "Old Type II". The school was built before the creation of the Venezuelan [...]

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• IMPLEMENTACIÓN DE CONSTRUCCIÓN VIRTUAL PARA MEJORAR LA PLANIFICACION DE OBRAS. USO DE MODELO 4D EN URBANISMO UBICADO EN VALENCIA, VENEZUELA

  Z. Giménez, R. Gutiérrez, G. Hernández

  Example of a collection (2017).

  
  

  Abstract

  The construction industry is considered as one of the industries with lower yields, frequent delays and reprogramming. Due to this and to avoid losses of time, costs and inconveniences in the execution, the virtual construction is used, that allows to analyze previously the constructive sequences and the possible interferences between the different activities through a real time scenary according to the programmed schedule . This article shows the implementation of BIM technology in a modular housing development in Venezuela. Four 4D simulations were carried out, two initially due to the original planning and its timely improvement, and two subsequent corresponding to reprogramming due to actual delays in execution due to lack of concrete supply. The main results were: problems of programming logic, interferences between activities, unreal sequences, among others in the first models. As for the models of the reprogramming gave resulting times very similar to reality; This means that the models work both in ideal situations and in situations of uncertainty. Building information modeling solutions introduce a new way of working, based on the creation and use of coherent and coordinated information, wich allows for faster decision making, better documentation and the possibility of predicting the drawbacks Even before the work began.

  Abstract
  The construction industry is considered as one of the industries with lower yields, frequent delays and reprogramming. Due to this and to avoid losses of time, costs and inconveniences [...]

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• A simple FEM-DEM technique for fracture prediction in materials and structures

  Z. F, O. E.

  Example of a collection (1970).

  
  

  Abstract

  This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method (FEM) and the discrete element method (DEM). Once a crack is detected at an element side in the FE mesh, discrete elements are generated at the nodes sharing the side and a simple DEM mechanism is considered to follow the evolution of the crack. The combination of the DEM with simple 3-noded linear triangular elements correctly captures the onset of fracture and its evolution, as shown in several examples of application in two and three dimensions.

  Abstract
  This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method [...]

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• New draft 1

  Collection of Engineering Science and Technology, an International Journal (2017).

  
  

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Online first articles (not assigned to a volume)