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The increase of awareness with sustainability and the desire of reducing the energy consumption in the construction sector haved increased the application of External Thermal Insulation Composite Systems (ETICS) across Europe in the last decades. Nevertheless, the implementation of appropriate maintenance strategies is still neglected. The aim of this study is to analyse the impact of different maintenance strategies. For that purpose, a condition-based maintenance model, based on Petri nets, is used to evaluate three maintenance strategies: MS1—total replacement only; MS2—combination of minor intervention and total replacement; and MS3—combination of cleaning operations, minor intervention, and total replacement. In the end, a multi-criteria analysis is used to discuss the impact of the three maintenance strategies proposed, evaluating the remaining service life, the global costs over time, the ETICS’ degradation condition, and the number of replacements (end of service life) over the time horizon. For this purpose, a sample of 378 ETICS was analysed, based on in situ visual inspections, carried out in Portugal. The results from this study reveal that maintenance plays an important role to increase the durability of ETICS, and therefore their sustainability. Regular maintenance can promote the extension of the ETICS’s service life between 88% and 159% (between 15 to 27 years), improve the global degradation condition of the ETICS, and reduce the impact on users by reducing the number of deeper interventions. Further research is essential to optimise the maintenance strategies (time interval between inspections, stakeholders’ performance criteria, and environmental exposure).
Cláudia Ferreira; Ana Silva; Jorge de Brito; Ilídio Dias; Inês Flores-Colen. Condition-Based Maintenance Strategies to Enhance the Durability of ETICS. Sustainability 2021, 13, 6677 .
AMA StyleCláudia Ferreira, Ana Silva, Jorge de Brito, Ilídio Dias, Inês Flores-Colen. Condition-Based Maintenance Strategies to Enhance the Durability of ETICS. Sustainability. 2021; 13 (12):6677.
Chicago/Turabian StyleCláudia Ferreira; Ana Silva; Jorge de Brito; Ilídio Dias; Inês Flores-Colen. 2021. "Condition-Based Maintenance Strategies to Enhance the Durability of ETICS." Sustainability 13, no. 12: 6677.
Façades, as the most external building envelope component, are subject to different ex-ternal environmental loads, such as: Temperature, precipitation, damp, and wind. Therefore, the contribution of environmental actions to the occurrence of defects in façades claddings is an important subject of study since these actions strongly affect the degradation process and natural ageing of these components during their service life. In this study, a methodology to support decision-makers in the process of selecting a façade cladding system and the maintenance strategy to implement is presented and discussed. This methodology covers the performance of four façade claddings (ceramic tiling systems (CTS), natural stone claddings (NSC), external thermal insulation composite systems (ETICS), and architectural concrete façades (ACF)) over time, according to three environmental exposure variables (exposure to damp, distance from the sea, and orientation). The databases were established based on the diagnosis of the degradation condition of these claddings in-service conditions, in Portugal. The results reveal that the environmental exposure variables have a significant impact on maintenance requirements and costs. For all the categories of the environmental exposure condition variables, under all scenarios, ETICS is the least favorable constructive solution while CTS is the most advantageous solution. Furthermore, the results show that properly implemented maintenance activities enhance the performance level of building components, which positively affects their degradation behavior over time.
Cláudia Ferreira; Joana Barrelas; Ana Silva; Jorge de Brito; Ilídio Dias; Inês Flores-Colen. Impact of Environmental Exposure Conditions on the Maintenance of Facades’ Claddings. Buildings 2021, 11, 138 .
AMA StyleCláudia Ferreira, Joana Barrelas, Ana Silva, Jorge de Brito, Ilídio Dias, Inês Flores-Colen. Impact of Environmental Exposure Conditions on the Maintenance of Facades’ Claddings. Buildings. 2021; 11 (4):138.
Chicago/Turabian StyleCláudia Ferreira; Joana Barrelas; Ana Silva; Jorge de Brito; Ilídio Dias; Inês Flores-Colen. 2021. "Impact of Environmental Exposure Conditions on the Maintenance of Facades’ Claddings." Buildings 11, no. 4: 138.
In façades design, the selection of constructive solutions plays an important role. The materials used should withstand the expected degradation agents and mechanisms. However, this choice is still based on intuitive criteria. To support decision-makers in the cladding system selection process, this study considers the behaviour of the constructive solutions over time, their maintenance needs, and costs on a multi-criteria analysis methodology. For that purpose, six façade claddings are evaluated: ceramic tiling systems; natural stone claddings; rendered façades; painted surfaces; ETICS; and architectural concrete façades. The databases were established based on the diagnosis of the degradation of these claddings in real in-service conditions, in Portugal. The findings of this study provide an objective framework for selecting façades claddings’ solutions. The results reveal that, according to the different criteria and preferences of the owners/managers of the buildings, different solutions can be achieved, allowing selecting more suitable and economical materials and maintenance strategies. By comparing to the most usually selected conditions of constructive solutions (initial costs and no preventive maintenance), the maintenance strategy can be changed if the weight of the durability and performance criteria is, at least, 1%, and the constructive solution can be changed if the weight is, at least, 17%.
Cláudia Ferreira; Ilídio S. Dias; Ana Silva; Jorge de Brito; Inês Flores-Colen. Criteria for selection of cladding systems based on their maintainability. Journal of Building Engineering 2021, 39, 102260 .
AMA StyleCláudia Ferreira, Ilídio S. Dias, Ana Silva, Jorge de Brito, Inês Flores-Colen. Criteria for selection of cladding systems based on their maintainability. Journal of Building Engineering. 2021; 39 ():102260.
Chicago/Turabian StyleCláudia Ferreira; Ilídio S. Dias; Ana Silva; Jorge de Brito; Inês Flores-Colen. 2021. "Criteria for selection of cladding systems based on their maintainability." Journal of Building Engineering 39, no. : 102260.
The diagnosis of the building’s façades pathology is extremely important to support rational and technically informed decisions regarding maintenance and rehabilitation actions. With a reliable diagnosis, the probable causes of the anomalies can be correctly identified, and the correction measures adopted can be more compatible with the existing elements, promoting the durability of the façades. Visual inspection is the most common approach to identify anomalies in a building’s façade and, in many cases, this technique is sufficient to support the decision to intervene. However, the pathological phenomenon is complex, and the anomalies observed may indicate the presence of other defects, or some anomalies may not be visible in a simple visual observation. This study intends to discuss the application of emerging technologies on the diagnosis and anamneses of building’s façade, in order to automatise the collection of reliable on-site data and, thus, reduce the uncertainty of the diagnosis. The use of these techniques can help existing inspection methodologies, already tested, based mainly on the visual assessment of the buildings’ elements degradation condition.
Ilídio Dias; Inês Flores-Colen; Ana Silva. Critical Analysis about Emerging Technologies for Building’s Façade Inspection. Buildings 2021, 11, 53 .
AMA StyleIlídio Dias, Inês Flores-Colen, Ana Silva. Critical Analysis about Emerging Technologies for Building’s Façade Inspection. Buildings. 2021; 11 (2):53.
Chicago/Turabian StyleIlídio Dias; Inês Flores-Colen; Ana Silva. 2021. "Critical Analysis about Emerging Technologies for Building’s Façade Inspection." Buildings 11, no. 2: 53.
In condition-based maintenance plans, the schedule of inspections is an important step. Condition-based actions are performed according to prescribed condition criteria (i.e., condition, cost, availability, among other factors), and the main purpose of inspections is to evaluate the façade’s condition and plan its correction in order to reduce the risk of failure of the cladding. Therefore, the main goal of this study is to implement multi-objective optimization to understand whether there is an optimal time interval for performing the inspections. For that purpose, a Petri-net condition maintenance model is used to assess the influence of different maintenance plans on the overall degradation of natural stone claddings. In this model, the maintenance activities can only be performed after an inspection has been carried out. The definition of the best maintenance policy results in a conflict of objectives. Owners/managers seek to achieve a maintenance strategy that minimizes service life costs and maintain the cladding in a safe and minimal degradation condition. Multi-objective optimization procedures are capable of considering several conflicting objectives. In this paper, the objective functions considered are minimization of the service life costs, maximization of the efficiency index, maximization of the service life, and minimization of the total number of replacements over the time horizon.
Cláudia Ferreira; Ana Silva; Jorge De Brito; Ilídio S. Dias; Inês Flores-Colen. Optimization of Inspection Period in Natural Stone Claddings. Applied Sciences 2020, 10, 8236 .
AMA StyleCláudia Ferreira, Ana Silva, Jorge De Brito, Ilídio S. Dias, Inês Flores-Colen. Optimization of Inspection Period in Natural Stone Claddings. Applied Sciences. 2020; 10 (22):8236.
Chicago/Turabian StyleCláudia Ferreira; Ana Silva; Jorge De Brito; Ilídio S. Dias; Inês Flores-Colen. 2020. "Optimization of Inspection Period in Natural Stone Claddings." Applied Sciences 10, no. 22: 8236.
Existing maintenance policies have several limitations, mainly due to the lack of knowledge regarding the durability and performance of buildings. Usually, the maintenance policies are insufficiently accurate, neglecting the risk of failure over time and the global costs associated with repairs. In this study, a condition-based maintenance model, based on Petri nets, is proposed to evaluate the impact of three maintenance strategies of ceramic claddings in pitched roofs (CCPR): MS1—only total replacement; MS2—composed of total replacement and minor intervention and MS3—composed of total replacement, minor intervention and cleaning operations. In this study, 146 CCPR were inspected in situ, with a total area of 43,991.6 m2. The remaining service life of the CCPR; the global costs over the claddings’ lifetime (considering inspection, maintenance, replacement and disposal costs); the claddings’ degradation condition and the number of replacements during the time horizon are used to evaluate the performance of the different maintenance strategies through a simplified multi-criteria analysis. The results show that the gains in performance, in terms of expected service life and durability, of the consideration of preventive maintenance actions (minor interventions or cleaning operations) outweigh the increase of the operation costs.
Cláudia Ferreira; Ana Silva; Jorge De Brito; Ilídio S. Dias; Inês Flores-Colen. Maintenance Modelling of Ceramic Claddings in Pitched Roofs Based on the Evaluation of Their In Situ Degradation Condition. Infrastructures 2020, 5, 77 .
AMA StyleCláudia Ferreira, Ana Silva, Jorge De Brito, Ilídio S. Dias, Inês Flores-Colen. Maintenance Modelling of Ceramic Claddings in Pitched Roofs Based on the Evaluation of Their In Situ Degradation Condition. Infrastructures. 2020; 5 (9):77.
Chicago/Turabian StyleCláudia Ferreira; Ana Silva; Jorge De Brito; Ilídio S. Dias; Inês Flores-Colen. 2020. "Maintenance Modelling of Ceramic Claddings in Pitched Roofs Based on the Evaluation of Their In Situ Degradation Condition." Infrastructures 5, no. 9: 77.
Nowadays, the degradation of the built environment is becoming a serious economic, cultural and environmental problem in several developed countries, after several decades of adopting an attitude of “built and let decay”. The lack of maintenance policies led to additional costs and risks for owners and increased the aesthetic degradation of our cities. In this study, a condition-based maintenance model, based on Petri nets, is used to analyse the influence of alternative maintenance strategies on the overall degradation of natural stone claddings. For this purpose, three maintenance strategies are considered: i) total replacement; ii) combination of minor intervention and total replacement; and iii) combination of cleaning operations, minor intervention and total replacement. The impact of the alternative maintenance strategies on the future performance and remaining service life of natural stone claddings is discussed. In this study, a sample of 203 natural stone claddings, located in Portugal, is analysed and the degradation of these claddings in-service condition is evaluated through in-situ inspections. Furthermore, a simplified multi-criteria analysis is carried out to evaluate the economic impact of each maintenance strategy in comparison with the increased durability achieved through its adoption. The results reveal that the adoption of other maintenance activities (minor interventions or cleaning operations) increases the operational costs, as expected, but promotes the durability of the claddings. The adoption of maintenance actions allows increasing the predicted service life of NSC (148 years for MS2 and 177 years for MS3), when compared with NSC that are not subjected to any kind of preventive maintenance (70 years).
C. Ferreira; A. Silva; J. de Brito; I.S. Dias; I. Flores-Colen. Definition of a condition-based model for natural stone claddings. Journal of Building Engineering 2020, 33, 101643 .
AMA StyleC. Ferreira, A. Silva, J. de Brito, I.S. Dias, I. Flores-Colen. Definition of a condition-based model for natural stone claddings. Journal of Building Engineering. 2020; 33 ():101643.
Chicago/Turabian StyleC. Ferreira; A. Silva; J. de Brito; I.S. Dias; I. Flores-Colen. 2020. "Definition of a condition-based model for natural stone claddings." Journal of Building Engineering 33, no. : 101643.
Usually, maintenance models consider maintenance actions as perfect, i.e. these interventions can restore the components to the “as good as new” state. However, in many situations, this assumption is too simplistic, and moreover it is not true. In this study, imperfect maintenance actions are considered. For that purpose, a new methodology is developed to quantify the impact of maintenance actions on buildings' envelope components. This methodology is based on a probabilistic approach, implemented through a stochastic maintenance model based on Petri Nets (PN). The quantification of the impact of maintenance actions on building components is estimated by assessing the impact of these actions on the overall degradation condition of the component, which is expressed by a numerical index called severity of degradation index, Sw. This is a conceptual study, in which the maintenance plans are composed of condition-based maintenance actions, and the schedule of the actions is carried out based on the condition of the components. In the definition of the maintenance plans, four levels of interventions were considered: inspections; cleaning operations; minor interventions; and total replacement. The results reveal that the adoption of minor interventions or cleaning operations increases the operational costs but, when performed with an adequate periodicity, allows maintaining the components’ performance at high standards for most of their service life, thus promoting their durability.
C. Ferreira; A. Silva; J. de Brito; I.S. Dias; I. Flores-Colen. The impact of imperfect maintenance actions on the degradation of buildings’ envelope components. Journal of Building Engineering 2020, 33, 101571 .
AMA StyleC. Ferreira, A. Silva, J. de Brito, I.S. Dias, I. Flores-Colen. The impact of imperfect maintenance actions on the degradation of buildings’ envelope components. Journal of Building Engineering. 2020; 33 ():101571.
Chicago/Turabian StyleC. Ferreira; A. Silva; J. de Brito; I.S. Dias; I. Flores-Colen. 2020. "The impact of imperfect maintenance actions on the degradation of buildings’ envelope components." Journal of Building Engineering 33, no. : 101571.