Stochastic maintenance models for ceramic claddings

Abstract

Maintenance decision-making involves a series of multiple objectives, some of them contradictory. Usually, stakeholders intend to find the optimal maintenance strategy, to minimize the economic burden, while simultaneously maximizing the buildings' performance. In this study, a condition-based maintenance model, based on Petri nets, is proposed to evaluate the consequences of alternative maintenance strategies to maintain and improve the performance of ceramic claddings. This maintenance model is a full lifecycle model that integrates the stochastic assessment of the degradation condition of the claddings, and also inspections, maintenance and renewal processes. 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 uncertainties associated with the degradation process, as well as with the definition of the effects of maintenance actions are considered by modelling the transitions times in Petri nets as random variables. Considering the complexity of Petri nets, the statistical descriptors of the performance of the assets (e.g. mean condition, probability of applying maintenance) were computed using Monte Carlo simulation. The impact of the different maintenance strategies in the claddings' service life is discussed, comparing the different alternatives also from an economic point of view.

Maintenance Modelling of Ceramic Claddings in Pitched Roofs Based on the Evaluation of Their In Situ Degradation Condition

“…This model, besides including the stochastic assessment of the degradation condition of the elements, also integrates the inspection and maintenance processes. A detailed description of this methodology is given in Ferreira et al [24].…”

“…In this methodology, four types of interventions are used in the maintenance programs: inspections, cleaning operations, minor interventions and total replacement [21,24,[34][35][36][37][38]. In inspections, visual assessment (and non-destructive tests, when necessary) is used to identify the existing anomalies and, consequently, assess the real degradation condition of the CCPR.…”

“…As mentioned above, MS1-only total replacement; MS2-composed of total replacement and minor intervention and MS3-composed of total replacement, minor intervention and cleaning operations are the maintenance strategies studied. The maintenance strategies were defined based on previous works [24,38] and on experts' judgements.…”

“…Therefore, in this study, the maintenance of ceramic claddings in pitched roofs (CCPR) is the main focus. The life cycle Petri net-based model previously proposed by the authors [24] is implemented to evaluate the impact of different maintenance strategies (MS) over time and promote the durability of CCPR in a cost-effective way. Therefore, the following maintenance strategies are assessed: MS1-only total replacement; MS2-composed of total replacement and minor intervention and MS3-composed of total replacement, minor intervention and cleaning operations.…”

Condition-Based Maintenance Models for Stone Claddings

“…Below, the meaning of each part of the model is briefly described. More information about the model can be seen in Ferreira et al (2019). The maintenance model implemented is a condition-based model, where it is assumed that maintenance actions are planned after the condition has been assessed through inspections.…”