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2023 | Buch

Maintainability of Building Envelope Elements

Optimizing Predictive Condition-Based Maintenance Decisions


Über dieses Buch

This book introduces a maintenance model that will assist decision-makers in their choice of building maintenance policies.

The model is stochastic and condition-based that analyses the impact of different maintenance strategies on the durability and performance of different buildings envelope elements (facades, windows, and roofs). As non-structural elements, the maintenance of buildings envelope can be disregarded stakeholders. However, as first barrier to the external environment, these elements are critical to buildings' overall performance and are expected to meet aesthetic, comfort, safety, and durability requirements. The methodology presented is innovative. The maintenance model is based on a Petri net formalism and includes degradation, inspection, maintenance, and renewal processes. The model provides key information, such as: i) the impact of different maintenance strategies on the service life and durability of the building components; ii) the impact of maintenance on their performance over time; iii) the life cycle costs; and iv) the impact of maintenance on the buildings' use.

The book will be of use to a variety of professionals in the construction sector.


Chapter 1. Maintenance of Buildings and Components
For decades, the attitude “build and let decay” has been adopted in the building sector, leading the built park to unacceptable degradation levels and unsustainable maintenance costs. This attitude is even more pronounced in buildings’ envelope elements. Since buildings are fundamental assets in Society, maintenance is the only way to keep their operational capability for as long as economically possible, without compromising their reliability or safety. In the construction sector, maintenance is not as advanced as in the industrial sector. The stakeholders tend to be deeply concerned about new projects, but the use and maintenance phases continue to be neglected. The performance of maintenance activities over the service life of buildings has a positive impact on Society, allowing increasing the sustainability of constructions and improving the resilience of the built environment. However, to implement maintenance in a more systematic and optimized way in the building sector, the development of more accurate tools to aid the planning of maintenance activities is needed.
Cláudia Ferreira, Ana Silva, Jorge de Brito, Inês Flores-Colen
Chapter 2. Condition-Based Maintenance
Different maintenance policies and strategies can be adopted to improve the durability and sustainability of buildings. Unplanned maintenance is often carried out in response to failures or users’ demands, being extremely expensive, when the failure of an element is already associated with a serious pathological scenario, and when its failure occurs at a time of economic constraints. The planned maintenance is organised and controlled, intending to increase the performance of the building components and reduce the likelihood of problems that can occur during their service life. To change the attitude “let decay”, the maintenance strategy implemented intends to correct anomalies resulting from use, agents and mechanisms of degradation and the natural aging of materials, guaranteeing reasonable costs and an increased building durability. To analyse the influence of the maintenance strategies on the buildings’ envelope elements, key performance parameters such as durability, life cycle costs and efficiency index, are used.
Cláudia Ferreira, Ana Silva, Jorge de Brito, Inês Flores-Colen
Chapter 3. The Use of Petri Nets to Model the Maintainability of Buildings
Petri nets are used to create the maintenance model, corresponding to a mathematical and graphical tool suitable to model dynamic systems. The maintenance model developed can be considered a complete life cycle model. In addition to integrating the stochastic assessment of the degradation condition of the building components, the inspection and maintenance processes of the building components is also included. The degradation process is composed of a discrete scale of five degradation conditions, from A (no visible degradation) to E (generalized degradation). Furthermore, it is assumed that the degradation condition of the building components is not known over time and is determined only when the inspection is carried out. It is considered that inspections are frequent, with the time intervals being pre-defined by the owner/manager of the building. Regarding maintenance activities, it is assumed that an efficient maintenance program is composed of maintenance activities that allow reducing the degradation of the building component and increasing its service life, including replacement activities corresponding to the building component’s end-of-life to restore to the condition “as-good-as-new”.
Cláudia Ferreira, Ana Silva, Jorge de Brito, Inês Flores-Colen
Chapter 4. Maintainability of Buildings’ Envelope
The maintenance model described in Chap. 3 is applied to analyse individually nine constructive solutions (six façade claddings: ceramic tiling systems (CTS), natural stone claddings (NSC), rendered façades (RF), painted surfaces (PS), external thermal insulation composite systems (ETICS), architectural concrete façades (ACF); two window frames types: aluminium window frames (AWF), wooden window frames (WWF); and one roof cladding solution: ceramic claddings in pitched roofs (CCPR)). For each constructive solution, three maintenance strategies are addressed, ranging from a maintenance strategy where preventive maintenance is not applied (most common maintenance strategy nowadays) to a maintenance strategy with a higher level of preventive maintenance (including cleaning operations and minor interventions). The results are assessed through four parameters: service life and durability, efficiency index, life cycle costs, and number of total replacements.
Cláudia Ferreira, Ana Silva, Jorge de Brito, Inês Flores-Colen
Chapter 5. Multi-objective Analysis and Comparison of Different Maintenance Strategies
Since the parameters used to assess the influence of the maintenance strategies on the buildings’ envelope elements are interdependent, the constructive solutions’ advantages and disadvantages change according to the parameters analysed. To assess the constructive solutions in a global way, multi-objective strategies are implemented to optimize the outcomes and aid the decision-makers in the decision process. A multi-criteria decision analysis is implemented to compare the different maintenance strategies, while a multi-objective optimization is used to optimize the inspections’ frequencies.
Cláudia Ferreira, Ana Silva, Jorge de Brito, Inês Flores-Colen
Chapter 6. Lessons Learned and Opportunities to Go Forward
In this chapter, the main results obtained in Chaps. 4 and 5 are used to propose a customised maintenance plan for the different building components analysed. Furthermore, research paths for future works are suggested. The following research paths are suggested: computer implementation of maintenance plans; impact of regular maintenance on unplanned maintenance; global maintenance plan of buildings’ envelope; definition of insurance policies; building information modelling; and adaptation to other classification systems.
Cláudia Ferreira, Ana Silva, Jorge de Brito, Inês Flores-Colen
Maintainability of Building Envelope Elements
verfasst von
Cláudia Ferreira
Ana Silva
Jorge de Brito
Inês Flores-Colen
Electronic ISBN
Print ISBN