Abstract
In the field of building inspection and diagnosis, uncertainty is common and surveyors are aware of it, although it is not easily measured. This research proposes a model to quantify uncertainty based on the inspection of rendered façades. A Bayesian network is developed, considering three levels of variables: characteristics of the building, façade and exposure conditions; causes of defects; and defects. To compute conditional probabilities, the results of an inspection campaign from the literature are used. Then, the proposed model is validated and verified using inspection results from another sample, the combination of a strength-of-influence diagram and sensitivity analysis and the application of the model to a case study. Results show that the probabilities computed by the model are a reasonable representation of the hesitancy in decision making during the diagnosis process based only on visual observation. For instance, design and execution errors show lower probabilities due to not being verifiable a posteriori without detailed documentation. The proposed model may be extended and replicated for other building materials in the future, as it may be a useful tool to improve the perception of uncertainty in a key stage of building maintenance or rehabilitation.
Highlights
Physical degradation is one of the processes that may result in the obsolescence of buildings, as some performance requirements stop being fulfilled and, eventually, the building or its elements reach the end of their service life
The analysis of the case study highlighted that the detected defects had been predicted by the proposed Bayesian network (BN) model with reasonable levels of uncertainty, as only two of the detected defects had a probability of occurrence lower than 50%
Surveyors are normally conscious of that uncertainty, it is difficult to quantify it
Summary
Chemical and mechanical degradation agents gradually affect building elements and, together with natural ageing, lead to deterioration [1] This general issue requires action to extend the buildings’ service life, such as carrying out maintenance activities to hinder the degradation mechanisms. Uncertainty is associated with the inspection and diagnosis activities performed to assess the degradation state of buildings and their elements. Even though this uncertainty is rarely quantified, surveyors, designers, engineers and prescribers are aware of some level of subjectivity inherent to all diagnoses, as well as of the vulnerability and unpredictability of outcomes stemming from recommendations and decisions. The levels of uncertainty vary according to several contextual factors
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
