Optimal metric for condition rating of existing buildings: is five the right number?

Abstract

In the context of the built environment in the recent years the concept of maintenance has changed from corrective to preventive maintenance. There is evidence that preventive maintenance is much more efficient than corrective maintenance, since severe deteriorations that may represent danger to people are avoided, and also money is saved. To make periodic inspections of the buildings is useful to quantify the extent to which deteriorations are severe or not, in order to facilitate decision making and prioritize interventions. To this purpose many scales have been used and are used to assess the severity of damage and degradation of the building components. But it appears evident that there is not consensus among users and these scales are different between them, with different number of degrees and metrics for the measurement of the condition state. The main goal of this paper is to calculate which is the optimal metric (which is the optimal number of degrees) of a severity scale of damages in buildings, so the corresponding scale could be of widespread and of common use among professionals, avoiding the problems of comparison between different evaluators. The proposed methodology to calculate the optimal metric of a scale can be also extended to other scopes.

Elementary School Buildings Condition Assessment: Case of Primorje-Gorski Kotar County (Croatia)

“…[5,19,20,37]. Certain authors use predefined assessment scales when analysing the building elements' condition, which is most often carried out by surveys or field inspection [44]. These scales can consist of a different number of degrees (points) for evaluation, such as a 3-point scale (good/fair/bad condition) [37], a 5-point scale (very good/good/fair/bad/awfully bad condition) [2,5,19,45], and a 7point scale or more points [2].…”

Condition assessment of building façades based on hazard to people

“…Given the categorical nature of the variable, it has been considered appropriate to classify the measure of the probability of detachment based on 5 different degrees: very low (y = 0), low (y = 1), medium (y = 2), high (y = 3) and very high (y = 4). The number of five degrees is based on the study presented in Ruiz et al (2019), where the direct assignment method is used in the field of assessing the gravity of damage to buildings. This measure y j is consequence of the identification of certain identifiable symptoms in the façade.…”

“…In the next section a statistical study is developed with the aim of characterizing which are these symptoms and their relationship with the assignment of a probability measure. About the selection of a metric of five degrees it should be highlighted that in Ruiz et al (2019), the most suitable metric (number of degrees) of the scale is estimated following a methodological process (including experimental and calculation processes), and not based in the opinion of the authors of the scale, as happens in others scales. It should be added that there are many different scales in the scope of condition state of buildings, with different metrics (different number of degrees).…”

“…This scale is applied through the direct assignment methodology (DA), based on the generic definitions of each degree. In Ruiz (2014a) and in Ruiz et al (2019) is also demonstrated and characterized the existence of certain level of variability among technicians, when assigning gravity values using DA methodology, due to the fuzzy condition of the attribute to be evaluated. Therefore, the main objective of this paper is to make an alternative proposal to the direct assignment method (DA) to evaluate the degree of gravity in building façades, based on objectively measurable parameters, in order to reduce as much as possible the degree of variability when assigning a certain degree of gravity G. More specifically, the proposal consists in the appropriate selection of objective and measurable indicators and the associated calculation methods.…”

“…On the other hand, it is important to highlight that, currently, there are many scales used to assess the grade of severity of damage (or condition state index) of the constructive elements in buildings. There is no consensus and these scales are different, with different number of degrees and metrics, according to the study to which they belong (Ruiz et al 2019). In Ruiz (2014a) is proposed a scale of gravity of damages in buildings, with the aim of being of widespread and of common use among professionals.…”