The interest of this research is motivated by the huge constructive development in the building sector, which has led to an enormous volume of buildings worldwide over the last decades. This fact, as well as poor management in conservation of buildings, mainly in urban cities, has led to total degradation situations on the facades of building stocks. To infer on the evolutional process of degradation that occurs in the facade, during its service life and based on the information obtained from inspections, the method for the data analysis (e.g. survival analysis techniques) is as important as the truthfulness and usefulness of the data collected on the subjects (facades) under study.
In this paper we propose a method based on the design of indicators for prospecting and global data collection on the injury state of the inspected facades. The method analyzes how to perform the identification, classification, methodology, resources and quality of the data in order to be reliable, testable and measurable. The proposed model enables the macro inspection and monitoring of large-scale urban zones and the data obtained allow the researcher to understand and manage the predictive degradation phenomenon and, in turn, eliminate potential risks in the urban front.
This paper deals with, on one hand, the introduction of survival analysis techniques for being used in building maintenance and, on the other hand, the application of this methodology for analyzing a large building stock in order to obtain information for maintenance strategies and/or prevention policies. In particular, in this contribution the description of the time to the event when the event of interest is some damage (or some level of degradation or extent) on the building façade is the main goal to reach.
For the time being, building follow-up is based on inspections. However, data coming from building inspections are always not completed, but censored, due to the fact that, at each inspection time, the event of interest is already happened, or not yet. In order to solve this problematic, the existing methodology for fields like medicine, biology, industrial engineering or event history analysis is adapted, and routines in S-PLUS for a numerical and graphical systematic analysis are implemented. Estimates for non-parametric durability and hazard functions are derived.
The possibilities of the proposed methodology will be illustrated with its application to the building façades in Hospitalet de Llobregat, the second most important city in population in Catalonia (Spain), where more than 14.000 buildings have been inspected. The analysis of the results allows technicians to detect different zones and levels of intervention to be applied in the city.