Consideration of the Effects of Air Temperature on Structural Health Monitoring through Traffic Light‐Based Decision‐Making Tools

Abstract

The real-time analysis of a structure’s integrity associated with a process to estimate damage levels improves the safety of people and assets and reduces the economic losses associated with interrupted production or operation of the structure. The appearance of damage in a building changes its dynamic response (frequency, damping, and/or modal shape), and one of the most effective methods for the continuous assessment of integrity is based on the use of ambient vibrations. However, although resonance frequency can be used as an indicator of change, misinterpretation is possible since frequency is affected not only by the occurrence of damage but also by certain operating conditions and particularly certain atmospheric conditions. In this study, after analyzing the correlation of resonance frequency values with temperature for one building, we use the data mining method called “association rule learning” (ARL) to predict future frequencies according to temperature measurements. We then propose an anomaly interpretation strategy using the “traffic light” method.

Dynamic Identification for Representative Building Typologies: Three Case Studies from Bucharest Area

“…Such relatively small variations were reported also in other studies aimed to monitor and track the dynamic characteristics of buildings; they were related mostly to the atmospheric conditions that can slightly modify the building`s dynamic parameters [9,11,12,23,31].…”

“…A simple and relatively inexpensive method to evaluate the building state consists of monitoring the variation with time of its fundamental period and damping. In practice, this is done by recording and processing building oscillations caused by ambient sources of vibrations [7][8][9][10][11][12], to detect potential changes of these parameters. Once changes are detected, their nature and magnitude are analyzed with respect to the reference values, and warnings are issued if damage is identified.…”

Forecasting Time-Variable Earthquake Risk for Reinforced Concrete Buildings During Aftershock Sequences Based on Operational Earthquake Forecasting and Resonance Period Elongation

“…Having the resonance frequencies of buildings before damage, or the more expensive option of installing permanent instrumentation in critical structures, is indispensable for rapid damage assessment. For example, a real-time online algorithm could be developed using a solution like that proposed by Guéguen and Tiganescu [54], based on the traffic light concept. Additionally, false alarms would have to be taken into account by integrating natural frequency variations and the slow recovery of the elastic properties after a seismic event, as reported by Guéguen et al [56] and Astorga et al [17].…”

“…This strategy has been already applied for post-earthquake crisis management, which consists in visually inspecting the buildings and classifying them according to occupancy safety based on an empirical expert appraisal [19,20]. It has also been used for continuous and online condition-based solutions for structural aging [54]. Typically, the "traffic light" defines a "green" level, indicating that the buildings are safe, with no apparent damage and can be occupied again, an "orange" level indicating that the buildings present all the characteristics of damaged buildings but with a high level of uncertainty, and a "red" level indicating that occupancy should be suspended immediately and the building demolished.…”

Earthquake risk in reinforced concrete buildings during aftershock sequences based on period elongation and operational earthquake forecasting

“…This strategy has already been applied for post-earthquake crisis management, which consists in visually inspecting buildings and classifying them according to occupancy safety based on an empirical expert appraisal [23,24]. It has also been used for continuous and online condition-based solutions for structural aging [72]. Typically, the "traffic light" defines a "green" level as indicating that the buildings are safe, have no apparent damage, and can be occupied again, an "orange" level as indicating that the buildings present all of the characteristics of damaged buildings, but with a high level of uncertainty, and a "red" level as indicating that occupancy should be suspended immediately and the building demolished.…”