MQTT based event detection system for structural health monitoring of buildings

Abstract

Structural Health Monitoring (SHM) consists in a fundamental research field which aim to evaluate the current status of an infrastructure with the main purpose to identify damages and prevent catastrophic events. This paper presents an SHM solution that implements an automatic system based on the MQTT protocol and IoT devices for detecting seismic events. In particular, the architecture consists of a set of accelerometer sensors which communicate by means of a decentralized network topology (i.e., an Ad hoc Network configuration). Moreover, the system has the capacity to transmit the information about the events detected in real-time using cloud services. In order to verify the proper operation, the system was deployed on an actual building and the information acquired by the sensors was registered along four months. In this context, a relevant event detected was selected for analyzing the dynamic response of the building during a seism. Results show that the acceleration values increase as a function of the building height. Regarding the seismic event analyzed, the RMS values of acceleration identified on the basement were 0.26, 0.22, and 0.22 cm/s2 and in the case of the eighth floor were 1.18, 1.33, and 0.59 cm/s2 for the longitudinal, transverse, and vertical axes, respectively. Additionally, a first assessment regarding the structural health status of the building was performed through the OMA methodology (Operational Modal Analysis). Specifically, the FDD (Frequency Domain Decomposition) mechanism was used to determine the first four frequencies and its respective vibration modes.