Building Structural Health Monitoring Under Earthquake and Blasting Loading: The Chilean Experience

Near real-time structural health monitoring (SHM) has been used in Chile since mid-2009. Chile is located in one of the most active seismic zones in the world so initially SHM was driven mainly by research demands to evaluate the earthquake response of structures. In addition, one of the main industries of Chile is mining, which has operational characteristics that include strong vibrations generated by blasting and heavy machinery operations. This article presents research and professional experiences on building monitoring under environmental, earthquake and blasting vibration conditions. A low-cost monitoring system is used to monitor most of the structures. To identify modal characteristics, different techniques are used such as Stochastic Subspace Identification (SSI), Multivariable Output Error State Space (MOESP), and symbolic data analysis. Currently, more than 20 structures are being monitored by the procedures described in this article. A typical system consists of sensors, a local and a remote processing system, a robust data server and several communications media. The system provides information such as maximum response values, instrumental intensity, acceleration, velocity, displacement and modal parameters and, in parallel with numerical models, expected demands on structural member. All of this information is processed in near-real-time to obtain an indication of system changes that could be related with the damage.