Date of this Version
Liao, Y., Wood, R.L., Mohammadi, M.E., Devkota, K., and Wittich, C.E. (2019). Damage assessment of a sixteen story building following the 2017 Central Mexico Earthquake. Proceedings of the 12th Canadian Conference on Earthquake Engineering, Canadian Association for Earthquake Engineering, Quebec City, QC.
The 2017 M7.1 Central Mexico Earthquake caused significant infrastructural damage in the Mexico City area. The earthquake contained a significant pulse in the long period, resulting in numerous buildings severely damaged or collapsed. This paper discusses a reinforced concrete building which was still partially occupied post-earthquake. The building’s interior walls were examined to have substantial damage, including some extensive cracking. In January 2018, the authors visited the structure and collected detailed assessment data. The data collection included ground-based lidar scans and recorded ambient vibrations of the damaged structure using accelerometers. Eleven scans were collected from the four exterior facades to create a three-dimensional point cloud of the building. The collected point cloud data were used to measure and quantify the permanent deformation of the structure at three corners as well as to generate depth maps of two parallel exterior walls. The measurements based on the lidar point cloud data are accurate with an error of 2 mm at 10 meters, enabling high resolute and accurate assessments. As for the accelerometers, one setup with sixty minutes of ambient vibrations data collection was performed. Twenty unidirectional accelerometers were installed on the basement, ground, second, fourth, eighth, tenth and roof floors at southwest and northeast corners to capture the torsional and translational acceleration structural response. The collected data can be used to perform system identification throughout operational modal analysis to demonstrate the dynamic and modal properties of the structures. Both the lidar and system identification sensing techniques provide essential input to establish and calibrate a detailed finite element model. The outputs are used to validate through the comparison of modal frequencies obtained in operational modal analysis method. Besides, the finite element model also provides a detailed response and insight to understand performance under future earthquakes.