Assessing structural safety under repeated earthquakes: Integration of an energy-based function in Nsmos®

Abstract. The authors have developed and integrated a new function into an existing operational monitoring system (NSmos®) to assess structural safety of a steel structure during repeated earthquakes, such as the 2016 Kumamoto earthquakes. Using data from the system's accelerometers, the acceleration and displacement of each story of a building are estimated. The acceleration is then multiplied by the pre-inputted story weight to estimate the earthquake-induced shear force. Based on the resulting restoring force, the earthquake’s induced hysteretic energy is calculated and added to that of previous earthquakes. This cumulative energy is then compared to the building's energy-dissipation capacity, which is determined from the specifications of its structural members in accordance with energy-based design theory. Finally, the accuracy of this approach is verified through computational analysis.