The impact of total acceleration control for semi-active earthquake hazard mitigation

Total structural acceleration regulation is a means of managing structural response energy and enhancing the performance of civil structures undergoing large seismic events. A quadratic output regulator that minimizes the total structural acceleration energy is developed and tested on a realistic non-linear, semi-active structural control case study. Suites of large scaled earthquakes are used to quantify statistically the impact of this type of control in terms of changes in the statistical distribution of controlled structural response. Structural responses are shown and statistically characterised for a three-story steel moment-resisting frame with realistic non-linear behavior. Total structural acceleration control is shown to be more effective than typical displacement focused optimal structural control methods, by providing equivalent or better performance in terms of displacement and hysteretic energy reductions, while also significantly reducing peak story accelerations and the associated damage and occupant injury. For earthquake engineers faced with the dilemma of balancing displacement and acceleration demands this control strategy essentially eliminates that concern, making it a very attractive solution to mitigate seismic hazards. These results are also presented in a unique graphical form showing the statistical distribution to highlight the impact of control for a suite of ground motions with a given probability of occurrence. Hence, by presenting structural response in terms of statistical distribution, rather than specific data, the results, as best seen graphically, are immediately applicable to a variety of standard hazard analysis methods, which lie at the core of the trend towards performance-based design in earthquake engineering.