PERFORMANCE LEVEL IMPROVEMENT OF STEEL FRAME BUILDING EQUIPPED WITH OPTIMIZED ACTIVE TENDON SYSTEM

Abstract

The optimized active control system is tested on a steel-framed benchmark building to enhance the structure's performance level against seismic loads. The building is equipped with active tendon actuators at predetermined locations to counteract the external seismic forces. The optimal actuator configuration is searched using PMR-NSGA-II (Population Guided & Modified Reference-Point Based Non-Dominated Sorting Genetic Algorithm-II) to provide an effective and economical control system arrangement. The analysis is conducted via the 3D nonlinear time history analysis considering tri-directional excitations. The performance assessments at the structural and element levels are undertaken to evaluate the building's performance level per FEMA 356 and ASCE41-17, respectively. The active tendon system could effectively suppress the structure's dynamic response against various seismicity levels. The additional dissipation capacity provided by the control force could effectively reduce the yielding and damage of the structural elements. The inter-story drifts are reduced from a range of 2.07%-5.30% to 0.66%-1.92% in the X-direction and from a range of 0.4%-1.23% to 0.4%-0.89% in the Y-direction. The performance level of the structural elements is improved to be 100% below the IO level for all ground motions, except for the Chi-Chi record, where only 13.44% of elements are experiencing the IO-to-LS level. The control system offers great merits in protecting the building against seismic hazards, thus mitigating adverse effects on human activities and safety.