Study on Residual Response of Steel Moment Frames Equipped with TADAS Yielding Devices Subjected to Seismic Excitations

Recent approaches in seismic design of structures appreciate a lot of the utilization of structural control systems and energy absorbing devices as a means of reduce the damage caused by earthquakes. Due to their efficiency and appropriate seismic response assessment, TADAS metal dampers are a kind of the energy absorbing systems in passive structural control drawn many researchers and structure designers' attention in order to design new structures and improve seismic performance of existing structures. Growing increase of the utilization of this kind of systems in many countries around the world, such as Japan and U.S., beside the compilation of regulations and building codes in relation to these systems demonstrate the tendency of engineering society to benefit from this simple technology.
It is very important, in structure studies after earthquakes, to recognize residual displacement and permanent deformations of structures in order to determine their remaining capacity and extent of damage incurred due to the earthquake. This will be a decisive factor in rehabilitation and repair possibility or destruction necessity of structures.
The present research studies the residual displacements behavior of steel moment frames equipped with TADAS yielding devices. For this purpose, SAC steel moment frames with 3, 9 and 20 stories have been used, and structural responses including residual displacements, maximum displacement, relative-story displacement and maximum absolute acceleration have been evaluated by dint of SAP2000 features in nonlinear static and dynamic time-history analyses utilizing 11 far-field seismic records, scaled by methods based on 2800 standard rules and ASCE 7-10 instructions. Results show that, on average, the maximum residual inter-story drifts are reduced 75% to 80%, 15% to 85% and 30% to 80% for the 3-, 9- and 20-story models, respectively. In addition, on average, the maximum displacements are reduced approximately 50% for the 3-story model and 10% to 40% for both 9- and 20-story models. The ratio of residual to maximum displacements are reduced 50% to 65%, 50% to 55% and 20% to 50% for the three models, respectively. Results reveal that the effectiveness of TADAS dampers in reducing the responses and enhancing the seismic performance of building frames are reduced with increasing the height of the structure. Incorporating TADAS dampers also results in more uniform distribution of seismic displacement demands through the height of the structure. Results of this study and comparing the responses with performance limit states defined in FEMA P-58 based on the amount of residual deformations demonstrate that structures equipped with TADAS dampers are more seismic resilient than non-equipped structures.