Nonlinear Seismic Performance Assessment of Energy-Based Steel Structures with Rigid Connections

In evaluating the seismic performance of existing multi-story buildings, strain-based static pushover and time-history nonlinear analyses are traditionally used, as stated in the regulations. In addition, by evaluating the performance levels of symmetrical and asymmetrical structures, it will also be possible to design the mechanism with damping energy capacity that will completely absorb the earthquake energy in case of an inadequate situation in absorbing the earthquake energy. In this study, using real earthquake data, the usability of the energy-based performance analysis approach in the structure was investigated on a 20-story steel structure with rigid connections for symmetric and asymmetric structures. This study was conducted to demonstrate the usability of the energy-based method in evaluating the performance level of buildings under the effect of several earthquakes. In addition, the energy-based method was preferred to determine how much earthquake energy generated in the buildings could be distributed in symmetrical and asymmetrical structures. The selected 11 earthquake data were scaled and the input energies to the structure and the energies distributed by the structure (dissipated hysteretic energy, modal energy, dumping energy, and kinetic energy) were analyzed. Additionally, moment-rotation and axial force-strain behaviors were evaluated for the performance levels of the inspected symmetric and asymmetric structures. At the end of the study, the energy-based concept was confirmed by comparing it with the static pushover analysis results in determining the seismic performances of high-rise structures with very low dynamic mass participation rates. Energy-based analyses have shown that the symmetrical structure absorbs earthquake energies more than the asymmetrical structure and remains at the immediate occupancy (IO) level, as expected. It was concluded that the asymmetric structure remained at a controllable damage (LS) level. Energy-based evaluation has been used as a performance analysis method in the literature. In addition to performance analysis, this study aimed to calculate how much energy is required for the damping mechanism to be added to the structure so that an asymmetric structure behaves like a symmetric structure. This constitutes the original value of the article. So, it has been determined that in order for the asymmetric model to be at the immediate use level, a damper with an energy capacity of 0.062 m2/sec2 is needed, which can absorb earthquake energy from the outside, depending on the building mass.