Analytical Study on Seismic Strengthening of Existing Reinforced Concrete Buildings by Implementation of Energy Absorbers

When an earthquake phenomenon occurs, it destroys the weak members of the RC buildings, therefore, the damages during severe earthquakes stimulate nonlinear behavior of the structure. The structural and nonstructural damages caused by earthquakes are essentially due to the lateral acceleration and displacements. Accordingly, seismic load evaluation is significant for seismic design assessment and performance. One of the considerable challenges is to establish the optimal design to retrofit existing buildings against the effect of predicted earthquakes with minimal disturbance of the existing structure and the residents in a short time. This research presents an analytical study of an energy dissipation system for seismic strengthening of existing Reinforced Concrete RC building. The proposed analytical study was conducted to investigate the implementation of SHARK energy absorber to the bracing system of existing building located in high seismic zones of Turkiye. The proposed system, which aims to provide high protection of the structure during severe ULS earthquakes, long-term reliability against wear and fatigue problems, high redundant safety level, easy visual inspection, and easy to replace at low cost along with preventing earthquake damages by controlling the maximum inter-story drifts. The SHARK system performs as a bilinear hysteretic device which consists of fixation plates and a dissipative core that dissipates the energy by a series of hysteretic lamellas. To investigate the performance of the proposed design and configuration nonlinear time history analyses NLTHA was carried out by applying a pair of 11 selected earthquake records on 8- Story RC buildings. The main investigated parameters which are (i) Displacement, (ii) Inter Story Drift Ratio, acceleration, and Input Energy are studied according to the different configurations of energy dampers. The obtained results of SHARK damper implementation and the absorbed seismic energy showed that the seismic responses of the strengthened structures were significantly higher than the original structures. The maximum displacement and drift reduction values of the strengthened buildings are between 70% and 80% in comparison with their original buildings. Further The maximum acceleration reduction values of the strengthened buildings are between 4% and 20% in comparison with their original buildings. The levels of input energy decreased considerably the reduction is on average about 64% and 70%, as a result the structure was able to resist various earthquakes events.