Design of Triple Concave Friction Pendulum isolators using meta-heuristic optimization methods

The primary objective of this research is the optimal design of a Triple Concave Friction Pendulum (TCFP) isolator utilizing the metaheuristic Particle Swarm Optimization (PSO) algorithm. This algorithm has garnered significant attention in structural engineering due to its exceptional capability in solving complex optimization problems. By simulating the collective behavior of the particles, the PSO method intelligently navigates the design space to identify optimal solutions with high precision and efficiency. Seismic isolation, as an advanced technology in earthquake engineering, significantly reduces seismic forces by increasing the natural period of the structure. This reduction in forces leads to decreased accelerations at the building’s floor levels, consequently minimizing inter-story drifts. This enhances the overall stability, safety, and resilience of the structure, reducing the risk of structural damage and ensuring long-term durability under seismic loading conditions. The implementation of seismic isolation systems alters the behavior of the superstructure, effectively causing it to act as a rigid body. This characteristic ensures that non-structural elements, such as partition walls, mechanical and electrical installations, and internal building equipment, sustain minimal damage under seismic forces. This aspect is particularly critical for sensitive structures, including hospitals, data centers, research laboratories, and high-rise buildings, where maintaining the functionality of these elements during an earthquake is vital for operational continuity, occupant safety, and post-earthquake recovery. With advancements in earthquake engineering technology, innovative and efficient isolation systems have been developed and introduced, among which friction pendulum systems stand out as one of the most prominent due to their reliability, adaptability, and effectiveness in diverse seismic scenarios. Triple Concave Friction Pendulum (TCFP) isolators are recognized as one of the most advanced types of seismic isolators. These isolators feature four distinct sliding surfaces, each characterized by unique properties, including friction coefficient, radius of curvature, and displacement capacity. These attributes enable designers to precisely adjust the design parameters to optimize the effective stiffness and the damping of the isolation system for various performance levels under earthquakes of differing intensities. This flexibility makes TCFP isolators an ideal choice for seismic retrofitting of structures, particularly in high-seismic-risk regions where robust protection is essential for safeguarding lives and infrastructure. The primary focus of this research is the optimal design of various parameters of the TCFP isolator. To achieve this goal, the PSO algorithm is employed, which conducts an intelligent search within the design space to identify the best combination of parameters. The objective functions considered in this study include single-objective optimization to minimize drift (inter-story displacement), roof acceleration, and isolator displacement. Additionally, multi-objective functions, such as the combination of drift-roof acceleration and roof acceleration-isolator displacement, have been investigated. These objective functions are carefully selected to simultaneously enhance the structure’s performance under various earthquake scenarios while maintaining a balanced trade-off between different performance criteria. This research aims to provide a practical and efficient approach to improving the seismic performance of structures. Its findings can assist engineers in designing more resilient and safer structures while optimizing construction and maintenance costs, contributing to sustainable infrastructure development in earthquake-prone areas worldwide.