Seismic Analysis of High-Rise Building using Negative Stiffness Device

Abstract

Abstract: Natural hazard mitigation is one of the most important issues facing civil engineers today. In structural engineering, one of the constant challenges is to find new and better means of protecting existing and new civil structures from the damaging effects of destructive environmental forces, such as wind, waves and earthquakes. Earthquakes are considered the most destructive environmental forces for civil engineering structures. Seismic forces and displacements in existing structures can be effectively reduced in an approach where the structure is intentionally weakened (stiffness and strength are reduced) and damping is added. However, the approach also results in inelastic excursions and permanent deformation of the structural system during a seismic event. A new concept previously proposed by the authors simulates apparent weakening by incorporating a mechanical system that produces true negative stiffness in the structural system. In doing so, inelastic excursions and permanent deformations may be substantially reduced or eliminated. True negative stiffness means that the force must assist motion, not oppose it as in the case of a positive stiffness spring. A passive device capable of exhibiting true negative stiffness, negative stiffness device (NSD), without external power supply is studied in this project work. A pre-compressed spring is used to generate the force to push the structure and a lever-mechanism is adapted to amplify the generated force.