Presentation Title

Performance Assessment of Different Isolation Systems in Term of Seismic Energy

Faculty Mentor

Dr. Giuseppe Lomiento

Start Date

18-11-2017 9:45 AM

End Date

18-11-2017 10:00 AM

Location

9-243

Session

Engineering/CS 1

Type of Presentation

Oral Talk

Subject Area

engineering_computer_science

Abstract

In Earthquake engineering, seismic isolation systems are a practical way for engineers to reduce the seismic forces that a building would normally experience under typical seismic design methods and improve the seismic performance of the structure. However, the dispute and limitations between two design methods in earthquake engineering, Displacement Based Design (DBD) and Force Based Design (FBD), encouraged researchers to look for new ways to analyze seismic events, such as Energy Based Design (EBD) methods. This study investigates the performance of a structure with different isolation systems in terms of seismic energy absorption and dissipation. The effect of the seismic isolation is analyzed by means of numerical dynamic simulations on a three-story building. The benefits of including seismic isolation systems of different types is assessed in terms of amount of energy absorbed by the structural frame, and compared with the energy absorbed by an identical structure without seismic isolation systems. Parametric analyses are performed in order to determine optimal properties of the seismic isolation system, aimed at reducing the amount of seismic energy affecting the structural frame below minimum levels to prevent damages.

Summary of research results to be presented

The results of this study include the Energy comparison of a Seismic isolated building with a non-isolated building, and the effects that the isolator’s stiffness(k) value has in the structure during seismic events.

Numerical simulations for several seismic events show that 94% of the peak energy of the isolated system is absorbed by isolators. The remaining energy, about 6%, is distributed to the rest of the structure. The results are then compared to the absorbed energy of the non-isolated structure, which in general is two(2) to three(3) times bigger. It is observed that the total amount of energy absorbed by a structure heavily depends on the seismic event, while the percentage of energy absorbed by the isolation system is consistent regardless of the ground motion.

The study also investigates the performance that isolators with different stiffness have in a building. The correlation between stiffness and natural period is well known; a decrease in stiffness causes an increase of the building’s natural period, which in general decreases the total energy the building absorbs in a seismic event. The correlation between the stiffness of the isolators and the percentage of energy absorbed by the above structure has not been studied extensively. Results from a parametric analysis show that the stiffer the isolator, the more energy the building system absorbs from a seismic event. This result supports the idea that the design of the isolation stiffness may be driven by a reduction of the energy absorbed by the structure below acceptable levels.

This document is currently not available here.

Share

COinS
 
Nov 18th, 9:45 AM Nov 18th, 10:00 AM

Performance Assessment of Different Isolation Systems in Term of Seismic Energy

9-243

In Earthquake engineering, seismic isolation systems are a practical way for engineers to reduce the seismic forces that a building would normally experience under typical seismic design methods and improve the seismic performance of the structure. However, the dispute and limitations between two design methods in earthquake engineering, Displacement Based Design (DBD) and Force Based Design (FBD), encouraged researchers to look for new ways to analyze seismic events, such as Energy Based Design (EBD) methods. This study investigates the performance of a structure with different isolation systems in terms of seismic energy absorption and dissipation. The effect of the seismic isolation is analyzed by means of numerical dynamic simulations on a three-story building. The benefits of including seismic isolation systems of different types is assessed in terms of amount of energy absorbed by the structural frame, and compared with the energy absorbed by an identical structure without seismic isolation systems. Parametric analyses are performed in order to determine optimal properties of the seismic isolation system, aimed at reducing the amount of seismic energy affecting the structural frame below minimum levels to prevent damages.