Improvement of the Performance-Based Seismic Design Method of Cable Supported Bridges with the Resilient-Friction Base Isolation Systems

Heungbae Gil,Dooyong Cho,Junho Gong,Kyoungbong Han

doi:10.3390/app10113942

Abstract

In areas of civil engineering, the resilient friction base isolator (R-FBI) system has been used due to its enhanced isolation performance under seismic excitations. However, because nonlinear behavior of the R-FBI should be reflected in seismic design, effective stiffness (Keff) of the R-FBI is uniformly applied at both peak ground acceleration (PGA) of 0.08 g and 0.154 g which use a multimodal response spectrum (RS) method analysis. For rational seismic design of bridges, it should be required to evaluate the dynamics of the R-FBI from in-field tests and to improve the seismic design procedure based on the performance level of the bridges. The objective of this study is to evaluate the dynamics of the R-FBI and to suggest the performance-based seismic design method for cable-supported bridges with the R-FBI. From the comparison between the experiments’ results and modal shape analyses, the modal shape analyses using primary (Ku) or infinite stiffness (fixed end) showed a great agreement with the experimental results compared to the application of Keff in the shape analysis. Additionally, the RS or nonlinear time history method analyses by the PGA levels should be applied by reflecting the dynamic characteristics of the R-FBI for the reasonable and efficient seismic design.

Highlights

Studies on base isolators applied to bridges or buildings started in the late 1970s in countries such as the United States, New Zealand, Japan, and European countries and began in earnest in the mid-1980s [1,2]
The field tests were conducted to evaluate the dynamics of a cable-supported bridge with the resilient-friction base isolator (R-FBI)
The bridge dynamics from the experimental data were compared with the modal shape analyses

Summary

Introduction

Studies on base isolators applied to bridges or buildings started in the late 1970s in countries such as the United States, New Zealand, Japan, and European countries and began in earnest in the mid-1980s [1,2]. The resilient-friction base isolator (R-FBI) system has been broadly implemented as an alternative to aseismic design of long-span bridges [4,5,6]. As this kind of system is independent of the changes in the magnitude of seismic load or excitation of the period, it has enhanced performance in the reduction of displacement response [7]. The R-FBI system has been the most applied isolator in both bridges and nuclear power plants in Korea and many researchers have studied the enhancement of its performance and application [2,6,8,9,10]

Objectives

Methods

Results

Conclusion