Journal of Applied Mathematics and Physics, 2014, 2, 1073-1078

Published Online November 2014 in SciRes. http://www.scirp.org/journal/jamp

http://dx.doi.org/10.4236/jamp.2014.212123

How to cite this paper: Le, T.S., Huh, J. and Park, J.-H. (2014) Earthquake Fragility Assessment of the Underground Tunnel

Using an Efficient SSI Analysis Approach. Journal of Applied Mathematics and Physics, 2, 1073-1078.

http://dx.doi.org/10.4236/jamp.2014.212123

Earthquake Fragility Assessment of the

Underground Tunnel Using an Efficient SSI

Analysis Approach

Thai Son Le1, Jungwon Huh1*, Jae-Hyun Park2

1Department of Civil and Environmental Engineering, Chonnam National University, Yeosu, Ko rea

2Department of Geotechnical Research Engineering, Korea Institute of Civil Engineering and Building

Technology, Goyang, Korea

Email: *jwonhuh@chonnam.ac.kr

Received Sep te mber 2014

Abstract

This paper represents a simplified seismic fragility analysis approach of the underground tunnel

structure in consideration of the soil-structure interaction (SSI) effec t. SSI effect founds to be es-

sential in the estimation of dynamic analysis of underground structures like tunnels and thus

needs to be considered. The ground response acceleration method for buried structures (GRAMBS)

known to be a very efficient quasi-static method that can consider SSI effect is used in the pro-

posed approach to evaluate seismic structural responses without sacrificing much accuracy. Seis-

mic fragility curves are then developed by applying the maximum likelihood estimates (MLE) to

responses of a large set of artificial ground motion t ime histories generated for multiple different

levels of earthquake intensity. It is also assumed in this paper that the seismic fragility curve can

be represented by a two-parameter lognormal distribution function with median and log-standard

deviation that need to be defined using MLE.

Keywords

Soil-Stru ctu r e In ter ac tio n, Maximum Likelihood , Fragility Curves, Dynamic Ana lysis

1. Introduction

So far, soil-structure interaction (SSI) analysis is one of the main methods which are being used to observe the

struc tural behavior under seismic excitation considering interaction effect between soil and structure. Also it is

known that, due to unbounded nature of ground system, the computational size of this method is very large. For

this reason, the GRAMBS that can reduce the computational cost of analysis has been proposed [ 1] . In addition,

there is a necessity of a comprehensive methodology for risk assessment of tunnel structure, which has been

mainly based on the expert judgment or empirical fragility curves derived from actual damage record in past

earthquake. The study presents the development of fragility curves by integrating a simplified SSI analysis me-

*