TA project: DRESBUS

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TITLE OF PROPOSAL: Dynamic Response of Box-shaped underground structures

HOST TA FACILITY: 
IFSTTAR, Nantes, France

TA AGREEMENT BETWEEN USERS AND FACILITY:
3 August 2009

STARTING DATE:
August 2009

END DATE:
June 2010

NO. OF USERS (researchers):
6

LEAD USER:
Yener Özkan - Middle East Technical University (Turkey)

ADDITIONAL USERS:
Deniz Ülgen - Middle East Technical University (Turkey)
Selman Sa─člam - Middle East Technical University (Turkey)
Christos Vrettos - Technical University Kaiserslautern (Germany)
Andreas Becker - Technical University Kaiserslautern (Germany)
Dong Chen - Technical University Kaiserslautern (Germany)


SUMMARY OF PROPOSED RESEARCH:

Seismic safety of underground facilities such as pipelines, culverts, subways and tunnels becomes an essential requirement for continuing economic and social development. Many engineers earlier thought that the underground structures had been inherently safe against earthquakes, but then, especially after the failure of some underground facilities during 1995 Kobe, Japan, 1999 Kocaeli, Turkey and 1999 Chi Chi, Taiwan earthquakes the safety evaluation of the underground structures become a major concern of the engineers.
In this study, dynamic response of box shaped underground structures buried in dry sand and saturated sand will be examined experimentally under harmonic sinusoidal motions by considering the nonlinear behavior of both structure and surrounding soil. For this purpose, a series of centrifuge tests will be carried out (see setup in fig. 1). The dynamic strains of the buried model and the dynamic soil pressures acting on the buried model will be investigated with special reference to the dynamic soil structure interaction. The response acceleration in the ground will also be examined. Specific variables considered in this study are: 1) Input motion characteristics, 2) Rigidities of model. Three different models (see fig. 2) are planned to be used in the tests with varying rigidities. Results of the experiments will be evaluated in order to make an assessment of dynamic soil pressures acting on the buried structure under different motions. Nonlinear finite element method will be integrated with the test results in order to calibrate the parameters by back-analyses. The findings of this study are expected to make significant contribution in the development of seismic design procedures of underground structures and validation of numerical modeling.