TA Project: DRESBUS II

Click here to read the final report of the DRESBUS II project.

A concise presentation of the project's aim and main outcomes is available in the Joint brochure of the SERIES TA facilities.

TITLE OF PROPOSAL: Investigation of the seismic behaviour of shallow rectangular underground structures in soft soils using centrifuge experiments

HOST TA FACILITY: IFSTTAR, Nantes, France

TA AGREEMENT BETWEEN USERS AND FACILITY:
signed

STARTING DATE: January 2011

END DATE: December 2012

NO. OF USERS (researchers): 8

LEAD USER: 
Manolis Rovithis - Earthquake Planning and Protection Organisation (EPPO-ITSAK) (Greece)

ADDITIONAL USERS: 

Kyriazis Pitilakis - Aristotle University of Thessaloniki (Greece)
Grigoris Tsinidis - Aristotle University of Thessaloniki (Greece)
Anastasios Anastasiadis - Aristotle University of Thessaloniki (Greece)
Dimitris Pitilakis - Aristotle University of Thessaloniki (Greece)
Konstantia Makra - Earthquake Planning and Protection Organization (EPPO - ITSAK) (Greece)
Manolis Kirtas - Technological Educational Institute of Serres (Greece)
Roberto Paolucci - Politecnico di Milano (Italy)


SUMMARY OF PROPOSED RESEARCH:

Underground structures such as tunnels, metro and parking stations constitute a crucial component of the transportation network in urban areas. Τhe important socio - economic nature of these structures and the associated impact in case of earthquake induced damage denote the paramount importance of safe seismic design, especially in seismic prone regions.

Obviously, seismic behaviour of underground structures differs substantially from aboveground structures due to the particular geometry and structural system of the former and the strong stress coupling with the surrounding soil. However, design of underground structures employed in modern seismic codes is based primarily on simplified guidelines, given the lack of well-documented case histories and postearthquake observations as well as the complexity of experimental tests in large-scale facilities.
To this end, Middle East Technical University (METU) proposed in IFSTTAR – Nantes an experimental investigation on seismic behaviour of underground structures within the framework of SERIES (Centrifuge modeling of dynamic behavior of box shaped underground structures in sand). This proposal extends the above experimental study, posing a series of original questions and further numerical developments with respect to the on-going METU experimental program.

The presently proposed research explores several critical open issues aiming at the development of a reliable and accurate analytical method for the seismic design of this kind of structures. To this end it is complementary but more general than the already agreed METU project. In particular it is proposed to perform well – focused centrifuge tests to investigate the following critical points:

(i) Seismic earth pressures distribution along the side-walls, which is also the main research point of the METU proposal.

(ii) Seismic shear stresses distribution along the perimeter of underground structures.

(iii) Impedance functions for underground structures to model kinematic and inertial soil structure interaction effects in the transversal and longitudinal direction. 

The production of high quality experimental data will be extremely valuable in order to better understand the seismic behaviour of underground structures and to validate numerical models. Along these lines, the collaboration of the two research teams on the production of a well-constrained set of experimental results will certainly enhance the research effort towards the development of reliable code regulations for seismic design of underground structures.

What's next

Series logo small   SERIES Concluding Workshop
  Joint with US-NEES "Earthquake Engineering Research Infrastructures

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