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Dynamic Response and Instability of Seabed-Coastal Structure Systems under Waves

Final Report Summary - DRISCS (Dynamic Response and Instability of Seabed-Coastal Structure Systems under Waves)

Coastal and offshore structures built to protect coastal regions constitute a significant part of marine infrastructure across Europe with its long coastlines. The instability of such structures is induced primarily by the action of oscillatory and impact forces caused by severe waves. Geotechnical aspects play a significant role in initiation of these instabilities. Thus, evaluation of wave-induced response of seabed around coastal protection structures plays a key role in mitigation of the associated hazard. Particularly, the analyses of such soil-structure systems require accurate modeling of seabed response under waves. This four-year research project funded by the Marie Curie Career Integration Grant (MC-CIG) in FP7 of the EU titled “Dynamic Response and Instability of Seabed-Coastal Structure Systems under Waves” with acronym DRISCS, analyzes the dynamic response and instability of seabed soil around common coastal protection systems such as a rubble-mound breakwater and a caisson type gravity quay wall under standing waves.
It was found in DRISCS that the conditions leading to instability of the seabed-structure systems depend on the variations of key physical parameters of both the soil and the structure in time domain during wave loading as well as in the spatial directions around the structures. In the project, the focus was on the wave-induced liquefaction of underlying seabed and backfill soil of the quay-wall and to the best of our knowledge, this has been the first time liquefaction-induced failure potentials of a rubble-mound breakwater and a caisson type gravity quay wall were analyzed in a comprehensive fashion. Parametric studies conducted to understand the conditions leading to liquefaction of soil under wave action revealed the importance of relative movement of seabed soil interacting with structures, the breakwater and quay wall. While this is one of the main contributions of the project DRISCS to the state-of-the-art engineering practice, novel soil constitutive relationships have also been developed along the way to better understand the elemental behavior of soils at the fundamental level. Another contribution was that the analyses of such coastal systems resulted in developing many computational tools and numerical models useful to engineers, students and early career researchers working in this field.
With this project, the researcher, Dr. Ulker, has been given the opportunity to establish his research group at the host institution, Istanbul Technical University Institute of Earthquake Engineering and Disaster Management in Istanbul, Turkey. He has completed the reintegration period by securing a permanent faculty position as an associate professor there. Project DRISCS can be considered as a milestone in Dr. Ulker’s professional research career in that he has gotten the chance to set the foundations of a work group in not only the host institution ITU, but also in the host country on the fields, computational geomechanics and coastal-geotechnical engineering. Please see for more details.