Alper Sezer

Offshore wind power technology presents a viable solution to address significant challenges related to energy and climate change. Moreover, it has the potential to stimulate economic growth and create employment opportunities. Considering Türkiye's favourable geographical location and extensive coastline, the integration of offshore wind power stands as a pivotal factor in helping the country attain its energy targets from 2035 to 2053. There are currently no installed offshore wind turbines (OWTs) in Türkiye; however, the Turkish Ministry of Energy and Natural Resources has delineated three development zones in the Sea of Marmara for the installation of OWTs. With the commencement of developments in these specified areas, strategic plans aim to increase the installed capacity of OWTs. This study is an attempt to evaluate possible and plausible locations of wind turbine installation within Turkish maritime boundaries, which are estimated to have a high potential for offshore wind energy. Moreover, types of foundations supporting OWTs along with their associated design criteria are enlisted. Considering Türkiye's position in a seismically active region, an overview of seismic hazards is summarized, and the impact of relevant seismic hazards on foundations is discussed. It should be emphasized that, despite the drawbacks due to tourism and international seaborne traffic, Türkiye, having a population more than 85 million, has a great wind energy potential, which needs extensive and meticulous assessment for a sustainable future.

Earthquakes cause cyclic shear deformations in soil and build-up of excessive pore water pressure as a result of undrained loading, accompanied with rearrangement of soil particles and degradation in stiffness of the soil due to decrease in effective stresses. During loading, the onset of soil liquefaction is defined as a stress state in which the excess pore water pressure is equalized to the total stress. From this point of view, assessment of the pore water pressure development pattern under cyclic loading has been one of the most salient research topics in geotechnical and earthquake engineering. In this study, results of a series of cyclic triaxial tests on non-plastic silt specimens consolidated under 100 kPa effective isotropic consolidation pressure were used to question the modelling ability of pore pressure development models previously proposed for sands. Tests were performed on specimens of 6 different initial relative densities (Dr) ranging between 30-80% and 10 different cyclic stress ratios (CSR). The key parameters of pore water pressure development and shear deformation in the energy-based model used are relative density, cyclic stress ratio and number of cycles. The results revealed that, these energy-based models have a strong potential in evaluation of pore water pressure development pattern of non-plastic silts. Test results also show that the increase in relative density and decrease in CSR causes a ladderlike behavior among pore water pressure and cyclic shear strain, which is relevantly rendered by energy-based models.

Application of toughness limit in assessment of soil compaction identifiers In geotechnical engineering, the precise evaluation of compaction parameters is essential for quality control assessment. One option is the use of the toughness limit (TL), concisely defined as the water content, at which the behaviour of fine-grained soils evolves from an almost adhesive-plastic to tough-plastic. A database consisting of more than 1000 test results, including the compaction characteristics and Atterberg limits, was compiled to establish correlations between the TL, Atterberg limits, optimum degree of saturation, and compaction properties. The results revealed that the TL has the potential to evaluate many indices and compaction identifiers for different types of soils.