Kil‐Wan Ko

Abstract To be competitive in offshore wind energy production, safe and economical foundation design is essential. In recent years, tripod suction bucket foundations have been considered as an alternative to conventional foundations owing to their unique features suitable for offshore construction environments, economic installation, and high overturning resistance. However, it is difficult to accurately predict the behavior of tripod foundation because the load acting on the tripod is complex i

When connected piles are used as settlement reducers, the proportion of vertical load carried by the pile may come close to the allowable load of the pile. To reduce not only the vertical load, but also the lateral load and bending moment to which the pile is subjected, the disconnected piled raft (DPR) has been introduced as an effective design for the role of the settlement reducers. Although several DPRs have been constructed, most of the research efforts on DPRs are limited to the structural

The rocking behavior of a shallow foundation of a bridge pier has emerged as an effective mechanism for reducing the seismic load on the superstructure during a strong earthquake. However, a lack of understanding regarding the rocking behavior of shallow foundations has hindered the application of the rocking foundation design philosophy to construction. In this study, the soil-rounding effect on embedded foundations was evaluated to increase understanding of the rocking mechanism. A centrifuge

Rocking foundations have emerged as an attractive design to reduce the seismic loads of structures during strong earthquakes. However, they cannot be applied in the field directly because of the permanent deformation caused by their rocking behavior. To reduce the permanent deformation induced by a rocking foundation, installation of an unconnected pile below the foundation has been suggested as an improved design. The region of significant plastic strains beneath the foundation caused by the ro

Understanding of the soil-foundation-structure interaction (SFSI) is crucial for seismic design. The period-lengthening ratio (PLR) has been studied using both analytical and experimental methods. In this study, to obtain a PLR that reflects the non-linear characteristics of the soil, dynamic centrifuge testing is conducted and the PLR is evaluated for different seismic intensity and frequency characteristics. The results indicate that the PLR of a single-degree-of-freedom (SDOF) structure incre

The evaluation of the excess pore water pressure ratio (ru), the ratio of the excess pore water pressure of the soil, is a defining approach to assessing liquefaction occurrence. Rarely is ru measured, so surficial observations of sand boils, fissures, and soil settlements have provided indirect evidence of liquefaction occurrence in case histories. Acceleration responses during undrained cyclic loadings incorporate shear strain and stress responses of the liquefied soil. Therefore, the use of a

The magnitude (Mw) 8.3 Tokachi-oki earthquake occurred in September 2003, causing extensive damage in Hokkaido, Japan, and triggering extensive soil liquefaction in the region. The Port of Kushiro was one of the locations where surficial evidence of liquefaction was observed but was also a well-instrumented location with four pore-water pressure transducers installed in the backfill of the quay wall. However, all of the sensors malfunctioned during the earthquake. As a result, the pore-water pre