Kim, I.H., Lee, H.S., Cho, W.C. and Song, D.S., 2013. Shoreline changes due to groin construction in Namae and Sodol Beaches, South Korea The present study beach has a long stretch of 5.27km bounded by Namae Harbor in north and Sodol Harbor in south which are located in the eastern coast of Korea. In 2007, a groin was constructed at the southern part of Namae Harbor. In order to analyze the pattern of shoreline change due to the groin construction, a beach survey has been accomplished since 2008 right after the groin construction. The temporal and spatial changes in beach topography are also investigated based on the echo sounding data. The survey data along the coastline showed that a continuous accretion occurred around the groin in the south of Namae Harbor due to the north-directed currents mainly due to diffracted waves formed after the groin construction. Thus the southern beach of study area has been eroded steadily. Also, beach widths and plane area of the beach in the south of the groin were decreased in summer and was increased in winter season. In winter, the ground-based surveying was even impossible due to the severe sand loss in the southern part of study area. Moreover, the survey results revealed that the beach volume was increased and foreshore slope became steeper in 2011 than 2010 survey. Therefore, the continuous beach monitoring along the shoreline is necessary, especially in the seriously eroding beach such as Sodol Beach. More fundamental measures for reliable prediction of potential beach change prior to complementary construction of coastal structures are also needed to maintain the value of the beach.

Pier structures in port and fishing harbor facilities require dynamic analyses during the design phase to account for external dynamic forces because of their high flexibility. Dynamic forces are frequently approximated as equivalent static forces for design purposes in practical engineering applications, but the fluctuational effects induced by these dynamic forces can be neglected. As the frequency range of wave forces acting on pier structures (0.05–1.0 Hz) significantly overlaps with the typical natural frequency range of pier structures (0.25–4.0 Hz), the response of a pier structure can be amplified because of the dynamic effects of the waves. In this study, we conducted a dynamic analysis by applying wave forces—a representative dynamic load—to a pier structure. The results were compared with those from a static analysis. A fatigue life assessment, which is often overlooked in static analyses, was also performed. The findings indicated that the concrete at the connection between the upper pier and steel piles exhibited a fatigue life of 27.3 years. The steel piles exhibited fatigue lives of 27.1 and 8.3 years depending on the weld details, falling short of the expected structural durability. Based on these results, recommendations for pier structures are proposed.

W.D. Lee, M.K. Kim, D.S. Hur, W.C Cho and J.S. Yoon, 2013 Characteristics of sand transport around the submerged breakwaters installed in Songdo Beach, Busan, South Korean, Journal of Coastal Research, Special Issue No. 65, pp. 2143–2148, ISSN 0749-0208.--> Songdo Beach, a pocket beach, is directly affected by wave activities. During the First Coast Repair Project (2000–2009), two submerged breakwaters were installed to reduce incoming wave energy and trap the sand eroded from the beach. After that the submerged breakwaters have played an important roll to determine the hydrodynamics behind the submerged breakwaters and the sand transport along the Songdo beach. For these reasons, five-year monitoring (2004–2008) was carried out for the prediction of shoreline change and for the maintenance of shoreline of Songdo beach. On the basis of the accumulated monitoring data, we analyzed the sand movement in Songdo beach to predict beach erosion. The results reveals that beach erosion occurs by the typhoons during the summer season but beach is recovered in its equilibrium during calm wave period. We also analyzed the flow pattern behind the submerged breakwaters to provide the preliminary data for a long-term stability of the shoreline.