평상시 해상조건에서의 상시진동계측 결과를 이용한 부유식 안벽 모델의 동적 특성 평가

Abstract

Recently many studies are being carried out to enhance loading and unloading capability of the existing land-based berthing system and to reduce total logistics cost by developing new-type harbor infrastructures and equipments. To handle the increasing containership and transshipment cargos in time, a new-type floating mobile quay is being developed in this study. The floating-type mobile quay is designed to maximize the handling capability by using both sides of very large container ship and is also expected to utilize for enlargement of an existing berth eco-friendly.For the purpose of analyzing economical and structural feasibility and obtaining core technologies in design, fabrication, ballasting, integration and maintenance of a floating mobile quay, one-sixth scale model with 50m x 30m x 5m dimension of pontoon-type floating mobile quay was constructed in the yard of Samsung Heavy Industries in Geoje, Korea. After turning out four individual modules (with 25m x 15m x 5m) on a floating dock, they were launched, ballasted, and then integrated by post-tensioning. An intensive field test at an open sea area was carried out to verify the structural stability and safety of the mobile quay and crane workability at the operating room during last December.Since these kinds of intensive field experiments in open sea are very difficult to exercise due to high costs of sensor installation and ship rent, an alternative way is also adopted herein based on the ambient vibration measurements under normal sea condition. Ambient vibration test, which can be carried out with simple and economic measurement system, is quite appropriate as a preliminary tool to understand the fundamental dynamic characteristics of a large scale floating structure.Two times of ambient vibration tests were carried out for an individual module of floating mobile quay (with 15mx25mx5m) and for an integrated floating quay (with 30mx50mx5m) and the resonant frequencies and corresponding mode shape