## 1 Introduction  
The ports connecting marine and land transportation are expanding to perform various functions, such as waterfront space and eco-friendly facilities, as well as fundamental functions for commerce and the fishery. These ports also include functions to create safer coasts and ports through the reinforcement of existing facilities, in addition to the development of port peripheral areas linked with leisure facilities. Thus, it is necessary to comprehensively review the planning aspects of the development and use of port peripheral areas in harbor structures. Accordingly, the mutual influence of facilities in the hinterland is complicated by the topographical characteristics and economic and social functions of ports. However, in accordance with the trend of placing more emphasis on the quality of life, sensitivity to disasters caused by climate change has increased. Hence, the needs for harbor structures to reduce disasters has increased. In particular, in areas where serious disasters are expected, the interest for disaster-reducing facilities is high. As global warming due to climate change is expected to increase the intensity and frequency of typhoons [1], storm surges must be urgently prevented because of an increase in the expected casualties and flood damage. As typhoon intensity is expected to increase because of the rising sea levels and temperatures due to the effects of global warming [2], the damage caused by storm surges is expected to increase rapidly. Hence, the requirement to reinforce coastal structures has increased with increases in wave height. Coastal and water side areas should be especially protected from inundation by wave overtopping. To quantify wave overtopping in coastal areas, the EurOtop manual provides empirical formulas for various coastal structures through physical experiments [3], and a numerical model was developed to apply simple harbor geometry [4]. Various types of barriers have been constructed to prevent such inundation. The Eider Barrier of the radial gate type was built in 1973, in Germany [5]. This barrier is part of the dike defense line of the North Friesian coast. In England, the Thames Barrierwas built in 1982 to prevent inundation by high tides (with floods from the upstream of the Thames) and had its official opening in 1984 [6]. Gates of the rotary segment type are normally located on a flat face flush with the river bed when in the gate housing and then rotated 90 degree to close the barrier in an emergency. In 1953, the south-western area of the Netherlands was threatened by a severe storm and was flooded by sea water. After this disaster, the storm surge barrier called the Maeslant Barrier was built in 1997, in the Netherlands [7]. This barrier consists of two sector-gates. The same type of barrier, called the St. Petersburg Flood Protection Barrier, was built in 2011 in Russia [8]. In a normal state, these gates are parked in docks. However, these gates are moved to the center of the waterway to close the channel during severe storms. In 2013, the Venice Flood Barrier, which is one the first four gates of the MOSE project, was built at the Lido inlet in Italy [9]. These gates of the flap type are raised by compressed air pumped into each hollow gate. Recently, a movable barrier type was proposed, such as a flap type that could be installed on the revetment, as shown in Figure 1[10]. This barrier is usually used as a tourist deck but stands up to prevent wave overtopping when a storm surge occurs. Movable barriers should have an effective operational method and the ability to adequately block against wave overtopping. A movable barrier is composed of a double deck, with two hinges installed on the upper deck. Hinges are installed at the end of the deck and the middle of the deck. When the upper deck on the land side is pushed by the actuators, the barrier stands in the form of a triangle since rotation occurs at the hinge. To resist upward forces, such as the uplift force, three-axis bearings are installed on the lower deck.