This paper introduces a temporary watertight structure under development which consists of a membrane-type barrier and support cables. The membrane-type barrier consists of flexible materials such as cable and a membrane. Model experiments were conducted to determine the conditions required to obtain structural stability and achieve good watertight performance for the flexible barrier based on the new concept. Furthermore, numerical simulation using multipurpose structural analysis code; LS-DYNA 3D based on a finite element method (FEM) is conducted.
Recently, much attention is being focused on the greenhouse effect. As countermeasures for the greenhouse effect, emission controls and segregation of greenhouse gases such as carbon dioxide or marsh gas are being studied all over the world. It is said that sea water levels will rise as global warming causes increased ice melting around the polar zones. Rising sea levels could cause disasters due to large waves, tsunamis, and storm surges even in areas that are not presently at highrisk. Though raising tide embankments is one possible countermeasure, such work is expensive and time consuming because geological formations around high-risk areas are often complicated. Another effective step might be to close the gap between breakwaters. But these gaps between breakwaters are generally shipways so it is impossible to close them permanently. In the Netherlands, ground level is lower than sea level, so the risk of storm surges is large. In Amsterdam, storm surge barriers which are sectoral shape have been installed at the estuary of New Waterway to stem the effect of water surface elevation (Manen, 1997). The breadth of New Waterway is 360m, the main structure of the barriers is as large as the Eiffel Tower, and it weighs 30,000t. This barrier is for defense against storm surges, so time required for setup is an important consideration.