Tokyo Bay storm surge barrier: A conceptual design of the moveable barrier

Tokyo Bay storm surge barrier: A conceptual design of the moveable barrier

Tian, K.

Jonkman, S.N. (mentor)
Van der Toorn, A. (mentor)
Hoogenboom, P.C.J. (mentor)
Esteban, M. (mentor)

Civil Engineering and Geosciences

Hydraulic Engineering

Hydraulic Structures and Flood Risk

2014-10-06

Introduction Typhoons and tsunamis are dangerous phenomena for our society and Japan has been exposed to both of these hazards. The risks of these hazards are getting bigger and bigger due to the growing population in the cities near these ‘dangerous’ coasts. This thesis focuses on the design of a storm surge barrier located in Tokyo bay to reduce the flooding risk of Tokyo and its surrounding areas, based on a global-to-detailed approach. Design framework The span between Yokosuka and Futtsu is considered as the most suitable location for the placement of a barrier. Typhoons had been considered as the main threat. Requirements: § Resist Ise-wan types of typhoon (1959) § Contain navigation channel sufficient for future usage § Maintain as much as possible water exchange between bay and sea Design process Based on the requirements and analysis it is chosen for a barrier that is partly closure dam and partly moveable barrier, from which the moveable barrier is placed above the under water dam at the deepest part of the span. Since this thesis focuses on the moveable barrier, the design process proceeds with only the design of the moveable barrier. As it is presumed that earthquakes will be critical for this project during the chosen design life, a new concept, the floating moveable barrier, is chosen for further design due to its great potential regarding earthquake resistance. Considering the cost and the preferred weight and size of the gate, the inflatable rubber gate is applied for the floating moveable barrier. A preliminary for this floating moveable barrier is drafted to find the required main dimensions and configurations. Based on this preliminary design it is found that by placing maximum 5 floating moveable barriers, both the navigation channel and the gap between the floating moveable barrier and the under water dam can be left open without the water level rise inside the protected area exceeds its acceptable limit. In the last design step the earthquake resistance of the floating moveable barrier regarding resonance is checked based on an analytical dynamic model. Based on the results from dynamic model the floating moveable barriers over the span is expected to be stable during the earthquakes. But because of the simplicity of the used model and limited validation material, more research regarding the dynamic behaviour of the floating barrier is needed. If the floating barriers appear to be unstable, the sag of the mooring line can be changed to adjust the stiffness of the system. Conclusion and recommendation Overall the floating moveable barrier has been considered as a technically feasible design and it has shown great potential in its effectiveness regarding the earthquake resistance and flexibility in maintenance and replacement. Recommendations for future research: § Check dynamic behaviour under both earthquake and storm conditions using more detailed numerical model including the contribution of the water damping and the sag of the mooring lines § Anchor design § Economical feasibility analysis § Possible closure methods for the gap between the underwater dam and the floating moveable barrier. § Possible erosion problems of the gap between the floating moveable barrier and the under water dam.

floating moveable barrier
Tokyo Bay
typhoon
tsunami
earthquake

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Student theses

master thesis

(c) 2014 Tian, K.