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Movable Flap-Gate Type Seawall

Recent years have seen increasingly serious damage from tsunamis generated by major earthquakes or flooding caused by torrential rain, making disaster-proofing our towns an urgent issue. Hitachi Zosen’s Movable Flap-Gate Type Seawall uses the power of nature itself, in the form of tsunamis or storm surges, to the maximum, preventing flooding damage. Given the rarity of these phenomena, the system has been designed to extremely high standards of reliability in order to ensure the requisite level of protection when called upon. You can see a demonstration of this at Hitachi Zosen’s Disaster Prevention Solutions Laboratory.

Overview of Products in the Movable Flap-Gate Type Seawall

1Establishing technology as floodgates or backflow prevention gates in rivers

Large tidal floodgate

Backflow prevention gate

Using the technology we developed through our tidal floodgates and backflow prevention gates, we have developed a range of products to prevent flood damage from tsunamis or storm surges.

2Use as a seabed system

Use as a flood prevention measure (movable breakwater) in port mouths, etc.

(Bay mouths, port mouths, river mouths, etc.)

<2013 Sea Trials completed>

Use as a breakwater in ports, etc.

(Bay mouths, port mouths, river mouths, etc.)

3Use as land-based system

neo RiSe Series

(Land gates)

(Building entrances)

(Subway entrances)

(Building wall-mounted type)

(Movable seawalls, airport runways, river mouths, etc.)

(For air-conditioning ducts)
<2013 Initial Unit delivered>

Use in Seabed Systems

Seabed-type Movable Flap-Gate Type Breakwater

The seabed-type Movable Flap-Gate Type Breakwater system uses a series of doors along the seabed which are rotated and lifted up using their buoyancy to form a continuous, movable breakwater. This is installed for two purposes: as a breakwater for tsunamis and storm surges designed to control water level changes behind the breakwater, and as a breakwater designed to increase the calmness of the area behind.

Type I Tsunami & Storm Surge Breakwater: Movable Flap-Gate Type Breakwater

Installation location ・ Installation drawing

Operational illustration

Type II Breakwater: Movable Flap-Gate Type Breakwater

Installation location ・ Installation drawing

Operational illustration

Features

The main feature of this product is how it provides the cheapest defensive system by using the natural forces at the site, or in other words the power of tsunamis and storm surges, to the maximum.

  1. The flaps normally lie flat on the seabed to prevent obstruction of marine traffic and sea currents, and therefore have negligible visual impact.
  2. Allows for a cheap defensive system through using structures and mechanisms that make effective use of natural forces.
  3. Constant monitoring of flap rotation provides visual feedback on the system status for extra reliability.

Movable Flap-Gate Type Breakwater System Installed on the Seabed Sea Trial Done at New Yaizu Port

Hitachi Zosen, Toyo Construction, and Penta-Ocean Construction have carried out actual sea-based trials of a Movable Flap-Gate Type Breakwater system installed on the seabed at New Yaizu Port in Yaizu City, Shizuoka Prefecture. The results of the two-year sea trial have been published.

Test device <completed at the factory>

Breakwater Tsunami and storm surge breakwater

View of installation at New Yaizu Port

Final report (October 10, 2013) (digest edition)

Please use the Inquiries form for inquiries regarding this matter. Select “Marine and Disaster Prevention Systems” for the inquiry category. (Department in charge: Frap-Gate Project Department, Steel Structure & Disaster Prevention Business Unit, Infrastructure Business Headquarters)

Use in Land-based Systems: neo RiSe Series

NETIS Registration Number: KK-120055-A

Land-Mounted Movable Flap-Gate Type Seawall

“neo RiSe®” is an abbreviation for “No Energy, No Operation, Rising Seawall,” a new approach to tsunami and storm surge protection distinguished by allowing closure of openings without external power or human intervention. Storm surges can be forecast, allowing time to operate the gates to close the opening. But tsunamis are triggered by earthquakes, which strike without warning, and so the gates need to be closed in a very short time indeed. This problem is what neo RiSe® has been designed to solve. We also offer neo RiSe-A, designed to blend in with building exteriors, and neo RiSe-L, design to allow easy installation into existing facilities, to provide solutions for a range of scenarios.

Normally

neo RiSe®

neo RiSe – A

neo RiSe – L

When a tsunami arrives

Features

  1. In an emergency, the gates can automatically shut by using natural forces, without the need for human intervention, allowing both guaranteed operation and ensuring the safety of the operators.
  2. Employs a simplified design with no drive system or controllers for enhanced reliability and minimal maintenance.
  3. Can be used in conjunction with auxiliary manually-operated systems for operational checking and inspection prior to a tsunami or storm surge.

Delivery and installation track record for principal products

neo RiSe® Land-Mounted Movable Flap-Gate Type Seawall Tokushima Prefecture (Hiwasa Port)
Main specifications
Model neo RiSe®
Dimensions width 4.9m × height 1.0m
Materials Stainless steel
Vertical load T-14
Completion date April 2014
neo RiSe® Land-Mounted Movable Flap-Gate Type Seawall Tokushima Prefecture (Toyomasu Region)
Main specifications
Model neo RiSe®
Dimensions width 15.0m × height 3.0m
Materials Stainless steel
Vertical load 2MPa
Completion date March 2015
neo RiSe-A Land-Mounted Movable Flap-Gate Type Seawall Osaka Prefecture (Nippon Life East Building)
Main specifications
Model neo RiSe – A
Dimensions width 4.26m × height 1.09m
Materials Stainless steel
Vertical load T-2
Completion date December 2014

neo RiSe-D Air-Conditioning Duct-Mounted Flap-Gate Type Cut-off Wall

The neo RiSe-D Air-Conditioning Duct-Mounted Flap-Gate Type Cut-off Wall system is a modification of the existing neo RiSe® to allow it to be used in air-conditioning ducts. This system uses movable cut-off walls to prevent flooding from entering from openings that are never able to be closed, such as ventilation ducts or through-holes. Equipment such as ventilation ducts will remain under water for a considerable time once floodwaters enter them, so the neo RiSe-D is extremely watertight.

Features

  1. Using buoyancy to operate the cut-off wall in a sudden flood, they automatically shut without human intervention.
  2. They are opened manually after checking that water has drained once the water levels have dropped.
  3. They also offer ample protection against flooding from tsunamis.

neo RiSe-W Building Wall-Mounted Flap-Gate Type Cut-off Wall

The neo RiSe-W Building Wall-Mounted Flap-Gate Type Cut-off Wall is, like the neo RiSe-D, a modification of the existing neo RiSe® to prevent flooding into openings in walls that cannot be closed at any time, such as for air-conditioning equipment. In addition, they automatically open when the water levels drop, allowing air ventilation functions to resume.

Features

  1. Using buoyancy to operate the cut-off wall in a sudden flood, they automatically shut without human intervention.
  2. They also offer ample protection against flooding from tsunamis.

neo RiSe-SL Land-Mounted Ultra-Long Span Movable Flap-Gate Type Seawall

The neo RiSe-SL Land-Mounted Ultra-Long Span Movable Flap-Gate Type Seawall is a modified system which retains the properties of the existing neo RiSe® while allowing water to be held back continuously over long distances.

Normally

When a tsunami arrives

Features

  1. They have been modified from the existing neo RiSe® to deal with propagation-aligned waves.
  2. Even when an excess force is applied that is outside the designed force, such as being rammed by a drifting ship, it will avoid total collapse and maintain its disaster-alleviation function.
  3. One unit has been made compact to ensure ease of inspection.

Hitz Disaster Prevention Solution Laboratory

Located within Hitachi Zosen’s Sakai Works, this facility presents information about the neo RiSe® Movable Flap-Gate Type Seawall testing equipment, discharge crushing method, and hybrid LED through demonstrations and panel displays. The Disaster Prevention Solution Laboratory is open to the public. Please contact us from the link below if you are interested in visiting.

Hitz Disaster Prevention Solution Laboratory (Hitz DPSL for short)

Principal equipment: neo RiSe® testing equipment
For factory entrances neo RiSe®
width 5.0m × height 1.2m
For office building entrances neo RiSe – A
width 3.0m × height 1.0m
For subway entrances neo RiSe – L
width 2.0m × height 0.5m

neo RiSe® testing equipment

Large-scale neo RiSe® water flow operation check equipment

This allows us to check operations in an environment close to one following completion of the product. (This is not a permanent exhibit.)

Applicable sizes width Maximum 18m
height Maximum 4m
Storage capacity 600m3
Installation Hitachi Zosen Sakai Works
Flow operation check video

For those who cannot make it to the Hitz Disaster Prevention Solution Laboratory

For those who cannot make it to the Hitz Disaster Prevention Solution Laboratory, we provide a mobile demonstration unit so you can see the neo RiSe® in action.

Operation video
Internet Inquiries
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