Infrastructure and Disaster Prevention Systems

Flap-Gate Type Seawall against flood disaster

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 Flap-Gate Type Seawall against flood disaster 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 our Disaster Prevention Solutions Laboratory.

Major products

Overview of Products in the 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.

Moveable Flap-Gate Type Breakwater

(Bay mouths, port mouths, river mouths, etc.)
<2013 Sea Trials completed>

Use as a breakwater in ports, etc.

Moveable Flap-Gate Type Breakwater

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

3Use as land-based system

neo RiSe Series

neo RiSe®

(Land gates)

neo RiSe - A

(Building entrances)

neo RiSe - L

(Subway entrances)

neo RiSe - W

(Building wall-mounted type)

neo RiSe - SL

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

neo RiSe - D

(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 Flap-Gate type Breakwater against Tsunami/Storm Surge
Installation drawing / Installation location
Type II Flap-Gate Type Breakwater for Wave Protection
Installation drawing / Installation location

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. 1The flaps normally lie flat on the seabed to prevent obstruction of marine traffic and sea currents, and therefore have negligible visual impact.
  2. 2Allows for a cheap defensive system through using structures and mechanisms that make effective use of natural forces.
  3. 3Constant 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>
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 Flap-gate Retractable 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

When a tsunami arrives

neo RiSe®

neo RiSe - A

neo RiSe - L

Features

  1. 1In 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. 2Employs a simplified design with no drive system or controllers for enhanced reliability and minimal maintenance.
  3. 3Can be used in conjunction with auxiliary manually-operated systems for operational checking and inspection prior to a tsunami or storm surge.

neo RiSe-D Flap-gate for Air-conditioning ducts

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

neo RiSe-W Flap-gate for In-wall Installation

The neo RiSe-W Flap-gate for In-wall Installation 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. 1Using buoyancy to operate the cut-off wall in a sudden flood, they automatically shut without human intervention.
  2. 2They also offer ample protection against flooding from tsunamis.

neo RiSe-SL Super Long Span Flap-gate Retractable Seawall

The neo RiSe-SL Super Long Span Flap-gate Retractable 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. 1They have been modified from the existing neo RiSe® to deal with propagation-aligned waves.
  2. 2Even 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. 3One 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

Running water operation confirmation 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

Achievements

Achievements in construction of a Seabed-type Movable Flap-Gate Type Breakwater System

For the first time in Japan, a Seabed-type Movable Flap-Gate Type was adopted for this construction.

Name of construction project Construction of coastal measures at Ofunato Fishing Port (Stage 2, Hosoura District)
Orderer Iwate Prefecture
Contractor Hitachi Zosen Corporation
Dimensions Pure span: 32.0 meters × Effective height: 13.0 meters
Number of doors 4 doors (Width: 8.0 meters × Effective height: 13.0 meters)
Construction site Massaki-cho, Ofunato City, Iwate Prefecture
Construction period October 1, 2017 to December 1, 2020
Manufacturing plant Sakai Works, Hitachi Zosen (Sakai City, Osaka Prefecture)

neo RiSe® Land-mounted Flap-gate Retractable 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 Flap-gate Retractable Seawall Tokushima Prefecture (Toyomasu Region)

Main specifications
Model neo RiSe®
Dimensions width 15.0m × height3.0m
Materials Stainless steel
Vertical load 2MPa
Completion date March 2015

neo RiSe-A Land-mounted Flap-gate Retractable Seawall Osaka Prefecture

Main specifications
Model neo RiSe - A
Dimensions width 4.26m × height 1.09m
Materials Stainless steel
Vertical load T-2
Completion date December 2014

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