Oct 30, 2017

First Order Received for a Seabed-Mounted Flap-Gate Type Seawall

Hitachi Zosen Corporation recently received their first order for a seabed-mounted flap-gate type seawall from Iwate Prefecture, for its Ofunato Fishing Port (hereinafter, “the Port”) coastal high tide countermeasures project. This order was their first for a seabed-mounted seawall. Hitachi Zosen has a strong track record in delivering their neoRiSe® land-mounted seawalls, but now, with the commercialization of their seabed-mounted seawalls, they can provide a greater range of tsunami countermeasures.

â– Order Background
Hitachi Zosen has worked on developing seabed-mounted flap gates in 2003, land-mounted gates in 2009, and building wall-mounted gates and air-conditioning duct-mounted gates in 2011. Hitachi Zosen have built up a track record in delivering land, building wall, and air-conditioning duct gates.
The seabed-mounted gate type that Hitachi Zosen have now received their first order for was developed in conjunction with Toyo Construction Co., Ltd. (Koto-ku, Tokyo; President: Kyoji Takezawa) and Penta-Ocean Construction Co., Ltd. (Bunkyo-ku, Tokyo; President: Takuzo Shimizu), and its performance was verified in actual marine use at Shinyaizu Fishing Port (Yaizu City, Shizuoka Prefecture). The results of this marine testing over three years, from 2011 to 2013, met their expectations for its basic functions and reliability.
This order was received from Iwate Prefecture as part of its restoration work for the Port, which was severely damaged in the Great East Japan Earthquake. Hitachi Zosen are responsible for the design, construction, transport, and installation of this seabed-mounted flap gate-type seawall. In addition, after this particular order is completed, this will be the first construction project in Japan of a seawall that automatically rises through tsunami wave force to block ingress of water.

Project Overview
1. Client : Iwate Prefecture (Governor: Takuya Tasso)
2. Project : Ofunato Fishing Port Coastal High Tide Countermeasures Construction (Hosoura District Seawall No. 2)
3: Machinery : Seabed-mounted Flap Gate Seawall
4. Dimensions : Clear span: 32 m / Effective height: 12 m
5. Location : Near Massaki-cho, Ofunato City, Iwate Prefecture (seabed at a depth of 5 m)
6. Value : 2,344,000,000 yen (before tax)
7. Construction : October 2017 to March 2020
8. Assembly : Sakai Works

Rendering: When raised (source: Iwate Pref.)

Rendering: When lowered (source: Iwate Pref.)