Dokai Bay Seibu Gas Pipeline
HEIGHT: 3.2 m
WIDTH: (circular)
TOTAL IMMERSED LENGTH: 434 m
DEPTH AT BOTTOM OF STRUCTURE: 18.2 m
ENVIRONMENTAL CONDITIONS:
Busy shipping channel.
FABRICATION METHOD:
4 m long cylindrical concrete sections were joined together
with epoxT resin and post-tensioned to form 45 m
immersed element.
WIDTH: (circular)
TOTAL IMMERSED LENGTH: 434 m
DEPTH AT BOTTOM OF STRUCTURE: 18.2 m
ENVIRONMENTAL CONDITIONS:
Busy shipping channel.
FABRICATION METHOD:
4 m long cylindrical concrete sections were joined together
with epoxT resin and post-tensioned to form 45 m
immersed element.
Kita-Kyushu City,
Japan
Seibu Gas Co
Mitsui Construction Company
45m
434m
18.2m
Project construction
1977-04-30
10
One tube
3.2m
circular
The immersed elements were manufactured using the match casting fabrication
method. Watertightness was greatly enhanced through prestressing so that no waterproofing
was provided. Because of ship traffic, immersion work was carried out at
night. Construction time was 14 months.
method. Watertightness was greatly enhanced through prestressing so that no waterproofing
was provided. Because of ship traffic, immersion work was carried out at
night. Construction time was 14 months.
4 m long cylindrical concrete sections were joined together
with epoxT resin and post-tensioned to form 45 m
immersed element.
with epoxT resin and post-tensioned to form 45 m
immersed element.
Two 25 ton jacks. Mooring
bollards.
bollards.
Busy shipping channel.
The immersed elements were launched by 700 t floating crane and towed by tugboat
to a mooring point where an element was placed on a self-elevating platform. The selfelevating
platform loaded with an element was towed to the construction site by tugboat.
Alter securing the platform, the element was lifted and then lowered with a gantry
crane.
to a mooring point where an element was placed on a self-elevating platform. The selfelevating
platform loaded with an element was towed to the construction site by tugboat.
Alter securing the platform, the element was lifted and then lowered with a gantry
crane.
Gina type rubber gasket
immersion joints.
immersion joints.
Waterproofing was provided only around the epoxy resin joints using urethane resin.
After backfilling, mortar grouting was carried out in the spaces between the elements
and crushed stone foundation.
and crushed stone foundation.
Section up to the top of the immersed elements was filled with crushed stone. 3 m of
marine a99regate cover was provided over the tunnel.
marine a99regate cover was provided over the tunnel.