Dokai Bay Conveyor Tunnel
HEIGHT: 4.55 m
WIDTH: 8.218 m
TOTAL IMMERSED LENGTH: 1,363 m
DEPTH AT BOTTOM OF STRUCTURE: 20.9 m
ENVIRONMENTAL CONDITIONS:
There was a requirement not to interfere with marine traffic in the busy Wakamatsu
Fairway, a busy international sea lane. For this reason new construction methods were
devised including the jack-up platform.
FABRICATION METHOD:
Manufactured in new drydock, Nippon Steel Corporation's
Tobata Works, (24 m x 95 m. Outlet 13 m x 10 m).
Elements were made in pairs, towed in turn and temporadly
moored and immersion works carded out.
WIDTH: 8.218 m
TOTAL IMMERSED LENGTH: 1,363 m
DEPTH AT BOTTOM OF STRUCTURE: 20.9 m
ENVIRONMENTAL CONDITIONS:
There was a requirement not to interfere with marine traffic in the busy Wakamatsu
Fairway, a busy international sea lane. For this reason new construction methods were
devised including the jack-up platform.
FABRICATION METHOD:
Manufactured in new drydock, Nippon Steel Corporation's
Tobata Works, (24 m x 95 m. Outlet 13 m x 10 m).
Elements were made in pairs, towed in turn and temporadly
moored and immersion works carded out.
Kitakyushu City,
Japan
Mitsui Mining Coke Industries Ltd
Mitsui, Kajima Joint Venture
80m
1363m
20.9m
Project construction
1972-04-30
17
Two tubes each carrying a conveyor belt for transporting coke.
4.55m
8.218m
Used jack-up platform for placement of elements. Elements cast in a specially constructed
sheet pile cofferdam drydock, two at a time. The total length of tunnel included
17 elements plus a 55.5 m connection section (9.2 m wide)
sheet pile cofferdam drydock, two at a time. The total length of tunnel included
17 elements plus a 55.5 m connection section (9.2 m wide)
Manufactured in new drydock, Nippon Steel Corporation's
Tobata Works, (24 m x 95 m. Outlet 13 m x 10 m).
Elements were made in pairs, towed in turn and temporadly
moored and immersion works carded out.
Tobata Works, (24 m x 95 m. Outlet 13 m x 10 m).
Elements were made in pairs, towed in turn and temporadly
moored and immersion works carded out.
Underwater retention bollard.
Automatic joining
mechanism (coupler)
Automatic joining
mechanism (coupler)
There was a requirement not to interfere with marine traffic in the busy Wakamatsu
Fairway, a busy international sea lane. For this reason new construction methods were
devised including the jack-up platform.
Fairway, a busy international sea lane. For this reason new construction methods were
devised including the jack-up platform.
The drydock was flooded and the box element towed by tugboat. The element was
then secured to the underwater bollards situated in the Sakai River. Ballast was placed
into pockets on top of element. Immersion work was carried out by shipboard crane
where there was a lack of depth, and by self-elevating platform elsewhere.
then secured to the underwater bollards situated in the Sakai River. Ballast was placed
into pockets on top of element. Immersion work was carried out by shipboard crane
where there was a lack of depth, and by self-elevating platform elsewhere.
Single cantilever gasketted
joint. Omega gasket used
across joint.
joint. Omega gasket used
across joint.
6 mm thick circumferential steel plate attached with steel studs.
Screeded foundation placed from jack-up barge.
3.0 m of 40 mm crushed stone.