October 30, 2000
Construction of the World's Largest Panta Dome Push-up Structure,
The Nisseki Mitsubishi Kudamatsu Coal Storage Dome, an immense structure taking shape along Higashi Kaigan-dori Avenue in the city of Kudamatsu in Yamaguchi Prefecture, is being built as a "relay point" for the Chugoku Electric Power Co., Inc. to store coal imported from overseas for later distribution to its thermal power plants. The coal silo, which is a special hexagonal doughnut-shaped structure that is 45 meters high and 251 meters in diameter, can hold six piles of coal weighing 50,000 tons each. The revolutionary shape of the silo was designed by a consortium of makers, builders, and, especially, the Chugoku Electric Power Co., Inc., the company in charge of the engineering, which sought to incorporate the best characteristics of existing storage facilities to create a silo that could be operated efficiently and transported with slimmed-down equipment. In the creation of such a large space structure, a tremendous amount of time and labor is usually required to assemble the steel frame from the ground up. However, the panta dome structure used here was built using a patented method conceived by Dr. Mamoru Kawaguchi, a professor at Hosei University. The large frame roof, which had been folded up, was assembled on the ground, then hydraulic jacks were used over a period of five days to lift it up to its final height of 45 meters. The advantages of assembling such a structure on low ground included improved safety and work efficiency, as well as a marked reduction in construction time. This project, of which there are seven examples in the world (five in Japan alone), is at a push-up area of 41,000 square meters, weight of 6,500 tons and lifting height of 30 meters. It is the largest in the world and is the first of its kind in the Chugoku region. This is also the third such project that has been executed by Takenaka Corporation; the first was the World Memorial Hall's Panta Dome in Kobe (completed in 1984), and the second was Namihaya Dome in Kadoma City in Osaka Prefecture (completed in 1996). |
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| Brief description of the Push-Up
Method
(2) The contact sections become hinges that are connected with pins
that allow for smooth movement.
(3) When the 56 hydraulic jacks that are installed in the locations
of push-up equipment (four jacks at each of the 14 locations) are extended
by a computer installed in a central command room, it looks like a giant
crab standing up (Figure 2).
(4) Struts are added every two to three meters, and the structure is
pushed up seven meters each day.
(5) Pushed up 30 meters, its shape finalizes when it reaches 45 meters
in height, then the structure is fixed into place. (Figure 3)
(6) After the steel frame finishing of the connecting sections is completed,
the support columns are removed. Introduction of precision measuring technology A profile of the coal silo looks like a nonsymmetrical mountain. Because it is pushed up to a height of 45 meters, a very precise construction method is needed. Therefore, pushing up was done with the assistance of precision measuring instruments such as an electrooptical meter that measures height and horizontal position, a pressure transformer that measures the reaction force of the jacks, and strain gauges that confirm the stress on members. The process is controlled by computer from a central command room. Schedule for subsequent work After completion of the framework, construction
will begin on the roof and on the facilities for machinery and electricity.
Outline of the Nisseki Mitsubishi Kudamatsu Coal Storage
Dome
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(1)
Temporary working platforms are set up in each corner, and the steel frame
truss is assembled on top of them. The profile of the assembled frame shown
in Figure 1 looks like a crab with its legs outstretched.
