Method for constructing cylindrical tank
There is provided a method for constructing a cylindrical tank, including the step of assembling a metal inner tank by individually and sequentially conducting, on an internal side of a PC wall, raising of an inner tank lateral plate by a jack-up unit and welding of a next-stage inner tank lateral plate onto a lower section of the raised inner tank lateral plate, further including the step of installing a guide pair configured to sandwich the raised inner tank lateral plate onto the next-stage inner tank lateral plate that is to be welded therebeneath. As a result, in the case of adopting the jack-up construction system, it is possible to prevent an inner tank lateral plate from being attached next from falling.
1. A method for constructing a cylindrical tank, comprising the steps of:
assembling a metal inner tank by individually and sequentially conducting, on an internal side of a concrete outer tank, raising of an inner tank lateral plate by a jack-up unit and welding of a next-stage inner tank lateral plate onto a lower section of the raised inner tank lateral plate;
installing a guide pair configured to sandwich the raised inner tank lateral plate onto the next-stage inner tank lateral plate that is to be welded therebeneath; and
transferring the next-stage inner tank lateral plate in a circumferential direction of the tank while the raised inner tank lateral plate is sandwiched between the guide pair to utilize the raised inner tank lateral plate as a transfer rail for the next-stage inner tank.
2. The method according to claim 1 , wherein the raised inner tank lateral plate is vertically aligned with the next-stage inner tank lateral plate therebeneath while the raised inner tank lateral plate is sandwiched between the guide pair.
3. The method according to claim 1 ,
wherein the guide pair has guide rollers that are configured to be rotatable about rotation shafts extending vertically, and roll on plate surfaces of the raised inner tank lateral plate, and
in the transferring step, the next-stage inner tank lateral plate is transferred in a state where a position of the next-stage inner tank lateral plate in a radial direction of the tank coincides with a position of the raised inner tank lateral plate in the radial direction of the tank.
4. The method according to claim 1 ,
wherein a plate surface of the raised inner tank lateral plate that faces an internal side of the tank is provided with a joint to which a jig that positions and fixes the adjacent inner tank lateral plates is attached when the adjacent inner tank lateral plates are welded to each other,
the method further comprising the step of installing a first guide member out of a pair of guide members that constitute the guide pair at a level below the joint, the first guide member being opposed to a plate surface of the raised inner tank lateral plate that faces the internal side of the tank.
5. The method according to claim 4 , further comprising the step of
installing a second guide member out of the pair of the guide members that constitute the guide pair so as to extend to a level above the first guide member, the second guide member being opposed to a plate surface of the raised inner tank lateral plate that faces an external side of the tank.
6. The method according to claim 1 ,
wherein the guide pair has guide rollers that roll on plate surfaces of the raised inner tank lateral plate.
7. The method according to claim 6 ,
wherein a plate surface of the raised inner tank lateral plate that faces an internal side of the tank is provided with a joint to which a jig that positions and fixes the adjacent inner tank lateral plates is attached when the adjacent inner tank lateral plates are welded to each other,
the method further comprising the step of installing a first guide member out of a pair of guide members that constitute the guide pair at a level below the joint, the first guide member being opposed to a plate surface of the raised inner tank lateral plate that faces the internal side of the tank.
8. The method according to claim 7 , further comprising the step of
installing a second guide member out of the pair of the guide members that constitute the guide pair so as to extend to a level above the first guide member, the second guide member being opposed to a plate surface of the raised inner tank lateral plate that faces an external side of the tank.