| 摘要 |
PROBLEM TO BE SOLVED: To reduce fieldworks. SOLUTION: A carriage 20, on which a unit 14 for a road is placed, is made to travel on an upper-layer side road 17a under a built state, and the unit 14 for the road is projected from the upper-layer side road 17a. One end side of the unit 14 for the road is placed on the lifting-lowering section 28 of a carriage 25 on a lower-layer side road 12, and the unit 14 for the road is further projected by making the carriage 25 travel and laterally moving the unit 14 by a lateral moving section 23. The other end side of the unit 14 for the road is put on the lifting-lowering section 28 of a carriage 26 on the lower-layer side road 12, the carriages 25, 26 are made to travel, and the unit for the road is lowered by bringing down the lifting-lowering sections 28 of the carriages 25, 26, and arranged between bearing sections 15. |
