Shimizu Corporation / RC floor slab removal unit type equipment for horizontal cutting and 20% productivity improvement
Process of removing composite girder slabs (provided by Shimizu Corporation)
Shimizu Corporation has developed a cutting technology called the "floor slab cool cut method" that can streamline the removal process of concrete slabs for composite girders for large-scale highway renewal work. Uses a unit-type wire saw cutting device that can handle horizontal and vertical cutting. The joint between the floor slab and the steel girder is horizontally cut from the floor slab in the direction perpendicular to the bridge axis. The conventional process of removing floor slabs between girders before cutting joints can be omitted, and productivity is expected to improve by about 20%.
The cutting device "Foundation Frame Cool Cut" used in the floor slab cool cut method is a technology developed mainly to improve the efficiency of block cutting of foundation structures. After dropping the wire saw into the bottom of the slits provided on the three outer sides of the target block, the bottom of the block is horizontally cut by pulling the wire saw laterally toward the cutting device arranged on the remaining one side.
The same construction method uses the horizontal pulling cutting function of the cutting device. Cut horizontally from the side of the steel girder at the upper part of the joint surface between the floor slab and the steel girder. Since the cutting distance of one block is limited to the girder width, the tension of the wire saw is stabilized and the cutting accuracy is improved. In order to prevent damage to the steel girders, the thickness of the floor slab concrete left after cutting can be reduced to about 20 mm, and the work of removing the remaining concrete by water jet can also be reduced.
The removal of the existing concrete floor slabs accounts for about 30% of the total work in the floor slab replacement work for composite girders. We will actively adopt this construction method because it can greatly reduce the time required for removal work, including the effect of introducing a unit-type cutting device that can be easily relocated.
