STUDY ON A LIFTING DEMOLITION METHOD USING DIAGONAL SLAB CUTTING

Takahiro Nakamura; Takeshi Ishida; Tomohiro Yoshida

Abstract:

In Japan, urban construction projects often require demolition of existing structures, and the number of high-rise building demolition cases has been increasing in recent years. Conventional above-ground demolition methods include the top-down demolition method, in which heavy equipment is placed on the rooftop to dismantle the structure floor by floor, and the block demolition method, in which large sections of the structure are cut into blocks and lowered using tower cranes. However, these techniques present several challenges, such as debris fall risk, dust dispersion, extensive use of temporary supports, and increased construction time and cost. To address these challenges associated with high-rise demolition work and to enhance productivity, this study proposes a novel technique using a concrete cutter capable of diagonal slab cutting. The specifications of the cutter were experimentally examined, and the method was applied in the field to assess its feasibility and effectiveness. Results indicated that inward blade orientation is optimal for diagonal cutting. On-site application achieved an average cutting speed of 0.78 meters per minute. Compared to the conventional block demolition method, the proposed approach shortened the construction period by approximately two months, resulting in a 20%-time reduction. These findings demonstrate the practical advantages of diagonal slab cutting in enhancing demolition efficiency for high-rise buildings.