Study on tension of tensile material in fall-down method of exterior wall demolition

Abstract

When an exterior wall of a small-scale building was demolished, a fall-down method using manual labor is applied. In the method, tensile materials such as wire ropes are placed on the exterior wall to prevent the wall from collapsing in the outward direction. Next, the wall is divided into sections, and the lower section of the wall is manually weakened by the worker; then, the wall is pulled down using the tensile material. However, it is possible that the wall falls during the manual weakening of the lower section of the wall, leading to accidents and casualties. One of the accident cases is considered to be the excessive tension of the tensile material. In this study, the relationship between tension and sagging in the tensile material have been examined by experiments. After that, the fall displacement of the wall to outside of the building was examined, and the appropriate tension of the tensile material was examined. The results indicated that the tensile material must be slightly loosened when the workers are still working inside or in the vicinity of the building. Moreover, when the wall is pulled down using the tensile material, the lower section of the wall gets damaged due to buckling of the reinforcing bar and crushing of the concrete. This study also examined how the tension of the tensile material gets transmitted to the lower section of the wall. The results highlighted that the tension of the tensile material is directly proportional to the force applied to the lower section of the wall.