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Yanggu, South Korea

Hoon P.,Chonbuk National University | Chul-Gi S.,Korea Kacoh Co
Science and Technology of Energetic Materials | Year: 2010

Recently, the number of cement silos that must be demolished due to unsatisfactory functional conditions has increased. A cylindrical shell structure that is constructed in the slip form method, a cement silo is composed of an internal structure that consists of a cone and ring girder and an external structure that consists of a cylindrical shell. As these two structures are two separate structures and have reciprocal effects on collapsing movements, it is not easy to apply explosive demolition. The design and execution of a method used to demolish a 10,000 ton level cylindrical cement silo by blasting were described in this study ; moreover, the effects of ground vibration and dust were examined. Source


Park H.,Chonbuk National University | Park H.-K.,Korea Kacoh Co | Ko J.-H.,Korea Kacoh Co | Suk C.-G.,Korea Kacoh Co
Science and Technology of Energetic Materials | Year: 2013

With the deterioration and functional loss of structures, there is an increasing demand for demolition and various demolition technologies have been developed. In case of large-scale concrete, application of some mechanical demolition techniques is limited because of the structural characteristics, and explosive demolition or explosive demolition combined with mechanical demolition is applied recently due to the effect to the surrounding environment by the ground vibration. In this study, we compared peak particle velocity (PPV) of ground vibration depending on average fragment size (Dav) in case of explosive demolition design for large-scale concrete foundation using the relation among specific charge (Sc), charge constant (K), and transmitting medium constant (n) as well as the relation between average concrete fragment size (Dav) and specific charge (Sc). Source


Park H.,Chonbuk National University | Suk C.-G.,Korea Kacoh Co | Choi S.-H.,Chonbuk National University | Kang H.-M.,Chonbuk National University | And 2 more authors.
Science and Technology of Energetic Materials | Year: 2014

Progressive collapse is the partial or entire collapse of structures caused by the local damage of structural members arising from an abnormal load such as impact or explosion. Explosive demolition is a method to induce progressive collapse of the whole structure by removing primary structural members through blasting. Unlike progressive collapse, the explosive demolition induces progressive collapse of the structure by controlling the local damage of structural members at appropriate delay time. In this study, the progressive collapse resisting capacity depending on the number of floors in the structure, height of column at the target floor for blasting, and changes in the span length among the explosive demolition design variables of RC frame structure was evaluated. The final collapse pattern of each analysis model with vertical and free fall displacements applied to the direct top elements of the removed columns were analyzed using the AEM (Applied Element Method) based ELS (Extreme Loading for Structures) software. Also, the vertical displacement applied to the direct top elements of the removed columns was compared with the vertical internal force applied to the adjacent columns. The normal stress of reinforcing bar acting on as per time between the girders, which are the removed columns and adjacent columns, and the adjacent column connections were compared, and the progressive collapse resisting capacity by the catenary action was analyzed. Source


Kim H.-S.,Chonbuk National University | Cho S.-H.,Chonbuk National University | Park H.,Korea Kacoh Co | Suk C.-G.,Korea Kacoh Co
Rock Fragmentation by Blasting, FRAGBLAST 10 - Proceedings of the 10th International Symposium on Rock Fragmentation by Blasting | Year: 2013

In the late 1980s, wall-slab structures were applied to most construction projects for high-rise apartment buildings in Korea. Mechanical demolition of shear wall-slab structured apartments causes structural instability and generates environmental problems in the neighborhood, such as dust, noise and ground vibration during the preparatory work and the demolition process. Recently, a shear wall structured apartment has been demolished by means of an advanced explosive demolition technique that combines various collapse behaviors to minimize environmental impacts on the vicinity of the target structure. In this study, we simulated the collapse behavior of the shear wall apartment according to the blast scenario of the explosive demolition using ELS (Extreme Loading for Structures) software. The collapse behavior and diffusion area of debris obtained from the simulation results were compared with that from the actual explosive demolition experiment results. © 2013 Taylor & Francis Group. Source


Park H.,Chonbuk National University | Suk C.-G.,Korea Kacoh Co | Ko Y.-H.,Korea Kacoh Co | Cho S.-H.,Chonbuk National University
Science and Technology of Energetic Materials | Year: 2013

Progressive collapse is a phenomenon in which the local damage of structural members occurring due to abnormal load, such as impact or explosion, leads to the partial collapse or total collapse of the structure. Explosive demolition is a method of inducing the progressive collapse of a structure by removing the main structural members through blasting. Unlike progressive collapse, in explosive demolition the local damage of the structural members can be controlled at appropriate time intervals by blasting, to induce the progressive collapse of the structure and control the collapse behavior. Therefore, to induce the progressive collapse of an entire structure, it is important to select an appropriate time interval for the demolition of surrounding structural members according to the load redistribution of the structure. In this study, a progressive collapse analysis was carried out in order to consider and apply the load redistribution of structural members due to local damages to the explosive demolition design of the reinforced concrete structure. The occurrence of progressive collapse according to the number and position of column elements to remove was examined using ELS (Extreme Loading for Structures) software based on AEM (Applied Element Method). The vertical velocity and displacement of elements on top of the removed columns were compared, and the vertical internal force applied to the columns surrounding the removed column as a result of load redistribution was analyzed. Source

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