• International Journal of High-Rise Buildings
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• v.5 no.1
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• pp.43-50
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• 2016

The reinforced-concrete multi-story shear-wall structure, which can free a building from beams and columns to allow the planning of a vast room, has increasingly been used in Japan as a high-rise reinforced-concrete structure. Since this structural system concentrates the seismic force onto multi-story shear walls inside, the bending deformation of the walls may cause excessive deformation on the upper floors during an earthquake. However, it is possible to control the bending deformation to within a certain level by setting high-strength and rigid beams (outriggers) at the top of the multi-story shear walls; these outriggers restrain the bending behavior of the walls. Moreover, it is possible to achieve high energy dissipation by placing vibration control devices on the outriggers and thus restrain the bending behavior. This paper outlines the earthquake response analysis of a high-rise residential tower to demonstrate the effectiveness of the outrigger frame incorporating vibration control devices.

• Advances in concrete construction
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• v.4 no.2
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• pp.89-105
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• 2016

The post - fire investigation is conducted on a fire-affected reinforced concrete shear wall building to ascertain the level of its strength degradation due to the fire incident. Fire incident took place in a three-storey building made of reinforced concrete shear wall and roof with operating floors made of steel beams and chequered plates. The usage of the building is to handle explosives. Elevated temperature during the fire is estimated to be $350^{\circ}C$ based on visual inspection. Destructive (core extraction) and non-destructive (rebound hammer and ultrasonic pulse velocity) tests are conducted to evaluate the concrete strength. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) are used for analyzing micro structural changes of the concrete due to fire. Tests are conducted for concrete walls and roof slab on both burnt and unburnt locations. The analysis of test results reveals no significant degradation of the building after the fire which signifies that the structure can be used with full expectancy of performance for the remaining service life. This document can be used as a reference for future forensic investigations of similar fire affected concrete structures.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.2
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• pp.85-91
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• 2021

This paper introduces a modified Karagozian & Case concrete model (K&C model) for the numerical analysis of a steel-fiber-reinforced concrete (SFRC) structure subjected to projectile impact. The original K&C model was calibrated to consider the effects of steel fibers accurately by modifying the strength surfaces and input parameters. Single element tests were then conducted and compared with uniaxial and triaxial compressive data to verify the modified model. With the application of a dynamic increase factor, the finite element model of the SFRC structure subjected to projectile impact was constructed. Thereafter, the applicability of the modified material model was examined by comparisons with the experimental results.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.220-227
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• 2002

This study introduces the fragility analysis method for the safety evaluation of reinforced concrete pier subject to earthquake. Damage probability is calculated instead of the failure probability from definition of the damage state in the fragility curve. Not only the damage model determined by the response of structure subject to earthquake, but also the plastic-damage model which can represent the local damage is applied to fragility analysis. The evaluation method of damage state by damage variable in global structure is defined by this procedure. This study introduces the fragility analysis method considering the features of nonlinear time history behavior of reinforced concrete element and the plastic behavior of materials. At last, This study gives one of the approach method for seismic margin evaluation with the result of fragility analysis to design seismic load.

• Coupled systems mechanics
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• v.7 no.3
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• pp.281-295
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• 2018

This study aims to investigate the capacity of different models to reproduce the nonlinear behavior of reinforced concrete framed structures. To accomplish this goal, a combined experimental and analytical research program was carried out on a large scaled reinforced concrete frame. Analyses were performed by SAP2000 and compared to experimental and VecTor2 results. Models made in SAP2000 differ in the simulation of the plasticity and the type of the frame elements used to discretize the frame structure. The results obtained allow a better understanding of the characteristics of all numerical models, helping the users to choose the best approach to perform nonlinear analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.177-178
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• 2016

The main structure of the building has been used reinforced concrete construction method in Korea. In recent years, it is necessary to demolition of buildings into urban redevelopment. But yet the demolition method is not being developed perfect. It is necessary to develop future deconstruction for safety and environment method. In this study, we surveyed the demolition method has been used in domestic construction. How the combination of these demolition method should be needed. Demolition method combinations were classified as low-rise, high-rise, middle. It suggested method to combine the demolition process of reinforced concrete structure with seven.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.195-202
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• 2002

Urbanization and development of industry makes people concerned about quality of circumstances. Problems of vibration are on the rise. Vibration makes inhabitants feel unpleasant and involves structural damage. The purpose of this study is to assess damage of reinforced concrete structures due to ground motions as the parameters of frequency, duration time and aspect ratio of structures are changed. Ground motions were modeled as sine waves. To compare sine waves with real ground motions, two cases are selected; one is blast loading case and the other is earthquake loading. It was intended to provide means to assess R/C structure damage due to ground motions.

• Computers and Concrete
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• v.3 no.5
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• pp.285-299
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• 2006

The free vibration of stiffened and damaged coupled shear walls is investigated using the mixed finite element method. The anisotropic damage model is adopted to describe the damage extent of the reinforced concrete shear wall element. The internal energy of a locally damaged shear wall element is derived. Polynomial shape functions established by Kwan are used to present the component of displacements vector on each point within the wall element. The principle of virtual work is employed to deduce the stiffness matrix of a damaged shear wall element. The stiffened system is reinforced by an additional stiffening beam at some level of the structure. This induces additional axial forces, and thus reduces the bending moments in the walls and the lateral deflection, and increases the natural frequencies. The effects of the damage extent and the stiffening beam on the free vibration characteristics of the structure are studied. The optimal location of the stiffening beam for increasing as far as possible the first natural frequency of vibration is presented.

• Coupled systems mechanics
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• v.6 no.4
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• pp.523-537
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• 2017

This study aims to investigate the capacity of different models to reproduce the nonlinear behavior of reinforced concrete framed structures. To accomplish this goal, a combined experimental and analytical research program was carried out on a large scaled reinforced concrete frame. Analyses were performed by SAP2000 and compared to experimental and VecTor2 results. Models made in SAP2000 differ in the simulation of the plasticity and the type of the frame elements used to discretize the frame structure. The results obtained allow a better understanding of the characteristics of all numerical models, helping the users to choose the best approach to perform nonlinear analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.149-152
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• 2006

Serviceability of reinforced concrete building is affected dominantly by long term deflection of slab. And in case of reinforced concrete building with flat plate slab, severe long term deflection was expected because it has no beams which have large flexural stiffness. Therefore it is important to calculate exactly long term deflection of RC flat plate structure to assure its serviceability. However, current codes couldn't calculate exactly long term deflection of RC flat plate structure because they don't consider effects of boundary condition and construction load. By the way, recently the method to calculate long term deflection of RC flat plate structure was proposed by considering these effects. In the present study, long term deflection of RC flat plate structure was analyzed by comparing this method with recent experimental results. In conclusion, long term deflection of RC flat plate structure was affected considerably by effects of boundary condition, construction load and tensile strength of concrete. And recently proposed method considers these effects reasonably but it should be modified to reflect creep effect of RC flat plate slab reasonably.