• Journal of Korean Society of Steel Construction
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• v.22 no.5
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• pp.487-496
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• 2010

The structural damping ratios for seismic design of nuclear power plant structures are specified in Regulatory guide 1.61 of the United States NRC for RC structures of 4%(OBE) and 7%(SSE), and for steel structures of 3%(OBE) and 4%(SSE), but not for steel-plate concrete (SC) structures that have been developed recently. The objective of this study is to investigate the damping ratios of SC structures by identifying the relative differences in the damping ratios between RC and SC structures. An experimental study was performed on four specimens, RC-S, RC-M, SC-S and SC-M, where S stands for shear-governed and M for moment-governed. The conducted method was free vibration testing by rupturing a brittle steel plate that linked the actuator and the mass center. The test results were analyzed to determine fundamental frequencies and damping ratios at various load levels. By examining the relative differences in damping ratios of four specimens, it is proposed for SC structures to use the same damping ratio of 4% as RC one at OBE, but 1% less damping ratio than RC one resulting in 6% at SSE.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5A
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• pp.369-378
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• 2011

In this paper, the response analysis of RC(Reinforced Concrete), SC(Steel-Plate Concrete) containment buildings subjected to a large aircraft impact is performed using Autodyn-3D as Hydrocode. Until now, the impact load in the analysis of aircraft impacts has been applied to target structures at the local area by using the impact load-time history function of Riera. However in this paper, the results of aircraft crash are analyzed by using an aircraft model similar to Boeing 767 and verified by comparing the generated history of the aircraft crash against the rigid target with another history by using the Riera's function. To estimate the resistivity of the impact, the response and safety of SC containment buildings, this study is performed by comparing the four cases of plane concrete, reinforced concrete, bonded containment liner plate at reinforced concrete, and SC structure. Thus, the different behaviors between SC and RC structures when they are subjected to the extreme impact load could be anticipated. Consequently, the improved safety is expected by replacing RC structure with SC structure for nuclear power plants.

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.3
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• pp.41-48
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• 2010

In this paper, the analysis of impact damage behavior of a reinforced concrete structure that undergoes both a shock impulsive loading and an impact loading due to the air blast induced from an explosion is performed. Firstly, a pair of multiple loadings are selected from the scenario that an imaginary explosion accident is assumed. The RC structures strengthened with advanced composite materials (ACM) are considered as a scheme for retrofitting RC wall structures subjected to multiple explosive loadings and then the evaluation of the resistant performance against them is presented in comparison with the result of the evaluation of a RC structure without a retrofit. Also, in order to derive the result of the analysis similar to that of real explosion experiments, which require the vast investment and expense for facilities, the constitutive equation and the equation of state (EOS) which can describe the real impact and shock phenomena accurately are included with them. In addition, the numerical simulations of two concrete structures are achieved using AUTODYN-3D, an explicit analysis program, in order to prove the retrofit performance of a ACM-strengthened RC wall structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.225-233
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• 2003

Recently, the concern for displacement-based design has been increased as a performance based design method in which the deformation capacity of structure becomes so important. In this paper, a process is presented to accurately evaluate the deformation capacity of multistory RC frame structure. In the calculation of drift of frame, the deformation of beam and column as well as the deformation of anchorage and joint are considered. From the comparison between previous test and calculation results, the usefulness of the process is verified. The proposed process is also applied to the multiple story RC frame buildings(5, 10, 15 stories) designed to have strong column-weak beam. The results showed that the deformation capacity of the buildings could be not properly evaluated when deformations of anchorage and joint were ignored.

• Journal of the Society of Disaster Information
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• v.15 no.3
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• pp.418-426
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• 2019

Purpose: After analyzing the seismic capability of low-rise RC grid structures with insufficient seismic performance, the purpose of the project is to install steel slab hysteretic dampers (SSHD) to improve the seismic performance of beams and columns, and to suggest measures to minimize damage to the structure and human damage when an earthquake occurs. Method: The evaluation of the seismic performance of a structure is reviewed based on the assumption that the seismic performance is identified for the grid-type subway systems that are not designed to be seismic resistant and the installation of an SSHD system, a method that minimizes construction period, if insufficient, is required. Result: After the application and reinforce of structure with SSHD, and the results of eigenvalue analysis are as follows. The natural periodicity of longitudinal direction was 0.55s and that of vertical direction was 0.58s. Conclusion: As results of cyclic load test of structure with SSHD, the shear rigidity of damper is 101%, the energy dissipation rate is 108% and, plastic rotation angle of all column and beam is satisfied for $I_o$ level and therefore it is judged that the reinforce effect is sufficient.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.91-92
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• 2012

RC structure which is located at shoreline has more serious damages compared with inland structure, because it is directly exposed to chlorine ion which is called incoming salt. In the transmission of incoming salt, differences in transmitted volume of incoming salts could occur according to the influences of local shoreline topography which includes surrounding weather conditions, types of building placements, obstacles of wind tunnel etc. And therefore, for the application of boundary conditions for durable offshore structure design against the salt attack, comparative analysis through wind tunnel test and fluid value simulation are executed in order to investigate the moving and adhesion process of incoming salt to offshore structure.

• Molecules and Cells
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• v.44 no.3
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• pp.179-185
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• 2021

Vancomycin response regulator (VncR) is a pneumococcal response regulator of the VncRS two-component signal transduction system (TCS) of Streptococcus pneumoniae. VncRS regulates bacterial autolysis and vancomycin resistance. VncR contains two different functional domains, the N-terminal receiver domain and C-terminal effector domain. Here, we investigated VncR C-terminal DNA binding domain (VncRc) structure using a crystallization approach. Crystallization was performed using the micro-batch method. The crystals diffracted to a 1.964 Å resolution and belonged to space group P212121. The crystal unit-cell parameters were a = 25.71 Å, b = 52.97 Å, and c = 60.61 Å. The structure of VncRc had a helix-turn-helix motif highly similar to the response regulator PhoB of Escherichia coli. In isothermal titration calorimetry and size exclusion chromatography results, VncR formed a complex with VncS, a sensor histidine kinase of pneumococcal TCS. Determination of VncR structure will provide insight into the mechanism by how VncR binds to target genes.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.473-480
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• 2012

In order to develop an effecive seismic strengthening metghod for existing concrete structure, structural tests of aramid FRP reinforced RC columns are performed. The test variables were strengthening methods of aramid sheet and strip. The test results were evaluated by comparing strength and energy dissipation capacities of non-reinforced and reinforced specimens. The test result comparison showed that aramid sheet reinforcement on RC column was evaluated as the most efficient way to increase strength and energy dissipation capacity.

• Computers and Concrete
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• v.4 no.6
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• pp.457-475
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• 2007

A simple analytical procedure to analyze reinforced concrete (RC) beams with cracked section is proposed on the basis of the simplified moment-curvature relations of RC sections. Unlike previous analytical models which result in overestimation of stiffness and underestimation of structural deformations induced from assuming perfect-bond condition between steel and concrete, the proposed analytical procedure considers fixed-end rotation caused by anchorage. Furthermore, the proposed analytical procedure, compared with previous numerical models, promotes effectiveness of analysis by reflecting several factors which can influence nonlinearity of RC structure into the simplified moment-curvature relation. Finally, correlation studies between analytical and experimental results are conducted to establish the applicability of the proposed analytical procedure to the nonlinear analysis of RC structures.

• Structural Monitoring and Maintenance
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• v.5 no.2
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• pp.189-204
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• 2018

This paper examines the seismic responses of a reinforced concrete (RC) frame core-tube building with pre-pressed spring self-centering energy dissipation (PS-SCED) braces. The PS-SCED brace system consists of friction devices for energy dissipation, pre-pressed combination disc springs for self-centering and tube members as guiding elements. A constitutive model of self-centering flag-shaped hysteresis for PS-SCED brace is developed to better simulate the seismic responses of the RC frame core-tube building with PS-SCED braces, which is also verified by the tests of two braces under low cyclic reversed loading. Results indicate that the self-centering and energy dissipation capabilities are well predicted by the proposed constitutive model of the PS-SCED brace. The structure with PS-SCED braces presents similar peak story drift ratio, smaller peak acceleration, smaller base shear force and much smaller residual deformations as compared to the RC frame core-tube building with bucking-restrained braces (BRBs).