• Construction Engineering and Management
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• v.17 no.4
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• pp.6-9
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• 2016

• Magazine of the Korea Concrete Institute
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• v.11 no.1
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• pp.267-277
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• 1999

The pushover analysis technique is now attracting the world-wide interest for the prediction of elastic and inelastic behavior of structures in the seismic evaluation of existing buildings. However, the reliability of this analysis technique has not been fully checked by the test results in the case of structures with nonseismic details. The objective of this study is to verify the correlation between the experimental and analytical responses of a 1:12 scale 10-story reinforced concrete frame with non-seismic details by using DRAIN-2DX program and the test results performed previously. It is concluded from this comparison that the overall responses such as the relations between story shear versus interstory drift and the local deformations such as plastic rotations can be predicted with quite high reliability.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.673-678
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• 2005

ACI 318 (1999) defines three types of moment frames: Ordinary Moment Resisting Concrete Frame (OMRCF), Intermediate Moment Resisting Concrete Frame (IMRCF), and Special Moment Resisting Concrete Frame (SMRCF). OMRCF is the most popular type of moment frame in mild seismic zones that requires the least detail and design requirements. This study focuses on the seismic performance of Ordinary Moment Resisting Concrete Frames (OMRCF) designed only for gravity loads. For this purpose a 3-story OMRCF was designed in compliance with the minimum design requirements in ACI 318 (1999). An one third 3 story specimen was made and tested. For scaled model, the similitude law of true replica was applied. The specimen was loaded with quasi-static reversed cyclic lateral loading. The overall behavior of OMRCF is quite stable without abrupt strength degradation. It is found that tested frame has the base shear strength larger than the design base shear for seismic zone 1, 2A and 2B calculated using UBC 1997.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.417-424
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• 2003

A bearing failure in RCS(Reinforced Concrete Column and Steel Beam) system is recognized as one of the distinct joint failure modes for the composite frames. Vertical and transverse reinforcement in addition to concrete are effective for better transfer of vortical forces through concrete bearing. To examine the effect of the vertical bars, tie bars, a U-type detail developed in this study and concrete confinement, local bearing tests were conducted using 22 small-scale concrete block specimens. Test results show that vertical reinforcement and tie bars mainly contribute to the bearing capacity. However larger amounts of tie reinforcement are required than those recommend from ASCE guidelines, to apply the nominal concrete strength as 2 $f_{ck}$ over the bearing area. Cross ties are proved to be highly effective for resisting the vertical forces. Maximum bearing strength can be increased upto 2.5 $f_{ck}$ . An accurate prediction model for bearing strength is proposed for better design of the composite Joint.

• Magazine of the Korea Concrete Institute
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• v.13 no.6
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• pp.121-126
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• 2001

• Magazine of the Korea Concrete Institute
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• v.3 no.2
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• pp.115-121
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• 1991

Slippage of beam longitudinal reinforcement at beam-column connections is an important cause of damage to reinforced concrete frames under static and dynamic loads, This paper summarizes the results of an experimen¬tal study on the effects of confinements and compressive strength of concrete on the local bond stress-slip cha¬racteristics of deformed bars. I t is concluded from experimental results that, as far as the bond splittmg cracks are restrained by the vertical column reinforcement, confinement of concrete by transverse reinforcement has insignigicant direct effect on the local bond behavior. The ultimate bond strength, however, Increases pro¬portionally with the square root of concrete compressive strength. An empirical model was developed for local bond st ressslip relationslip of deformed bars in confined concrete of different compressive strengths.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.370.2-370
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• 1999

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.2
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• pp.53-67
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• 2008

In this study, seismic control performance of friction dampers installed in a reinforced concrete shear wall-moment frame system, of which main lateral force resisting system is a shear wall, is investigated. Three configurations of friction dampers are investigated. One is a diagonal brace type reinforcing the shear wall directly, another is a diagonal brace type reinforcing the moment frame without the shear wall, and the other one is a vertical boundary element type installed at both ends of the shear wall. In addition, various levels of the total friction force and its distribution methods are examined. Time history analysis considering material nonlinearity is conducted for seismic loads increased by the enhanced design code compared to the initial design loads, and energy dissipation, lateral loads and structural member damages are analyzed. As a result, the shear wall-reinforcing diagonal brace type with the total friction force of 30 % of the reference friction force gives the best performance on the whole, and the distribution methods of the friction force do not have remarkable difference in effects. Also, concentrated installation in adjacent four stories shows just a little compromised control performance compared to the entire story installation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.1-9
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• 2014

Improving the earthquake resistance of buildings through seismic retrofitting using steel braces can result in brittle failure at the connection between the brace and the building, as well as buckling failure of the braces. In this study, a non-compression cross-bracing system using the Carbon Fiber Composite Cable (CFCC), which consists of CFCC bracing and bolt connection was proposed to replace the conventional steel bracing. This paper presented the seismic resistance of a reinforced concrete frame strengthened using CFCC X-bracing. Cyclic loading tests were carried out, and the maximum load carrying capacity and ductility were investigated, together with hysteresis of the lateral load-drift relations. Test results revealed that the CFCC X-bracing system installed RC frames enhanced markedly the strength capacity and no buckling failure of the bracing was observed.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.5
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• pp.13-21
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• 2012

In this study, the response modification factor for a RC IMRF is evaluated via pushover analysis, where 5-story structures were designed in accordance with KBC2009. The bending moment-curvature relationship for beams and columns was identified with a fiber model, and the bending moment-rotation relationship for beam-column joints was calculated using a simple and unified joint shear behavior model and the moment equilibrium relationship for the joint. The results of the pushover analysis showed that the strength of the structure was overestimated with negligence of the inelastic shear behavior of the beam-column joint, and that the average response modification factor for category C was 7.78 and the factor for category D was 3.64.