• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.119-126
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• 2022

This study proposed a BCM(Binding Column Method) that can reinforce the insufficient seismic force of piloti buildings that are not designed for seismic resistance. In addition, 4 reinforcement specimens and 1 reference specimen were manufactured for the proposed seismic reinforcement method. The effect of improving seismic performance before and after reinforcement was examined through repeated loading tests. As a result of experiment, seismic reinforcement specimen with BCM system showed hysteretic characteristics of a large ellipse with great energy dissipation ability and increased strength and stiffness, while reference specimen showed rapid reduction in strength and brittle shear failure column. In addition, it can be seen that the reinforcing effect is improved as the gap is narrow, the torque is large, and the thickness of the L-shaped steel sheet is thicker. The SC4 specimen showed the best seismic performance reinforcement effect.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.6
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• pp.119-128
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• 2008

In this study, new moment-resisting precast concrete beam-column joint is proposed for moderate seismic regions. It has the connection reinforcing bars, penetrated the joint and lap-spliced with the bottom bars of precast U-shaped PC beam. To evaluate the performance for noncontact lapped splice, experimental and analytical works were conducted. Major variables for tests are the length of lap, the diameter of connection reinforcing bars, and the distance between lapped bars. Analytic research was performed nonlinear finite element method. Analytic research focused on crack pattern, load-deflection curve, comparison of internal force, evaluation of ductility strains of reinforcement bar. Results of experimental and analytical works show that the these variables has much influence on flexural strength and ductility, and joint behavior.

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.57-62
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• 2006

Recent trends in the construction of building frame feature the use of composite steel concrete members. One of such system, RCS(Reinforced Concrete column and Steel beam) system, is known as a type of system to maximize the structural and economic benefits in the most efficient manner. This paper is focusing on an study of ultimate shear strength estimation of the interior beam-column joints of RCS system, with reinforced concrete column and steel beam. Current design methods as well as the majority of the previous researches for ultimate shear strength of the interior beam-column joint of RCS system are not easy to apply actual manner. There is a need to propose the rational macro models based on analytical approach. In this study, design method variables for interior beam-column joints of RCS system is studied assuming shear resistance of steel web panel, diagonal concrete strut mechanism and truss mechanism. Finally, calculated results based on the proposed design model are compared with test data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.163-171
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• 2001

Lateral confinement pressure generate improvements in strength and ductility of confined concrete. Carbon fiber sheets have a lot of merits, such as light weight, high strength and ease for construction, when it is applied to the defected structural member for the strengthening of shear and flexure. The purpose of this experimental study is to evaluate the strength characteristics of the reinforced concrete column confined with carbon fiber sheets. The main variables in this test are concrete strength ($290kgf/cm^2$ called N type, $505kgf/cm^2$ called H type) and pre-loading. In the test, a total of twelve specimens, which were all $10{\times}10cm$ in size, 117 cm in length, have a 2.85 reinforcement ratio, have been used. The results indicate that the strength was enhanced 26%~30% in N type, 11%~16% in H type specimens which was confined with carbon fiber sheets.

• Journal of Korean Association for Spatial Structures
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• v.24 no.1
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• pp.81-88
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• 2024

The purpose of this study is to experimentally analyze the seismic performance of beam-column specimens with vertical irregular, which were reinforced with RHS (Replaceable steel haunch system). a steel haunch system. To evaluate the seismic performance of the RHS, three specimens were manufactured and subjected to cycle loading tests. Retrofitted specimens have different beam-upper column stiffness ratio as a variable. The stiffness ratio of beam-upper column were considered to be 1.2 and 0.84. As a result of the test, the specimen reinforced with RHS showed improved maximum load and effective stiffness, and energy dissipation capacity compared to the non-retrofitted specimen with same beam-upper column stiffness ratio. The specimen with 0.84 beam-upper column stiffness ratio showed improved performance than the specimen with 12.

• Journal of the Korea Concrete Institute
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• v.29 no.2
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• pp.189-200
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• 2017

Nonplanar structural walls with C-shaped and H-shaped sections have been used as an efficient lateral force-resisting system for building structures. Since the nonplanar walls are subjected to axial load and bending moments about two orthogonal axes, complicated section analysis is required for flexure-compression design. In the present study, a straightforward design method for biaxially loaded C- and H-shaped walls was proposed by modifying the existing load contour method for columns with symmetric solid sections. For this, a strain compatibility section analysis program that can calculate biaxial moment strengths of arbitrary wall section was developed and its validity was verified by comparing with existing test results. Then, through parametric study, the interaction of biaxial moments at constant axial loads in prototype C- and H-shaped walls was investigated. The results showed that, due to unsymmetrical geometry of the wall sections, the biaxial interaction was significantly affected by the moment directions and axial loads. From those investigations, non-dimensional contour equations of the biaxial moments at constant axial loads for C- and H-shaped walls were suggested. Further, design examples using the proposed contour equations were given for engineering practice.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.113-120
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• 2020

Safety accidents, called industrial accidents in construction work, are causing a lot of casualties, property damage and social controversy in the event of an accident, causing the construction to lose public confidence. The risk of safety accidents at construction sites may continue to increase as the construction of high-rise, large-scale, and multi-purpose complex buildings has increased in recent years. In particular, the most frequently constructed apartment construction among reinforced concrete buildings is designed and constructed with a wall-like structure with no beams for each floor, while the lower floors are made of lamen with columns and beams. As a result, the transfer beam or transfer slab to withstand the upper load is installed on the upper part of the Ramen structure, so the system Dongbari, which is installed as a temporary material during concrete laying construction, may collapse at any time during plowing and curing. The purpose of this study is to apply IT convergence technology to prevent the collapse of the system Dongbari during concrete installation, and to apply many of the variables that may occur during construction on a case-by-case basis to check the stability of the system Dongbari and to propose a model of the anti-conducting prediction system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.289-301
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• 2017

As earthquakes have frequently happened all over the world, huge losses of human life and property have occurred. Therefore, retrofitting and strengthen technologies of non-seismically designed structures in Korea are urgent. Also, there has been a growing interest about seismic retrofitting, where researches on the topic have been actively pursued in Korea. The study results showed that ductility inducing retrofitting method is more superior stiffness inducing method. In Japan, Super Reinforcement with Flexibility (SRF) was introduced. Therefore, in this study, seismic performance evaluation was performed through pseudo dynamic test and uniaxial compression test for RC column retrofitted by PolyUrea for ductility inducing retrofitting material. Uniaxial compression test results showed that strength of all specimens retrofitted by PolyUrea was higher than that of RC specimens. Also, all specimens retrofitted by PolyUrea also showed ductile fracture behavior. In pseudo dynamic test, by appling real earthquake record, the seismic behavior of RC column reinforced by PolyUrea was evaluated through relative displacement, reinforcement strain, displacement ductility, and dissipation energy. The results showed that PolyUrea helped to enhance seismic performance of RC columns.

• Journal of Korean Society of Steel Construction
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• v.11 no.2 s.39
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• pp.143-151
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• 1999

An analytical study on the behavior of composite beams, which are composed of cold-formed profiled steel sheeting and normal strength concrete, is described. An analytical method to trace the nonlinear behavior of a composite beam is developed to include the nonlinear material properties of steel sheeting, reinforcing steel bar and concrete. A simple Power Model has also been proposed for the nonlinear moment-curvature relation of the composite beam. The model, which has been originally used to predict the flexural capacity of the beam to column connections, is adapted to the composite beams. The load-deflection behavior of the beams has been simulated by the step-by-step numerical integration using the moment-curvature relation obtained by the Power Model. The results have been compared with test results.

• Journal of Korean Society of Steel Construction
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• v.8 no.4 s.29
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• pp.85-94
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• 1996

This paper investigated structural behaviors of joint of concrete filled steel tube column and P.C reinforced concrete beam through a series of hysteretic behavior experiment. The results are summarised as follows: (1) The joint stiffness of concrete filled square steel tube column and P.C reinforecd beam was higher than that of concrete filled circular steel tube column and P.C reinforecd beam, and it was decreased as the increase of the number of hysteretic cycle. (2) The aspects of the hysteretic behavior in the joint was stable as the increase of the number of hysteretic cycle, and rotation resisting capacity of joint of concrete filled square steel tube column and P.C reinforced concrete beam was higher than those of the concrete filled circular steel tube column and P.C reinforced concrete beam. (3) Some restriction must be put upon the ratio of axial force in this joint model because the load carrying capacity was decreased by flexural and flexural-torsional buckling in case of the ratio of axial force 0.6. (4) The emprical formula to predict the ultimate capacity of joint model to superimpose shearing strength of steel web(H section) and bending strength of reinforced concrete beam was expected.