• Journal of Korean Society of Steel Construction
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• v.26 no.1
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• pp.43-53
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• 2014

A single plate connection(SPC) consists of a plate welded to the columns and bolts connected to the beam web. The SPC is widely used for a simple shear connection of steel structure because it is easy-to-fabricated, easy-to-installed and economical. The conventional SPC is used for 2 to 12 bolts in a single vertical row. It is designed to limit the plate thickness by bolt diameter to obtain flexible and ductile connections. The design strength for eccentric shear shall be the lesser of the shear strength of bolts or bearing strength of plate and when the design strength is decided by edge distance failure, the results can be very conservative. Although the research on special solution for 'weak-plate/strong-bolt' model with 2 to 4 bolts has been conducted by L. S. Muir, and W. A. Thonton, 2004, study on generalized design procedures did not conduct. This study proposed design procedure for evaluation of the design strength of eccentric shear bolt groups on a single plate connection based on the actual edge distance and the direction of bolt reaction forces by using elastic vector method(EVM) and instantaneous center of rotation method(ICM).

• Explosives and Blasting
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• v.34 no.1
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• pp.19-28
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• 2016

The number of industrial structures that must be demolished due to functional and structural deterioration has been increased. There is an increasing application of explosive demolition or explosive demolition combined with mechanical demolition to minimize temporal and spatial environmental hazardous factors created during the process of demolition. In this case study, to demolish the turbine foundation structure, which is a large-section reinforced concrete structure, the parital explosive demolition thchnique was conducted. As a result of the partial explosive demolition, the overall crushing of the blasting sections of beam-column joints structure with haunched beams and second-floor columns about the turbine foundation was satifactory, and the explosive demolition was completed without causing any damage to surrounding facilities.

• Journal of Korean Society of Steel Construction
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• v.22 no.3
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• pp.271-280
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• 2010

This study was programmed to fabricate a beam-to-column connection that is limited to a steel-welded moment connection with full-scale members, using SN steel. A cyclic seismic test was conducted of the nine specimens that were fabricated by choosing the test variable for the weld access hole geometry, connection design method, and RBS. From the test results, failure modes, the moment-drift behavior, and the strain distribution were provided. From the specimen material properties, the beam's nominal plastic flexural capacity and classified qualified connection as a special moment flame were calculated. By analyzing the skeleton part and the baushinger part, a range of strength-raising effects, and deformation ratios were provided, with which the seismic performance of the specimens were evaluated. The test results showed that the specimens eliminated their weld access holes that demonstrated higher seismic performance than the specimens' existing weld access holes, and that the WUF-W connection that was reinforced by the supplemental fillet weld around the shear tap that was fastened by five bolts demonstrated superior seismic performance.

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.441-448
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• 2014

From several researches, recently, it was found that using hollowed precast concrete (HPC) column made more compact concrete casting in joint region possible than using normal solid PC (Precast concrete) column. Therefore, the rigidity of joints can be improved like those of monolithic reinforced concrete (RC). After filling the hollow with grout concrete, however, it is expected that the HPC column behaviors like composite structure since PC element and grout concrete have different materials as well as there is a contact surface between two elements. These may affect the structural behavior and strength of the composite column. A compressive strength test was performed for the HPC column with parameter of hollow ratio for the case with and without grout in the hollow and the result is presented in this paper. The hollow ratios in the test are 35, 50 and 59% of whole section of column. Concentrated axial force was applied to top of the specimens supported as pin connection for both ends. In addition, finite element (FE) analysis was performed to simulate the failure behavior of HPC column for axial compression. As a result, it was found that the hollow ratio did not affect the initial stiffness of HPC filled with grout regardless of the strength difference of HPC and grout. However the strength was increased inversely corresponding to the hollow ratio. The structural capacity of HPC without grout closely related to the hollow size. Especially, the local collapse governs the overall failure when the thickness of HPC is too thin. Based on these effect, a suitable equation was suggested for calculation of the compressive strength of HPC column with or without grout. FE analysis considering the contact surface between HPC and grout produced a good result matched to the test result.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.3
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• pp.9-20
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• 1999

A method is proposed to estimate the joint damages of a steel structure from modal data using the neural networks technique. The beam-to-column connection in a steel frame structure is represented by a zero-length rotational spring of the end of the beam element, and the connection fixity factor is defined based on the rotational stiffness so that the factor may be in the range 0~1.0. Then, the severity of joint damage is defined as the reduction ratio of the connection fixity factor. Several advanced techniques are employed to develop the robust damage identification technique using neural networks. The concept of the substructural indentification is used for the localized damage assessment in the large structure. The noise-injection learning algorithm is used to reduce the effects of the noise in the modal data. The data perturbation scheme is also employed to assess the confidence in the estimated damages based on a few sets of actual measurement data. The feasibility of the proposed method is examined through a numerical simulation study on a 2-bay 10-story structure and an experimental study on a 2-story structure. It has been found that the joint damages can be reasonably estimated even for the case where the measured modal vectors are limited to a localized substructure and the data are severely corrupted with noise.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.11-20
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• 2010

With the amendment to the Building Act in November of 2005 that offered incentives in terms of floor area ratio and number of stories to apartment buildings adopting the Rahmen structure to facilitate remodeling, the construction industry is paying more attention to PC structures. As connections between PC columns and beams require complex design, it is very difficult to install and remove forms. Since forms made of plywood for such connections are fabricated and installed on site, a significant amount of labor is required, and constructability is low. Furthermore, after concrete casting, the forms are removed in a state in which they cannot be recycled, which leads to a significant amount of construction waste. For this reason, a solution to address such issues needs to be studied. However, many researchers have focused only on the structural performance of PC structures in Korea and elsewhere, ignoring the need for research on the forms used in building PC structure connections. Therefore, this research aims to develop a form that can improve the productivity of PC structure connection construction, and compare it with conventional forms to highlight its contribution to gains in productivity and economic viability.

• Journal of Korean Society of Steel Construction
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• v.21 no.2
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• pp.115-125
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• 2009

An experimental study was performed to investigate the cyclic behavior of the reinforced concrete frame with infilled steel plate. For this purpose, three-story compositewalls using infilled steel plates (RCSPW) were tested. The parameters for this test were the reinforcement ratio of the column and opening in the infilled steel plate. A reinforced concrete infilled wall (RCIW) and a reinforced concrete frame (RCF) were also tested for comparison. The deformation capacity of the RCSPW specimen was significantly greater than that of the RCIW specimen, although the two specimens exhibited the same load-carrying capacity. Like the steel plate walls with the steel boundary frame, RCSPW specimens showed excellent strength, deformation capacity, and energy dissipation capacity. Furthermore, by using infilled steel plates, shear cracking and failure of the column-beam joint were prevented. By using a strip model, the stiffness and strength of the RCSPW specimens were predicted. The results were compared with the test results.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.4
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• pp.27-37
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• 2012

The construction of a moment connection for a rectangular hollow section (RHS) column and a H-shaped beam is difficult because the RHS is a closed section. When a inner diaphragm is used for such a connection, in general, it is installed after cutting the HSS columns, which results in increased construction work. This paper suggests a new fabrication method to overcome such problems: An inner diaphragm is welded to inside a C-shaped section first, and then a column is fabricated by welding two C-shaped sections. This fabrication method is superior to a classic method in terms of constructibility. An experimental and a numerical study using Ansys 9.0 were performed in order to compare the strength of connections with respect to the presence of concrete, the corner shape of diaphragm, and the axis of loading. The experimental results including initial stiffness and ultimate loads are reported and the analytical results including load transfer mechanism, degree of stress concentration, and strain distribution are also reported.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.143-146
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• 2005

최근 들어 90도 표준갈고리의 대안으로 정착판을 지니는 헤드 철근(headed bar)에 대한 관심이 높아지고 있다. 헤드 철근의 정착내력은, 정착판의 지압력과 위험단면에서 헤드까지 정착길이의 부착력으로 발현된다. 실제 구조물에서는 정착되는 부재의 재료 및 기하학적 물성에 의해 다양한 파괴가 발생된다. 따라서 헤드 철근의 정착내력은 단순히 지압력과 부착력의 합으로 산정될 수 없으며, 발생 가능한 모든 파괴양상을 고려한 최소 내력으로 결정되어야 한다. 헤드 철근의 정착내력을 산정하기 위한 기본적인 해석모델로, CCT 절점에 정착된 헤드 철근의 트러스 모델을 제안하였다. 제안된 트러스 모델의 파괴는 부착파괴와 콘크리트의 압축파괴로 구분되며, 재료 및 기하학적 물성에 의해 파괴 양상이 결정된다. 이러한 트러스 모델은 외부 보-기둥 접합부와 같이 보다 복잡한 부위에 정착된 헤드철근의 정착 기구를 설명하는데 활용될 수 있다.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.158-163
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• 2005

This paper is focusing on the model to predict the ultimate shear strength on joints of composite system (RCS) with reinforced concrete columns and steel beams considering the transverse beam. It reviews the ratio of experimental shear strength to design strength calculated by existing desist equations which are proposed by Kanno, Wight, Noguchi and the rising of strength by the transverse beams. When the shear strength of joints is estimated, it is necessary to do research work for the stress transfer mechanism considering two concrete strut of inner and outer panel by web of the transverse beam. In order to confirm it requires further experimental and analytical study.