• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.410-418
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• 2021

This study was conducted in 8.2m wide single-span greenhouse to investigate the effect of presence or absence of rafter steel pipe joint and foundation conditions on greenhouse structural performance. Structural performance was evaluated by static loading test using the structural performance evaluation system for single-span greenhouse. The measured displacement was compared with the predicted result by numerical analysis. The displacement of each measurement location showed a significant difference regardless of the conditions of the foundation and presence or absence of rafter steel pipe joint. Compared to the hinge conditions, the difference in structural performance of the greenhouse in the fixed conditions was seen to be relatively large. The difference in structural performance according to presence or absence of rafter steel pipe joints, the lateral stiffness of the joint was 8.1% greater.

• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.337-347
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• 2011

In this study, seismic resistance of concrete encased U-shaped steel beam-to-steel H-shaped column connections was evaluated. Three specimens of the beam-to-column connection were tested under cyclic loading. The composite beam was integrated with concrete slab using studs. Re-bars for negative moment were placed in the slab. The primary test parameter was the details of the connections, which are strengthening and weakening strategies for the beam end and the degree of composite action. The depth of the composite beams was 600mm including the slab thickness. The steel beam and the re-bars in the slab were weld-connected to the steel column. For the strengthening strategy, cover plates were weld-connected to the bottom and top flanges of the steel beam. For the weakening strategy, a void using styrofoam box was located inside the core concrete at the potential plastic hinge zone. The test results showed that the fully composite specimens exhibited good strength, deformation, and energy dissipation capacities. The deformation capacity of the beam exceeded 4% rotation angle, which is the requirement for the Special Moment Frame.

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.59-69
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• 2006

This paper presents test results on reduced beam section (RBS)program addressed panel zone (PZ) strength as the key variables. PZ strength has been much debated issue for several decades. A desirable range of PZ strength has not yet been proposed despite the fact that a significant amount of RBS test data is available. Test results from this study and by others showed that panel zones could easily develop a plastic rotation of 0.01 radian without causing distress to the beam flange groove welds. At this deformation level, the amount of beam distortion (i.e., buckling) was about one half that developed in strong PZ specimens. A criterion for a balanced PZ strength that improves the plastic rotation capacity while reducing the amount of beam buckling is proposed.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.2
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• pp.15-26
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• 2010

The purpose of this study is to develop a precast concrete structural wall system that can assure reliable seismic performance. In previous studies, the connections of precast concrete structural walls have had some problems in their seismic performance. Therefore, this research proposes precast concrete structural walls which have an improved seismic performance. One is a hybrid precast concrete structural wall that is composed of a reinforced concrete component and a precast concrete component, and another is a precast concrete wall whose reinforcements have a partially reduced section and are partially unbonded from the surrounding concrete. To evaluate the seismic performance of the proposed precast concrete structural walls, the behavior of three specimens, including a reinforced concrete wall, were subjected to reversed cyclic combined flexure and shear. According to the test results, the proposed precast concrete structural walls have reliable seismic performance.

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.291-298
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• 2017

The objective of the present study is to evaluate the cyclic flexural behavior of a hybrid H-steel-reinforced concrete (HSRC) beam at the connection with a H-steel column. The test parameter investigated was the configuration of dowel bars at the joint region of the HSRC beam. The HSRC beam was designed to have plastic hinge at the end of the H-steel beam rather than the RC beam section near the joint. All specimens showed a considerable ductile behavior without a sudden drop of th applied load, resulting in the displacement ductility ratio exceeding 4.6, although an unexpected premature welding failure occurred at the flanges of H-steel beams connecting to H-steel column. The crack propagation in the RC beam region, flexural strength, and ductility of HSRC beam system were insignificantly affected by the configuration of dowel bars. The flexural strength of HSRC beam system governed by the yielding of H-steel beam could be conservatively evaluated from the assumption of a perfect plasticity state along the section.

• Journal of Korean Society of Steel Construction
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• v.22 no.2
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• pp.129-137
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• 2010

In this study, a five-story steel frame was designed in accordance with KBC2005 to evaluate the effect of the beam-column connection on the structural behavior. The connections were designed as a fully rigid connection and as a semirigid connection. A fiber model was utilized to describe the moment-curvature relationship of the steel beam and column, and a three-parameter power model was adopted for the moment-rotation angle of the semirigid connection. To evaluate the effects of higher modes on structural behavior, the structure was subjected to a KBC2005-equivalent lateral load and lateral loads considering higher modes. The structure was idealized as a separate 2D frame and as a connected 2D frame. The pushover analysis of 2D frames for the lateral load yielded the top displacement-base shear force, design coefficients such as overstrength factor, ductility ratio, and response modification coefficient, demanded ductility ratio for the semirigid connection,and distribution of plastic hinges. The sample structure showed a greater response modification coefficient than KBC2005, the higher modes were found to have few effects on the coefficient, and the lateral load of KBC2005 was found to be conservative. The TSD connection was estimated to secure economy and safety in the sample structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.145-146
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• 2010

A moment redistribution method was developed for earthquake design of reinforced concrete moment-resisting frames. For a frame designed with strong column-weak beam, the moment redistribution mechanism was investigated. Based on the result, the relationship between redistributed moment and plastic rotation in plastic hinges was established. By using the relationship, we developed a method for the evaluation of plastic rotations during the moment redistribution, addressing the effects of various design parameters including member stiffness, load condition, and plastic mechanism of structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.397-402
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• 2003

This paper presents strut-and-tie models for predicting shear strength of RC interior beam-column joints considering the plastic hinge rotation of adjacent beams. On seismic design of frame system, it is controlled beams to occur plastic hinges and to be ductile so as to dissipate earthquake energy efficiently. The plastic hinge deformation of beams is used as analysis parameter in terms of strain of beam tensile bars at column face. The shear strengths of beam-column joints are evaluated by combining direct strut mechanism with truss mechanism. It is assumed that the max force transferred by direct strut mechanism is based on the strength of cracked concrete element, and that by truss mechanism is based on bond capacity.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.4
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• pp.275-282
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• 2024

A recently proposed rapid-disassembly , carbon-minimized dismantle connection was tested using cyclic loading. To better understand the behavior of the test specimen, three-dimensional finite element (3D-FE) analyses were conducted using a "tied model" (bolted contact surfaces are tied together) and a "bolt-slip model" (contact surfaces slip and separate). The tied model suggests that plastic hinging of the beam occurs if the proposed connection behaves rigidly. The bolt-slip model suggests that the proposed connection, if manufactured and assembled properly, can dissipate energy to about 0.5 times that experienced by a rigid connection. However, when compared in a test, its moment-rotation hysteresis curve does not match well, which suggests that the low performance of the test specimen is attributable to a manufacturing deficiency. Regardless, the results corroborate the pinching phenomenon observed in the experimental hysteresis and fracture failure of the test specimen.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.2
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• pp.173-182
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• 2003

In equivalent static nonlinear analysis and in energy-based design, the structures are generally transformed into an equivalent SDOF system. In this study the seismic energy demands in multi story structures, such as three-, eight-, and twenty-story steel moment-resisting frames(MRF), buckling restrained braced frames(BRBF) and a damage tolerant braced frame(DTBF), are compared with those of equivalent single degree of freedom(ESDOF) systems. Sixty earthquake ground motions recorded In different soil conditions, which are soft rock, soft soil, and neat fault, were used to compute the input and hysteretic energy demands in model structures. In case the modal mass coefficient is less than 0.8, the effects of higher modes are considered in the process of converting into ESDOF According to the analysis results, the hysteretic and input energies obtained from 3 story and 8 story MRF and DTBF agreed well with the results from analysis of equivalent SDOF systems. However in the 20 story BRBF the results from ESDOF underestimated those obtained from the original structures.