• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.251-259
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• 2003

In this paper, an analytical approach hwas been conductsed to clarify the relationships between the axial force and the deformation capacity of steel- encased reinforced- concrete beam-columns. The analytical model was defined as a cantilever. Several parameters influencing the inelastic performance of the beam-columns were selected, as follows: including encased steel area ratios, and sectional shapes of the encased steel, material strengths, and shear-span- to-depth ratios. The Analytical results of the analysis showed that the axial force had to have a maximum limit to ensure the stable behavior of a steel- encased reinforced- concrete beam-column when it was subjected to both axial and repeated lateral loading under a constant rotation angle amplitude. The maximum axial force of the beam-column to be resisted under cyclic lateral loading was defined as the stable-limit axial force to ensure the required rotation angle amplitude. The Analytical results of the analysis indicate that the stable-limit axial load ratio increases as the steel strength increases or as the compressive strength of the concrete decreases. The stable-limit axial load ratio decreases as the encased steel ' s sectional area increases in the case of a 1-shaped sections and it is almost not influenced by the steel sectional area in the case of a cross-shaped section.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.575-586
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• 2004

This paper presents an experimental study on the flexural capacity of an encased(slim-floor) composite beam, which is a wider plate under bottom flange of H-beam with web openings. Five simple full-scale bending tests were conducted on the encased(slim-floor) composite beams at varying steel beam heights (250mm and 300mm), positions of web openings, and loading conditions. The test results revealed that the web-open encased composite beam had sufficient composite action, without any additional shear connection devices, because of the inherent shear-bond effects between the steel beam and the concrete, and a stable structural performance without web-opening reinforcements.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.247-258
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• 2007

This paper describes the results of an experimental study on the new type of encased composite beams that use deep deck plates, which could reduce the story height of buildings by controlling the bottom flange of steel beams. The profiled steel beam was thus developed. It was advantageous to the long span of the buildings. Seven full-scale specimens were constructed, and simply supported bending tests were conducted on the encased composite beams with different steel plate thicknesses, with and without shear studs, reinforcing bars, and web openings. The test results showed that the encased composite beams that were developed in this study had sufficient composite action without additional shear connectors due to their inherent shear-bond effects between the steel beams and concrete.

• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.619-626
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• 2009

The use of thin-walled flexural members has proven to be a practical way to achieve the lowest cost in the construction of prefabricated long-span, low-rise building frames in steel. On the other hand, most of these structures are subjected to corrosion due to environmental exposure, which can reduce their carrying capacity. Corrosion damage is a serious problem for these structures as it causes thickness loss. That is, the class of a section (plastic, compact, non-compact, or slender) may change from one to another due to the loss of thickness of the compression flange and web due to corrosion. In this study, the effects of corrosion on thin-walled members in long-span steel frames were evaluated with regard to the moment-rotation curve, initial stiffness, maximum load capacity, stiffness in the post-maximum capacity, and energy absorption.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.107-114
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• 2018

In this study, the damage detection method is proposed for the rotational stiffness of connections in steel moment frames by using artificial neural network(ANN). The flexural moment of columns, natural frequencies, modeshapes are used for the input layer in ANN while the damage index, that signify the damage level, is used for the output layer in ANN. The 5-story steel moment frame as an example structure is used to generate the train and test data. Total number of damage scenarios considered is 829. From the results of application, it is shown that the proposed method can accurately estimate the location and level of damages.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.97-103
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• 2004

Most of the columns in centrally braced steel frame buildings are usually designed as the gravity columns to reduce connection cost. For a rational seismic performance evaluation of centrally braced steel frame buildings, it is important to properly incorporate in the analysis  the P-${\Delta}$ effects arising from the gravity columns. An effective scheme for the P-${\Delta}$ effects modeling due to the gravity columns was illustrated based on the concept of fictitious leaning column. Seismic performance evaluation of inverted V braced steel frames with or without P-${\Delta}$ effects modeling was conducted by following the FEMA 273 NSP (Nonlinear Static Procedure). The problem in estimating dynamic P-${\Delta}$ modification factor (C3) in FEMA 273 was discussed. The results of this study indicated that the P-${\Delta}$ effects should be included in the seismic performance evaluation of centrally braced steel frames. This study also showed that the inverted V braced frames, retrofitted by applying the tie bars to redistribute the inelastic demand over the height of the building, exhibit significantly improved seismic performance.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.149-158
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• 2006

The reduced beam section (RBS) steel moment connection has performed well in past numerous tests. However there still remain several design issues that should be further examined. One such issue on RBS connection performance is the panel zone strength. Although a significant amount of test data are available, a specific recommendation for a desirable range of panel zone strength versus beam strength has yet to be proposed. In this paper, the effects of panel zone strength on the cyclic performance of RBS connection are investigated based on the available test database from comprehensive independent testing programs. A criterion for a balanced panel zone strength that assures sufficient plastic rotation capacity while reducing the amount of beam buckling is proposed. Numerical studies to supplement the test results are then presented based on the validated finite element analysis. Satisfactory numerical simulation achieved in this study also indicates that numerical analysis based on quality finite element modeling can supplement or replace, at least in part, the costly full-scale cyclic testing of steel moment connections.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1434-1440
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• 2015

IDM is a methodology for capturing and specifying processes and information flow during the life-cycle of a facility. The methodology can be used to document existing or new processes, and describe the associated information that need to be exchanged between parties. In this paper, the information model for BIM-based structural steel member design was defined using IDM methodology. The structural information offered in IFC was analyzed, and its adequacy was verified by applying the case study using Excel. As a result, $IFC2{\times}3$ offers the most structural design information for BIM-based structural steel member design, and some sectional properties omitted in $IFC2{\times}3$ were offered in IFC4. IDM methodology can be used effectively for developing BIM-based structural design systems.

• Journal of Korean Society of Steel Construction
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• v.19 no.5
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• pp.503-513
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• 2007

The seismic responses of a building are affected by the connection characteristics that have effects on structural stiffness. In this study, push-over analysis and time history analysis were performed to estimate structural behavior of 2D eight-story unbraced steel structures with partially restrained composite connections using a nonlinear dynamic analysis program. Nonlinear $M-{\theta}$characteristics of connection and material inelastic characteristics of composite beam and steel column were considered. The idealization of composite semi-rigid connection as fully rigid connection yielded an increase in initial stiffness and ultimate strength in the push-over analysis. In time history analysis, the stiffness and hysteretic behavior of connections have effects on base-shear force, maximum story-drift and maximum moment in beams and columns. For seismic waves with PGA of 0.4 g, the structure with the semi-rigid composite connections shows the maximum story-drift with less than the life safety criteria by FEMA 273 and no inelastic behavior of beam and column, whereas in the structure with rigid connections, beams and columns have experienced inelastic behaviors.

• Journal of Korean Society of Steel Construction
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• v.19 no.4
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• pp.383-393
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• 2007

A simplified model which incorporates the moment-axial tension interaction of the double-span beams in a column-removed steel frame is presented in this paper. To this end, material and geometric nonlinear parametric finite element analyses were conducted for the double-span beams by changing the beam span to depth ratio and the beam size within some practical ranges. The beam span to depth ratio was shown to be the most influential factor governing the catenary action of the double-span beams. Based on the parametric analysis results, a simplified piece-wise linear model which can reasonably describe the vertical resisting force versus the beam chord rotation relationship was proposed. It was also shown that the proposed method can readily be used for the energy-based progressive collapse analysis of steel moment frames.