• Steel and Composite Structures
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• v.10 no.6
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• pp.541-561
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• 2010

This paper presents finite element analyses, experimental measurements and finite element model updating of an arch type steel laboratory bridge model using semi-rigid connections. The laboratory bridge model is a single span and fixed base structure with a length of 6.1 m and width of 1.1m. The height of the bridge column is 0.85 m and the maximum arch height is 0.95 m. Firstly, a finite element model of the bridge is created in SAP2000 program and analytical dynamic characteristics such as natural frequencies and mode shapes are determined. Then, experimental measurements using ambient vibration tests are performed and dynamic characteristics (natural frequencies, mode shapes and damping ratios) are obtained. Ambient vibration tests are performed under natural excitations such as wind and small impact effects. The Enhanced Frequency Domain Decomposition method in the frequency domain and the Stochastic Subspace Identification method in the time domain are used to extract the dynamic characteristics. Then the finite element model of the bridge is updated using linear elastic rotational springs in the supports and structural element connections to minimize the differences between analytically and experimentally estimated dynamic characteristics. At the end of the study, maximum differences in the natural frequencies are reduced on average from 47% to 2.6%. It is seen that there is a good agreement between analytical and experimental results after finite element model updating. Also, connection percentages of the all structural elements to joints are determined depending on the rotational spring stiffness.

• Steel and Composite Structures
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• v.16 no.4
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• pp.417-436
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• 2014

During an earthquake, steel frame columns can be subjected to high axial forces combined with inelastic rotation demand resulting from story drift. Generally, the whole beam or component can be represented with one element. In elasto-plastic analysis, subdivision is necessary if the plastic deformation occurs within two ends of beams. If effects of the joint panel are necessarily considered in the analysis, the joint panel should be represented with an independent element. It is a special element to represent the shear deformation of the joint panel in the beam-column connection zone. Several analytical models for panel zone (PZ) behavior exist, in terms of shear force-shear distortion relationships. Among these models, the Krawinkler PZ model is the most popular one which is used in the AISC code. Some studies have pointed out that Krawinkler's model gives good results for the range of thin to medium column flanges thickness. This paper, introduces a new model to estimate the response of shear force-shear distortion for the PZ including column axial force. The model is applicable to both thin and thick column flange. To achieve an appropriate PZ mathematical model first, the effects of PZ strength and stiffness on connection response are parametrically studied using finite element models. More than one thousand and four-hundred beam-column connections are included in the parametric study, with varied parameters; then based on analytical results a simple mathematical model is presented. A comparison between the results of proposed method herein with FE analyses shows the average error especially in thick column flange is significantly reduced which demonstrates the accuracy, efficiency, and simplicity of the proposed model.

• Journal of architectural history
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• v.21 no.3
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• pp.7-28
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• 2012

This study is intended to Mindori structure which is general private houses' structural type among traditional types and is a basic study to confirm structural characteristics of Hwatong connection which is general connection type of column-beam-cross beam. It is aimed to analyze how main member, column, such as size, figure, thickness of Sungetuk and Dugeup affect on structure. Following conclusions are drawn. 1. According to connection conditions, models with big coefficient of friction show stable hysteretic behavior until the angle rotation of member reaches 1/60 and models with small coefficient of friction show dramatical increase in load after the angle rotation of member reaches 1/24. After the angle rotation of member reaches 1/30, separation distance of members is identified physically and cracks are not observed. 2. Specimens with big coefficient of friction show similar inner force regardless of column size(except column size 150mm) and models with small coefficient of friction show increasing inner force as the column size increases. Specimens with same sectional area have similar inner force even though the column figures are different. The thickness of Sungetuk and Dugeup doesn't affect inner force greatly, however, when the thickness of Sungetuk is thin, it could lead to failure of structure as it breaks. 3. The bigger the size of column and the coefficient of friction are, the smaller Bending stiffness depreciation ratio is. 4. Energy Dissipation Efficiency differs from the coefficient of friction. When the coefficient of friction is big, square column shows bigger than round one and it is bigger when the thickness of Sungetuk and Dugeup is thicker. When the coefficient of friction is small, round column shows bigger than square one.

• Journal of Korean Society of Steel Construction
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• v.15 no.5 s.66
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• pp.519-529
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• 2003

In recent years, the use of cold-formed steel roof truss has been increased in the steel houses and high-rise apartments. The design of the roof truss anchor connections has been based on the experience and decision of designers. In this paper, the structural behavior of anchor connections based on experimental and decision is described. In the tests, truss members and connection members were jointed directly with self-drilling screw fasteners and the simple shaped connection member with excellent workability and structural capacity was used to connect roof truss and sub-structure. The connecting method was selected according to the construction material of sub-structure: chemical anchor for reinforced concrete structure and welding or DX-Pin for steel structures. The pull-out tests of various type anchor connection were executed to obtain the strength and the stiffness and the result have been compared with AISI(1996) and AlSC(1989) specifications, Simple formulas for the shear strength of screw connections have been propose and compared with tests.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.691-700
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• 2008

Contemporary architectural structures have diverse and complex forms. Such structural variety demands requisite performance from the connections in the steel structure so that the latter could resist a horizontal force, such as an earthquake. The connections are the all-important components that create the discontinuous form and that support stress concentration, determining the stiffness and toughness of the entire steel frame. In this study, a real-scale column-to-beam connection was constructed in the 600MPa-grade high-strength and high-performance steel, to test its behavior. Its material and welding characteristics were examined in this study, and its structural performance was analyzed by conducting seismic-resistance tests on the full-scale, cross-shaped column-to-beam welded connections with non-scallop, ordinary-scallop, and reinforced-scallop details. The weld ability of the high-strength, high-performance steel was also evaluated, and data regarding the seismic design for practical application were provided.

• Journal of Korean Society of societal Security
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• v.3 no.1
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• pp.33-42
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• 2010

This study predicts the stress history for truss bridge with local damages by using global-local model combination method. For this end, the global structure is modeled by 3D frame elements and the selected local details are modeled by shell elements. Then superposition principle enable the global-local model to be combined interactively. Because the frame model cannot consider the rigidity of gusset plate and the interation of structural members due to the complexity of stress distribution in truss connection. The section modification factors are proposed to calibrate the stiffness of global frame element. The global-local model combination is verified by comparing the numerical results with experimental data obtained from the proof loading test to the operating truss bridge. Furthermore, stress histrories of the truss bridge are generated in the consideration of the rigidity of truss connection with local damage by using the combination method.

• Steel and Composite Structures
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• v.19 no.6
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• pp.1403-1419
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• 2015

When precast concrete infill panels are connected to steel frames at discrete locations, interaction at the structural interface is neither complete nor absent. The contribution of precast concrete infill panels to the lateral stiffness and strength of steel frames can be significant depending on the quality, quantity and location of the discrete interface connections. This paper presents preliminary experimental and finite element results of an investigation into the composite behaviour of a square steel frame with a precast concrete infill panel subject to lateral loading. The panel is connected at the corners to the ends of the top and bottom beams. The Frame-to-Panel-Connection, FPC4 between steel beam and concrete panel consists of two parts. A T-section with five achor bars welded to the top of the flange is cast in at the panel corner at a forty five degree angle. The triangularly shaped web of the T-section is reinforced against local buckling with a stiffener plate. The second part consists of a triangular gusset plate which is welded to the beam flange. Two bolts acting in shear connect the gusset plate to the web of the T-section. This way the connection can act in tension or compression. Experimental pull-out tests on individual connections allowed their load deflection characteristics to be established. A full scale experiment was performed on a one-storey one-bay 3 by 3 m infilled frame structure which was horizontally loaded at the top. With the characteristics of the frame-to-panel connections obtained from the experiments on individual connections, finite element analyses were performed on the infilled frame structures taking geometric and material non-linear behaviour of the structural components into account. The finite element model yields reasonably accurate results. This allows the model to be used for further parametric studies.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.482-493
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• 2003

Flat plate structures subjected to lateral load have less deformability than conventional moment frames, due to the brittle failure of plate-column connection. In the present study, parametric study using nonlinear finite element analysis was performed to investigate the deformability of flat plates. The numerical results show that as number of continuous spans increases, the deformability of flat plates considerably decreases. Therefore, existing experiments using sub-assemblages with 1 or 2 spans may overestimate the deformability of flat plates, and current design provisions based on the experiments may not be accurate in estimating the deformability. A design method estimating the deformability was developed on the basis of numerical results, and verified by comparison with existing experiment. In the proposed method, the effects of primary design parameters such as direct shear force, punching shear capacity, aspect ratio of connection, number of spans, and initial stiffness of plate can be considered.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.65-68
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• 2008

This paper verified the lateral resisting capacity of CFT column-RC flat plate connection in comparison with general RC column-flat plate connection and detected moment capacity and ductility capacity of connection according to lateral force-displacement ratio. We made and tested specimens which have different variables respectively and as a result derive a following conclusion. In CFT specimen a critical section was extended and initial stiffness and moment increased 35%, 25$^{\sim}$35% respectively in comparison to general RC column specimen. In all specimens generally shear governed behaviors and in CFT specimen complemented with seismic band, flexure behavior region of slab was extended and also ductility ratio and energy absorptance increased.

• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.481-490
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• 2005

This paper summarizes the full-scale test results on the CFT column-to-flat plate connections subjected to gravity loading. CFT construction has gained wide acceptance in a relatively short time in domestic building construction practice due to its various structural and construction advantages. Constructing an underground parking floor as a flat plate system is often regarded as essential for both cost savings and rapid construction. Efficient details for CFT-column-to-flat-plate connections have not been proposed yet, however, and their development is urgently needed. Based on some strategies that maximize economical field construction, several connecting schemes were proposed and tested based on a full-scale model. The test results showed that the proposed connection details can exhibit punching shear strength and connection stiffness comparable to or greater than those of their R/C flat plate counterpart.