• International Journal of High-Rise Buildings
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• v.9 no.2
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• pp.155-166
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• 2020

To connect exterior reinforced concrete (RC) columns with the steel belt truss, the gusset plates are welded to the steel plates embedded in the RC column. Then, the concrete around an embedded plate is very likely to be damaged by the heat input from a long-time (6 to 48 hours) welding of the embedded and gusset plates at a joint between RC columns and steel belt truss. However, very few studies have assessed the concrete damage caused by the welding heat between embedded and gusset plates, and no clear onsite solution has been found. In this paper, experimental tests have been carried out on 4 full-scale specimen to analyze the effect of long-time (about 6 hours) onsite welding (1-side welding and 3-side welding) between a gusset plate and an embedded plate in high strength concrete with compressive strength of 55 MPa and 80 MPa on RC columns. The effect of the long-time welding heat of embedded and gusset plates, which are used in real high-rise building construction sites, on concrete is analyzed in terms of the following three items: 1) temperature distribution, 2) pattern and characteristics of cracks, and 3) effect of the cracks on the compressive strength of RC column. Based on the experimental results, even though the heat input up to about 150? from the long-time onsite welding on the high-strength concrete column for the joint could result in concrete cracks in a radial form, it is found that the welding cracks have no effect on the axial stiffness and strength of the concrete column.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.53-61
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• 2017

In this study, specimens were produced with a column member and a wooden gusset only by inserting an wooden gusset which is a substitute for steel plate into the center of a slit-processed column member. The moment resistance performance of the specimens was compared with that of control specimens that used a steel plate. The measured maximum moments of the specimens produced with GFRP-reinforced wooden laminated gussets and pins were lower by 24% on average compared to the steel plate-inserted specimens, but they showed good toughness. The fracture shape suggests that it was fractured along the annual rings between the pin and the end of the column member. The rigid specimen that integrated a laminated wood and a wooden laminated gusset with adhesive showed 2.8 times greater initial rigidity and 40% greater maximum moment on average compared to the control specimen. The rigid specimens mainly fractured on a glulam around glue line.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.826-833
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• 1998

The energy-absorbing characteristic of impact limiters affects the cask design so significantly that it should be evaluated as accurate as possible. The objective of this study is to find the influence of the impact limiter's steel case and gusset plates which enclose the shock absorbing cellular material on the impact energy absorption. The influence of impact limiter's steel case and gusset plate stiffeners on the impact energy absorption behavior under horizontal drop impact was evaluated for a radioactive isotope transport cask. Though the impact limiters mitigate the impact damage of the cask, the impact limiter's steel case and gusset plate stiffeners increase the impact force so significantly that should be designed as soft as possible. The impact analysis without considering impact limiter's steel case and gusset plates stiffener gives non-conservative results, so the stiffness of the steel case and gusset plates should be considered in impact analysis.

• Journal of Korean Society of Steel Construction
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• v.25 no.2
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• pp.179-186
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• 2013

Steel braced frames are commonly used because braced frames are one of the most economical and efficient seismic resisting systems. However, research into the behavior of multi-story X-braced frame systems with mid-span gusset plates, as used in practice, is limited. As a result, their seismic performance and the influence of connection design on this performance are not well understood. Detailed nonlinear computer analyses of the frame were performed prior to building the test specimens and were used to aid the design and to predict the system performance. These analyses suggested significantly different behavior for the midspan gusset plate than that noted for the corner gusset plate connections. This paper summarizes the results of a full scale, 2-story braced frame analysis and test on concentrically braced frames.

• Steel and Composite Structures
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• v.17 no.5
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• pp.735-751
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• 2014

Concrete-filled steel tube (CFT) composite columns, either circular (CCFT) or rectangular (RCFT), have many economical and aesthetic advantages but the behavior of their connections are complicated. This study aims to investigate, through an experimental program, the performance and behavior of different connections configurations between circular concrete filled steel tube columns (CCFT) and gusset plates subjected to shear and axial compression loadings. The study included seventeen connection subassemblies consisting of a fixed length steel tube and gusset plate connected to the tube end with different details tested under half cyclic loading. A notable effect was observed on the behavior of the connections due to its detailing changes with respect to capacity, failure mode, ductility, and stress distribution.

• Journal of Korean Society of Steel Construction
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• v.13 no.6
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• pp.609-619
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• 2001

It is almost impossible to evaluate the ultimate strength theoretically, because the behavior of Gusset-Tube connection stiffened with rib-plate is considerably complicate. Therefore in this study a finite element model of gusset-tube connection stiffened with rib-plate was established. The validity of finite element analysis was examined through comparing with previous experimental result and the behavior and strength of the connection was examined. From the parametric study considering lateral force ratio, eccentricity, gusset length based on finite element model, the stiffened effect was estimated and stiffening method was proposed.

• Journal of Korean Society of Steel Construction
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• v.21 no.2
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• pp.105-113
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• 2009

To improve braced frame performance, the connection strength, stiffness, and ductility must be directly considered in the frame design. The resistance of the connection must be designed to resist seismic loads and to help provide the required system ductility. In addition, the connection stiffness affects the dynamic response and the deformation demands on the structural members and connections. In this paper, current design models for gusset plate connections are reviewed and evaluated usingthe results of past experiments. Current models are still not sufficient to provide adequate connection design guidelines and the actual stress and strain states in the gusset plate are very nonlinear and highly complex. Design engineers want simple models with beam and column elements to make an approximate estimation of system and connection performance. The simplified design models are developed and evaluated to predict connection stiffness and system behavior. These models produce reasonably accurate and reliable estimation of connection stiffness.

• Journal of Korean Society of Steel Construction
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• v.21 no.1
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• pp.63-70
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• 2009

Failure modes result in fracture or tearing, which may cause deterioration of resistance and reduction of inelastic deformation capacity. The potential failure modes for Special Concentrically Braced Frames (SCBFs) include fracture or tearing of the brace, net section fracture of the brace or gusset plate, fracture of the gusset plate welds, shear fracture of the bolts, block shear, excessive bolt bearing deformation, and buckling of the gusset plate. HSS tubular braces are commonly used in SCBFs, and net section fracture of the tubular brace may also occur through the brace net section at the end of the slot cut into the tube to slip over the gusset plate. This failure mode is categorized as a tension failure mode, and may cause dramatic loss of resistance and brittle behavior. Net section reinforcement is required according to AISC design specifications (AISC 2001). In this paper, the need to reinforce the net section area was discussed. Initially, the results of the net section fracture tests done by the University of California in Berkeley were presented with the modeling of these tests using FE models. To investigate the possibility of net section fracture in an actual frame, the slot end hole model was adapted to the frame FE model, and alternate near-fault histories were applied with tension-dominated cycles, since previous analyses showed that loading history was the most critical factor in net section fracture. The need for this reinforcement (cover plate) and the tension-dominated near-fault history were investigated.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.523-533
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• 2011

The demand for the circular hollow section (CHS) has been increasing due to its structural advantage in long-span structures and high-rise buildings. There are not enough researches on the CHS structure, though. The behavior of the gusset plate CHS joint, to predict the ultimate strength, is not easy to predict because the load deflection curve does not show consistency. Therefore, in this study, experiments and finite element analysis (FEA) were carried out to determine the ultimate strength according to the proposed ultimate deformation limit. Finally, a reasonable ultimate strength formula was proposed through comparisons with other design guides.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.445-455
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• 2020

Shear lag phenomenon has long been taken into consideration in various structural codes; however, the AISC provisions have not proposed any specific equation to calculate the shear lag ratio in some cases such as fillet-welded connections of front-to-front double channel sections. Moreover, those equations and formulas proposed by structural codes are based on the studies that were conducted on riveted and bolted connections, and can be applied to single channel sections whilst using them for fillet-welded double channels would be extremely conservative due to the symmetrical shape and the fact that bending moments will not develop in the gusset plate, resulting in less stress concentration. Numerical models are used in the present study to focus on parametric investigation of the shear lag effect on fillet-welded tension connection of double channel section to a gusset plate. The connection length, the eccentricity of axial load, the free length and the thickness of gusset plate are considered as the key factors in this study. The results are then compared to the estimates driven from the AISC-LRFD provisions and alternative equations are proposed.