• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.4018-4023
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• 2010

Various kinds of shear connector such as headed stud, channel, perforated steel plate and others are commonly used to transfer stress and present composite performance in composite structures, and many researches have been conducted to improve the characteristics of different types of shear connectors. It is focused in this study on the bending performance of steel pipe pile cap with the open type perforated shear connector for the composite connection to the spread footing. Nonlinear analysis was conducted, using ABAQUS, a finite element analysis program, to obtain information for determining the characteristics of the structure and to allow various parametric analysis for bending performance of steel pipe pile cap with the open perforated shear connector.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.451-458
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• 2008

In this study 3- and 6-story flat plate structures designed only for gravity load are retrofitted with steel plates and braces and their seismic performances are evaluated to verify the effect of seismic retrofit. According to the analysis results obtained from nonlinear static and dynamic analyses both the strength and stiffness are significantly enhanced as a result of the seismic retrofit. Especially the effect of column jacketing could be enhanced significantly when slabs were reinforced to prevent premature punching shear failure. When buckling-restrained braces are used instead of conventional braces, the structures showed more ductile behavior, especially in the 3-story structure.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.5
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• pp.389-397
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• 2010

This paper presents the effects of the tunnel stability using rebar steel pipe which is the steel pipe reinforced by rebar. In order to carry out this research, not only the theoretical and experimental study for bending stiffness of normal steel pipes and rebar steel pipes but also numerical analysis of tunnel stability are performed. It is clearly found from the results that 65% of bending stiffness of the rebar steel pipe is larger than that of the normal steel pipe. The results obtained from the numerical analysis of tunnel stability show that about 10% of tunnel stability is increased in case of the rebar steel pipe. The rebar steel pipe, therefore, may be very useful to develope the tunnel stability economically.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.455-462
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• 2013

The effects of earthquakes can be devastating especially to existing structures that are not based on earthquake resistant design. This study proposes a steel grid shear wall that can provide a sufficient lateral resistance and can be used as a seismic retrofit method. The pushover analysis was performed on RC structure with and without the proposed steel grid shear wall. Obtain the performance point that the target structure for seismic loads applied to evaluate the response and performance levels. The capacity spectrum at performance point is nearly elastic range, so satisfied the performance objectives(LS level). And response modification factor(R factor) were calculated from the pushover analysis. The R factor approach is currently implemented to reflect inelastic ductile behavior of the structures and to reduce elastic spectral demands from earthquakes to the design level. The R factor increases from 2.17 to 3.25 was higher than the design criteria. As a result, according to reinforcement by steel grid shear wall, strength, stiffness, and ductility of the low-rise RC structure has been appropriately improved.

• Journal of the Korean Geotechnical Society
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• v.20 no.5
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• pp.67-78
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• 2004

Soil-steel bridges are made of flexible corrugated steel plates buried in the well-compacted granular soil. One kind of possible collapses of these structures could be initiated by shear or tension failure in the soil cover subjected to vehicle loads. Current design codes provide the requirements for the minimum depth of the soil cover to avoid problems associated with soil cover failures. However, these requirements were developed for short span (less than 7.7 m) structures which are made of unstiffened plates of standard corrugation (150$\times$50 m). Numerical analyses were carried out to investigate the behavior of long span soil steel bridges according to thickness of the soil cover. The span of structures were up to 20 m and deep corrugated plates (381$\times$140 m) were used. The analysis showed that the minimum cover depth of 1.5 m could be sufficient to prevent the soil cover failure in the structures with a span exceeding 10 m. Additional analyses were performed to verify the reinforcement effect of the concrete relieving slab which can be a special feature to reduce the live-load effects. Analyses revealed that the bending moment of the conduit wall with a relieving slab was less than 20% of that without a relieving slab in a case of shallow soil cover conditions.

• Journal of the Korea Concrete Institute
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• v.21 no.2
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• pp.129-138
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• 2009

Recently, for more demands of the economical benefits and environmental conservation, many engineers prefer to choose remodeling. Artificial openings are often unavoidable to make house wider, which will degrade wall strength and stiffness by losing effective wall section that may cause the weakening of system capacity. In these cases the damaged shear walls need to be retrofitted by additional materials or members. In this research, four specimens were tested to investigate the capacity of the damaged wall and the retrofitted wall. The artificially damaged wall was prestressed by tendons to improve the shear capacity of the wall, and the other walls were retrofitted by adding steel plate at the surface for the same purpose. Consequently, these retrofitted walls had improved capacity and stiffness in both shear and flexure. Especially, the wall with steel plate showed ductile behavior after ultimate load and the prestressed wall had greater stiffness than the unstrengthened prototype wall.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.79-86
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• 2008

Four RC shear wall specimens with a/d of 2.2 are designed. And a flexural retrofitting is performed for one specimen by both enlarging wall section and adding additional vertical reinforcements. Also the effectivity of jaketting wall sides is evaluated for the two methods using only steel plate or welded wire mesh with enlargement of section. Cyclic loads are applied to the retrofitted specimens according to the loading history proposed by ACI under constant axial force. Test result showed that the strength and ductility of specimen were improved where the section was enlarged after the installation of additional vertical reinforcements. Confining the ends of wall by U shape W.W.F. with enlargement of section showed most excellent structural capacity regarding to the strength and ductility. Retrofitting by using steel plate was much effective not only to protect the abrupt decrease of strength after yield but also to improve the deformation capacity.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.153-156
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• 2008

The objective of the present study is to evaluate the flexural behavior of reinforced concrete columns externally strengthened with wire rope and T-shape steel plate units. Three strengened columns and a control unstrengthened column were tested under cyclic lateral load simultaneously subjected to a constant axial load. All columns had same section size, and the arrangement of longitudinal reinforcement and internal hoop. The spacing of wire rope range from 40 ${\sim}$ 80mm, which corresponds from 1.0 ${\sim}$ 0.5, respectively, times the minium amount of hoop specified in seismic design of ACI 318-05. Test results showed that the proposed unbonded-type strengthening procedure is very effective for improving the flexural ductility of reinforced concrete columns.

• Journal of Korean Society of Steel Construction
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• v.13 no.5
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• pp.503-511
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• 2001

Structures are designed against earthquakes and reinforced concrete shear walls or steel bracings are usually used as aseismic resistant element. However their hysteretic characteristics in plastic region ductility and capacity of energy absorption are not always good. Besides their stiffness is so rigid that structure designed by static analysis is occasionally disadvantageous. when dynamically analized. Generally a steel plate subjected to shear force has a good deformation capacity Also it has been considered to retain comparative shear strength and stiffness Steel shear wall can be used as lateral load resistant element for seismic design. However there was little knowledge concerning shear force-deformation characteristics of steel plates up to their collapse state In this study a series of shear loading tests of steel plate collapse state. In this study a series of shear loading tests of steel plate surrounded by vertical and horizontal ribs were conducted with the parameters of D/H ratios rib type and the loading patterns. The test result is discussed and analyzed to obtain several restoring characteristics. that is shear force-deformation stiffness and yield strength etc.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.621-628
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• 2004

This paper introduces a new theory, that in a stiffened plate, a steel stiffener could be substituted a composite material in order to prevent from buckling. Changing a steel stiffener into a composite material would not only preclude welding, but could also prevent damage to the material due to fatigue and corrosion.A composite material is assumed to adhere to a steel plate, and is never separated from the plate until the steel plate reaches buckling.Such plate has variable shapes, with different lengths and widths, and also shows an anisotropic material property. LUSAS, a commercial finite element analysis package, was used in the buckling analysis.This paper investigated buckling behavior in anisotropic composite plates with variable parameters.