• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.189-192
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• 2001

This study is peformed to develop high strength lightweight concrete using synthetic lightweight coarse aggregate. The following conclusions are drawn; The unit weight is in the range of $1,855{\sim}1,883kgf/m^{3}$, which has showed about 75% that of normal cement concrete. The compressive strength is in the range of $240{\times}249kgf/cm^{2}$, the tensile strength is in the range of $30{\sim}33kgf/cm^{2}$ and the bending strength is in the range of $41{\sim}50kgf/cm^{2}$ at the age 7days. The high strength lightweight concrete which is contained fly ash within 10% is showed highest strength.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.3
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• pp.79-87
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• 2011

Deep corrugated steel plate structure has more compressive force and flexibility in bending behavior than short span structure. Asymmetric earth pressure distribution has occurred during construction. Ultimate strength and moment in domestic area, having superior ability at bending strain has been examined in this study. Based on the result of the study preceded, performance of Deep corrugated steel plate specimen has been evaluated by comparing increase of strength according to the increase of reinforcement content in bolt connections and failure mode of specimen.

• Composites Research
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• v.30 no.6
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• pp.331-337
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• 2017

The composite lattice structures have advantages of high specific stiffness and strength and are mainly applied to the structures of launch vehicles that carry the compressive load. However, since these structures are manufactured by filament winding technology, there are some defects and voids found in the knots. For these reasons, the stiffness and strength of the lattice structures have to be compared with finite element model for predicting design load. But, the full scale test is difficult because time and space are limited and the shape of structure is complex, and hence the simple and reliable test methods for examination of stiffness are needed. In this paper, subelements of composite lattice structures were prepared and compressive and bending test were conducted for examination of stiffness of helical and hoop rib. Test methods for subelements of composite lattice structures that has curved and twisted shape were supposed and compared with finite element analysis results.

• Advances in concrete construction
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• v.11 no.5
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• pp.429-445
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• 2021

With regard to economic efficiency, composite fix beams are widely used to pass longitudinal shear forces across the interface. The current knowledge of the composite beam load-slip activity and shear capability are restricted to data from measurements of push-off. Modelling and analysis of the composite beams based on Euro-code 4 regarding to shear, bending, and deflection under differing loads were carried out using Finite Element through an efficient computer simulation and the final loading and sections capacity based on the failure modes was analysed. In bending, the section potential was increased by an improvement of the strength in both steel and concrete, but the flexural and compressive resistance growth is very weak (3.2% 3.1% and 3.0%), while the strength of the concrete has increased respectively from 25 N/mm² to 30, 35, and 40 N/mm² compared to the increment of steel strength by 27% and 21% when it was raised from 275 to 355 and 460 N/mm², respectively. It was found that the final flexural load capacity of fix beams was declined with increase in the fix beam span for both three steel strength. The shear capacity of sections was remained unchanged at constant steel strength and different length, but raised with final yield strength increment of steel sections by 29%, and 67% when it was raised from 275 N/mm² to 355 N/mm² and 460 N/mm², respectively.

• Steel and Composite Structures
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• v.5 no.1
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• pp.35-47
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• 2005

This paper presents the results of a series of tests carried out on hollow and concrete-filled coldformed steel sections subjected to axial and bending forces. The effects of eccentricity ratio and strength of in-fill on the behaviour of these sections were studied. A total of forty-eight medium sized columns and six beams were tested to failure. Extensive measurements of material properties, strains, axial shortening and lateral deflection were carried out. Interaction of local and overall buckling was observed in the tests. Failure mode observations were local buckling coupled with overall buckling. A description of the specially fabricated end fixtures for applying eccentric loading to the columns and to simulate pinned end condition is also presented. The experimental results of hollow columns are compared with the existing Indian, British and American codes of practice and the results of concrete-filled columns are compared with EC4 recommendations. It is seen that in the case of hollow columns predictions based on British and American codes of practice and in the case of concrete-filled columns predictions based on EC4 recommendations agree reasonably well with the experimental results. From the experiments it is seen that the provision of in-fill substantially increases the ultimate load carrying capacity of the order of one and a half to two times and the increase in strength of the in-filled concrete from a low grade concrete of compressive strength 24.94 MPa to a high grade concrete of compressive strength 33.26 MPa increases the ultimate load carrying capacity by one and a half times irrespective of the eccentricity of loading.

• Journal of the Korea Institute of Building Construction
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• v.17 no.5
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• pp.393-401
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• 2017

This study presents an evaluation of basic properties of light weight mortar with expanded polystyrene bead(EPB) and waste expanded polystyrene(WEP) by varying replacement rations. In order to evaluate the basic properties of the light weight mortar with EPB and WEP, unit weight, compressive strength, flexural strength, water absorption ratio, thermal conductivity and distribution of polystyrene (EPB and WEP) in hardened mortar were performed. As a result, unit volume, compressive strength, bending strength, water absorption and thermal conductivity of light weight mortar were increased, but area distribution of polystyrene decreased with increasing the replacement ratio of WEP.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.171-174
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• 2009

This study analyzes the change of the basic characteristics of pavement concrete according to the reinforcement of macro-fiber and the results of the study can be summarized as follows. In the case of the compressive strength of the concrete, the fiber reinforced pavement concrete shows a small decreasing level compared to the basic mixing of pavement concrete (hereafter referred as 'Plain') based on the aging of 28 days. In particular, the polypropylene fiber made in Korea represents a decrease in the strength about 12% compared with that of the Plain. In the case of the tensile strength, it shows certain improvements in the tensile performance compared with that of the Plain. In particular, in the case of the polyvinyl alcohol fiber that shows the largest improvement in tensile performance, it shows an increase in its strength about 21%. In the case of the bending strength, there are no improvements in its strength in the fiber reinforced concrete compared to that of the Plain.

• Steel and Composite Structures
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• v.50 no.4
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• pp.383-401
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• 2024

The research comprehensively studies the axial compression performance of T-shaped concrete-filled thin-walled steel tubular (CTST) long columns after fire exposure. Initially, a series of tests investigate the effects of heating time, load eccentricity, and stiffeners on the column's performance. Furthermore, Finite Element (FE) analysis is employed to establish temperature and mechanical field models for the T-shaped CTST long column with stiffeners after fire exposure, using carefully determined key parameters such as thermal parameters, constitutive relations, and contact models. In addition, a parametric analysis based on the numerical models is conducted to explore the effects of heating time, section diameter, material strength, and steel ratio on the axial compressive bearing capacity, bending bearing capacity under normal temperature, as well as residual bearing capacity after fire exposure. The results reveal that the maximum lateral deformation occurs near the middle of the span, with bending increasing as heating time and eccentricity rise. Despite a decrease in axial compressive load and bending capacity after fire exposure, the columns still exhibit desirable bearing capacity and deformability. Moreover, the obtained FE results align closely with experimental findings, validating the reliability of the developed numerical models. Additionally, this study proposes a simplified design method to calculate these mechanical property parameters, satisfying the ISO-834 standard. The relative errors between the proposed simplified formulas and FE models remain within 10%, indicating their capability to provide a theoretical reference for practical engineering applications.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.169-177
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• 2011

This paper presents the results of the systematic finite element analysis of the in-plane bending moment of T-joints subjected to cyclic loadings. T-joints were fabricated using high-strength, circular, hollow sections. Three-dimensional, nonlinear finite element models of the welded T-joints were constructed to investigate the strength, rotational-stiffness characteristics, and failure modes. A wide scope of structural behaviors explain the influence of the joint geometric parameters, such as the chord and brace wall slenderness ratios and the ratio of the brace to the chord diameter, as well as the yield strength ratios and compressive-chord-stress effects on the ultimate in-plane bending moment capacity of the T-joint.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.189-192
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• 2002

This study is performed to properties of strength of concrete using recycled aggregate. The compressive strength is in the range of $232kgf/cm^2{\sim}375kgf/cm^2$, the tensile strength is in the range of $27kgf/cm^2{\sim}35kgf/cm^2$, and bending strength is in the range of $58kgf/cm^2{\sim}67kgf/cm^2$ at the curing age of 28days. The test result shows that the strengths tend to decreased with increase using recycled aggregate.