• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.10a
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• pp.258-266
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• 1996

The purpose of this study is to make a reasonable correction in construction stage through exact prediction of long-time differential column shortening that occurs in the high-rise RC building. For this, a self-developed program adopted PCA code is used to predict differential column shortening with sequential loading process. Using this program, the amount of the different column shortening of Amatapura Apartment in Indonesia is predicted and the effect is analyzed. From the result, the major factor affecting the shortening amount in columns is elastic strain and the effect of shrinkage is very small rather than creep. And maximun differential column shortening is appeared near the middle of the building.

• Journal of ILASS-Korea
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• v.3 no.2
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• pp.34-41
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• 1998

The present experimental study investigates the effect of an initial disturbance on the breakup mechanism of a liquid column. With varying the maginitude of the inital disturbance, we measure the surface wave of liquid column with adopting laser shadow method and analyze the growth rate of liquid column and breakup frequency. The experimental results show that thebreakup characteristics of liquid column is significantly influenced by the frequency of the initial disturbance. We concluded that the most uniform droplet occurs when the frequency of initial disturbance coincides with the natural frequency of the liquid column.

• Earthquakes and Structures
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• v.21 no.6
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• pp.653-667
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• 2021

In this study, cyclic loading tests were conducted on the precast concrete (PC) wide beam (WB)-column joints. Two beam-column joint specimens were fabricated with the arrangement and anchorage details of the reinforcing bars penetrating the beam and column as variables. Through a cyclic loading test, the lateral load-story drift ratio responses, seismic performance characteristics (e.g., ductility, overstrength factor), energy dissipation, strength and stiffness degradations of each specimen were compared and analyzed based on the various indices and the current structural codes (ACI 318-19 and ACI 374.1-05 report). In addition, the shear lag effect was confirmed through the gauge values of the PC beam, and the differences in seismic performance between the specimens were identified on that basis.

• Structural Engineering and Mechanics
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• v.20 no.5
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• pp.505-526
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• 2005

The influence of the inter-story structural pounding on the seismic behaviour of adjacent multistory reinforced concrete structures with unequal total heights and different story heights is investigated. Although inter-story pounding is a common case in practice, it has not been studied before in the literature as far as the authors are aware. Fifty two pounding cases, each one for two different seismic excitations, are examined. From the results it can be deduced that: (i) The most important issue in the inter-story pounding is the local effect on the external column of the tall building that suffers the impact from the upper floor slab of the adjacent shorter structure. (ii) The ductility demands for this column are increased comparing with the ones without the pounding effect. In the cases that the two buildings are in contact these demands appear to be critical since they are higher than the available ductility values. In the cases that there is a small distance between the interacting buildings the ductility demands of this column are also higher than the ones of the same column without the pounding effect but they appear to be lower than the available ductility values. (iii) It has to be stressed that in all the examined cases the developed shear forces of this column exceeded the shear strength. Thus, it can be concluded that in inter-story pounding cases the column that suffers the impact is always in a critical condition due to shear action and, furthermore, in the cases that the two structures are in contact from the beginning this column appears to be critical due to high ductility demands as well. The consequences of the impact can be very severe for the integrity of the column and may be a primary cause for the initiation of the collapse of the structure. This means that special measures have to be taken in the design process first for the critically increased shear demands and secondly for the high ductility demands.

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.340-355
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• 1978

Model reactions were often applied in the measuring of the mass transfer coefficient and interfacial area between gas and liquid, which are the most important factors in the design of equipment for gas absorption accompanied with chemical reaction this study, wetted wall column was applied to the sulfite-system among the known model reactions. It was found that one could not ignore the effect of contact time on the determination of mass transfer coefficient and interfacial area. When the reaction rate is very high or very low, the differences of absorption rate would be very large in according to the length of column, that is to the contact time. But the effect of contact time was free about the rate constant $k_2=5.5{\times}10^6m^3/kmol{\cdot}s$, that means the rate of gas absorption become independent upon the hydrodynamics of the equipment. It has shown that instead of steel column could be applied the fine grain-graphite column.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.1-9
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• 2009

An analysis program to predict the behavior of a concrete filled steel tube column (CFT) was developed. It considered confining effect, material nonlinearity, strain hardening of steel, and initial axial load. With the developed program, axial load-bending moment interaction analyses, moment-lateral displacement relation analyses, and lateral load-lateral displacement relation analyses were performed. For the verification of the developed program, analysis results were compared with the test results from the other researches. The verified results showed that the developed program predicted the behavior of the CFT column with agreeable accuracy. And they showed that it is necessary to consider the confining effect for the reasonable analysis of the CFT column. A simple parametric study was performed and it chose the strength of unconfined concrete and the thickness of a steel tube as the major parameters affecting the behavior of the CFT column. The parametric analysis results showed that the CFT column had higher strength and smaller ductility by increasing the strength of concrete. But the CFT column showed higher strength and larger ductility by increasing the thickness of the steel tube.

• Journal of KSNVE
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• v.7 no.1
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• pp.91-97
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• 1997

An analysis is presented on the stability of an elastic cantilever column having the elastic restraints at its free end, carrying an added tip mass, and subjected to uniformly distributed follower forces. The elastic restraints are formed by both a translational spring and a rotatory spring. For this purpose, the governing equations and boundary conditions are derived by using Hamilton's principle, and the critical flutter loads and frequencies are obtained from the numerical evaluation of the eigenvalue functions of this elastic system. The added tip mass increases as a whole the critical flutter load of the elastic cantilever column, but the presence of its moment of inertia of mass has a destabilizing effect. The existence of the translational and rotatory springs at the free end increases the critical flutter load of the elastic cantilever column. Nevertheless, their effects on the critical flutter load are not uniform because of their coupling. The translational spring restraining the free end of the cantilever column decreases the critical flutter load by coupling with a large value of tip mass, while by coupling with the moment of inertia of tip pass its effect on the critical flutter load is contrary. The rotatory spring restraining the free end of the cantilever column increases the critical flutter load by coupling with the tip mass, but decreases it by coupling with the moment of inertia of the tip mass.

• Computers and Concrete
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• v.14 no.5
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• pp.613-633
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• 2014

A double-skinned composite tubular (DSCT) column, which consists of concrete and inner and outer tubes, was finally developed to overcome the weaknesses of concrete filled tube columns by reducing the self-weight of the column and confining the concrete triaxially. Research pertaining to the stiffness and strength of the column and the confining effect in a DSCT column has been carried out. However, detailed studies on the confining stress, especially the internal confining stress in a DSCT column, have not been carried out. Internal and external confining stresses should be evaluated to determine the effective confining stress in a DSCT column. In this paper, the confining stresses of concrete before and after insertion of an inner tube were studied using finite element analysis. The relationship between the internal or external confining stresses and the theoretical confining stress was investigated by parametric studies. New modified formulae for the yield and buckling failure conditions based on the formulae suggested by former researchers were proposed. Through analytical studies, the modified formulae were verified to be effective for economic and reasonable design of the inner tubes in a DSCT column under the same confining stress.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.649-660
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• 2009

A nonlinear column model of an internally confined hollow (ICH) reinforced concrete (RC) column was suggested and a parametric study was performed. The suggested column model considered the confining effect and the material nonlinearity of concrete. To verify the suggested column model, its analysis results were compared with the test results from previous researchers and a quasi static test performed in this study. They showed that the suggested column model was reasonable and had acceptable accuracy. The results from parametric studies showed that the thickness of the internal tube, concrete strength, and the hollow ratio of the ICH RC column affected its behavior.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1988.10a
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• pp.36-42
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• 1988

In this study, a formulation of the idealized plate element based upon the idealized structural unit method(ISUM) firstly proposed by Ueda et．al is made in an attempt to analyze the geometric nonlinear behaviour up to the buckling strength of thin-walled long structures like box-column structure including the coupling effect between local and global buckling. An application to the example box-column is also performed and it is found that the present method gives reliable results with consuming very short computing times and therefore is very useful for evaluation of the buckling strength of thin-walled long structures.