• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.270-278
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• 1999

This paper describes the collapse characteristics of the rectangular tube under eccentric compressive load. Overall buckling stress and bifurcation criterion (slenderness ration)are investigated. modified secant formula(MSF) is proposed to decide overall buckling stress. The bifurcation criterion which can distinguish between the local and overall buckling mode shapes is suggest by equating the local and overall buckling stresses. Additionally the effect of initial imperfection on bifurcation criterion is investigated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.16-28
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• 2000

The steady rotating flows in eccentric annulus has been studied by a numerical method based on the spectral collocation method. The inner cylinder has a constant angular velocity while the outer on e is stationary. Flow between eccentric cylinders is of considerable technical importance as it occurs in journal bearings. In the present work, the governing equations for laminar flow are expressed as Navier-Stokes equations, including the non-linear convection terms. The solutions were utilized i, estimate the effects of the nonlinear terms on the load acting on the rotating cylinder. Based on the half and the full Sommerfeld methods, the load on the rotating cylinder is evaluated with eccentricity, by integrating the pressure and skin friction around the cylinder. The attitude angle and Sommerfeld reciprocal are calculated from the load. Also, the torque on the rotating inner cylinder was calculated. considering the skin friction. The attitude angle and Sommerfeld reciprocal are decreased with eccentricity. Viscous damping coefficient due to the skin friction becomes larger with decreasing the annular space. It is found the non-linear effects of the convection terms on the flow and the load are important. especially on the attitude angle, for relatively wide annular configurations however, the effects on those are minor for very narrow annular ones.

• Current Optics and Photonics
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• v.7 no.4
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• pp.337-344
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• 2023

Three-point bending is the main method for measuring the elastic modulus of a thin plate. Although various displacement transducers may be used to measure the bending, these are single-point measurements, and it is difficult to eliminate the error caused by eccentric load and shear force. Error-correction models for the elastic modulus of quartz glass using digital speckle interferometry are proposed for eccentric load and shear force. First, the positional misalignment between maximum deflection and load is analyzed, and the error caused by eccentric load is corrected. Then, the additional displacement caused by shear force at different positions of the quartz glass plate is explored. The effect of shear deformation is also corrected, by measuring two points. Since digital speckle interferometry has the advantage of full-field measurement, it can simultaneously obtain deflection data for multiple points to realize error correction. Experimental results are presented to demonstrate that the proposed model can effectively correct the measurement error of the elastic modulus.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.683-691
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• 2003

Recently, the steel has been increaseingly used as an integrated part of high-rise buildings, which often composed of steel structures, steel reinforced concrete structures and composite structures. The steel base is designed to transfer the stresses induced from steel column to the reinforced concrete footing through the base plate. However, in the design of steel structures and steel reinforced concrete structure, it is generally difficult to evaluate the bearing strength of the steel base subjected to large axial force. Furthermore, the material used in steel base is quite different from those used in other connections and a load transferring mechanism of steel base is very complicated in nature. Therefore, a special attention must be placed in design and construction of steel base. In generally, the bearing strength test and research of the steel base subjected to concentrated load are carried out. But, in the design of the structures, uniaxial eccentric load is loaded to the steel base of the steel structures. In this research, the bearing strength and the me of failure considering eccentric loads and eccentric length, were experimented when eccentric load is loaded to the steel base of steel structures. Based on the test results, a basic design reference is suggested for a reasonable design of steel structures, steel reinforced concrete structures and composite structures.

• Journal of Korean Society of Steel Construction
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• v.11 no.1 s.38
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• pp.89-98
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• 1999

The objective of this paper is to investigate the structural behavior of concrete filled steel tubular columns subjected to eccentric load. With experiment and analytical study, the buckling behavior of columns is investigated and compared with each other to the view of main parameters. Appling foreign standards in the experimental results, we suggested new strength formula of concrete-filled steel tubular columns. The parameters are slenderness, eccentric ratio, and concrete filled or not. The experiment are carried out by simple loading.

• Earthquakes and Structures
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• v.17 no.6
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• pp.623-633
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• 2019

A large number of available concrete buildings designed only considering gravity load that require seismic rehabilitation because of failure to meet plasticity criteria. Using steel bracings are a common type of seismic rehabilitation. The eccentric bracings with vertical link reduce non-elastic deformation imposed on concrete members as well as elimination of probable buckling problems of bracings. In this study, three concrete frames of 10, 15, and 20 stories designed only for gravity load have been considered for seismic improvement using performance-based plastic design. Afterwards, nonlinear time series analysis was employed to evaluate seismic behavior of the models in two modes including before and after rehabilitation. The results revealed that shear link can yield desirable performance with the least time, cost and number of bracings of concrete frames. Also, it was found that the seismic rehabilitation can reduce maximum relative displacement in the middle stories about 40 to 80 percent. Generally, findings of this study demonstrated that the eccentric bracing with vertical link can be employed as a suitable proxy to achieve better seismic performance for existing high rise concrete frames.

• Structural Engineering and Mechanics
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• v.8 no.1
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• pp.85-102
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• 1999

With the advent of computer, the finite element method has become a most powerful numerical method for structural analysis. However, bridge designers are reluctant to use it in their designs because of its complex nature and its being time consuming in the preparation of the input data and analyzing the results. This paper describes the development of a computer based finite element model using the idea of eccentric beam elements for the analysis of slab-on-girder bridges. The proposed method is supported by a laboratory test using a reinforced concrete bridge model. Other bridge analytical schemes are also introduced and compared with the proposed method. The main aim of the comparison is to prove the effectiveness of the shell and eccentric beam modelling in the studies of lateral load distribution of slab-on-girder bridges. It is concluded that the proposed finite element method gives a closer to real idealization and its developed computer program, SHECAN, is also very simple to use. It is highly recommended to use it as an analytical tool for the design of slab-on-girder bridges.

• Advances in concrete construction
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• v.10 no.2
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• pp.151-159
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• 2020

An experimental study on the stress-strain relation of PVC-CFRP confined reinforced concrete columns subjected to eccentric compression was carried out. Two parameters, such as the CFRP strips spacing and eccentricity of axial load, were considered. The experimental results showed that all specimens failed by compressive yield of longitudinal steel bar and rupture of CFRP strips. The bearing capacity of specimen decreases as the eccentricity or the CFRP strips spacing increases. The stress-strain relation of specimens undergoes two stages: parabolic and linear stages. In the parabolic stage, the slope of stress-strain curve decreases gradually as the eccentricity of axial loading increases while the CFRP strips spacing has little effect on the slope of stress-strain curve. For the linear stage, the slope of stress-strain curve decreases as the eccentricity of axial load or the CFRP strips spacing increases. A model for predicting the stress-strain relation of columns under eccentric compression is proposed and it agrees well with various test data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1749-1755
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• 2014

Technique for analyzing a pile installed by vibrohammer was developed and parametric studies were executed in order to evaluate reliability of the developed technique. Comparing the accelerations obtained from parametric studies of varying eccentric moment and frequency, it can be seen that magnitude of maximum acceleration was proportional to the eccentric moment and square of frequency. It can also be seen that amplitude of displacement was roughly proportional to the eccentric moment but has nothing to do with the frequency. It can be said that all of the analysis results reflect characteristics of behavior of a pile in case of free vibration. Comparing the dynamic load transfer curves, maximum dynamic unit toe resistance was constant regardless of the eccentric moment and the frequency and it can be seen that dynamic unit skin friction was affected by the eccentric moment not by frequency. Comparing all of the analysis results, it can be said that the developed technique is reliable.

• Computers and Concrete
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• v.25 no.1
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• pp.1-14
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• 2020

This study presents applications of the multivariate adaptive regression splines (MARS) method for predicting the ultimate loading carrying capacity (N_u) of rectangular concrete-filled steel tubular (CFST) columns subjected to eccentric loading. A database containing 141 experimental data was collected from available literature to develop the MARS model with a total of seven variables that covered various geometrical and material properties including the width of rectangular steel tube (B), the depth of rectangular steel tube (H), the wall thickness of steel tube (t), the length of column (L), cylinder compressive strength of concrete (f'_c), yield strength of steel (f_y), and the load eccentricity (e). The proposed model is a combination of the MARS algorithm and the grid search cross-validation technique (abbreviated here as GS-MARS) in order to determine MARS' parameters. A new explicit formulation was derived from MARS for the mentioned input variables. The GS-MARS estimation accuracy was compared with four available mathematical methods presented in the current design codes, including AISC, ACI-318, AS, and Eurocode 4. The results in terms of criteria indices indicated that the MARS model was much better than the available formulae.