• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.337-342
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• 1994

This experimental study is aiming to investigate the hysteritic behavior of high-strength R/C columns subjected to axial load and lateral load reversals. The five 1/4 scaled specimens were made of high-strength concrete with the design strength load(n=0.2f'cAg, n=0.4f'cAg) and type of transverse reinforcement. From the test results, strength and stiffness degradation of columns under higher axial load is much more serious than that under lower axial load. ductility of columns is enhansed with increasing amount of transverse reinforcement, shear strength is depended on the level of axial load.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1439-1449
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• 2007

The challenging aspect of CWR (continuous welded rail) is the additional axial forces in rails, mainly due to the thermal expansion of steel plate girder and rail itself. It has been found that these axial forces are proportional to girder length, total bridge length and bolt tightening forces. Also these forces are dependent to girder support conditions, types of bearings and their arrangements. With CWR, the authors' previous studies show that performance improvements like noise reduce, fatigue resistances and bearing durability increment can be expected. In addition to these effects, secondary effects due to the semi integral behavior between rail and bridge girder also can be expected. Special bearings which can reduce the absolute maximum axial forces have been developed, and applied to real 100m span bridge. The performance improvements were verified through site measurements and numerical analysis. The purpose of this study is to confirm the expected performance improvement aspects of steel plate girder bridges with CWR. To verify these aspects, girder stiffness changes, rail axial force changes, girder displacements and noise level were thoroughly measured and compared.

• Structural Engineering and Mechanics
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• v.5 no.1
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• pp.1-19
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• 1997

A numerical procedure for dynamic analysis of structures including lateral-torsional coupling, axial force effect and soil-structure interaction is presented in this study. A simple soil-structure system model has been designed for microcomputer applications capable of reflecting both kinematic and inertial soil-foundation interaction as well as the effect of this interaction on the superstructure response. A parametric study focusing on inertial soil-structure interaction is carried out through a simplified nine-degree of freedom building model with different foundation conditions. The inertial soil-structure interaction and axial force effects on a 20-storey building excited by an Australian earthquake is analysed through its top floor displacement time history and envelope values of structural maximum displacement and shear force.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.81-84
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• 2006

The purpose of this study is to investigate the inelastic behavior of hollow reinforced concrete bridge piers under varying axial load. The role of the variable axial load is very important in the ductility, strength, stiffness, and energy dissipation. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The proposed numerical method for the inelastic behavior of hollow reinforced concrete bridge piers under varying axial load is verified by comparison with reliable experimental results.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1043-1049
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• 2008

Trouble by excessive axial stress in CWR layed on a bridge is frequently happen, and this problem is induced from lack of considering on the track/structure interface on preliminary design stage. In this study, the sensitivity evaluation for the major influencing parameters, that is, expansion length of span, stiffness of super structure, arrangement of bearing, and strength of sub-structure, to the axial force in CWR on a bridge is conducted. From the sensitivity study, the guideline to reduce axial force efficiently in CWR for bridge engineer was suggested. The suggested guideline may not applicable for every case, but it is helpful for preliminary design of bridge.

• Steel and Composite Structures
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• v.30 no.1
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• pp.69-79
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• 2019

Numerous problems have always vexed engineers with buckling, corrosion, bending, and over-loading in damaged steel structures. The present study aims to study the possible effects of Carbon Fiber Reinforced Polymer (CFRP) for strengthening deficient Steel Square Hollow Section (SHS) columns. To this end, the effects of axial loading, stiffness values, axial displacement, the shape of deficient on the length of steel SHS columns were evaluated based on a detailed parametric study. Ten specimens were tested to failure under axial compression in laboratory and simulated by using Finite Element (FE) analysis based on numerical approach. The results indicated that the application of CFRP sheets resulted in reducing stress in the damage location and preventing or retarding local deformation around the deficiency location appropriately. In addition, the retrofitting method could increase loading the carrying capacity of specimens.

• Steel and Composite Structures
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• v.44 no.1
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• pp.1-15
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• 2022

The weld quality has always been an important factor affecting the development of exposed CFT column-base joint. In this paper, a new type of exposed RCFST column-base joint is proposed, in which the high strength steel bars (USD 685) are set through the column and reinforced concrete foundation without any base plate and anchor bolts. Three specimens, the varying axial force ratio (0, 0.25 and 0.5), were tested under cyclic loadings. In addition, the bending moment capacity, energy dissipation capacity and deformation capacity of column-base joints were clarified. The experimental results indicated that the axial force ratio increases the stiffness and the bending moment and improves the energy dissipation capacity of column-base joints. This is because a large axial force can limit the slip between steel tubular and infilled concrete effectively. The specimens show stable hysteresis behavior.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.278-283
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• 1997

This paper proposes a systematic design method for axial(or thrust) magnetic bearings using optimal design methodology. The objective of the optimal design is to minimize bearing volume. The constraints include the bearing load capacity, linearized bearing stiffness and damping, the magnetic flux density, and geometric relations. In order to obtain design values which can be applied to fabrication of bearings, branch and bound method was introduced in the postprocessing procedure of optimal design results. Verification of the proposed design methodology was perfomed by an example.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.949-954
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• 2003

In this paper, simplified modeling approach describing the hysteretic behavior of reinforced concrete columns is discussed. The inelastic response of a reinforced concrete column or pier subjected to cyclic deformation reversals or earthquake ground motion is evaluated by use of lumped hysteretic representation. For this purpose, the hystertic model under axial force variation is developed and implemented into a nonlinear finite element analysis program. The analytical predictions obtained with the new formulation are compared with test results and reveal accuracy and applicability in terms of strength and stiffness. In addition, comparison between results with and without axial force variation stresses the importance of the proposed approach.

• Structural Engineering and Mechanics
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• v.45 no.3
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• pp.277-309
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• 2013

Beam-to-column connections behaviour plays an important role in the analysis and design of steel and precast concrete structures. The paper presents a computer-based method for geometrically nonlinear frames with semi-rigid beam-to-column connections. The analytical procedure employs modified stability functions to model the effect of axial force on the stiffness of members. The member modified stiffness matrix, and the modified fixed end forces for various loads were found. The linear and nonlinear analyses were applied for two planar steel structures. The method is readily implemented on a computer using matrix structural analysis techniques and is applicable for the efficient nonlinear analysis of frameworks.