• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.4
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• pp.49-58
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• 1984

A series of cyclic triaxial tests were carried out on undisturbed samples to clarify the cyclic behavior of Bangkok(Ransit) soft clay. Based on the test results obtained from the cyclic tests employing different initial shear stress and different confining stress, the cyclic properties of clay such as shear strain development and cyclic strength were investigated. The results showed that with increase in the initial shear stress, the stress-strain curve was flattened to some extent. The cyclic strength expressed by the stress ratio was higher in the test with $1.0kgf/cm^2$ of confining stress, while the cyclic strength expressed by the deviator stress was higher in the test with $1.5kgf/cm^2$ of confining stress.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.2
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• pp.31-39
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• 2019

Cracked component analysis is needed for structural integrity analysis under seismic loading. Under large amplitude cyclic loading conditions, the change in material properties can be complex, depending on the magnitude of plastic strain. Therefore the cracked component analysis under cyclic loading should consider appropriate cyclic hardening model. This study introduces a procedure for determining an appropriate cyclic hardening model for cracked component analysis. The test material was nuclear-grade TP316 stainless steel. The material cyclic hardening was simulated using the Chaboche combined hardening model. The kinematic hardening model was determined from standard tensile test to cover the high and wide strain range. The isotropic hardening model was determined by simulating C(T) test under cyclic loading using ABAQUS debonding analysis. The suitability of the material hardening model was verified by comparing load-displacement curves of cyclic C(T) tests under different load ratios.

• Structural Engineering and Mechanics
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• v.59 no.2
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• pp.291-312
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• 2016

Seismic performance evaluation of shear wall is essential as it is the major lateral load resisting member of a structure. The ultimate load and ultimate drift of the shear wall are the two most important parameters which need to be assessed experimentally and verified analytically. This paper comprises the results of monotonic tests, quasi-static cyclic tests and shake-table tests carried out on a midrise shear wall. The shear wall considered for the study is 1:5 scaled model of the shear wall of the internal structure of a reactor building. The analytical simulation of these tests is carried out using micro and macro modeling of the shear wall. This paper mainly consists of modification in the hysteretic macro model, developed for RC structural walls by Lestuzzi and Badoux in 2003. This modification is made by considering the stiffness degradation effect observed from the tests carried out and this modified model is then used for nonlinear dynamic analysis of the shear wall. The outcome of the paper gives the variation of the capacity, the failure patterns and the performance levels of the shear walls in all three types of tests. The change in the stiffness and the damping of the wall due to increased damage and cracking when subjected to seismic excitation is also highlighted in the paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.4024-4030
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• 2010

Axial load tests and cyclic load tests for FRP reinforced rectangular CFT columns were carried out The main parameters were width-thickness ratio of a steel tubeand FRP layer numbers for the axial load tests and were concrete strength and FRP layer numbers for cyclic load tests. The maximum strength and ductility capacity were compared between the current CFT columns and the FRP reinforced CFT columns. Finally, the axial design formulas were presented for the FRP reinforced CFT columns.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.5
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• pp.227-235
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• 2013

Friction energy dissipative devices have been increasingly implemented as structural seismic damage protecting systems due to their excellent seismic energy dissipating capacity and high stiffness. This study develops rotational friction energy dissipative devices and verifies experimentally their cyclic response. Based on the understanding of the differences between the traditional linear-motion friction behavior and the rotational friction behavior, the configuration of the frictional surface was determined by investigating the characteristics of the micro-friction behavior. The friction surface suggested in this paper consists of brake-lining pads and stainless steel sheets and is normally stressed by high-strength bolts. Based upon these frictional characteristics of the selected interface, the rotational friction energy dissipative devices were developed. Bolt torque-bearing force tests, rotational friction tests of the suggested friction interfaces were carried out to identify their frictional behavior. Test results show that the bearing force is almost linearly proportional to the applied bolt torque and presents stable cyclic response regardless of the experimental parameters selected this testing program. Finally, cyclic tests of the rotational friction energy dissipative devices were performed to find out their structural characteristics and to confirm their stable cyclic response. The developed friction energy dissipative devices present very stable cyclic response and meet the requirements for displacement-dependent energy dissipative devices prescribed in ASCE/SEI 7-10.

• Journal of the Korean Geotechnical Society
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• v.40 no.3
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• pp.65-75
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• 2024

This study investigates liquefaction-induced settlement through strain-controlled tests using a cyclic direct simple shear device on clean sand specimens. By focusing on the accumulated shear strain, soil density, sample preparation method, and cyclic waveshape, this study attempts to enhance the understanding of soil behavior under seismic loading and its further deformation. Results from tests conducted on remolded samples reveal insights into excess pore water pressure development and post-liquefaction volumetric strain behavior, with denser samples exhibiting lower volumetric strains than looser samples. Similarly, the correlation between the frequency and amplitude variations of the wave and volumetric strain highlights the importance of wave characteristics in soil response, with shear strain amplitude changes, varying the volumetric strain response after reconsolidation. In addition, samples prepared under moist conditions exhibit less volumetric strain than dry-reconstituted samples. Overall, the findings of this study are expected to contribute to predictive models to evaluate liquefaction-induced settlement.

• Journal of the Korean Geotechnical Society
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• v.27 no.3
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• pp.63-73
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• 2011

The behavior of laterally cyclic loaded piles is affected by the magnitude and number of cycles of cyclic lateral loads as well as loading method (1-way or 2-way loading). In this study, calibration chamber tests were carried out to investigate the effects of loading method of cyclic lateral loads on the behavior of piles driven into sand. Results of the chamber tests show that the permanent lateral displacement of 1-way cyclic loaded piles is developed in the same direction as the first loading, whereas that of 2-way cyclic loaded piles is developed in the reverse direction of the first loading. 1-way cyclic lateral loads cause a decrease of the ultimate lateral load capacity of piles, and 2-way cyclic lateral loads cause an increase of the ultimate lateral load capacity of piles. The change of ultimate lateral load capacity with loading method of cyclic lateral loads increases with increasing number of cycles. It is also observed that the 1-way cyclic loads generate greater maximum bending moment than 2-way cyclic loads for piles in cyclic loading step and generates smaller maximum bending moment for piles in the ultimate state. It can be attributed to the difference in compaction degree of the soil around the piles with loading method of cyclic lateral loads. In addition, it is founded that 1-way and 2-way cyclic lateral loads cause a decrease in the maximum bending moment of piles in the ultimate state compared with that of piles subjected to only monotonic loads.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.109-120
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• 2013

This paper presents the results of a laboratory investigation into a study on undrained characteristics of a geogrid-encased stone column (GESC) installed in soft clay under cyclic load. In order to analyze behavior of settlement, pore water pressure, stress concentration ratio and strain of the GESC compared to a stone column, a series of reduced-scale laboratory tests were performed. The model tests show that GESC provides a simple and effective method of deformation resistance and settlement restraint when a short-term cyclic load is applied. The maximum strain of geogrid occurred at 1.2D and 1.5D from the top of the column. This paper highlights the importance of considering overlay effect and replacement ratio on cyclic load supporting GESC.

• Journal of Korean Association for Spatial Structures
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• v.15 no.4
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• pp.73-80
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• 2015

The new rotary friction damper was developed using several two-nodal rotary frictional components with different clamping forces. Because of these components, the rotary friction damper can be activated by building movements due to lateral forces such as a wind and earthquake. In this paper, various dependency tests such as displacement amplitude, forcing frequency and long term cyclic loading were carried out to evaluate on the structural performance and the multi-slip mechanism of the new damper. Test results show that the multi-slip mechanism is verified and friction coefficients are dependent on displacement amplitute and forcing frequency except long term cyclic loading.

• Journal of Mechanical Science and Technology
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• v.15 no.9
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• pp.1281-1291
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• 2001

The hereditary integral form of a quasi-linear viscoelastic law has been employed. Four new concepts have been employed: 1. a reduced relaxation function with a non-linear exponential function of time, 2. an inverse method to determine the scale factor of the elastic response, 3. an instant elastic recovery strain during unloading, and 4. the results of a constitutive model for cyclic tests may be a function of the Heavyside class. These concepts have been supported by agreement between measured and predicted responses of soft connective tissue to three types of multiple cyclic tests which include rest periods of no extension and alternations between different strain levels. Such agreement has not been attained in the previous studies. Chun and Hubbard (2001) is our companion experimental analysis paper.