• Structural Engineering and Mechanics
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• v.28 no.1
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• pp.39-52
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• 2008

Column shear failures observed during recent earthquakes and experimental data indicate that shear deformations are typically associated with the amount of transverse reinforcement, column aspect ratio, axial load, and a few other parameters. It was shown that in some columns shear displacements can be significantly large, especially after flexural yielding. In this paper, a piecewise linear model is developed to predict an envelope of the cyclic shear response including the shear displacement and corresponding strength predictions at the first shear cracking, peak strength, onset of lateral strength degradation, and loss of axial-load-carrying capacity. Part of the proposed model is developed using the analysis results from the Modified Compression Field Theory (MCFT). The results from the proposed model, which uses simplified equations, are compared with the column test data.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.704-709
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• 2001

Experimental methods to determine non-linear properties of rubber materials for finite element analysis is discussed. In simple tension tests, dumbbell specimens are generally used to obtain states of pure tension strain. It is shown that the strip specimens of which length is over 10 times of the width can be also used. In simple compression tests, the effect of the friction between the test specimen and the platens is investigated. the new test method with the tapered platen is proposed in order to overcome the effect of friction and it is verified by experimental and finite element analysis results. In pure shear tests, it is shown that the width of the specimen must be at least 10 times of the height. The mechanical conditioning is suggested to stabilize the properties of the rubber materials. Also, engine mount for automotive is analyzed and experimented for each cases.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.27-33
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• 2011

In general, the shear strength of a clay specimen under the direct shear test and the triaxial compression test increases with an increase in the shear rate. This study investigates the effects of shear rate and silt content on the stress-strain behavior of remolded Gwangyang clay, by changing the shear rate and the silt content. Based on the results of the triaxial compression tests, the equi-strain line of remolded Gwangyang clay shows initially positive slope and then becomes flat at certain strain level. As the strain level where the equistrain becomes flat is different depending on the soil with different silt contents, this can be considered as the inherent property of soil.

• Structural Monitoring and Maintenance
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• v.5 no.1
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• pp.39-50
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• 2018

Taking three types of bridge bearings with diameter being 100 mm as examples, the theoretical analysis, the experimental research as well as the numerical simulation of these bearings is conducted. Since the normal compression and shear machines cannot be applied to the small-size bearings, an improved equipment to test the properties of these bearings is proposed and fabricated. Besides, the simulation of the bearings is conducted based on the explicit finite element software ANSYS/LS-DYNA, and some parameters of the bearings are modified in the finite element model to reduce the computation cost effectively. Results show that all the research methods are capable of revealing the fundamental properties of the small-size bearings, and a combined use of these methods can better catch both the integral properties and the inner detailed mechanical behaviors of the bearings.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.2
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• pp.173-178
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• 1991

The rheological properties of acorn crude starch gel and refined starch gel were investigated by puncture test, back-extrusion test and retrogradation test. Puncture test was a useful method to compare the different gel type and concentration, and to calculate the compression and shear coefficient. Maximum extrustion force and adhesiveness were also examined by performing back-extrustion test. The retrogradation rate was analysed by Avrami equation in retrogradation test.

• Steel and Composite Structures
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• v.24 no.1
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• pp.1-13
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• 2017

In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.888-895
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• 2006

In this study, anisotropically consolidated undrained shear(CAU) test was performed to examine the variation of the shear strength according to the stress history. The specimen having 30% relative density was homogeniously prepared, and 200KPa of back pressure was applied to increase the B value more than 0.95. To make NC specimens, the vertical stress was applied on the specimen by 100KPa, 200KPa and 400KPa, and to make OC specimens, the vertical stress was applied upto 400KPa and was reduced to 200KPa and 100KPa resulting in OCR 2 and 4 respectively. The test result indicates the shear strength for the OC specimens are slightly higher then that of the NC specimens at the same confining pressure. The elastic modulus varies according to the confining stress and considerably affected by preconsolidation stress.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.585-593
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• 2010

On the basis of the strain-based shear strength model developed in the previous study, a strength model was developed to predict the direct punching shear capacity and unbalanced moment-carrying capacity of interior and exterior slab-column connections. Since the connections are severely damaged by flexural cracking, punching shear was assumed to be resisted mainly by the compression zone of the slab critical section. Considering the interaction with the compressive normal stress developed by the flexural moment, the shear strength of the compression zone was derived on the basis of the material failure criteria of concrete subjected to multiple stresses. As a result, shear capacity of the critical section was defined according to the degree of flexural damage. Since the exterior slab-column connections have unsymmertical critical sections, the unbalanced moment-carrying capacity was defined according to the direction of unbalanced moment. The proposed strength model was applied to existing test specimens. The results showed that the proposed method predicted the strengths of the test specimens better than current design methods.

• Geomechanics and Engineering
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• v.17 no.1
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• pp.31-45
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• 2019

In this study the spatial variability of soils is substantiated physically and numerically by using random field theory. Heterogeneous samples are fabricated by combining nine homogeneous soil clusters that are assumed to be elements of an adopted random field. Homogeneous soils are prepared by mixing different percentages of kaolin and bentonite at water contents equivalent to their respective liquid limits. Comprehensive characteristic laboratory tests were carried out before embarking on direct shear experiments to deduce the basic correlations and properties of nine homogeneous soil clusters that serve to reconstitute the heterogeneous samples. The tests consist of Atterberg limits, and Oedometric and unconfined compression tests. The undrained shear strength of nine soil clusters were measured by the unconfined compression test data, and then correlations were made between the water content and the strength and stiffness of soil samples with different consistency limits. The direct shear strength of heterogeneous samples of different stochastic properties was then evaluated by physical and numerical modelling using FISH code programming in finite difference software of $FLAC^{3D}$. The results of the experimental and stochastic numerical analyses were then compared. The deviation of numerical simulations from direct shear load-displacement profiles taken from different sources were discussed, potential sources of error was introduced and elaborated. This study was primarily to explain the mathematical and physical procedures of sample preparation in stochastic soil mechanics. It can be extended to different problems and applications in geotechnical engineering discipline to take in to account the variability of strength and deformation parameters.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.3
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• pp.1-7
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• 2000

The aim of the work described in this paper is to study the shear characteristics of the weathered granite soil. To this end, a series of consolidated undrained triaxial compression tests are carried out to investigate the shear parameters-cohesion and internal friction angle for the degree of saturation and degree of weathering. From the results, it is found that the shear parameters of weathered granite soil are influenced on the degree of saturation, degree of weathering and disturbance. Especially, internal friction angle is more influenced on the upper factors than cohesion. And shear parameters are more acted on the degree of saturation than the degree of weathering in the test range. It is, therefore, recommended that must be considered the conditions of granite soil-degree of saturation, degree of weathering and disturbance etc-in case of the calculation of bearing capacity, stability analysis and other designs with shear parameters.