• Proceeding of KASS Symposium
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• 2006.05a
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• pp.182-188
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• 2006

This study propose cutting body portion-high strength bolts to improve deformation capacity of High strength bolts, which are the mechanical fasteners used for End-plate connection. And, we report that loading test results of steel beam-to-column connection using high deformation capacity-high strength bolts in accordance with SAC2000 loading program. As a result, the initial stiffness and the maximum strength of the connection using high deformation capacity-high strength bolts, are approximately the same in comparison with those of the end-plate connection using the existing high strength bolts. But the deformation capacity of the connection is more than twice as much as those.

• Journal of Korean Association for Spatial Structures
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• v.6 no.3 s.21
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• pp.123-130
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• 2006

This study propose cutting body portion-high strength mechanical fasteners to improve deformation capacity of High strength bolts, which are the mechanical fasteners used for End-plate connections. And, we report that loading test results of steel beam-to-column connection using high deformation capacity-high strength bolts in accordance with SAC2000 loading program. As a result, the initial stiffness and the maximum strength of the connection using high deformation capacity-high strength bolts, are approximately the same in comparison with those of the end-plate connection using the existing high strength bolts. But the deformation capacity of the connection is more than twice as much as those.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.201-206
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• 2001

This paper presents truss model that can be used to determine the deformation as well as strength of RC members. This model is constituted to address plastic hinge rotation at tile deformation concentrated regions under severe lateral load. The behavior of each element of truss model is evaluated on the basis of stress field analysis. The deformation is obtained by combining element deformations with joint rotation. Initial strength is calculated at the first failure of any element, and strength deterioration after failure depends on the strength reduction of this element. The proposed model will provide useful tools in seismic design of ductility-required members.

• Journal of the Korean Society for Heat Treatment
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• v.3 no.4
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• pp.1-9
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• 1990

In this study, the ausformed martensite cooled to $-196^{\circ}C$ with various deformation degrees in Fe-30%Ni-0.24%C alloy was transformed to reversed austenite at $500^{\circ}C$ by cyclic reverse martensitic transformation. The effects of prior deformation and the number of cyclic reverse transformation on the microstructure and the mechanical properities of reversed anstensite were investigated. Experimental results showed that the strength of reversed austenite was higher than that of original austenite. This is due to higher dislocation density and grain refining. The reversed austenite formed from ausformed martensite was highly strengthened by prior deformation. This strengthening effect of reversed austenite is attributed to higher dislocation density than grain fefining. The yield strength of reversed austenite below 30% prior deformation, but above 30% prior deformation the strength of reversed austenite is lower than that of deformed austenite. This is due to partly disappearance of strain hardening effect at higher deformation degree by reverse transformation. The strength of reversed austenite is increased with the number of cyclic transformation. Especially, it is principally strengthened by the first cyclic transformation and shows higher increase in yield strength than that of ultimate tensile strength.

• Korean Journal of Materials Research
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• v.23 no.10
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• pp.568-573
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• 2013

The deformation properties of a TiC-Mo eutectic composite were investigated in a compression test at temperatures ranging from room temperature to 2053 K and at strain rates ranging from $3.9{\times}10^{-5}s^{-1}$ to $4.9{\times}10^{-3}s^{-1}$. It was found that this material shows excellent high-temperature strength as well as appreciable room-temperature toughness, suggesting that the material is a good candidate for high-temperature application as a structure material. At a low-temperature, high strength is observed. The deformation behavior is different among the three temperature ranges tested here, i.e., low, intermediate and high. At an intermediate temperature, no yield drop occurs, and from the beginning the work hardening level is high. At a high temperature, a yield drop occurs again, after which deformation proceeds with nearly constant stress. The temperature- and yield-stress-dependence of the strain is the strongest in this case among the three temperature ranges. The observed high-temperature deformation behavior suggests that the excellent high-temperature strength is due to the constraining of the deformation in the Mo phase by the thin TiC components, which is considerably stronger than bulk TiC. It is also concluded that the appreciable room-temperature toughness is ascribed to the frequent branching of crack paths as well as to the plastic deformation of the Mo phase.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.561-568
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• 2005

The factors affecting the long-term design strength of geogrid can be classified into factors on creep deformation, installation damage, temperature, chemical degradation and biological degradation. Especially, creep deformation and installation damage are considered as main factors to determine the long-term design strength of geogrid. Current practice in the design of reinforced soil is to calculate the long-term design strength of a reinforcement damaged during installation by multiplying the two partial safety factors, $RF_{ID} and RF_{CR}$. This method assumes that there is no synergy effect between installation damage and creep deformation of geogrids. Therefore, this paper describes the results of a series of experimental study, which are carried out to assess the combined effect of installation damage and creep deformation for the long-term design strength of geogrid reinforcement. The results of this study show that the tensile strength reduction factors, RF, considering combined effect between installation damage and creep deformation is less than that calculated by the current design method.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.327-334
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• 2002

This paper develops an optimized torsional design method of asymmetric wall structures considering deformation capacities of walls. Contrary to the current torsional provisions, a deformation based torsional design is based on the assumption that stiffness and strength are dependent. Current torsional provisions specify two design eccentricity of stiffness to calculate the design forces of members. But such a methodology leads to an excessive over-strength of some members and an optimal torsional behavior is not ensured. Deformation-based torsional design uses displacement and rotation angle as design parameters and calculates base shear for inelastic torsional response directly. Because optimal torsional behavior can be defined based on the deformation of members, deformation based torsional design procedure can be applied to the optimal and performance-based torsional design. To consider the effect of accidental eccentricity, an over-strength factor is defined. The over-strength factor is determined from performance level, torsional resistance and arrangement of walls.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.3-14
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• 2000

Anisotropic consolidation, shear, a transportational component during or after deposition each may produce anisotropic fabrics, which result in the anisotropic properties of soils. Nevertheless, the isotropically consolidated compression triaxial tests are commonly used in practice to determine the strength of the anisotropically consolidated soils because of their practicality and simplicity. In this paper the effects of anisotropic consolidation on the strength properties of soils are discussed. For the sandy soils consolidated under a constant vertical consolidation pressure, the deformation modulus decreases with decreasing consolidation pressure ratio($\sigma$$\sub$3c/'/$\sigma$ sub 1c/'), but the liquefaction resistance increases. For the saturated cohesive soils, both the undrained shear strength and undrained creep strength decrese with decreasing the consolidation pressure ratio. When the in-situ strength properties of the anisotropically and normally consolidated soils are determined by the isotropically consolidated tests, the undrained shear strength and creep strength of saturated cohesive soils as well as the deformation modulus of sandy soils are measured to be higher than the rear in-situ values. This, therefore, could lead to a dangerous judgement in stability analysis

• Structural Engineering and Mechanics
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• v.57 no.4
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• pp.681-701
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• 2016

This paper presents an experimental study of six steel reinforced high strength concrete T-shaped short-limb shear walls configured with T-shaped steel truss under low cyclic reversed loading. Considering different categories of ratios of wall limb height to thickness, shear/span ratios, axial compression ratios and stirrup reinforcement ratios were selected to investigate the seismic behavior (strength, stiffness, energy dissipation capacity, ductility and deformation characteristics) of all the specimens. Two different failure modes were observed during the tests, including the flexural-shear failure for specimens with large shear/span ratio and the shear-diagonal compressive failure for specimens with small shear/span ratio. On the basis of requirement of Chinese seismic code, the deformation performance for all the specimens could not meet the level of 'three' fortification goals. Recommendations for improving the structural deformation capacity of T-shaped steel reinforced high strength concrete short-limb shear wall were proposed. Based on the experimental observations, the mechanical analysis models for concrete cracking strength and shear strength were derived using the equivalence principle and superposition theory, respectively. As a result, the proposed method in this paper was verified by the test results, and the experimental results agreed well with the proposed model.

• Tunnel and Underground Space
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• v.7 no.2
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• pp.108-115
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• 1997

Uniaxial and biaxial compressive tests were conducted on limestone specimens containing artificial joints and a circular hole to investigate the influence of inclination and number of joints on compressive strength and deformation behavior of rock with a circular hole. Under uniaxial and biaxial compressive condition, the inclination of joints showing the maximum and minimum strength were 0$^{\circ}$ and 30$^{\circ}$ respectively, which was independent of the number of joints. Under uniaxial compressive condition, relative maximum strength of rock with n=1 and 3 to intact rock with a circular hole were 12.5%~82.8% and 11.4~62.5% respectively, and under biaxial compressive condition, 18.2~91.0% and 17.0~87.5% respectively. The influence of the number of joints on the decrease of compressive strength was greater under uniaxial than under biaxial compressive condition. Under uniaxial and biaxial compressive condition, axial and lateral deformations of rock showed the least values where $\alpha$=30$^{\circ}$. Under uniaxial compressive condition, axial and lateral deformation at maximum strength of rock have the increasing tendency with increase the number of joints. But they have the decreasing tendency under biaxial compressive condition. Under uniaxial and biaxial compressive conditions, axial deformation of circular hole was greater than lateral deformation without respect to the number of joints and the inclination of joints.