• Steel and Composite Structures
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• v.42 no.2
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• pp.265-275
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• 2022

A new type of precast steel reinforced concrete (PSRC) column was put forward in this paper. In order to study the static performance of PSRC column and hollow precast steel reinforced concrete (HPSRC) column subjected to combined compression and shear loading, a parametric test was carried out and effects of axial compression ratio, concrete strength and shear ratio on the mechanical behavior of composite PSRC column and HPSRC column were explored. In addition, the cracks development, load-span displacement relationship, strain distribution and shear bearing strength of column specimens were emphatically focused. Test results implied that shear failure of all specimens occurred during the test, and higher strength of cast-in-place concrete, smaller shear ratio and larger axial compression ratio could lead to greater shear resistance, but when the axial compression ratio was larger than 0.36, the shear capacity began to decrease gradually. Furthermore, truss-arch model for determining the shear strength of PSRC column and HPSRC column was proposed and the calculated results obtained from proposed method were verified to be valid.

• Magazine of the Korean Society of Agricultural Engineers
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• v.23 no.3
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• pp.96-104
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• 1981

In order to investigate the characteristics of the shear strength of the unsaturated cohesive soils which has mean characters of sand and clay widely used for banking, I selected soil samples from An-sung district and, against it, performed direct shear test and unconfined compression test changing grain size, compaction energy and moisture content and also performed triaxial compression test under optimum moisture content. The results are as follows; 1.As the passing percent of the No. 200 sieve increased from 23.6% to 56.1%, cohesion increased from 0. 202kg/cm2 to 0. 398kg/cm2 under the direct shear test and from 0.38 kg/cm2 to 1. 05kg/cm2 under the tria4al compression test, internal friction angle decreased from 44. 78$^{\circ}$ to 34. 34$^{\circ}$ under the direct shear test and from 31. 88$^{\circ}$ to 13. 31$^{\circ}$ under the triaxial compression test. 2.Cohesion showed it's maximum value around OMC and internal friction angle showed a tendency to increase according to the decrease of water content but it's increasing ratio was relatively slow. 3.Decreasing ratio of cohesion and internal friction angle was relatively sensitive according to the decrease of compaction energy. 4.The smaller of the vertical stress and the coarser of the grain size of samples, changing of the volume showed a tendency to increase and as the increase of water content, the shear displacement (dh) at failure shear stress ($\tau$f) showed maximum and the $\tau$f-dh curve was gentle. 5.To synthesize the results of the direct shear test and the triaxial compression test, cohesion showed higher under the triaxial compression test and internal friction angle showed a tendeney to appear higher under the direct shear test. It seems that we can get correspondent results by removing the side friction of mold with soils and adjusting the vertical stress and shearing speed under the direct shear test.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.132-144
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• 2001

Iln order to figure out criteria of bentonite for using as impervious material of waste landfill, laboratory experiments were performed to reveal the geotechnical properties of soil-bentonite mixtures such as compaction test, direct shear test, unconfined compression test, triaxial compression test, consolidation test and permeability test. The results of the study are summarized as follows ; 1. Based on the compaction test, optimum moisture content increased with the increase of bentonite content, but maximum dry density decreased. 2. In unconfined compression test, the maximum strength of the soil-bentonite mixtures appeared at 10% bentonite content. The correlation equation between stress($\sigma$) and strain($\varepsilon$) of the soil-bentonite mixtures is given by ; $\sigma=\frac{a\cdot\varepsilon}{\varepsilon^n+b}$ 3. In shear test of the mixtures. the shear strength showed an increasing trend with increase of bentonite content and the maximum shear strength appeared at 10% bentonite content. 4. In consolidation test, the coefficient of compressibility $(a_v)$$(m_v)$$(C_v)$

• Proceedings of the Korean Geotechical Society Conference
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• 2000.02a
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• pp.71-78
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• 2000

SHANSEP method involves the consolidation to stresses in excess of the preconsolidation pressure in order to overcome sample disturbance effect. The concept of SHANSEP is based on an approach to laboratory test which attempts to reproduce the in-situ conditions more closely than is possible in routine tests and evaluates normalized strength parameters for the soil as a function of OCR. But SHANSEP method can be applied only to fairly uniform clay deposits, and is unsuitable for a random deposit. In this study, CK/sub o/U triaxial compression test and incremental loading consolidation test were performed for the application of SHANSEP method on Yangsan clay. During the K/sub o/-consolidation, triaxial specimens were consolidated to stress equal to two times the in-situ vertical effective stress. And for overconsolidated condition, the specimens were swelled to a known vertical effective stress in order to have the desired OCR. With the results of CK/sub o/U triaxial compression test using the block samples, the relationship between c/sub u//σ/sub vc/' and OCR on Yangsan clay was established. For evaluating the undrained shear strength of Yangsan clay with depth, CK/sub o/U triaxial compression test was performed using the piston samples taken from Yangsan site. And also undrained shear strength was analyzed from the in-situ test such as Cone Penetration Test(CPT), Dilatometer Test(DMT), and Field Vane Test(FVT) and was compared with that of CK/sub o/U triaxial compression test.

• Steel and Composite Structures
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• v.13 no.5
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• pp.437-449
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• 2012

Concrete filled steel tube (CFST) structures have recently seen wide use in China, but studies of the shear problem of CFST are inadequate. This paper presents an experimental study on the shear capacity of circular concrete filled steel tube (CCFT) specimens with and without axial compression force. Shear capacity, ductility, and damage modes of CCFTs were investigated and compared. Test results revealed the following: 1) CCFTs with a small shear span ratio may fail in shear in a ductile manner; 2) Several factors including section size, material properties, shear span ratio, axial compression ratio, and confinement index affect the shear capacity of CCFTs. Based on test results and analysis, this paper proposes a design formula for the shear capacity of CCFTs.

• Journal of Ocean Engineering and Technology
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• v.25 no.3
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• pp.34-39
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• 2011

This study investigated the shear and CBR characteristics of dredge soil-bottom ash-waste tire powder-mixed lightweight soil, which was developed to recycle dredged soil, bottom ash, and waste tire powder. Test specimens were prepared with various contents of waste tire powder ranging from 0 to 100% at 50% intervals by the weight of the dry dredged soil. Several series of triaxial compression tests and CBR tests were conducted. The shear strength characteristics of the lightweight soil were compared using two different shear tests (triaxial compression test and direct shear test). The experimental results indicated that the internal friction angle of the lightweight soil obtained by the direct shear tests was greater than that by the triaxial shear tests. However, the cohesion value obtained by the triaxial shear tests was greater than that by the direct shear tests. The CBR value of the lightweight soil decreased from 35% to 15% as waste tire powder content increased.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.101-111
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• 2021

Two different types of shear-friction tests were classified by external loadings and referred to as a push-off and a pull-off test. In a pull-off test, a tension force is applied in the transverse direction of the test specimen to produce a shear stress at the shear plane. This paper presents a method to evaluate shear transfer strengths of uncracked pull-off specimens. The method is based on the compression field theory and different constitutive laws are applied in some ways to gain accurate shear strengths considering softening effects of concrete struts based on Modified Compression Field Theory (MCFT) and Softened Truss Model (STM). The validity of the proposed method is examined by applying to some selected test specimens in literatures and results are compared with the predicted values. A general agreement is observed between predicted and measured values at ultimate loading stages in initially uncracked pull-off test specimens. A shear strength evaluation formula considering the effective compressive strength of a concrete strut was proposed, and the applicability of the proposed formula was verified by comparing with the experimental results in the literature.

• Journal of the Korean Society for Railway
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• v.3 no.1
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• pp.34-41
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• 2000

The analysis of static and dynamic characteristics of reinforced roadbed materials was performed through model and laboratory tests. The strength characteristic of reinforced roadbed materials such as HMS-25 and soil were investigated through the unconfined axial compression test, the model soil box test and the combined resonant column and torsional shear test. The unconfined axial compression strength of HMS-25 shows a steady increasement in strength due to the chemical hardening reaction between HMS-25 and water. The result of model soil box test reveals that railroad roadbed of HMS-25 is better than that of soil in several aspects, such as, bearing capacity and settlement. The combined resonant column and torsional shear test result indicates that shear modulus of HMS-25 and soil increase with the power of 0.5 to the confining pressure and linear relationship to normalized shear modulus and damping ratio.

• Transactions of Materials Processing
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• v.10 no.4
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• pp.319-328
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• 2001

Quantitative evaluation of the tribological conditions at the tool-workpiece interface in metal forming is usually accomplished by the ring compression test. This paper describes an experimental investigation into friction factor under warm forming conditions according to the lubricants and the lubricating methods using the ring compression test. Four different lubricants, two water based graphite and two oil based graphite lubricants, and three different lubricating methods were applied in the experiments. Calibration curves with the friction shear factor were obtained using FEM analysis and verified by the experimental results. The influence of lubricant and lubricating methods on friction are discussed. In the ring compression test, the lower friction factor got to spray the oil based lubricant on die and billet in warm forging temperature.

• Journal of the Korean GEO-environmental Society
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• v.13 no.5
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• pp.41-49
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• 2012

In this study, laboratory test, in-situ vane shear test and piezocone penetration test in the study area were conducted to investigate the engineering characteristics of soft soils at Cheongra District, Songdo District in Incheon City, the west coast of Gyeonggi province, and Sihwa District in Ansan city. The correlations among compression index, and in-situ vane shear test, and cone resistance were obtained. The variations of liquid limit, plasticity index, water content and compression index with respect to depth exhibit strong similarity. This means that they have strong correlations, which can be used to evaluate the local characteristics of the study area. Thus, the correlations between compression index and physical properties were analysed to investigate the engineering characteristics of soft soil in the study area. The relationships between the measured piezocone factor by empirical methods, and undrained shear strength obtained by triaxial compression test or in-situ vane shear test were compared. It shows the significant correlation and piezocone factors, $N_{kT}$are suggested for the study area.