• Geomechanics and Engineering
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• 제31권5호
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• pp.519-527
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• 2022

Shear failure in soil is the primary cause of most geotechnical structure failures or instability. Soil water content is a significant factor affecting soil shear strength. In this study, the shear strength of samples with different water contents was tested. The shear strength, cohesion, and internal friction angle decreased with increasing water content. Based on the variation of cohesion and internal friction angle, the water content zone was divided into a high-water content zone and low-water content zone with a threshold water content of 15.05%. Cohesion and internal friction angle have a good linear relationship with water content in both zones. Environmental Scanning Electron Microscopy (ESEM) test presented that the aggregates size of the compacted loess gradually increases with increasing water content. Meanwhile, the clay in the compacted loess forms a matric that envelops around the surface of the aggregates and fills the inter-aggregates pores. A quantitative analysis of bound water and free water under different water contents using a nuclear magnetic resonance (NMR) test was carried out. The threshold water content between bound water and free water was slightly below the plastic limit, which is consistent with the results of shear strength parameters. Combined with the T2 distributions obtained by NMR, one can define a T2 relaxation time of 1.58 ms as the boundary point for bound water distribution without free water. Finally, the effects of bound water and free water on shear strength parameters were analyzed using linear regression analysis.

• 한국자동차공학회논문집
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• 제5권2호
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• pp.87-93
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• 1997

The bonding strength evaluation of light weight materials for electrical vehicle applications has been performed through single lap joint tests in which the design parameters such as fillet, joint style, adherend, bonding overlap length,bonding thickness, and environmental condition(soaking time in $25^{\circ}C$ water) are considered. It is experimentally oberved that lap shear strength of joint increases for higher fillet height, longer overlap length, and thinner bonding layer thickness. Al-Al adherend combination shows much higher lap shear strength than AL-FRP and FRP-FRP adherend combinations. Riveting at adhesive bonded joint of AL-AL adherend combination makes lap shear strength decrease. Effect of soaking time on lap shear strength is negligible.

• Steel and Composite Structures
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• 제25권5호
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• pp.603-615
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• 2017

This experimental research presents the seismic performance of steel reinforced high-strength concrete (SRHC) short columns. Eleven SRHC column specimens were tested under simulated earthquake loading conditions, including six short column specimens and five normal column specimens. The parameters studied included the axial load level, stirrup details and shear span ratio. The failure modes, critical region length, energy dissipation capacity and deformation capacity, stiffness and strength degradation and shear displacement of SRHC short columns were analyzed in detail. The effects of the parameters on seismic performance were discussed. The test results showed that SRHC short columns exhibited shear-flexure failure characteristics. The critical region length of SRHC short columns could be taken as the whole column height, regardless of axial load level. In comparison to SRHC normal columns, SRHC short columns had weaker energy dissipation capacity and deformation capacity, and experienced faster stiffness degradation and strength degradation. The decrease in energy dissipation and deformation capacity due to the decreasing shear span ratio was more serious when the axial load level was higher. However, SRHC short columns confined by multiple stirrups might possess good seismic behavior with enough deformation capacity (ultimate drift ratio ${\geq}2.5%$), even though a relative large axial load ratio (= 0.38) and relative small structural steel ratio (= 3.58%) were used, and were suitable to be used in tall buildings in earthquake regions.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.768-776
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• 2006

Recently in spite of Development of Investigation machine, in Application of Geotechnical Properties by empirical recommendation to the Slope Stability Analysis. It is generally Application of convenience and conservative Geotechnical Properties by Borehole Shear Test(BST) in Representative Zone that Non-Division of Increase as the depth of Strength Parameters In Deep Weathered Zone. Therefore, it is become environment pollution and Non-Economical Slope Design to Application of convenience and conservative Geotechnical Properties. The production mechanism of Deep Weathered Zone is tend to Weathering Degree low and Strength increase by increase as the depth. it is realistic design that Division of Deep Weathered Zone and application Geotechnical Properties of Each Layer. In this Paper, Determined The Relationship of Strength Parameters between Standard Penetration Test(SPT), Borehole Shear Test(BST) and empirical recommendation also Applyed each strength parameters of divided zone to the Slope Stability Analysis by continuous Borehole Shear Test(BST) in Deep Weathered Zone during design of The 2nd Bridge Connection Road of Incheon International Airport.

• Structural Engineering and Mechanics
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• 제67권4호
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• pp.347-358
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• 2018

The main aim of this research was to investigate the shear strength of non-prismatic steel fiber reinforced concrete beams under monotonic loading considering different parameters. Experimental program included tests on fifteen non-prismatic reinforced concrete beams divided into three groups. For the first and the second groups, different parameters were taken into consideration which are: steel fibers content, shear span to minimum depth ratio ($a/d_{min}$) and tapering angle (${\alpha}$). The third group was designed mainly to optimize the geometry of the non-prismatic concrete beams with the same concrete volume while the steel fiber ratio and the shear span were left constant in this group. The presence of steel fibers in concrete led to an increase in the load-carrying capacity in a range of 10.25%-103%. Also, the energy absorption capacity was increased due to the addition of steel fibers in a range of 18.17%-993.18% and the failure mode was changed from brittle to ductile. Tapering angle had a clear effect on the shear strength of test specimens. The increase in tapering angle from ($7^{\circ}$) to ($12^{\circ}$) caused an increase in the ultimate shear capacity for the test specimens. The maximum increase in ultimate load was 45.49%. The addition of steel fibers had a significant impact on the post-cracking behavior of the test specimens. Empirical equation for shear strength prediction at cracking limit state was proposed. The predicted cracking shear strength was in good agreement with the experimental findings.

• 한국산학기술학회논문지
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• 제16권3호
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• pp.2234-2241
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• 2015

본 연구에서는 국내 지반의 전단강도정수와 콘지수 사이의 상관관계를 확립하기 위하여 먼저 콘관입 모델을 통한 이론적 상관관계를 정리하고 이의 신뢰도를 높이기 위하여 인공신경망 기법을 적용하였다. 이론적 상관관계는 이론식을 유도하면서 적용한 가정들로 인하여 신뢰성 있는 지반의 거동을 예측하기 어려운 측면이 있다. 따라서 인공신경망 기법을 적용하여 이론적, 경험적 방법과 같은 기존의 방법과는 다른 새로운 측면에서 지반의 거동 특성을 파악할 필요성이 있다. 인경신경망 모델은 국내의 다양한 건설현장에서 수행한 지반조사 보고서를 통해서 입력자료를 확보한 뒤에 모델학습을 수행하였다. 연구결과 측정값과 예측값의 오차가 크지 않았고, 비교적 고르게 분포함을 알 수 있었다. 추후 보강된 인공신경망 모델을 구축하면 국내 특정 지역뿐만 아니라 일반화된 지역에 보편적으로 적용할 수 있을 것으로 기대된다.

• Smart Structures and Systems
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• 제14권5호
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• pp.785-809
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• 2014

In this paper, an Adaptive nerou-based inference system (ANFIS) is being used for the prediction of shear strength of high strength concrete (HSC) beams without stirrups. The input parameters comprise of tensile reinforcement ratio, concrete compressive strength and shear span to depth ratio. Additionally, 122 experimental datasets were extracted from the literature review on the HSC beams with some comparable cross sectional dimensions and loading conditions. A comparative analysis has been carried out on the predicted shear strength of HSC beams without stirrups via the ANFIS method with those from the CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 - 94 codes of design. The shear strength prediction with ANFIS is discovered to be superior to CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 - 94. The predictions obtained from the ANFIS are harmonious with the test results not accounting for the shear span to depth ratio, tensile reinforcement ratio and concrete compressive strength; the data of the average, variance, correlation coefficient and coefficient of variation (CV) of the ratio between the shear strength predicted using the ANFIS method and the real shear strength are 0.995, 0.014, 0.969 and 11.97%, respectively. Taking a look at the CV index, the shear strength prediction shows better in nonlinear iterations such as the ANFIS for shear strength prediction of HSC beams without stirrups.

• Steel and Composite Structures
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• 제37권5호
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• pp.517-532
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• 2020

This paper firstly developed a new type of Double Skin Composite (DSC) beams using novel enhanced C-channels (ECs). The shear behaviour of novel ECs was firstly studied through two push-out tests. Eleven full-scale DSC beams with ECs (DSCB-ECs) were tested under four-point loading to study their ultimate strength behaviours, and the studied parameters were thickness of steel faceplate, spacing of ECs, shear span, and strength of concrete core. Test results showed that all the DSCB-ECs failed in flexure-governed mode, which confirmed the effective bonding of ECs. The working mechanisms of DSCB-ECs with different parameters were reported, analysed and discussed. The load-deflection (or strain) behaviour of DSCB-ECs were also detailed reported. The effects of studied parameters on ultimate strength behaviour of DSCB-ECs have been discussed and analysed. Including the experimental studies, this paper also developed theoretical models to predict the initial stiffness, elastic stiffness, cracking, yielding, and ultimate loads of DSCB-ECs. Validations of predictions against 11 test results proved the reasonable estimations of the developed theoretical models on those stiffness and strength indexes. Finally, conclusions were given based on these tests and analysis.

• Steel and Composite Structures
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• 제18권2호
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• pp.345-355
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• 2015

In this study, the effects of weld parameters on nugget size and tensile-shear strength of welding joint in electrical resistance spot welding of galvanized DP 600 steel sheets having 1.2 mm were investigated. Taguchi design method has been employed to examine the effects of five parameters of welding current, electrode pressure, welding time, clamping time and holding time by using the $L_{27}(5^3)$ orthogonal array. Results showed that the most effective parameters on tensile shear strength and the nugget size ratio (hn/dn) were found as welding current and welding time, whereas electrode pressure, clamping time and holding time were less effective factors. Max. 545 MPa strength was obtained through proposed optimum conditions by Taguchi technique.

• Computers and Concrete
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• 제31권1호
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• pp.33-52
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• 2023

This paper proposes and validates the extension of two models, previously formulated for the evaluation of the shear strength of reinforced concrete members with un-corroded reinforcements, to the case of beams with corroded stirrups. These extended models are based on the plasticity theory (this model has been proposed in the past by one of the authors) and on the simplified modified compression field theory. The response of these models is compared with that of the compression chord capacity model, which has recently been embedded with modifications that simulate the effects of steel corrosion. These latter modifications are first discussed and then introduced into the other two models. An existing database of slender and non-slender beams tested in laboratory by other researchers is revised and improved. Finally, all the considered models are applied to the selected specimens and a comparison is drawn between the shear strength resulting from the considered models and the shear strength resulting from the laboratory tests. The effects of corrosion on some important parameters of the ultimate shear response of the reinforced concrete beams are also discussed.