• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.65-70
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• 2001

The compression toe of structural wall is designed to resist the axial compression and shear force caused by wind or earthquake. The performance of shear wall used in tall building is highly influenced by combined shear and axial force. For this reason, it is possible to result in local brittle failure because of concentrated damage in the potential plastic hinge region under severe earthquake. Thus, it is necessary to establish the lateral confinement details at the plastic hinge of shear wall so that shear wall can behave a ductile manner, The objective of this study is to evaluate the seismic performance of L-shaped walls with different confinement details. For this purpose, three wall specimens were tested experimentally and also analyzed using Nonlinear FEM package.

• Journal of Korean Neurosurgical Society
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• 제45권2호
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• pp.122-126
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• 2009

Single-balloon kyphoplasty via an extrapedicular approach has been reported to be effective because it requires less time than conventional two-balloon kyphoplasty and has comparable therapeutic efficacy. However, single-balloon kyphoplasty is not popular because the extrapedicular approach is believed to be complicated and unsuitable for the thoracolumbar and lumbar spine. The authors describe a standardized surgical technique that utilizes a far-lateral extrapedicular approach for single-balloon kyphoplasty, which can be performed in any part of the spine by physicians without substantial difficulty.

• KCI Concrete Journal
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• 제13권1호
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• pp.53-60
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• 2001

Tests of cylindrical concrete specimens under lateral confining pressure of up to 5,000 psi were conducted for two different axial loading cases: monotonic compression and monotonic tension. The purpose of this experimental investigation is to provide stress-strain characteristics of plain concrete in triaxial stress conditions. Lateral confining pressure levels, loading rates, and strength of concrete specimens are varied as parameters. The loading rates are $34.75$\times$10^{-5}$ in/in/sec for fast, $\times$$6.95x10^{-5}$ in/in/sec for normal. and $0.579$\times$10^{-5}$ in/in/sec for slow loading cases. The concrete specimens used in the experiment have compressive strength of 3,500 psi and 6,500 psi, respectively. Findings of this experiment include dependency of the stress-strain behavior of concrete on the above parameters under two different types of loading conditions. The parametric study includes a series of 106 triaxial tests.

• Structural Engineering and Mechanics
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• 제43권2호
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• pp.147-161
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• 2012

This paper presents a curvature method for analysis of beam-columns with different materials and arbitrary cross-section shapes and subjected to combined biaxial moments and axial load. Both material and geometric nonlinearities (the p-delta effect in this case) were incorporated. The proposed method considers biaxial curvatures and uniform normal strains of discrete cross-sections of beam-columns as basic unknowns, and seeks for a solution of the column deflection curve that satisfies force equilibrium conditions. A piecewise representation of the beam-column deflection curve is constructed based on the curvatures and angles of rotation of the segmented cross-sections. The resulting bending moments were evaluated based on the deformed column shape and the axial load. The moment curvature relationship and the beam-column deflection calculation are presented in matrix form and the Newton-Raphson method is employed to ensure fast and stable convergence. Comparison with results of analytic solutions and eccentric compression tests of wood beam-columns implies that this method is reliable and effective for beam-columns subjected to eccentric compression load, lateral bracings and complex boundary conditions.

• Steel and Composite Structures
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• 제21권2호
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• pp.357-371
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• 2016

Column base connections are critical components in steel structures because they transfer axial forces, shear forces and moments to the foundation. Exposed column bases are quite commonly used in low- to medium-rise buildings. To investigate shear transfer in exposed column base plates, four large scale specimens were subjected to a combination of axial load (compression or tension) and lateral shear deformations. The main parameters examined experimentally include the number of anchor rod, arrangement of anchor rod, type of lateral loading, and axial force ratio. It is observed that the shear resisting mechanism of exposed column base changed as the axial force changed. When the axial force is in compression, the resisting mechanism is rotation type, and the shear force will be resisted by friction force between base plate and mortar layer. The specimens could sustain inelastic deformation with minimal strength deterioration up to column rotation angle of 3%. The moment resistance and energy dissipation will be increased as the number of anchor rods increased. Moreover, moment resistance could be further increased if the anchor rods were arranged in details. When the axial force is in tension, the resisting mechanism is slip type, and the shear force will be resisted by the anchor rods. And the shear resistance was reduced significantly when the axial force was changed from compression to tension. The test results indicated that the current design approach could estimate the moment resistance within reasonable acceptance, but overestimate the shear resistance of exposed column base.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.129-134
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• 2003

The importance of understanding the response of structural composites to impact and CAI cannot be overstated to develop analytical models for impact damage and CAI strength predictions. This paper presents experimental findings observed from quasi-static lateral load tests, low velocity impact tests, CAI strength and open hole compressive strength tests using 3mm thick composite plates ($[45/-45/0/90]_{3s}$ - IM7/8552). The conclusion is drawn that damage areas for both quasi-static lateral load and impact tests are similar and the curves of several drop weight impacts with varying energy levels (between 5.4 J and 18.7 J) fallow the static curve well. In addition, at a given energy the peak force is in good agreement between the static and impact cases. From the CAI strength and open hole compressive strength tests, it is identified that the failure behaviour of the specimens was very similar to that observed in laminated plates with open holes under compression loading. The residual strengths are in good agreement with the measured open hole compressive strengths, considering the impact damage site as an equivalent hole. The experimental findings suggest that simple analytical models for the prediction of impact damage area and CAI strength can be developed on the basis of the failure mechanism observed from the experimental tests.

• Steel and Composite Structures
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• 제32권2호
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• pp.199-212
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• 2019

This paper presents an investigation on seismic behavior of out-of-code Q690 circular high-strength concrete-filled thin-walled steel tubular (HCFTST) columns made up of high-strength (HS) steel tubes (yield strength $f_y{\geq}690MPa$). Eight Q690 circular HCFTST columns with various diameter-to-thickness (D/t) ratios, concrete cylinder compressive strengths ($f_c$) and axial compression ratios (n) were tested under the constant axial loading and reversed cyclic lateral loading. The obtained lateral load-displacement hysteretic curves, energy dissipation, skeleton curves and ductility, and stiffness degradation were analyzed in detail to reflect the influences of tested parameters. Subsequently, a simplified shear strength model was derived and validated by the test results. Finally, a finite element analysis (FEA) model incorporating a stress triaxiality dependent fracture criterion was established to simulate the seismic behavior. The systematic investigation indicates the following: compared to the D/t ratio and axial compression ratio, improving the concrete compressive strength (e.g., the HS thin-walled steel tube filled with HS concrete) had a slight influence on the ductility but an obvious enhancement of energy dissipation and peak load; the simplified shear strength model based on truss mechanism accurately predicted the shear-resisting capacity; and the established FEA model incorporating steel fracture criterion simulated well the seismic behavior (e.g., hysteretic curve, local buckling and fracture), which can be applied to the seismic analysis and design of Q690 circular HCFTST columns.

• Clinical Pain
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• 제20권2호
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• pp.122-126
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• 2021

When a patient represents pain in foot, physician can easily overlook compression neuropathy of peripheral nerve as it is uncommon. Among nerve entrapment syndrome encountered in the foot, selective compression in lateral branch of deep peroneal nerve (DPN) is rare. We report a case of a patient with pain and dysesthesia in dorsolateral foot which turned out as lateral branch of deep peroneal nerve entrapment syndrome caused by talonavicular joint effusion. We would like to share diagnostic work up flow and conservative treatment courses. This case manifests the importance of the deep peroneal nerve and its branches in clinical setting of pain and ankle instability.

• Journal of Korean Neurosurgical Society
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• 제39권5호
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• pp.366-369
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• 2006

Objective : There are various surgical approaches to far-lateral lesions in the L5-S1 intervertebral space. Of these is the validity of a paramedian tangential approach is being investigated in this study. Methods : A retrospective study was conducted on 25 patients who had been diagnosed as having a far-lateral L5-S1 disc herniations, osteophyte, costal process hypertrophy, and had undergone a paramedian tangential approach from November 1999 through December 2003. The degree of symptoms and improvement were compared via the visual analog pain scale, before and after surgery. Results : This study included 4 males and 21 females with a mean age of $62{\pm}11.8$ years old. The average follow-up period after surgery was $8.2{\pm}2.7$ months. The visual analog pain scale taken before surgery was $6.7{\pm}1.1$ points, while the post-surgical scale was $2.4{\pm}0.9$ points showing a significant degrease [p < 005]. There were no complications that developed during surgery. Conclusion : A paramedian tangential approach is less invasive in the soft tissue than that of the median approach. This approach may effectively reduce nerve root compression and expand intervertebral foramens, and is devoid of the risk of spinal instability after surgery. The authors suppose that a paramedian tangential approach is quite an effective technique to relive compression in the far-lateral L5-S1 intervertebral space.

• Clinics in Shoulder and Elbow
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• 제14권1호
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• pp.89-93
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• 2011

목적: 외측 상완 표피 신경증에 의한 전완부 외측부 통증을 주소로 내원한 환자를 보고하고자 한다. 대상 및 방법: 한명의 여성 환자를 적어도 6주 정도의 보존적인 치료로 조절되지 않아 이두박건 성형술로 치료하였다. 술 후 1년 지나 임상증상을 관찰하고 이두박건 성형술 후 회외전력의 약화나 파열 소견이 있는지 조사하였다. 결과: 술 후 즉시 임상 증상은 소실되었으며 회복 과정에서 특이한 문제는 없었다. 회외전력의 약화소견이나 원위 이두박건의 파열도 관찰되지 않았다. 결론: 외측 상완표피 신경증을 이두박건 성형술로 성공적으로 치료한 증례를 문헌 고찰과 함께 보고하고자 한다.