• 한국지반신소재학회논문집
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• 제17권4호
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• pp.199-212
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• 2018

본 연구에서는 깊은 굴착에 따른 인접구조물의 손상 평가 및 벽체 구조물의 안정성 평가를 하기 위한 지표의 거동 및 벽체 부재력의 효율적인 예측기법에 대한 내용을 다루었다. 우선적으로 지표의 거동 및 벽체 부재력에 영향을 미치는 매개 변수에 대한 연구를 수행하였고, 이를 토대로 다양한 굴착 조건에 대해 수치해석을 실시한 결과를 통해 데이터베이스를 구축하였다. 구축된 데이터베이스를 토대로 벽체의 부재력과 지표의 거동 각각의 해석 결과에 대한 인공신경망 엔진 학습을 수행하였으며 학습된 인공신경망을 이용하여 예측된 결과와 사용된 데이터베이스의 결과를 비교하여 인공신경망 엔진이 벽체의 부재력 및 지표의 거동예측에 효율적임을 검증하였다.

• Geomechanics and Engineering
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• 제22권6호
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• pp.497-507
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• 2020

This paper presents the results of a three-dimensional numerical investigation into the effect of new tunnel construction on structural performance of existing tunnel lining. A three-dimensional finite difference model, capable of modelling the tunnel construction process, was adopted to perform a parametric study on the spatial variation of new tunnel location with respect to the existing tunnel with emphasis on the plan crossing angle of the new tunnel with respect to the existing tunnel and the vertical elevation of the new tunnel with respect to the existing one. The results of the analyses were arranged so that the effect of new tunnel construction on the lining member forces and stresses of the existing tunnel can be identified. The results indicate that when a new tunnel underpasses an existing tunnel, the new tunnel construction imposes greater impact on the existing tunnel lining when the two tunnels cross at an acute angle. Also shown are that the critical plan crossing angle of the new tunnel that would impose greater impact on the existing tunnel depends on the relative vertical location of the new tunnel with respect to the existing one, and that the overpassing new tunnel construction scenario is more critical than the underpassing scenario in view of the existing tunnel lining stability. Practical implications of the findings are discussed.

• 전산구조공학
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• 제11권1호
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• pp.237-249
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• 1998

본 논문에서는 건축 구조물에서 널리 사용되는 보-거더 구조계 슬래브에서 분포하중과 차량하중이 작용하는 경우에 지지부가 되는 가로보와 거더의 처짐이 슬래브 부재력에 미치는 영향을 연구하였다. 전체 패널에 한개의 가로보가 존재하는 단일 가로보(one-beam) 구조계 슬래브와 두 개 존재하는 이중 가로보 (two-beam)구조계 슬래브에서 지지부가 되는 가로보와 거더 및 슬래브의 강성을 변화시키면서 유한요소해석을 수행하였으며, 얻어진 결과를 토대로 회귀분석을 수행하여 설계시 지지부 처짐 영향을 고려할 수 있도록 보정계수를 제시하였다. 또한 제안된 보정계수를 대표적인 구조물의 설계방법에 적용시켜 그타당성을 검증하였다.

• 한국전산구조공학회논문집
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• 제18권1호
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• pp.79-91
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• 2005

본 논문에서는 프리스트레스를 이용한 가시설 공법(IPS)에 적용되는 띠장의 거동의 해석 및 설계절차에 대한 연구를 수행하였다. 띠장에 초기장력이 도입되는 구조계는 탄성지반위에 놓인 보이론에 의하여 부재력이 산출되고, 토압에 의한 부재력은 장력을 부정정력으로 취하여 부정정 구조해석을 통하여 띠장의 축력 및 휨모멘트를 계산하였다. 지반은 압축력 전담요소, 케이블은 인장력 전담요소를 사용하여 등분포 토압 및 편토압을 받는 띠장의 전산해석을 수행하였다. 기존의 가시설 설계에 적용되는 토압을 적용하여 IPS 띠장설계를 실시하였고, 긴장력과 설계토압에 의한 축력과 휨모멘트를 계산하여 축응력과 휨응력을 도출하고 합성응력검토를 수행하였다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.45-48
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• 2007

The aim of this study is to estimate the compressive force of steel member using a system identification technique with vibration measurements. To date, several methods have been presented to estimate the compressive force using static and/or dynamic responses of the steel member. However, each and every one of these methods has its disadvantages as well as advantages in its procedures, level of accuracy, and equipment requirements. The paper reports a qualitative investigation of vibration under monoharmonic excitation. The methodology utilizes the relationship between the natural frequencies, the structural parameters, and the compressive force of the member. In this paper, experimental results are presented with a steel beam subjecting to several compressive forces and the proposed method is validated using both numerical and experimental data.

• Structural Engineering and Mechanics
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• 제5권6호
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• pp.803-815
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• 1997

It is well understood that concentrated forces applied in the plane of a beam or panel (such as a wall or slab) lead to splitting forces developing within a disturbed region forming beyond the bearing zone. In a linearly elastic material the length of the disturbed region is approximately equal to the depth of the member. In concrete structures, however, the length of the disturbed region is a function of the orthotropic properties of the concrete-steel composite. In the detailing of steel reinforcement within the disturbed regions two limit states must be satisfied; strength and serviceability (in this case the serviceability requirement being acceptable crack widths). If the design requires large redistribution of stresses, the member may perform poorly at service and/or overload. In this paper the results of a plane stress finite element investigation of concentrated loads on reinforced concrete panels are presented. Two cases are examined (i) panels loaded concentrically, and (ii) panels loaded eccentrically. The numerical investigation suggests that the bursting force distribution is substantially different from that calculated using elastic design methods currently used in some codes of practice. The optimum solution for a uniformly reinforced bursting region was found to be with the reinforcement distributed from approximately 0.2 times the effective depth of the member ($0.2D_e$) to between $1.2D_e$ and $1.6D_e$. Strut and tie models based on the finite element analyses are proposed herein.

• Structural Engineering and Mechanics
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• 제45권3호
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• pp.277-309
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• 2013

Beam-to-column connections behaviour plays an important role in the analysis and design of steel and precast concrete structures. The paper presents a computer-based method for geometrically nonlinear frames with semi-rigid beam-to-column connections. The analytical procedure employs modified stability functions to model the effect of axial force on the stiffness of members. The member modified stiffness matrix, and the modified fixed end forces for various loads were found. The linear and nonlinear analyses were applied for two planar steel structures. The method is readily implemented on a computer using matrix structural analysis techniques and is applicable for the efficient nonlinear analysis of frameworks.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.385-390
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• 1995

In segmentally erected bridges, the structural systems are changed as the construction stages progress and redistribution of member forces occurs due to time dependent effects of concrete and relaxation of perstressing steel. Therefore, structural analysis is required at each construction stage. In this study, nonlinear analysis program of the segmentally erected prestressed concrete box girder bridges is developed to raise the efficiency in making input file for the main program and analysis of the results produced by the main program.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1713-1718
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• 2010

An ultimate strength evaluation of the through plate girder bridge using nonlinear inelastic analysis is presented. In this method, separate member capacity checks after analysis are not required, because the stability and strength of the structural system and its component members can be rigorously treated in analysis. The method captures the inelastic redistribution of internal forces throughout a structural system, and allows an economic use of material for highly indeterminate steel bridges.

• Structural Engineering and Mechanics
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• 제9권3호
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• pp.305-321
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• 2000

This paper develops a simplified, but effective, algorithm in obtaining critical slab design moments for parking garages. Maintaining the uniformly distributed load concept generally adopted in the design of building structures, this paper also introduces the equivalent vehicle load factors, which can simulate the vehicle load effects without taking additional sophisticated numerical analyses. After choosing a standard design vehicle of 2.4 tons through the investigation of small to medium vehicles made in Korea, finite element analyses for concentrated wheel loads were conducted by referring to the influence surfaces. Based on the obtained member forces, we determined the equivalent vehicle load factors for slabs, which represent the ratios for forces under vehicle loads to these under uniformly distributed loads. In addition, the relationships between the equivalent vehicle load factors and sectional dimensions were also established by regression, and then used to obtain the proper design moments by vehicle loads. The member forces calculated by the proposed method are compared with the results of four different approaches mentioned in current design codes, with the objective to establish the relative efficiencies of the proposed method.