• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.171-176
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• 2002

There are many railway structures which were designed without conidering aseismic capacity. In special, masonry structures constructed long time ago should be reviewed about their resistance to earthquake. In this paper, technique to evaluate the capacity of masonry railway bridge is tried to develop by means of FEM analysis. In general FEM analysis program, 3-D solid element is used for masonry structures and response spectrum analysis procedure is tried. In addition, 3-D solid element has material properties equivalent to mortar-brick composite body. Used FEM program is ABAQUS-CAE.

• 한국구조물진단유지관리공학회 논문집
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• 제26권5호
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• pp.1-9
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• 2022

이 연구에서는 Hwang et al.(2021a, 2021b)가 제시한 강봉 트러스 시스템과 FRP 시트로 보강된 조적벽체의 면내·외 내진성능을 비교평가하였다. 면내·외 가력에서 FRP 시트로 보강된 조적벽체의 최대 내력은 각각 무보강 조적벽체의 71% 및 85% 수준으로 순수 조적벽체의 내력을 발휘하지 못하고 더 낮은 내진 성능을 보였다. 강봉 트러스 시스템으로 보강된 조적벽체의 최대 내력은 무보강 조적벽체에 비해 약 1.8배 높았다. 강봉 트러스 시스템은 FRP 시트 부착 공법에 비해 최대 내력, 강성, 에너지 소산능력 향상에 뛰어났다. 하지만, FRP 시트로 보강된 조적벽체의 경우, FRP시트를 조적벽체의 전체에 보강함으로써 조적벽체가 과보강되었고, 실험체가 미끄러짐 파괴가 발생 강성발현 증가효과가 미미한 것으로 판단된다. 추후, FRP 시트를 조적벽체의 일부분만 보강한 실험체와 강봉 트러스 시스템으로 보강한 실험체의 내진성능을 비교하는 후속연구가 필요하다.

• Earthquakes and Structures
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• 제6권4호
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• pp.409-436
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• 2014

Although it is widely accepted that the interaction -between masonry infill and structural members significantly affects the seismic response of reinforced concrete (RC) frames, this interaction is generally neglected in current design-oriented seismic analyses of structures. Moreover, the role of masonry infill is expected to be even more relevant in the case of existing frames designed only for gravitational loads, as infill walls can significantly modify both lateral strength and stiffness. However, the additional contribution to both strength and stiffness is often coupled to a modification of the global collapse mechanisms possibly resulting in brittle failure modes, generally related to irregular distributions of masonry walls throughout the frame. As a matter of principle, accurate modelling of masonry infill should be at least carried out by adopting nonlinear 2D elements. However, several practice-oriented proposals are currently available for modelling masonry infill through equivalent (nonlinear) strut elements. The present paper firstly outlines some of the well-established models currently available in the scientific literature for modelling infill panels in seismic analyses of RC frames. Then, a parametric analysis is carried out in order to demonstrate the consequences of considering such models in nonlinear static and dynamic analyses of existing RC structures. Two bay-frames with two-, three- and four-storeys are considered for performing nonlinear analyses aimed at investigating some critical aspects of modelling masonry infill and their effects on the structural response. Particularly, sensitivity analyses about specific parameters involved in the definition of the equivalent strut models, such as the constitutive force-displacement law of the panel, are proposed.

• 한국방재학회 논문집
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• 제7권1호통권24호
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• pp.1-9
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• 2007

본 연구는 국내에 시공된 조적조 건축물의 특징을 반영한 조적벽체의 반복가력과 모의진동대 실험을 통해 얻어진 결과를 근거로 하여 유리섬유로 보강된 보강조적벽체의 전단내력식을 제안하는 것을 목적으로 한다. 실험결과, 개구부가 없는 조적벽체의 파괴를 지배하는 모드는 Rocking이였고, 개구부가 있는 경우는 개구부 주변에 균열이 집중되었다. 비보강 조적벽체의 전단내력식은 UBC에서 제시한 식이 실험과 가장 유사한 값을 보였다. 본 연구를 통해 제안되어지는 유리섬유 보강조적벽체의 전단내력식은 다음과 같다. $$V_n=0.02A_n{\sqrt{f'_m}}+0.022b_gh_g(1+2{\alpha})^3{\sqrt{f_g}}(N/mm^2)$$.

• 한국구조물진단유지관리공학회 논문집
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• 제7권4호
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• pp.181-189
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• 2003

1960~70년대에 시작된 대도시 인구 집중화로 인해 다수의 조적조 건축물이 시공되었으며, 현재 이들은 상당수 구조 성능 저하 현상이 발생하고 있다. 노후 조적조 건축물의 특성 분석을 통해 벽체에서 발생하는 균열들이 가장 큰 열화요인이며 그 다음으로 큰 영향을 주는 요인은 기초로 분석되었으며, 열화 정도와 진행 속도는 사용유형, 시공년도와 큰 상관관계가 있는 것으로 분석되었다. 또한, 건물의 존치기간이 길어짐에 따라 전체적인 안전수준을 떨어지게 되는데 조적조 건축물에 있어서 열화 정도의 한계에 이르는 시기는 존치기간 30년으로 분석되었다.

• Earthquakes and Structures
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• 제14권1호
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• pp.55-71
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• 2018

This paper investigates the role of the masonry infills on the correlation between widely used earthquake Intensity Measures (IMs) and the damage state of 3D R/C buildings taking into account the orientation of the seismic input. For the purposes of the investigation an extensive parametric study is conducted using 60 R/C buildings with different heights, structural systems and masonry infills' distributions. The results reveal that the correlation between the IMs and the seismic damage can be strongly affected by the masonry infills' distribution, depending on the special characteristics of the structural system, the number of stories and the incident angle.

• Structural Engineering and Mechanics
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• 제50권4호
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• pp.541-561
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• 2014

This paper approaches the issue of seismic vulnerability assessment strategies for facade walls of traditional masonry buildings through the development of a methodology and its subsequent application to over 600 building facades from the old building stock of the historic city centre of Coimbra. Using the post-earthquake damage assessment of masonry buildings in L'Aquila, Italy, an analytical function was developed and calibrated to estimate the mean damage grade for masonry facade walls. Having defined the vulnerability function for facade walls, damage scenarios were calculated and subsequently used in the development of an emergency planning tool and in the elaboration of an access route proposal for the case study of the historic city centre of Coimbra. Finally, the methodology was pre-validated through the comparison of a set of results obtained from its application and also resourcing to a widely accepted mechanical method on the description of the out-of-plane behaviour of facade walls.

• Structural Engineering and Mechanics
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• 제34권4호
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• pp.417-447
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• 2010

The uncertainty often observed in experimental strengths of masonry constituents makes critical the selection of the appropriate inputs in finite element analysis of complex masonry buildings, as well as requires modelling the building ultimate load as a random variable. On the other hand, the utilization of expensive Monte Carlo simulations to estimate collapse load probability distributions may become computationally impractical when a single analysis of a complex building requires hours of computer calculations. To reduce the computational cost of Monte Carlo simulations, direct computer calculations can be replaced with inexpensive Response Surface (RS) models. This work investigates the use of RS models in Monte Carlo analysis of complex masonry buildings with random input parameters. The accuracy of the estimated RS models, as well as the good estimations of the collapse load cumulative distributions obtained via polynomial RS models, show how the proposed approach could be a useful tool in problems of technical interest.

• Structural Engineering and Mechanics
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• 제5권5호
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• pp.587-598
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• 1997

A numerical model for masonry is proposed by following an internal variable approach originally developed in the field of elastic-plastic analysis. The general features of the theoretical framework are discussed by focussing on finite element models applicable to incremental elastic-plastic problems. An extremum property is derived and its implications in terms of convergence for convenient algorithms are briefly discussed, by including the case of softening materials and damage effects. Next, a numerical model is presented, which is suitable for masonry, can be developed according to the same internal variable formulation and enjoys similar properties. Some numerical results are presented and compared with the response of a masonry shear wall subjected to pseudodynamic tests.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.957-962
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• 2010

Foundation systems in urban sites are often necessary to be constructed with little vibrations and displacements to surroundings. In order to assess applicability of a new foundation system for urban sites based on soil-cement mixing technique, vibrations and displacements induced by soil-cement construction process is evaluated. Soil-cement columns were constructed to reinforce soft ground near an old masonry wall in an urban redevelopment site, and the vibrations and displacements of the old masonry wall during construction were measured. Results indicate that the vibrations and displacements induced by soil-cement construction were little and not critical to the stability of the masonry wall.