• 한국공간구조학회논문집
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• 제18권1호
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• pp.55-65
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• 2018

In order to reduce the seismic response of the spatial structure, a seismic isolation system with sufficient flexibility is used. The natural period of structure with seismic isolation system got be long to avoid prominent period. In this study, The seismic response of the truss-arch structure, which is modeled in three types according to the rise-span ratio is analyzed on El-centro, Northridge and Artificial Earthquake and compared with the seismic response of the truss-arch structure with lead rubber bearing(LRB). When seismic load is applied to the truss arch with isolation system, the horizontal acceleration response of the truss arch is reduced and vertical seismic response is also reduced. The application of the seismic isolation system is effective in controlling the seismic response.

• 한국지진공학회논문집
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• 제23권2호
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• pp.89-99
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• 2019

In order to increase the seismic safety of nuclear power plant (NPP) structures, a technique to reduce the seismic load transmitted to the NPP structure by using a seismic isolation device such as a lead-rubber bearing has recently been actively researched. In seismic design of NPP structures, three directional (two horizontal and one vertical directions) artificial synthetic earthquakes (G0 group) corresponding to the standard design spectrum are generally used. In this study, seismic analysis was performed by using three directional artificial synthetic earthquakes (M0 group) corresponding to the maximum-minimum spectrum reflecting uncertainty of incident direction of earthquake load. The design basis earthquake (DBE) and the beyond design basis earthquakes (BDBEs are equal to 150%, 167%, and 200% DBE) of G0 and M0 earthquake groups were respectively generated for 30 sets and used for the seismic analysis. The purpose of this study is to compare seismic responses and seismic fragility curves of seismically isolated NPP structures subjected to DBE and BDBE. From the seismic fragility curves, the probability of failure of the seismic isolation system when the peak ground acceleration (PGA) is 0.5 g is about 5% for the M0 earthquake group and about 3% for the G0 earthquake group.

• Structural Engineering and Mechanics
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• 제78권5호
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• pp.637-649
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• 2021

Great efforts have been conducted to investigate the seismic performances of the arch and rectangular underground structures, however, the differences between seismic responses of these two types of underground structures, especially the vault radian influencing the seismic responses of arch structures are not clarified. This paper presents a detailed numerical investigation on the seismic responses of arch underground structures with different vault radians, and aims to illustrate the rule that vault radian affects the seismic responses of underground structures. Five arch underground structures are built for nonlinear soil-structure interaction analysis. The internal forces of the structural components of the underground structures only under gravity are discussed detailedly, and an optimum vault radian for perfect load-carrying functionality of arch underground structures is suggested. Then the structures are analyzed under seven scaled ground motions, amounting to a total of 35 dynamic calculations. The numerical results show that the vault radian can have beneficial effects on the seismic response of the arch structure, compared to the rectangular underground structures, causing the central columns to suffer smaller axial force and horizontal deformation. The conclusions provide some directive suggestions for the seismic design of the arch underground structures.

• 국제초고층학회논문집
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• 제11권3호
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• pp.197-205
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• 2022

One of important design challenges in Chongqing Raffles City Plaza project is Sky Bridge structural design and its connection scheme in high level. This article systematically describes the structural system and its design and analysis methodology, with discussing the impacts on structural performance due to different connection approaches. The seismic isolation scheme in high level is innovatively adopted to the final design. Under the conditions of various load cases, the different models and assumptions are implemented. A full assessment on Sky Bridge's structural performance, seismic isolation, and its connection is conducted in terms of seismic performance based design. By co-operating with architecture, MEP and other disciplines, the structural economy index is fulfilled.

• Earthquakes and Structures
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• 제23권2호
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• pp.169-181
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• 2022

To research the dynamic response of the high-rise structure under the rocking ground motion, which we believed that the effect cannot be ignored, especially accompanied by vertical ground motion. Theoretical analysis and shaking table seismic simulation tests were used to study the response of a high-rise structure to excitation of a H-V-R ground motion that included horizontal, vertical, and rocking components. The use of a wavelet analysis filtering technique to extract the rocking component from data for the primary horizontal component in the first part, based on the principle of horizontal pendulum seismogram and the use of a wavelet analysis filtering technique. The dynamic equation of motion for a high-rise structure under H-V-R ground motion was developed in the second part, with extra P-△ effect due to ground rocking displacement was included in the external load excitation terms of the equation of motion, and the influence of the vertical component on the high-rise structure P-△ effect was also included. Shaking table tests were performed for H-V-R ground motion using a scale model of a high-rise TV tower structure in the third part, while the results of the shaking table tests and theoretical calculation were compared in the last part, and the following conclusions were made. The results of the shaking table test were consistent with the theoretical calculation results, which verified the accuracy of the theoretical analysis. The rocking component of ground motion significantly increased the displacement of the structure and caused an asymmetric displacement of the structure. Thus, the seismic design of an engineering structure should consider the additional P-△ effect due to the rocking component. Moreover, introducing the vertical component caused the geometric stiffness of the structure to change with time, and the influence of the rocking component on the structure was amplified due to this effect.

• 한국산학기술학회논문지
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• 제21권6호
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• pp.440-447
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• 2020

조적구조는 소규모 건축물에서는 내력벽으로 사용되나 일반적으로 비내력벽으로 간주되어 건축물 골조구조의 내부공간을 구분하는 칸막이벽으로 활용되어진다. 또한 조적공사에서 블록이나 벽돌간의 접착제로 모르타르를 사용하는 습식공법은 양생시간이 필요하여 기후조건에 영향을 받으며, 특히 지진과 같은 횡력에 대해 모르타르의 균열로 벽체의 전도붕괴 등이 발생할 수 있어 매우 취약한 구조이다. 본 연구에서는 이러한 조적구조의 약축방향 전단강성을 보완하고 습식공법의 단점을 개선하는 건식 콘크리트블록 공법을 제안하고 그 구조거동을 규명하고자 한다. 이에 본 연구에서는 콘크리트블록의 재료물성을 살펴보고 수평반복하중에 대한 구조거동실험을 통해 제안된 건식조립 콘크리트블록 벽체의 내진성능을 검증하고자 한다. 본 연구결과에 의하면 첫째로, 콘크리트블록은 KS규준에 C종 블록의 재료성능 이상을 확보하고 있어 습식공법을 대신하는 건식공법에 적용할 수 있을 것이다. 둘째로, 수평반복하중에 대한 벽체의 구조성능은 벽체의 수평길이가 길어짐에 따라 사용된 표준형블록의 증가로 다수의 대각선방향 균열대를 형성하면서 조립블록벽체의 내력이 커짐을 알 수 있다. 끝으로 제안된 건식조립 콘크리트블록 벽체구조는 높이와 길이에 의한 벽체의 형상비가 수평 하중을 받는 구조거동에 주요 영향변수로 판단되어 이를 고려한 내진성능평가가 필요하다.

• 한국지진공학회논문집
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• 제1권2호
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• pp.79-89
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• 1997

본 연구에서는 Haringx 이론에 근거하여 면진용 적층고무베어링의 기계적 역학특성을 살펴보고자 한다. 이를 위하여 제안된 수평강성 평가식을 검토하고 점성감쇠의 영향을 분석하기 위한 점탄성문제로의 확장을 통해 감쇠증폭을 역학특성을 평가하였다. 그리고 적층고무베어링에 대한 좌굴안정성평가를 수행하여 형상계수의 양향을 분석하였다. P-delta 효과를 고려한 적층고무베어링의 수평가성식을 면지구조물의 지진해석에 적용하여 동적잔단변형응답 해석결과를 실제 진동대를 이용한 실험결과와 비교하였다. 본 연구로부터 제안된 단순 수평강성 평가식은 설계수직하중내에서 적용가능하며 점탄성문제로 쉽게 확장이 가능하다. 좌굴안정식 평가로부터 적층고무베어링은 단일 고무판의 두께 증가비에 비하여 총 고무판두께 증가비가 좌굴하중감소에 크게 영향을 준다. 그리고 입력지진에 대한 면진구조물의 해석결과 적층고무베어링의 전단변형응답이 실제 실험결과와 매우 일치한 결과를 얻었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.66-69
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• 2006

Three reinforced concrete rigid frames and infilled rigid frames with new retrofitting system were tested under both vertical and cyclic loadings, Experimental programs were carried out to evaluate and improve the seismic performance of such test specimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility etc. under load reversals. All the specimens were modeled in one-third scale size. For specimens(RFHPC, RFAR) designed by the improving of seismic performance of the rigid frame using the high ductile fiber composite PC panel and ALC panel system, load-carrying capacities were increased $1.45{\sim}2.28$ times, and hysteretic behavior was very stable during the final tests in comparison with the standard specimen(SRF).

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.202-205
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• 2006

Three reinforced concrete shear wall and infilled shear wall using retrofitting system were constructed and tested under both vertical and cyclic loadings, Experimental programs were carried out to evaluate and improve the seismic performance of such test specimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility etc. under load reversals. All the specimens were modeled in one-third scale size. For specimens(RWAHC, RWXHC) designed by the improving of seismic performance using the high ductile fiber composite mortar, anchoring, and advanced detailing system for the reinforced concrete shear wall load-carrying capacities were increased $1.1{\sim}1.22$ times in comparison with the standard specimen(SRW).

• Steel and Composite Structures
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• 제32권6호
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• pp.717-729
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• 2019

A horizontal cyclic test was carried out to study the seismic performance of lightweight aggregate concrete filled steel tube (LACFST). The constitutive and hysteretic model of core lightweight aggregate concrete (LAC) was proposed for finite element simulation. The stress and strain changes of the steel tube and concrete filled inside were measured in the experiment, and the failure mode, hysteresis curve, skeleton curve, and strain curve of the test specimens were obtained. The influence of axial compression ratio, diameter-thickness ratio and material strength were analysed based on finite element model. The results show that the hysteresis curve of LACFST indicated favourable ductility, energy dissipation, and seismic performance. The LACFST failed when the concrete in the bottom first crushed and the steel tube then bulged, thus axial force imposed by prestressing was proved to be feasible. The proposed constitutive model and hysteretic model of LAC under the constraint of its steel tube was reliable. The bearing capacity and ductility of the specimen increase significantly with increasing thickness of the steel tube. The bearing capacity of the member improves while the ductility and energy dissipation performance slightly decreased with the increasing strength of the steel and concrete.