• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.253-256
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• 2008

본 연구는 목적은 1층에 연층/약층 및 비틀림 비정형성을 동시에 보유한 우리나라 비내진 현존 필로티형 저층 집합주택의 내진 취약성을 평가하는 것이다. 해석 구조물로서 4층 RC 집합 주택이 선정되었고, 선형 동적 해석법을 사용하여 해석되었으며, FEMA356에 의하여 평가되었다. 해석 결과 본 구조물은 FEMA356의 선형 동적 해석법 규정을 만족하였다.

• Steel and Composite Structures
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• 제52권2호
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• pp.217-236
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• 2024

The objective of this paper was to discuss the seismic performance of hybrid FRP-steel reinforced concrete shear wall with replaceable friction dampers at the feet of the wall. The hysteretic characteristics of five wall specimens were studied by pseudo-static loading tests. The results showed that the damage of the specimens was concentrated on the friction dampers, and the energy consumption capacity was increased while making up for the defect of low ductility of FRP reinforced wall specimens. And the repairability of the wall after earthquake was improved. Finally, a calculation method of initial stiffness of shear wall with replaceable dampers was proposed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.219-222
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• 2005

Many RC building structures of multiple uses constructed in Korea have the irregularities of torsion and soft story at bottom stories. A typical irregular building was selected as prototype and shaking table tests were performed to investigate the seismic performance of this building. The objective of this study is to evaluate the correlation between the experimental and analytical responses of this irregular building structure subjected to the earthquake excitation by using OpenSees(Open System for Earthquake Engineering Simulation). The results of analyses simulate well the behavior of the building having torsional irregularity and weak stories.

• Structural Engineering and Mechanics
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• 제30권6호
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• pp.733-761
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• 2008

The failure of reinforced concrete structures in recent earthquakes caused concern about the performance of beam column joints. Confinement of joint is one of the ways to improve the performance of beam column joints during earthquakes. This paper describes an experimental study of exterior beam-column joints with two non-conventional reinforcement arrangements. One exterior beam-column joint of a six story building in seismic zone III of India was designed for earthquake loading. The transverse reinforcement of the joint assemblages were detailed as per IS 13920:1993 and IS 456:2000 respectively. The proposed nonconventional reinforcement was provided in the form of diagonal reinforcement on the faces of the joint, as a replacement of stirrups in the joint region for joints detailed as per IS 13920 and as additional reinforcement for joints detailed as per IS 456. These newly proposed detailing have the basic advantage of reducing the reinforcement congestion at the joint region. In order to study and compare the performance of joint with different detailing, four types of one-third scale specimens were cast (two numbers in each type). The main objective of the present study is to investigate the effectiveness of the proposed reinforcement detailing. All the specimens were tested under reverse cyclic loading, with appropriate axial load. From the test results, it was found that the beam-column joint having confining reinforcement as per IS: 456 with nonconventional detailing performed well. Test results indicate that the non-conventionally detailed specimens, Type 2 and Type 4 have an improvement in average ductility of 16% and 119% than their conventionally detailed counter parts (Type1 and Type 3). Further, the joint shear capacity of the Type 2 and Type 4 specimens are improved by 8.4% and 15.6% than the corresponding specimens of Type 1 and Type 3 respectively. The present study proposes a closed form expression to compute the yield and ultimate load of the system. This is accomplished using the theory of statics and the failure pattern observed during testing. Good correlation is found between the theoretical and experimental results.

• 한국전산구조공학회논문집
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• 제29권3호
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• pp.261-268
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• 2016

동조액체감쇠기(TLD)는 에너지 소산장치로써 구조물의 동적응답을 제어하기 위해 개발되었다. TLD는 풍하중에 의한 구조물의 응답을 제어에 매우 효과적임을 보여줬다. 그러나 TLD가 설치된 구조물의 지진응답의 제어에 대해서는 충분한 연구가 이뤄지지 않았다. 이 연구의 목적은 TLD가 설치된 구조물에 여러 동조비와 질량비를 대입하여 지진에 대한 TLD의 성능을 도출하는 것이다. 이러한 목적을 위해, 수치해석 연구가 실시되며, 다른 토양 조건 또한 고려되었다. 그 결과 지진하중에 대한 TLD의 성능은 구조물의 고유주기, 감쇠비에 따라 다르게 나타났다. 또한 TLD의 동조비 다르게 나타남을 알 수 있었다.

• Earthquakes and Structures
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• 제4권2호
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• pp.157-179
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• 2013

Vulnerability studies on the existing building stock require that a large number of buildings is analyzed to obtain statistically significant evaluations of the seismic performance. Therefore, analytical evaluation methods need to be based on simplified methodologies of analysis which can afford the treatment of a large building population with a reasonable computational effort. Simplified Pushover-Based Earthquake Loss Assessment approach (SP-BELA), where a simplified methodology to identify the structural capacity of the building through the definition of a pushover curve is adopted, was developed on these bases. Main objective of the research work presented in this paper is to validate the simplified methodology implemented in SP-BELA against the results of more sophisticated nonlinear dynamic analyses (NLDAs). The comparison is performed for RC buildings designed only to vertical loads, representative of the "as built" in Italy and in Mediterranean countries with a building stock very similar to the Italian one. In NLDAs the non linear and degrading behaviour, typical of the structures under consideration when subjected to high seismic loads, is evaluated using models able to capture, with adequate accuracy, the non linear behaviour of RC structural elements taking into account stiffness degradation, strength deterioration, and pinching effect. Results show when simplified analyses are in good agreement with NLDAs. As a consequence, unsatisfactory results from simplified analysis are pointed out to address their current applicability limits.

• Earthquakes and Structures
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• 제7권6호
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• pp.1119-1139
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• 2014

A damage-based seismic design procedure for steel frame structures is formulated as an optimization problem, in which minimization of the initial construction cost is treated as the objective of the problem. The performance constraint of the design procedure is to achieve "repairable" damage state for earthquake demands that are less severe than the design ground motions. The Park-Ang damage index is selected as the seismic damage measure for the quantification of structural damage. The charged system search (CSS) algorithm is employed as the optimization algorithm to search the optimum solutions. To improve the time efficiency of the solution algorithm, two simplifying strategies are adopted: first, SDOF idealization of multi-story building structures capable of estimating the actual seismic response in a very short time; second, fitness approximation decreasing the number of fitness function evaluations. The results from a numerical application of the proposed framework for designing a twelve-story 3D steel frame structure demonstrate its efficiency in solving the present optimization problem.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.435-438
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• 2005

The use of new hybrid systems that combine the advantages of steel and reinforced concrete structures has gained popularity. One of these new mixed systems consists of steel beams and reinforced concrete shear wall, which represents a cost- and time-effective type of construction. A number of previous studies have focused on examining the seismic response of steel coupling beams in a hybrid wall system. However, the shear transfer of steel coupling beam-wall connections with panel shear failure has not been thoroughly investigated. The objective of this research was to investigate the seismic performance of steel coupling beamwall connections governed by panel shear failure. To evaluate the contribution of each mechanism, depending upon connection details, an experimental study was carried out The test variables included the reinforcement details that confer a ductile behaviour on the steel coupling beam-wall connection, i.e., the face bearing plates and the horizontal ties in the panel region of steel coupling beam-wall connections. It investigates the seismic behaviour of the steel coupling beams-wall connections in terms of the deformation characteristics. The results and discussion presented in this paper provide background for a companion paper that includes a design model for calculating panel shear strength of the steel coupling beam-wall connections.

• Earthquakes and Structures
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• 제13권5호
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• pp.473-484
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• 2017

The objective of this paper is to report on a study of the use of unstiffened thin steel plate shear walls (SPSWs) for the seismic performance improvement of reinforced concrete frames with deficient lateral rigidity. The behaviour of reinforced concrete frames during seismic activities was rehabilitated with an alternative and occupant-friendly retrofitting scheme. The study involved tests of eight 1/3 scale, one bay, two storey test specimens under cyclic quasi-static lateral loadings. The first specimen, tested in previous test program, was a reference specimen, and in seven other specimens, steel infill plates were used to replace the conventional infill brick or the concrete panels. The identification of the load-deformation characteristics, the determination of the level of improvement in the overall strength, and the elastic post-buckling stiffness were the main issues investigated during the quasi-static test program. With the introduction of the SPSWs, it was observed that the strength, stiffness and energy absorption capacities were significantly improved. It was also observed that the experimental hysteresis curves were stable, and the composite systems showed excellent energy dissipation capacities due to the formation of a diagonal tension field action along with a diagonal compression buckling of the infill plates.

• 한국지진공학회논문집
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• 제17권6호
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• pp.271-278
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• 2013

The hysteretic behavior of diagonal reinforced coupling beams is excellent during earthquakes. However, construction of the diagonal reinforced coupling beams is difficult due to complex reinforcement details required by current code procedures (ACI 318-11). Due to the detail requirement, reinforcement congestion and interference among transverse reinforcement always occur during construction field. When the aspect ratio of the beam is large, the interference of reinforcement becomes more serious. The objective of this paper is to simplify the reinforcement details of slender coupling beams by reducing transverse reinforcement around the beam perimeter. For this purpose, high- performance fiber reinforced cementitious composites are used for making coupling beams. Experiments were conducted using three specimens having aspect ratio 3.5. Test results showed that HPFRCC coupling beams with half the transverse reinforcement required by ACI 318-11 provided identical seismic capacities to the corresponding coupling beams having requirement satisfying the requirement specified in ACI 318-11.