• 전산구조공학
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• 제5권1호
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• pp.91-96
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• 1992

내진구조는 건축규준에 의하여 강제성을 띤 이후 많은 발전을 하였으나 아직도 완전하게 이해되지는 않고 있다. 본 논문은 실제로 발생하였던 두 지진의 지반운동을 10층의 철골조에 적용시켜 얻은 결과를 비교하였다. 1989년 California의 Loma Prieta에서 발생한 규모 7.1의 지진기록 12세트와 1985년 Chile의 Valparaiso에서 발생한 규모 7.8의 지진기록 9세트를 UBC의 지진지역 2B에 알맞게 조절하였다. 비슷한 규모를 가진 두 지진의 지반변위를 건물에 직접 적용시켜서 비교한 결과 그 지속시간이 긴 Chile지진이 상대적으로 지속시간이 짧은 California지진보다 약 2배 정도 큰 영향을 건물에 미치는 것이 발견되었다. 내진구조의 설계에 있어서 최대지반운동과 더불어 지반운동의 지속시간도 매우 중요하게 고려되어야 할 사항이다.

• 한국해양공학회지
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• 제31권3호
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• pp.196-201
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• 2017

A cylindrical structure has a very long period of heave and pitch motion response in ocean waves. To obtain the dynamic stability of a cylindrical structure, it is necessary to obtain the suitable metacentric height (GM). However, in a structure with sufficient metacentric height, Mathieu instability can occur if the natural frequency of the heave motion is double the natural frequency of the roll and pitch motion. This study carried out numerical calculations and experiments for vertical-axis wind turbines with cylindrical floaters, which had three different centers of gravity. In the regular wave experiment, the divergence of the structure motion without yaw was observed when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion. In the irregular wave experiment, the motion spectra of the structures with the different centers of gravity were compared, and one was very high when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion.

• 한국기계가공학회지
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• 제9권1호
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• pp.67-73
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• 2010

Finding sufficient supplies of clean energy for future is one of the society's most important challenges according to technologies. Alternative renewable energy source such as sun energy can be substituted for exceeding human energy need. The main factor affect to solar performance is a collective intensity. To enhance intensity, suitable equipment is a solar tracker. This paper presents design and evaluation of 1 layer polar motion control system for solar tracker suitable for building integrated system. To evaluation of tracking accuracy and adaptability, solar tracker with 64 links is implemented. In experimental results, the accuracy of tracking has under ${\pm}0.0287^{\circ}$ and the thickness has under 140mm.

• 한국공간구조학회논문집
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• 제13권1호
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• pp.79-86
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• 2013

For most of recent tall buildings, one characteristic is that their building shapes vary with height such as taper and setback, and this implies that the distribution of their structural components may also vary with height. Because of these structural variations, although the sectional shapes of these buildings are symmetric, it is difficult to say whether or not they are structurally symmetric. The acceleration responses of structurally asymmetric tall buildings are larger than those of non-eccentric buildings, thus raising the possibility of problems during strong winds and typhoons. This paper describes wind tunnel tests carried out using building models with height variations and acceleration response analyses, and discusses the resulting response characteristics. For tapered and setback buildings, although the across-wind accelerations are larger than those of a square building, the total root-mean-square accelerations remain small because of smaller along-wind and torsional rms accelerations. And it was found that the effects of statistical couplings between along-wind force and other two forces are negligible.

• 제어로봇시스템학회논문지
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• 제18권5호
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• pp.445-452
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• 2012

With the increasing number of high-rise and large-scale buildings, modern buildings are becoming intelligent, and are incurring high construction costs and requiring careful maintenance. Maintenance works for high-rise buildings significantly depend on human labor, unlike other construction processes that are gradually being automated. The resulting accidents may produce very high social and economic losses. To address this problem, herein, this paper proposes robotic building maintenance system using multi-robot concept, in specific, cleaning a building facade which is directly subjected to minimize human labor; that improves the process efficiency and economic feasibility. The sensor for detecting contamination of building's outer-wall glass is proposed; Kalman filter was used for estimating robots' status with the contamination of the window glass. Task allocation of the sensor based multi-robots for an effective way of task execution is introduced and the feasibility was verified through the simulations.

• 한국안전학회지
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• 제27권2호
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• pp.57-64
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• 2012

For the vibration control of earthquake-excited buildings, an optimal design method of integrated control system considering soil-structure interaction is studied in this paper. Interaction between soils and the base of the building is simply modeled as lumped parameters and equations of motion are derived. The equations of motion are transformed into the state space equations and the probabilistic excitations such as Kanai-Tajumi power spectral density function is introduced. Then an optimization problem is formulated as finding hybrid or integrated control systems which minimizes the stochastic responses of the building structure for given constraints. In order to investigate the feasibility of the optimization method, an example design and numerical simulations are performed with tenstory building. Finally, numerical results are compared with a conventional design case that soil-structure interaction is not considered.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 가을 학술발표회 논문집
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• pp.90-95
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• 1991

The Uniform Building Code (UBC) is the most widely used requirements for earthquake resistant design in the United States. In this paper, a mid-rise steel building is analyzed by applying 12 sets of actual strong-motion earthquake data that have been scaled to acne 2B levels. The simply extrapolated ground motion displacements are used for the dynamic loads. The results of dynamic analyses for a 10-story steel building are compared with the static and dynamic analysis requirements of UBC-88. It was found that computed lateral fortes using UBC-88 static procedure differed by about 60 percent depending on whether the natural period was computed using the UBC empirical method or the UBC recommended Rayleigh's method. The lateral fortes computed from the UBC response spectra were more than 10 times greater than those computed by UBC static procedures. The lateral forces obtained from both linear and nonlinear analyses using 1989 Loma Prieta ground mot ions compared very well with UBC response spectra results.

• 한국CDE학회논문집
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• 제19권1호
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• pp.68-79
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• 2014

Human model simulation has been widely used in various industrial areas such as ergonomic design, product evaluation and characteristic analysis of work-related musculoskeletal disorders. However, the process of building digital human models and capturing their behaviors requires many costly and time-consuming fabrication iterations. To overcome the limitations of this expensive and time-consuming process, many studies have recently presented a markerless motion capture approach that reconstructs the time-varying skeletal motions from optical devices. However, the drawback of the markerless motion capture approach is that the phenomenon of occlusion of motion data occurs in real-time human simulation. In this study, we propose a systematic method of discriminating missing or inaccurate motion data due to motion occlusion and interpolating a sequence of motion frames captured by a markerless depth camera.

• Earthquakes and Structures
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• 제26권1호
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• pp.17-30
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• 2024

Earthquakes can lead to substantial damage to buildings, with long-period ground motion being particularly destructive. The design of high-performance building structures has become a prominent focus of research. The double-story isolated structure is a novel type of isolated structure developed from base isolated structure. To delve deeper into the building performance of double-story isolated structures, the double-story isolated structure was constructed with the upper isolated layer located in different layers, alongside a base isolated structure for comparative analysis. Nonlinear elastoplastic analyses were conducted on these structures using different ground motion inputs, including ordinary ground motion, near-field impulsive ground motion, and far-field harmonic ground motion. The results demonstrate that the double-story isolated structure can extend the structural period further than the base isolated structure under three types of ground motions. The double-story isolated structure exhibits lower base shear, inter-story displacement, base isolated layer displacement, story shear, and maximum acceleration of the top layer, compared to the base isolated structure. In addition, the double-story isolated structure generates fewer plastic hinges in the frame, causes less damage to the core tube, and experiences smaller overturning moments, demonstrating excellent resistance to overturning and a shock-absorbing effect. As the upper isolated layer is positioned higher, the compressive stress on the isolated bearings of the upper isolated layer in the double-story isolated structure gradually decreases. Moreover, the compressive stress on the isolated bearings of the base isolated layer is lower compared to that of the base isolated structure. However, the shock-absorbing capacity of the double-story isolated structure is significantly increased when the upper isolated layer is located in the middle and lower section. Notably, in regions exposed to long-period ground motion, a double-story isolated structure can experience greater seismic response and reduced shock-absorbing capacity, which may be detrimental to the structure.

• Earthquakes and Structures
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• 제25권2호
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• pp.99-112
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• 2023

This paper investigates the influences of Soil-Structure Interaction (SSI) on the seismic behavior of two-dimensional reinforced concrete moment-resisting frames subjected to Far-Field Ground Motion (FFGM) and Near-Field Ground Motion (NFGM). For this purpose, the nonlinear modeling of 7, 10, and 15-story reinforced concrete moment resisting frames were developed in Open Systems for Earthquake Engineering Simulation (OpenSees) software. Effects of SSI were studied by simulating Beam on Nonlinear Winkler Foundation (BNWF) and the soil type as homogenous medium-dense. Generally, the building resistance to seismic loads can be explained in terms of Incremental Dynamic Analysis (IDA); therefore, IDA curves are presented in this study. For comparison, the fragility evaluation is subjected to NFGM and FFGM as proposed by Quantification of Building Seismic Performance Factors (FEMA P-695). The seismic performance of Reinforced Concrete (RC) buildings with fixed and flexible foundations was evaluated to assess the probability of collapse. The results of this paper demonstrate that SSI and NFGM have significantly influenced the probability of failure of the RC frames. In particular, the flexible-base RC buildings experience higher Spectral acceleration (Sa) compared to the fixed-base ones subjected to FFGM and NFGM.