• Title/Summary/Keyword: Collapse Point

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An Analysis Code and a Planning Tool Based on a Key Element Index for Controlled Explosive Demolition

  • Isobe, Daigoro
    • International Journal of High-Rise Buildings
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    • v.3 no.4
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    • pp.243-254
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    • 2014
  • In this study, a demolition analysis code using the adaptively shifted integration (ASI)-Gauss technique, which describes structural member fracture by shifting the numerical integration point to an appropriate position and simultaneously releasing the sectional forces in the element, is developed. The code was verified and validated by comparing the predicted results with those of several experiments. A demolition planning tool utilizing the concept of a key element index, which explicitly indicates the contribution of each structural column to the vertical load capacity of the structure, is also develped. Two methods of selecting specific columns to efficiently demolish the whole structure are demonstrated: selecting the columns from the largest index value and from the smallest index value. The demolition results are confirmed numerically by conducting collapse analyses using the ASI-Gauss technique. The numerical results suggest that to achieve a successful demolition, a group of columns with the largest key element index values should be selected when explosives are ignited in a simultaneous blast, whereas those with the smallest should be selected when explosives are ignited in a sequence, with a final blast set on a column with large index value.

Implication of rubber-steel bearing nonlinear models on soft storey structures

  • Saiful Islam, A.B.M.;Hussain, Raja Rizwan;Jumaat, Mohammed Zamin;Mahfuz ud Darain, Kh.
    • Computers and Concrete
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    • v.13 no.5
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    • pp.603-619
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    • 2014
  • Soft storey buildings are characterised by having a storey that has a large amount of open space. This soft storey creates a major weak point during an earthquake. As the soft stories are typically associated with retail spaces and parking garages, they are often on the lower levels of tall building structures. Thus, when these stories collapse, the entire building can also collapse, causing serious structural damage that may render the structure completely unusable. The use of special soft storey is predominant in the tall building structures constructed by several local developers, making the issue important for local building structures. In this study, the effect of the incorporation of an isolator on the seismic behaviour of tall building structures is examined. The structures are subjected to earthquakes typical of the local city, and the isolator is incorporated with the appropriate isolator time period and damping ratio. A FEM-based computational relationship is proposed to increase the storey height so as to incorporate the isolator with the same time period and damping ratio for both a lead rubber bearing (LRB) and high-damping rubber bearing (HDRB). The study demonstrates that the values of the FEM-based structural design parameters are greatly reduced when the isolator is used. It is more beneficial to incorporate a LRB than a HDRB.

Seismic fragility evaluation of the base-isolated nuclear power plant piping system using the failure criterion based on stress-strain

  • Kim, Sung-Wan;Jeon, Bub-Gyu;Hahm, Dae-Gi;Kim, Min-Kyu
    • Nuclear Engineering and Technology
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    • v.51 no.2
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    • pp.561-572
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    • 2019
  • In the design criterion for the nuclear power plant piping system, the limit state of the piping against an earthquake is assumed to be plastic collapse. The failure of a common piping system, however, means the leakage caused by the cracks. Therefore, for the seismic fragility analysis of a nuclear power plant, a method capable of quantitatively expressing the failure of an actual piping system is required. In this study, it was conducted to propose a quantitative failure criterion for piping system, which is required for the seismic fragility analysis of nuclear power plants against critical accidents. The in-plane cyclic loading test was conducted to propose a quantitative failure criterion for steel pipe elbows in the nuclear power plant piping system. Nonlinear analysis was conducted using a finite element model, and the results were compared with the test results to verify the effectiveness of the finite element model. The collapse load point derived from the experiment and analysis results and the damage index based on the stress-strain relationship were defined as failure criteria, and seismic fragility analysis was conducted for the piping system of the BNL (Brookhaven National Laboratory) - NRC (Nuclear Regulatory Commission) benchmark model.

A Literatual Study on the effects of Bloodletting on C.V.A. (중풍(中風)에 활용(活用)된 자락요법(刺絡療法)에 대(對)한 문헌적(文獻的) 고찰(考察))

  • Nam, Chang-Gyoo;Lee, Jin-Seop
    • The Journal of Internal Korean Medicine
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    • v.15 no.2
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    • pp.148-162
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    • 1994
  • A Literature study was done for identifying the effects of Bloodletting on C.V.A. The major results of the study were as follows. 1. The frequency of points of Bloodletting on C.V.A. were in order Twelve well point, Ship son, Gold SalivaJade Fluid, Paekoe, Chungchung, Sugu, Sosang, Taechu, Wijung, Kwanchung, etc. 2. The frequency of meridians of Bloodletting on C.V.A. were in order Extra-point, Tongmaek-kyong, Su-gworum-Shimpo-Kyong, Susoyang-Samcho-Kyong, Sutaeum-Pye-Kyong, Choktaeyang-Panggwang-Kyong. ete. 3. The frequency of the site of points of Bloodletting on C.V.A. were in order four extremities, face, neck and head, etc. 4. The effects of Bloodletting on C.V.A. is clear away heat and alleviate pain, therapy for waking up a patient from unconsciousness, dredge the meridian passage, expel wind-evil and promote blood circulation, emergency treatment for collapse, etc, 5. The effects of Bloodletting on the early stage of C.V.A. were wake up the patient from unconsciousness by clearing away the heat and The effects of Bloodletting on sequence of C.V.A. were dredge the meridian passage, 6. The frequency of points and meridians of Bloodletting on Hemiplegia were in order Twelve well point, Kyonjong, Extra-point, Chok soyang-Tam-Kyong, etc. 7. The frequency of points and meridians of Bloodletting on Aphasia were in order Gold Saliva Jade Fluid, Amun, Extra-point, Tongmaek-Kyong, etc. 8. The frequency of points and meridians of Bloodletting on Quadriplegia were in order Ship son, Twelve well point, Koktaek, Wijung, Extra-point, Chok soyang-Tam-Kyong, etc. 9, The frequency of points and meridians of Bloodletting on Vertigo were in order Four Gods Cleverness, Tuyu. Chanjuk, Paekoe, Taeyang, Extra-point, Yang-Kyong, etc. 10. The frequency of points and meridians of Bloodletting on Headache were in order Taeyang, Paekoe, Taechu, Extra-point, Tongmaek-Kyong, Yang-Kyong, etc. 11. The points and meridians of Bloodletting on Bells palsy were Chichang, Hyopko in Yangmyong-Kyong.

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Development of Slope Information Retrieval and Real-time Warnings System for a Landslide Disaster Reduction from Mobile Environments (모바일 환경에서의 산사태 재해 저감을 위한 사면 정보 검색 및 실시간 경고 시스템 개발)

  • Kim, Sung-Ho;Ji, Young-Hwan;Lee, Seung-Ho
    • The Journal of the Korea Contents Association
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    • v.10 no.2
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    • pp.81-88
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    • 2010
  • This paper describes a development of next generation information remote retrieval and warning system that enables the user to make slope information retrieval remotely for a rockfall and landslide disaster reduction from mobile environments. And this system will be able to warn with a real-time stability condition about the slope which circumference are contiguous in standard user location. Slope information which provides to the user, become the service which upgrades from depth deep information directness will be able to confirm in order from field with applies multimedia style information which is various. In order to retrieve slope information with the wire and wireless internet from the remote place, we used mobile PC carrying is simple. Also this system attached GPS receiver to mobile PC in order to confirm user location as a real-time from the electronic map from field. Specially this system user location divide the safety of the slope which within the area where are fixed in the center are representative with 'safe area', 'collapse area' and 'collapse forecast area' etc. And to indicate with the icon of each other different color simultaneously in the electronic map. With like that reason, this system which sees the user even while moving safety condition about circumferential slope from the electronic map is having the strong point will be able to grasp with a real-time in one eye. Also warning message leads at the case real-time when the collapse will occur in specific slope, to inform to the user. Therefore this system which sees will be able to reduce the disaster which is caused by in landslide a very big strong point and has.

Utilization of Drone LiDAR for Field Investigation of Facility Collapse Accident (붕괴사고 현장조사를 위한 드론 LiDAR 활용)

  • Yonghan Jung ;Eontaek Lim ;Jaewook Suk;Seul Koo;Seongsam Kim
    • Korean Journal of Remote Sensing
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    • v.39 no.5_2
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    • pp.849-858
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    • 2023
  • Investigating disaster sites such as earthquakes and landslides involves significant risks due to potential secondary disasters like facility collapse. In situations where direct access is challenging, there is a need to develop methods for safely acquiring high-precision 3D disaster information using light detection and ranging (LiDAR) equipped drone survey systems. In this study, the feasibility of using drone LiDAR in disaster scenarios was examined, focusing on the collapse accident at Jeongja Bridge in Bundang-gu, Seongnam City, in April 2023. High-density point clouds for the accident bridge were collected, and the bridge's 3D terrain information was reconstructed and compared to the measurement performance of 10 ground control points. The results showed horizontal and vertical root mean square error values of 0.032 m and 0.055 m, respectively. Additionally, when compared to a point cloud generated using ground LiDAR for the same target area, a vertical difference of approximately 0.08 m was observed, but overall shapes showed minimal discrepancies. Moreover, in terms of overall data acquisition and processing time, drone LiDAR was found to be more efficient than ground LiDAR. Therefore, the use of drone LiDAR in disaster sites with significant risks allows for safe and rapid onsite investigations.

Efficient Methods of Prediction Incorporating Equivalent Models for Elasto-Plastic Bending Behavior of Metallic Sandwich Plates with Inner Dimpled Shell Structure (등가형상을 이용한 딤플형 금속 샌드위치 판재의 효율적 굽힘 거동 예측)

  • Seong D. Y.;Jung C. G.;Yoon S. J.;Yang D. Y.
    • Transactions of Materials Processing
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    • v.14 no.8 s.80
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    • pp.718-724
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    • 2005
  • An efficient finite element method has been introduced for analysis of metallic sandwich plates subject to bending moment. A full model 3-point bending FE-analysis shows that the plastic behavior of inner structures appears only at the load point. The unit structures of sandwich plates are defined to numerically calculate the bending stiffness and strength utilizing the recurrent boundary condition for pure bending analysis. The equivalent models with the same bending stiffness and strength of full models are then designed analytically. It is demonstrated that the results of both models are almost the same and the FE-analysis method incorporating the equivalent models can reduce the computation time effectively. The dominant collapse modes are face buckling and face yielding. Since the inner dimpled structures prevent face buckling, sandwich plates with inner dimpled shell structure can absorb more energy than other types of sandwich plates during the bending behavior.

Bending Performance Evaluation of Reinforced Aluminum Square Tube Beams (보강 알루미늄 사각관 보의 굽힘 성능평가)

  • Lee Sung-Hyuk;Choi Nak-Sam
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.5
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    • pp.171-180
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    • 2005
  • Bending performances of aluminum square tube beams reinforced by aluminum plates under three point bending loads have been evaluated using experimental tests combined with theoretical and finite element analyses. A finite element simulation for the three-point bending test was performed. Basic properties of aluminum materials used for initial input data of the finite element simulation were obtained from the true stress-true strain curves of specimens which had been extracted from the Al tube beams. True stresses were determined from applied loads and cross-sectional area records of a tensile specimen with a rectangular cross-section by real-time photographing, and true strains were obtained from in-situ local elongation measurements of the specimen gage portion by the multi-point scanning laser extensometer. Six kinds of aluminum tube beam specimens adhered by aluminum plates were employed fur the bending test. The bending deformation behaviors up to the maximum load described by the numerical simulation were in good agreement with experimental ones. After passing the maximum load, reinforcing plate was debonded from the aluminum tube beam. An aluminum tube beam strengthened by aluminum plate on the upper web showed an excellent bending capability.

Effect of Hallux Point Insole on Foot Contact Area and Pressure (할룩스 포인트 인솔이 발의 접촉면적 및 압력에 미치는 영향)

  • Lee, Su-Kyong;Ahn, Su-Hong;Kim, Yong-Woon;Yang, Ki-Eun
    • PNF and Movement
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    • v.19 no.2
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    • pp.233-242
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    • 2021
  • Purpose: The purpose of this study was to determine the changes in foot contact area and pressure when walking with a functional insole that emphasizes the Hallux point as compared to a general insole. Methods: In this study, an experiment was conducted to investigate changes in plantar pressure and contact area for a functional insole that emphasized the Hallux point as compared to a general insole. A lower extremity robot was used for walking reproduction. First, the gait sequence according to the two insoles was determined through a randomized controlled trial comparison. According to the sequence procedure, the insole was attached to the shoe and then worn on the right side of the lower extremity robot for gait reproduction at a normal gait speed of 20 steps per minute. After programming the robot to walk, the experiment was carried out. The result value was determined by averaging the pressure and area data of the fore and rear foot measures after walking at 20 steps per minute. Results: The functional insole that emphasized the hallux point significantly increased the forefoot and rearfoot contact area (p < 0.05) and significantly decreased the forefoot and rearfoot contact pressure (p < 0.05) compared to the general insole. Conclusion: A functional insole that emphasizes the hallux point does not collapse the medial longitudinal arch during gait, increasing foot stability and reducing fatigue. Thus, this functional insole needs to be widely used clinically.

Analysis of Slope Stability through Sand Constructed Model Levee (모래로 축조(築造)한 제체(堤體)의 사면안정(斜面安定) 해석(解析))

  • Shin, Bang Woong;Choi, Gi Bong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.5 no.4
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    • pp.15-22
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    • 1985
  • The author has studied the collapse of a slope with seepage occuring in sand model with a trapezodial cross section. The primary objective of this study was to examine the failure phenomenon of embankment with respect to change in void pressure at embankment slope. The contents of this experiments are as follows; 1) Determination of exit point by seepage line. 2) Evaluation of partial failure at exit point. 3) The effects of seepage force at embankment.

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