• Structural Engineering and Mechanics
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• v.13 no.1
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• pp.35-52
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• 2002

It was shown in the previous study (Lee and Bertero 1993) that incremental collapse can lead to the exhaustion of the plastic rotation capacity at critical regions in a structure when subjected to the number of load cycles and load intensities as expected during maximum credible earthquakes and that this type of collapse can be predicted using the shakedown analysis technique. In this study, a minimum-weight design methodology, which takes into account not only the prevention of this incremental collapse but also the requirements of the serviceability limit states, is proposed by using the shakedown analysis technique and a nonlinear programming algorithm (gradient projection method).

• International Journal of Advanced Culture Technology
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• v.6 no.4
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• pp.255-261
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• 2018

In the field of excavation, it is important to recognize and analyze the factors that cause the ground collapse in order to predict and cope with the ground subsidence. However, it is difficult for field engineers to predict ground collapse due to insufficient knowledge of ground subsidence influence factors. Although there are many cases and studies related to the ground subsidence, there is no manual to help practitioners. In this study, we present the criteria for describing and quantifying the influential factors to help the practitioners understand the existing ground collapse cases and classification of the ground subsidence factors revealed through the research. This study aims to improve the understanding of the factors affecting the ground collapse and to provide a GSRp for the ground subsidence risk assessment which can be applied quickly in the field.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.813-817
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• 2007

Purpose: The zygomatic arch is a key element which composes the facial contour. In many cases of zygomatic arch fracture, it is difficult to fix rigidly the fractured segments. If reduced bone segments were not fixed rigidly, they are proven to be displaced by mastication or unintentional external forces. So, unfixed zygomatic arch fracture after reduction may require a external device of prevention of collapse. We introduce a new protector which stabilizing the fractured segments to prevent for collapse of the reduced zygomatic arch fracture. Methods: After reduction of zygomatic arch with blind approach(Gillies', Dingman or Keen's approach), bone segments was pulled with percutaneous traction suture in medial aspect of zygomatic arch. Then, the suture was fixed with Aqua $splint^{(R)}$, externally. And intraoperative and postoperative X-ray was done. The splint was removed on 14 days after the operation. Results: 5 patients were treated with this method. 4 patients of total patients had no collapse in zygomatic arch. There was minimal collapse in one patient. Postoperative complications such as facial nerve injury, mouth opening difficulty, contour deformity, infection, scar were not observed. Conclusion: In comparison with other techniques, this technique has several advantages which are simple and easy method, short operation time, no scar, less soft tissue injury, and facilitated removal of splint. Therefore, Aqua $splint^{(R)}$ would be a good alternative to prevent for collapse in unstable zygomatic arch fractures

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.3
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• pp.489-501
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• 2017

The collapse accidents during a open ground excavation in urban areas not only lead to human injuries and material damages in the construction site, but also lead to road sinks and damages to the adjacent facilities due to settlement of ground around the construction site. Therefore, during a open ground excavation in the urban areas, it is necessary to thoroughly prepare for prevention of collapse accidents, and consider whole construction stage such as planning, design and construction. In this study, the priorities to be managed mainly were obtained in order to prevent collapse accidents during a open ground excavation. After analyzing results from past accidents cases for open ground excavations, priorities were evaluated regarding collapse-inducing elements using the Delphi technique which is a decision-making method by consensus among experts. As a result, insufficient groundwater treatment, bad geotechnical investigation and instability on construction, etc. were obtained as priorities for prevention of collapse accidents.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.437-442
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• 2001

In Korea, collapse of railway slopes is frequently occurred due to tycoon or heavy rainfall doling rainy season and has been made personal and social damage greatly. In order to evaluate the stability of railway slopes under rainfall, explanatory variables and subordinate variables were selected for multivariate analysis. The sites which failure had occurred due to rainfall were investigated and critical rainfall was defined by the case that had high value of correlation factor after multivariate analyses for 121 cases had been executed. The maximum hourly rainfall during 24 hours before failure caused the collapse of railway embankment and the 0.3 square value of maximum hourly rainfall during 24 hours before failure caused the collapse of railway cut-slope, From the application to collapse examples, it is judged that critical rainfall curve will be used to estimate the stability of slopes.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.202-206
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• 2001

In this study, the risk assessment of small reservoir by collapse using GIS is evaluated. Direct damage distance from collapsed reservoir is estimated by empirical USBR equations and submerged area is calculated by USBR's idea. The amount of damage by collapsed reservoir is figured out by damage assessment of National Institute for Disaster Prevention.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.201-208
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• 2006

This study lotuses on the seismic behavior of 3-, 9-, and 20-story steel moment resisting frame (MRF) structures designed in accordance with the 2000 International Building Code using different Response Modification factors (R factors) 8, 9, 10, 11, and 12. For a detailed case study, 30 different structures were evaluated for twenty ground motions representing the hazard level which is equal to a 2% probability exceeding in 50 years (2% in 50 years). The results showed that the current R factors provide conservative designs for the 3- and 9-story buildings for the Collapse Prevention performance objective. However, the 20-story buildings designed without using the minimum requirement of spectral acceleration CS prescribed in the IBC 2000 did not satisfy the seismic performance for Collapse Prevention performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1483-1491
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• 2004

To assess the integrity of the pipeline is the most important problem to be solved first of all for prevention of any fracture accident of the pipeline. As a result of exerting such efforts, a number of plastic collapse assessment equations have been suggested, however, the scope of using or applying such assessment equations has not been exactly defined. In this study, the case that a surface crack existed in the circumferential direction in the external side of the natural gas pipeline and a bending load was applied to the pipeline was analytically identified as the most critical condition, and a plastic collapse assessment equation fur it was suggested. The flow stress of the API X65 linepipe was defined through the experiment conducted on SENT specimens. Also, a local assessing criterion of a 3-dimensional crack behavior considering not only the crack depth but also the crack length was suggested. Finally, a plastic collapse assessment equation for the API X65 linepipe was developed by performing the 3-dimensional finite element analysis.

• Journal of the Korean Society of Safety
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• v.38 no.3
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• pp.51-60
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• 2023

Investigation of the cause of the relatively recent building collapse accident in Gwangju revealed a lack of awareness about the safety of the dismantling construction system among stakeholders, in the form of issues such as illegal subcontracting, unauthorized design changes, and insufficient safety supervision. This study was conducted to analyze the safety interactions between the building dismantling construction system and the involved stakeholders and to propose ways to prevent accidents in related institutions and workplaces. AcciMap and STAMP-CAST analysis methods were used to evaluate safety interactions among the various stakeholders participating in building demolition work. Analysis results revealed that the collapse accident during the dismantling work was caused not only by structural causes occurring in the construction stage, but also by various causes throughout the system, such as the dismantling plan preparation stage and the construction permit stage. The results also revealed the need for proper implementation of safety control measures by various stakeholders to prevent collapse accidents during dismantling construction.

• Journal of the Korean Geotechnical Society
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• v.31 no.1
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• pp.15-24
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• 2015

This paper presents the results of a reduced-scale physical model investigation into the effect of drilling fluid with different mix designs for bore hole collapse prevention. The bore hole collapse prevention mechanism for the bentonite based drilling fluid was first discussed together with the effect of conditioning with different additives on engineering characteristics of bentonite based drilling fluid. Reduced-scale model tests were then carried out considering field procedures for cases with a decomposed granitic soil with 20% fines and a sand with various drilling fluids with different mix designs. The results indicated that the addition of polymer to the bentonite based drilling fluid decreases the amount of drilling fluid injected, the drilling fluid infiltration thickness and increases the final depth of excavation. Also revealed is that the effect of polymer on the performance of drilling fluid is more pronounced in the decomposed granite soil with 20% fines than the sand. Practical implications of the findings from this study are discussed in great detail.