• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.61-68
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• 2010

The collapsing accidents of pipe greenhouses in the farmhouse have been increased duo to heavy snow load. However, the study on exact structure analysis to prevent the collapse of pipe greenhouses is rare and the damage of the farmhouse is annually repeated. The method of existing structure analysis is basically made of linear elastic analysis based on the micro displacement. But the actual stiffness of the pipe greenhouse is significantly weaker than the stiffness of buildings and the load acting on the greenhouses gets to become relatively bigger. It means that the geometry shape of greenhouses changes so that the relation of strain-displacement gets to indicate a nonlinear behavior. Therefore, this study is performed to evaluate the structural safety so as to prevent the collapse of pipe greenhouses, which are the single-span greenhouse(farmhouse guidance shape, G) and multi-span greenhouse(farmhouse supply shape, 1-2W), by performing the large-displacement analysis considering nonlinear effects.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.98-104
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• 2018

Nondestructive strength Equations are commonly used to determine the strength of concrete. However, the application of the existing equations may include many errors because this method is proposed on the basis of limited experimental parameters while actual bridges have various parameters such as conditions of concrete mixtures, properties of concrete strength, etc. Also, the error among the existing equations causes the confusion when engineers select the proper estimation equation for the concerned bridge. In this study, a series of the field inspection and the test have been performed on 297 existing bridges, in order to evaluate the bridges, based on the test results of the in-depth inspection, and the estimated strengths by means of the nondestructive strength equations are analyzed and compared with results of the core specimen strengths. According to results of analyses, the nondestructive strength equation proposed by CNDT Committee of Architectural Institute of Japan had high relationship with core strength. However, the strengths predicted by this equation, are underestimated when concrete's strengths are over 30 MPa, otherwise, they are overestimated. Also in this paper, based on the relationship between the estimated nondestructive concrete strengths and the core specimen strengths the modified strength equation through simple correlation analysis is proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.141-148
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• 2021

In this study, the technology to prevent lateral deformation of steel dampers was reviewed and applied to the clamp type dampers. As for the experimental method, the rocking behavior was applied as in the previous study. The evaluation variables are the existing research results (SV-260) without lateral deformation prevention details and the test results (V-1, V-1R) with lateral deformation prevention details. Where, V-1 is the lateral deformation prevention detail at the lower part of the damper, and V-1R is the lateral deformation prevention detail at the lower part and upper part of the damper. As a result of evaluating the moment, drift ratio, and energy dissipation capacity relative to SV-260 at the time of maximum load, the maximum moments of V-1 and V-1R were increased by 1.22 times and 1.36 times compared to SV-260, and the maximum drift ratio increased by 2.41 times and 2.92 times. In addition, the energy dissipation capacity also increased by 1.39 times and 1.52 times, respectively. Therefore, the application of lateral deformation prevention details to the steel damper was evaluated as appropriate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.66-73
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• 2022

In this study, the experimental results of 7 dampers with the same strut height and similar cross-sectional area were compared based on the existing research results on steel dampers with rocking behavior. As steel plate dampers, SI-260, SV-260, SS-260 without Lateral deformation prevention detail(Ldpd), I-1, V-1, S-1 with Ldpd, and R20-260 with steel rod damper were evaluated. In addition, R15-260, which has a cross-sectional area of 0.56 times than other dampers, was also reviewed to appropriately evaluate the behavior of the steel rod damper. An important study result is the application superiority of the steel rod damper, which improved the unidirectional behavior of the steel plate dampers. This was proved in the moment-resistance capacity and displacement ratio evaluation. As a result of the evaluation, the R20-260, a steel bar damper, was evaluated as having the best performance. In addition, it is judged to have sufficient seismic resistance as it shows deformability up to a displacement ratio of 2.0.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.152-152
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• 2020

가뭄은 장기간에 걸쳐 광범위하게 발생하는 특징으로 인해 자연재해뿐만 아니라 사회·경제적으로도 큰 피해를 야기한다. 즉, 가뭄으로 인한 댐의 용수 공급 부족은 공업·농업뿐만 아니라 국민들의 생활에도 상당한 피해를 미친다. 하지만, 가뭄으로 인한 지역의 피해정도는 해당 지역의 특성 또는 가뭄에 대한 지역의 대처 능력에 따라 매우 상이하게 나타난다. 따라서, 가뭄에 의한 피해를 저감시키고 안전한 용수공급이 이루어질 수 있도록 지역의 특성 및 용수 공급 체계를 고려한 위험 정도를 분석하는 것이 필요하며, 사람들과 직접적인 연관성이 높은 물수급 관련 인자들을 고려하여 가뭄의 잠재적 영향 및 피해정도를 파악할 수 있는 가뭄 위험도 평가가 수행되어야 한다. 그러나 용수공급 및 수요 현황을 반영한 가뭄 노출성 및 취약성 평가는 아직 부족한 실정이며, 각 인자에 대한 가중치를 산정하는데 설문조사 또는 단순평균방법이 많이 이용되고 있다. 본 연구에서는 용수공급 체계 및 지역적 특성을 고려하고 객관적인 가중치 산정방안이 적용된 확률·통계적 가뭄 위험도를 평가방법을 제시하였다. 먼저, 용수공급 실패 사상의 발생 확률이 적용된 결합가뭄관리지수(Joint Drought Management Index, JDMI)를 통해 가뭄노출성지수(Drought Hazard Index, DHI)를 산정하고, 각 인자에 대한 영향정도를 객관적으로 판단할 수 있는 가우스 혼합 모델을 활용하여 가뭄취약성지수(Drought Vulnerability Index, DVI)를 산정하였다. 이 두 지수를 결합하여 가뭄위험도지수(Drought Risk Index, DRI)를 계산하고 위험도 평가를 수행하였다. 충청지역에 적용한 결과, DHI는 용수공급 실패 사상의 발생확률이 큰 보령시가 가장 높게 나타났으며, DVI는 농업적 요소의 가중치가 크게 산정됨에 따라 청주시가 가장 높게 산정되었다. DHI와 DVI가 결합된 DRI의 경우는 청주시가 가장 위험한 것으로 나타났다. 따라서, DRI가 가장 높은 청주시는 충정 지역의 가뭄 위험 경감을 위한 대응 수립시 우선적으로 고려되어야 한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.129-138
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• 2006

Composite deck plate using a pre-assembled re-bar truss for slab with corrugated zinc galvanized sheet iron at manufactory, is given the improvement on design, manufacture, and performance for construction work of cast-in-place reinforced concrete slab by enabling to cast concrete directly without the form work. There are two methods in analyzing composite deck : Simplified 2D analysis and 3D analysis. Although simplified 2D analysis is being used up to date, the use of 3D analysis, allowing for the vierendeel behavior of composite deck by real configuration correlating to bar reducing, is demanded. To compare the simplified 2D analysis applied to allowable stress design with 3D analysis applied to limit state design, 8 specimen are manufactured. Main variables include the depth of slab, the length of span, the diameter of bottom bar and lattice bar, and the presence of corrugated zinc galvanized sheet iron. The comparison from the experimental result and analytical result indicates that applying of simplified 2D analysis is possible for the use of D10 with bottom bar. However, it is more reasonable to apply 3D analysis which allows to indicate vierendeel behavior considered the real configuration.

• Fire Science and Engineering
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• v.31 no.6
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• pp.67-73
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• 2017

An aircraft maintenance hangar is a building that stores, maintains, and inspects expensive aircraft. The frequency of fire occurrence is low, but the resulting human and material damage can be very serious. Therefore, in this study, we conducted a qualitative analysis of the fire safety of the currently operating fire suppression systems for aircraft maintenance hangars using the Fault Tree method, and then performed a quantitative analysis using the failure rate data for the derived basic events and analyzed the importance of the minimal cut sets. As a result of the qualitative analysis by the minimal cut set, it was found that there were 14 accident paths that could be expanded to a large fire, due to the fire control failure of the aircraft hangar fire suppression system. The quantitative analysis revealed that, the probability of the fire expanding into a large one is $2.08{\times}E-05/day$. The analysis of the importance of the minimal cut set shows that four minimal cut sets, namely the fire detector and foam head action according to the zone and blocking of the foam by the aircraft wing and the fire plume, had the same likelihood of causing the fire to develop into a large one, viz. 24.95% each, which together forms the majority of the likelihood. It was confirmed for the first time by fault tree method that the fire suppression system of aircraft maintenance hangars is not suitable for fires under the aircraft wings and needs to be improved.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.69-77
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• 2015

In Korea, local governments have decided the location of shelters as part of their disaster planning. However, no quantitative standards, such as assuming different hazard and shelter types, shelters' capacity, are specified in that planning. To propose the direction of disaster evacuation policy, first of all, the current state of shelters' location and evacuation area is needed to be analyzed. In addition, considering topographical condition such as road slope and physical strength by age are important factors to measure optimal evacuation route. The purpose is to suggest a new methodology of estimating optimal evacuation route considering resistance of road slope and difference of walking speed by age. Moreover, as a case study of Seoul, Korea, using coverage analysis of GIS analysis tool, the accessible area (or vulnerable area) to the shelters is evaluated based on the spatial distribution of disaster evacuation shelters and their accommodation capacity, according to evacuation time within 7.5, 15 and 30 minutes. The main results are summarized as follows: 1) The average area of disaster evacuation shelter per person is calculated as 0.45 square meters. Considering that the minimum shelters' area per person is 1 square meters, only 45% of people in Seoul can be accommodated. 2) The ratio of inhabitants who live in accessible area within 7.5 minutes presents only 33% of all. Furthermore, the ratio of inhabitants by age group of 5~9 or over 65 years old shows significantly lower percentage in comparison with 15~49 years old people.

• Journal of the Korea Institute of Building Construction
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• v.10 no.6
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• pp.127-135
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• 2010

As logistics facilities have a high ceiling height, simple structure, and the need for a quick return on investment, it is usually essential to advance the construction schedule of such facilities. Accordingly, PC structures, which require less labor, cost and schedule, can be more competitive than RC structures. However, most construction companies in Korea are familiar with RC structure design, have negative perceptions regarding PC structures, and do not sufficiently adopt new construction techniques. The structure that this research features has 110 columns that are 14 m high and are built to the same specification, and applying an RC design to the structure will lead to issues related to constructibility, economic viability, project duration and safety. Therefore, this study intends to feature PC design as an alternative to the RC warehouse design, and perform a comparative analysis of the reduction in labor, cost and construction schedule to highlight benefits. The research outcomes herein will provide inputs to subsequent studies on new construction strategies to advance the construction schedule, improve quality and constructibility, enhance safety and save costs.

• Korean Journal of Construction Engineering and Management
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• v.19 no.3
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• pp.11-22
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• 2018

Existing efforts to reduce total egress time actually focused on reducing travel time. However, consideration to reduce perception time or response time was insufficient although the ratio of travel time is one-third of total egress time and situations which the safety cannot be ensured by only reducing travel time were aroused. Therefore, the concept of disaster information, which could reduce both perception time and response time got attention To analyze the effect of disaster information on occupant behaviour, this study identified a relationship between 10 major disaster information and 3 occupant behaviour factors in terms of reducing egress time. By referring the relationship, this study conducted an virtual egress experiment with survey on 4 cases, the elderly, intellectual disabled, hearing disabled and visual disabled, to identify disaster information which reduce total egress time effectively. Finally, by analyzing the experiment result, this study proposed the process of disaster information effect on occupant behaviour as complementing insufficient occupant behaviour to ensure the minimum level of safety and maximizing relatively high occupant behaviour to ensure enough level of safety. The results are expected to account for relationship between disaster information and occupant behaviour with more explanatory power in terms of egress time. With further studies of disaster information and group behaviour, these series of studies could provide basic references for disaster information and occupant behaviour.