• Safety and Health at Work
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• v.11 no.1
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• pp.1-9
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• 2020

Background: As the impact of climate change intensifies, exposure to heat stress will grow, leading to a loss of work capacity for vulnerable occupations and affecting individual labor decisions. This study estimates the future work capacity under the Representative Concentration Pathways 8.5 scenario and discusses its regional impacts on the occupational structure in the Republic of Korea. Methods: The data utilized for this study constitute the local wet bulb globe temperature from the Korea Meteorological Administration and information from the Korean Working Condition Survey from the Occupational Safety and Health Research Institute of Korea. Using these data, we classify the occupations vulnerable to heat stress and estimate future changes in work capacity at the local scale, considering the occupational structure. We then identify the spatial cluster of diminishing work capacity using exploratory spatial data analysis. Results: Our findings indicate that 52 occupations are at risk of heat stress, including machine operators and elementary laborers working in the construction, welding, metal, and mining industries. Moreover, spatial clusters with diminished work capacity appear in southwest Korea. Conclusion: Although previous studies investigated the work capacity associated with heat stress in terms of climatic impact, this study quantifies the local impacts due to the global risk of climate change. The results suggest the need for mainstreaming an adaptation policy related to work capacity in regional development strategies.

• Geomechanics and Engineering
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• v.35 no.1
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• pp.41-54
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• 2023

The use of a skirt, a vertical projection attached to the footing, is a recently developed method to increase the bearing capacity of soils and reduce foundation settlements. Most of the studies were focused on vertical skirted circular footings resting on clay while neglecting the rigidity and inclination of skirts. This study employs finite element limit analysis to investigate the bearing capacity enhancement of flexible and rigid inclined skirts in cohesionless soils. The results indicate that the bearing capacity initially improves with an increase in the skirt inclination but subsequently decreases for both flexible and rigid skirts. However, the rigid skirt exhibits more apparent optimum skirt inclination and bearing capacity enhancement than the flexible one, owing to differences in their failure mechanisms. Furthermore, the bearing capacity of the inclined skirted foundation increases with the skirt length, footing depth, and internal friction angle of the soil. In the case of rigid skirts, the bearing capacity increases linearly with skirt length, while for flexible skirts, it reaches a stable value at a certain skirt length. The efficiency of the flexible footing reduces as the footing depth and soil internal friction angle increase. Conversely, the efficiency of the rigid skirt decreases only with an increase in the depth of the footing. The paper also presents a detailed analysis of various failure patterns, highlighting the behaviour of inclined skirted footings. Additionally, nonlinear regression equations are provided to quantify and predict the bearing capacity enhancement with the inclined skirts.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.487-496
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• 2022

Most of the pile's vertical static load tests in construction sites are the proof load tests, which is difficult to accurately estimate the ultimate bearing capacity and analyze the reliability of piles. Therefore, a reliability analysis method based on the proof load-settlement (Q-s) data is proposed in this study. In this proposed method, a simple ultimate limit state function based on the hyperbolic model is established, where the random variables of reliability analysis include the model factor of the ultimate bearing capacity and the fitting parameters of the hyperbolic model. The model factor M = R_uR / R_uP is calculated based on the available destructive Q-s data, where the real value of the ultimate bearing capacity (R_uR) is obtained by the complete destructive Q-s data; the predicted value of the ultimate bearing capacity (R_uP) is obtained by the proof Q-s data, a part of the available destructive Q-s data, that before the predetermined load determined by the pile test report. The results demonstrate that the proposed method can easy and effectively perform the reliability analysis based on the proof Q-s data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.161-168
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• 2002

To evaluate seismic performance of bridges, two procedures far capacity spectrum method are presented. The capacity spectrum procedures include the reduction factor-ductility-period relationship in order to construct the inelastic demand spectra from the elastic demand spectra. Application of the procedures is illustrated by example analysis. Maximum displacements estimated by the procedures are compared to those by inelastic time history analysis for several artificial earthquakes. The results show that the maximum displacements estimated by the procedures are, on overall, smaller than those by the inelastic time history analysis

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.69-76
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• 2016

OBJECTIVES : The objective of this study is to propose a capacity analysis methodology for riverside bike-exclusive roads. METHODS : Three steps were performed to develop a methodology to estimate bikeway capacity. First, we reviewed previous studies on the vehicle-road capacity analysis and proposed their applicability to bikeways. Second, two assumptions were made based on the traffic flow characteristics of bikeways: (1) the capacitated state in bikeways occur within a bicycle platoon, and (2) a bicycle platoon consists of more than three bicycles running in close proximity. In addition, it is assumed that the mean time headway of a bicycle platoon represents the characteristics of the platoon. The normality of the mean-time headway of a bicycle platoon calculated using the central limit theorem leads to the development of a method that estimates the riverside bikeway capacity using data collected from two different riverside bike-exclusive roads (Han-river and Anyangcheon). We used a location-fixed video camera to record videos of running bicycles and wrote a special-purpose software program to code the time-headway data from the videos. RESULTS : Time headways from 189 bicycle platoons were analyzed. The estimated mean-time headway of the capacitated bicycle flow is 1.01 s, from which the capacity of the bikeway is found to be 3578 vehicles/h. CONCLUSIONS : The proposed method that estimates bikeway capacity could be applicable to the analysis of short-range congested area rather than planning the number of lanes. In other words, it determines the sections that are temporarily highly congested and proposes appropriate strategies to mitigate the congestion.

• Journal of Korean Society of Transportation
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• v.17 no.3
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• pp.87-96
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• 1999

It is very important to analyze the capacity of basic freeway section in terms of planning, design, and operation of roads. Capacity, in Korean Highway Capacity Manual was Published in 1992, had been determined by data collected in only 4-lane freeway. But, Korea is continuously planning and constructing multi-lane roads for increasing traffic demand. For this reason, it is necessary to determine the capacity for multi-lane freeways. This study goals are two-fold the determination of lane capacity for 8-lane freeway; and the development of methodology determining total capacity using lane friction factor This study utilized the data collected by loop detectors at a station of FTMS in Kyungbu expressway. For determining capacities, this study analyzed maximum flow rate in various aspects such as collecting period, each lane, and total lane in one-way. In addition, this study evaluated the breakdown in traffic flow relations in order to find out interrelation of breakdown among lanes. Through this analysis, this study determined lane friction factors, critical speed, and critical density. Finally, this study expressed a new methodology of capacity analysis for multi-lane freeways using some findings from this analysis.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.2
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• pp.169-187
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• 2008

Performance-based approaches as an alternative method of the existing force-based approach have gradually become recognized tools for the seismic design and evaluation. The maximum inelastic displacement response using capacity spectrum method (CSM) with elastic response spectrum is estimated from seismic response of equivalent linear system converted from nonlinear system. The purpose of this paper is to evaluate accuracy of capacity spectrum method using the equivalent SDOF methods of 4 types and the equivalent damping methods of 5 types for RC wall structure. In order to evaluate accuracy of capacity spectrum analysis, the shaking table test results for RC wall structures are compared with those by the capacity spectrum analysis. Also, the effect of bilinear capacity curves by two bilinear approximation methods for capacity spectrum analysis is compared.

• Journal of the Korea Safety Management & Science
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• v.7 no.4
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• pp.207-217
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• 2005

Line capacity calculation has been used to determine optimum efficiency and safe train service for train scheduling plan and investment priority order throughout detecting bottleneck section. Because of some problems of Yamagisi and UIC methods for line capacity calculation, developing of the method of line capacity caculation and evaluation for the Korea circumstance is important. This paper deals with the reliability improvement on the integrated system of TPS(Train Performance Simulator), PES(Parameter Evaluation Simulator), LCS(Line Capacity Simulator) and simulation and sensitivity analysis for line capacity.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.420-429
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• 2009

This study concerns bearing capacity of shallow and deep foundations on jointed rock mass. The main focus of this research lies on getting insight into the applicability of bearing capacity estimation methods developed by other researchers. First, an extensive literature review was performed on previous studies concerning bearing capacity of foundation on jointed rock mass. Second, a parametric study on a number of jointed rock conditions using the finite-element analysis. The results of the analysis were then compared with those computed by the bearing capacity estimation method.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1012-1017
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• 2008

In this study, We examine closely the capacity spectrum method which a kind of displacement-based method evaluated by displacement of structure as an alternative to the load-based analysis method. The displacement-based method can easily review the strength of structure, seismic performance, ductility. Seismic performance by using capacity spectrum method is divided into design response spectrum and capacity spectrum. We can diagram design response spectrum by deciding the design seismic factor depending on performance target, site classification, seismic level, return period as UBC-97. Capacity spectrum is a load-displacement curve obtained by Push-over analysis considering the geometric parameter and the material parameter. We execute the seismic performance evaluation by using the capacity spectrum method to reinforced concrete pier which has been seismic design. As a result, We confirmed that there is a yield point and a ultimate point close by design response spectrum of UBC-97.