• Title/Summary/Keyword: 강교

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Development of a Simulation Model for Supply Chain Management of Modular Construction based Steel Bridge (모듈러 공법 기반 강교 공급사슬 관리를 위한 시뮬레이션 모형 개발)

  • Lee, Jaeil;Jeong, Eunji;Kim, Sinam;Jeong, Keunchae
    • Korean Journal of Construction Engineering and Management
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    • v.23 no.2
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    • pp.3-15
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    • 2022
  • In this study, we develop a simulation model for Supply Chain Management (SCM) of modular construction based steel bridge. To this end, first, Factory Production/Site Construction system data for the steel bridge construction were collected, and supply chain, entities, resources, processes were defined based on the collected data. After that, a steel bridge supply chain simulation model was developed by creating data, flowchart, and animation modules using Arena software. Finally, verification and validation of the model were performed by using animation check, extreme condition check, average value test, Little' s law test, and actual case value test. As a result, the developed simulation model appropriately expressed the processes and characteristics of the steel bridge supply chain without any logical errors, and provided accurate performance evaluation values for the target system. In the future, we expect that the model will faithfully play a role as a performance evaluation platform in developing management techniques for optimally operating the steel bridge supply chain.

Analysis of Productivity Differences in Steel Bridge Manufacturing Plants According to Resource Allocation Methods for the Bottleneck (병목공정 자원할당 방식에 따른 강교 제작공장 생산성 차이 분석)

  • Lee, Jaeil;Jeong, Eunji;Jeong, Keunchae
    • Korean Journal of Construction Engineering and Management
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    • v.24 no.2
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    • pp.37-49
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    • 2023
  • In this study, we proposed resource allocation methodologies to improve the productivity of steel bridge manufacturing plants based on the constraint theory which is very popular in the area of manufacturing industries. To this end, after defining the painting process as a bottleneck, three resource allocation methodologies were developed: Operation Specific Resource Allocation (OSRA), Product Specific Resource Allocation (PSRA), and General Resource Allocation (GRA). As a result of experiments for performance evaluation using a simulation model of the steel bridge supply chain, GRA showed the best performance in terms of the Number of Work-In-Process (NWIP) and Waiting Time (WT), in particular, as workload itself and its variability were increased, the performance gap with the specific resource allocation became further deepened. On average, GRA reduced NWIP by 36.2% and WT by 34.6% compared to OSRA, and reduced NWIP by 71.0% and WT by 70.4% compared to PSRA. The reduction of NWIP and WT means alleviating the bottleneck of the painting process, which eventually means that the productivity of the steel bridge manufacturing plant has improved.

Improving Fatigue Strength of Weld Joints by Blast Cleaning used in Painting Steel Bridge (강교 도장용 블라스트 표면처리에 의한 용접이음의 피로강도 향상)

  • Kim, In-Tae;Jung, Young-Soo;Lee, Dong-Uk
    • Journal of Korean Society of Steel Construction
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    • v.23 no.2
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    • pp.137-146
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    • 2011
  • In the fabrication of steel bridges, blast cleaning prior to painting is carried out on the steel members to clean the forged surface and to increase the adhesive property of the applied painting systems. The effect of blast cleaning on the fatigue strength improvement of the weld joints, however, is not clear. In this study, Almen strips and steel specimens were blast-treated, conforming to ten types of blast-cleaning conditions deducted from the blast-cleaning conditions of seven steel structure fabrication companies. The arc height, roughness, hardness, and compressive residual stress were measured before and after the implementation of the ten blast-cleaning methods, and the relationship between the blast conditions and the measured values was studied. The geometry of the weld toe and the compressive residual stress near the weld toe were also measured before and after the blast cleaning of the butt-welded joints, and fatigue tests were carried out on the butt weld joints. The test results showed that blast cleaning significantly increases the fatigue strength and limit.

Service Life Prediction for Steel Bridge Coatings with Type of Coating Systems (도장계 종류에 따른 강교 도장의 공용수명 예측)

  • Lee, Chan Young;Chang, Taesun
    • Journal of Korean Society of Steel Construction
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    • v.28 no.5
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    • pp.325-335
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    • 2016
  • To predict service life of coating systems registered in Korean specifications for steel bridge coatings, field deterioration evaluation and accelerated weatherproof test were carried out, and deterioration models were drawn through regression analysis for evaluation results. For the coating systems that have not been used in field, regression analyses were carried out for the virtual evaluation results drawn by applying coordination factor to the field evaluation results for chlorinated rubber and urethane topcoat system. Service life prediction results showed that application of thermal sprayed coating (TSC) could extend service life of coatings to more than twice of general coatings.

Improvement of Blast Efficiency by Correlation Analysis of Impella Blast and Steel Balls for Surface Treatment of Steel Bridges (강교 보수도장의 표면처리를 위한 임펠라 블라스트와 스틸볼의 상관관계 분석을 통한 블라스트 효율 향상)

  • Chang, Byoung Ha;Jang, Dong Wook;Seo, Myoung Kook;Lee, Ho Yeon;Park, Jae Hyun
    • Journal of Drive and Control
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    • v.19 no.1
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    • pp.8-15
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    • 2022
  • The demand for the re-painting of steel bridges is increasing, but surface treatment is still centered on human resources for on-site re-painting processes. Worker safety accidents continue to occur because the work is performed in a narrow space. Recently, PS balls with excellent surface treatment have been used for blasting, but the working environment is poor due to the large amount of dust generated. In this study, an effective surface treatment method using impeller blasting equipment was developed. The correlation between steel ball size, impeller rotation speed, and exposure time was studied to optimize the efficiency of the surface treatment.