• Steel and Composite Structures
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• v.17 no.4
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• pp.405-429
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• 2014

In this paper, it is aimed to determine the structural behavior of suspension bridges considering construction stages and different soil conditions. Bosporus Suspension Bridge connecting the Europe and Asia in Istanbul is selected as an example. Finite element model of the bridge is constituted using SAP2000 program considering existing drawings. Geometric nonlinearities are taken into consideration in the analysis using P-Delta large displacement criterion. The time dependent material strength of steel and concrete and geometric variations is included in the analysis. Time dependent material properties are considered as compressive strength, aging, shrinkage and creep for concrete, and relaxation for steel. To emphases the soil condition effect on the structural behavior of suspension bridges, each of hard, medium and soft soils are considered in the analysis. The structural behavior of the bridge at different construction stages and different soil conditions has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. At the end of the analyses, variation of the displacement and internal forces such as bending moment, axial forces and shear forces for bridge deck and towers are given in detail. Also, displacement and stresses for bridge foundation are given with detail. It can be seen from the analyses that there are some differences between both analyses (with and without construction stages) and the results obtained from the construction stages are bigger. It can be stated that the analysis without construction stages cannot give the reliable solutions. In addition, soil condition have effect on the structural behavior of the bridge. So, it is thought that construction stage analysis using time dependent material properties, geometric nonlinearity and soil conditions effects should be considered in order to obtain more realistic structural behavior of suspension bridges.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.140-141
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• 2015

Although the depression of oversea construction market becomes more serious recent years, asian construction market is relatively dynamic, particularly in china. However, few research has been conducted about how to manage construction projects in china as foreign developers. Four important risks are identified from series of surveys using the WBS-RBS method, the result shows that the main risk of tender stage is 'Tender max price error', ' Bill of quantities error', 'Unusual low price' and 'Moral risk' respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.43-50
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• 2022

Even though the structural safety is confirmed in the design stage, the structural safety is not guaranteed in the construction stage because the structural system is not completed. In addition, since the construction period is shorter than the period of use of the building after completion, it is excessive to apply the same seismic load to the construction stage as in the design stage. ASCE 37-14 presents the concept of seismic load reduction factor during construction, but does not provide a clear application method. Therefore, in this study, the seismic load reduced according to the return period was applied to the example model of a residential middle-rise RC building. The construction stage of the example model was divided into five-story units, and seismic load with the change of the return period was applied to the construction stage models to analyze the change of seismic load during construction and to check the sectional performances of structural members. By comparing the design strength ratio of the shear wall at the design stage and the construction stage, the range of seismic load magnitudes that can assure the safety during construction of a residential middle-rise RC building was analyzed in terms of the return period.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.6
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• pp.45-53
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• 2018

The construction work to establish a safety management plan should be carried out Design for Safety(DFS) task by the designers from May 2016 according to the amendment of the Construction Technology Promotion Act. However, designers lack experience in construction work and lack of information on safety accidents, so it is not easy to predict a disaster that may occur during the construction phase. Therefore, the purpose of this study is to provide information about disasters that can occur in each construction work in order to enable designers to efficiently perform DFS task in the design phase. In this study, the construction work was classified by work unit and the disaster risk assessment was conducted using the Failure Mode and Effect Analysis technique. The disaster information by work unit analyzed in this study can be used to provide designers with an alternative to prevent disasters at the design stage. Disaster information by work unit of apartment construction can be used by designers to prepare an alternative for disaster prevention at the design stage.

• Journal of Korean Society of Steel Construction
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• v.29 no.4
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• pp.311-321
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• 2017

This paper deals with the flexural performance of a composite girder system designed to readily form a composite section without a formwork and to easily realize multistage preflexing and prestressing. After a 3-Dimensional finite element modeling for construction stage analysis, the parametric numerical analysis was performed to analyse the stress distribution on the composite girder sections and the prestressing effects along with concrete pouring method and strand tensioning method. Based on the stress distribution analysis, a favorable construction stage model has been rationally chosen and then the ultimate flexural strengths were evaluated to conduct a comparative study, which exceed the nominal flexural strength suggested by the current design specification(ASD). It can be concluded that the proposed composite girder and fabrication procedure should have a sufficient structural performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.3
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• pp.223-230
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• 2005

Lately, massive concrete structures are increasingly built. Mass concrete structures are cast in many stages with construction joints. Individually constructed segment exhibit different heat source properpies and time dependent properties. As such construction stages must be incorporated in a heat of hydration analysis model to truly reflect a real construction process. Thermal stress analysis is conducted to find the way of controlling the thermal crack of pier footing mat in this paper. The footing mat model fur the analysis is $12m\times14m$ area and 3m height. This study show the process of construction stage and analyzes the results for a foundation structure constructed in 2 stage pours.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.209-220
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• 2023

Recently, defects that occurred during the construction of apartment houses have become a social issue. Defects in apartment houses lead to waste of resources and economic loss, causing psychological and physical damage to customers, and a decrease in reliability and financial loss to construction companies. The purpose of this study was to analyze the impact of defect occurrence according to the difference in project management level in the apartment housing construction stage, and to investigate the extent to which the project manager's experience affects the defect occurrence rate. For the empirical analysis of the study, statistical analysis was conducted using data collected from 130 actual projects. The results of the analysis showed that schedule management, cost management, and quality management had a positive effect on reducing the defect occurrence rate in the execution stage of apartment housing construction, while human resource management productivity had a negative effect. This study theoretically demonstrated the importance of project management, and in practice, showed that schedule management, cost management, and quality management should be faithfully performed in the execution stage to reduce the rate of defects after project completion. It was also suggested that hiring an experienced project manager would help reduce project defects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.371-381
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• 2008

The systematic methodology for estimating construction cost approximately at planning and pre-design phase of a river facility construction project has not yet been established because of its unique characteristics including its relatively small project size in terms of cost. This research suggests a 4-level cost information structure and identifies critical factors affecting construction cost as a result of thorough analysis of accumulated historical cost data of river facility construction projects. Also, this research presents the framework of the approximate cost estimating methodology for river facility construction project a planning stage.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.259-260
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• 2016

Recently, world-wide focusing on the interest for the reduction of greenhouse gas emissions associated with climate change and global warming, South Korea also has set up a national greenhouse gas reduction target and action plans seeking to achieve them. In particular, in the construction area, to encourage green building certification of the building and carbon labeling acquisition of building products, in order to reduce the environmental impact caused by the industrial activities have been in steady efforts. Therefore, this study estimates the life cycle carbon footprint of building construction materials applied to carbon emissions reduction technology and analyzes the results. Through the CO₂ emissions analysis in construction phase and maintenance phase of the building, it provides basic resource for future research expansion and establishes a step-by-step whole life cycle carbon emissions reduction plan in new construction and existing buildings.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.694-700
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• 1998

PSC box bridge by MSS construction method may not be set at cross section at one step. Web and bottom flange(U member) would be set at first, top flange will be set later with a time lag. In this case, U member and top flange concrete have different strain history. As two different aged section behaves as the composite section, there would happen the redistribution of stress. This is come from time-dependent strain characteristics of concrete itself. In this study, two models are considered, one with considering the set time of cross section and the other without. By performing longitudinal analysis of two models on considering construction stage, the stress differences of two are compared. As the analysis results show a considerable differences in the stresses of cross section between two models, the set time of cross section is needed for rational design f PSC box girder bridge.