• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.597-604
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• 2012

The present study assessed the $CO_2$ emissions of concrete according to the type and replacement ratio of supplementary cementitious materials (SCM) and concrete compressive strength using a comprehensive database including 2464 cement concrete specimens and 776 cement concrete mixes with different SCMs. The system studied in $CO_2$ assessment of concrete based on Korean lifecycle inventory was from cradle to pre-construction, which includes consistent materials, transportation and production phases. As the performance efficiency indicators, binder and $CO_2$ intensities were analyzed, and simple equations to evaluate the amount of $CO_2$ emission of concrete were then formulated as a function of concrete compressive strength and the replacement ratio of each SCM. Hence, the proposed equations are expected to be practical and useful as a guideline to determine the type and replacement ratio of SCM and unit content of binder in concrete mix design that can satisfy the target compressive strength and $CO_2$ reduction percentage relative to cement concrete.

• Journal of the Society of Disaster Information
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• v.14 no.4
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• pp.409-420
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• 2018

Purpose: The purpose of this study is to present improvement measures for enhancing practicality through case analysis of Inner and Outer-Temporary Housing. Method: First, the basic functions and types of Temporary Housing, were discussed through prior research analysis. Second, a practicality problem was derived by analyzing cases of Temporary Housing. Third, improvement measures were proposed to ensure the practicality of Temporary Housing based on the problems identified. Results: Factors such as habitability, economics, construct ability and operation methods that should ultimately be improved in Temporary Housing, and these elements were divided into production, transportation, construction, and storage according to the life cycle, suggesting matters to be improved in order to improve practicality at each stage. Conclusion: The proposed improvements are considered to help develop inner and outer-temporary housing.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.727-736
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• 2009

Many of the researchers have tried to enhance the satisfaction of both users and owners of social infrastructures by applying the asset management methodology. This study is to develop more efficient asset management framework for bridge management. Based on various literature review, an asset management procedure for bridge management was suggested, and appropriate practices at each step were given. The suggested procedures include the determination of operation and maintenance strategy, level of service, performance measure, valuation of assets, and decision-makings. In addition, this study suggests an applicable decision-making process for the resource distribution based on the management strategy.

• Korean Journal of Construction Engineering and Management
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• v.16 no.6
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• pp.41-52
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• 2015

The number of military facilities has been rapidly increased due to growing requirement of modernization and military welfare. However, adequate maintenance has not implemented to these facilities. As a result, they are deteriorated quickly and require performance enhancement treatments. There are two ways of performance enhancement, reconstruction and remodeling. Despite the research result that remodeling within the standard remodeling range is more economical, remodeling of military facilities is not considered equivalent to reconstruction as an option of performance improvement. Therefore, derived from the relationship between performance change during life cycle of building and range of remodeling needs, this study tries to propose Remodeling Process Model(RPM) which uses a method to choose remodeling in a Specific Point of Time(SPT) when remodeling is considered more economical than reconstruction. In addition, this study suggests practical service life and functionality evaluation standard together which require to realize the RPM. This RPM make it possible to avoid the cases that facilities which do not have any problem on structural reliability but have low level of functionality miss appropriate remodeling timing and inevitably choose reconstruction as a performance improvement option. It also present the possibility of simple reconstruction / remodeling decision-making for facility managers who administrate building having various type, compilation and elapsed time. Consequently, this process model focusing on remodeling more may contribute to reduce resource waste caused by reconstruction.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.89-99
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• 2022

Bridges are a key infrastructure that underpins economic and social activities. In Korea, bridges began to be built with economic development in the 1970s and were built intensively in the 1980s and 1990s. In recent years, as the number of bridges with a service life of more than 30 years is increasing, continuous maintenance is required to ensure the safety of the bridges. In particular, in order to cope with the aging of bridges, research on technology development such as maintenance using ICT technology, preventive maintenance, life cycle cost reduction, and long life bridge is being actively promoted. This paper presents the results of correlation analysis based on the safety evaluation data of bridges as part of the research on the development of a model for estimating load-carrying capacity of bridges. As a analysis result, indicators highly correlated with the load-carrying capacity of the bridge was derived.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.9-18
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• 2020

Recently, studies of integrated management platform and performance-based maintenance decision-marking systems have proceeded to the efficient management of port facilities. The purpose of this study was to manage and operate port facilities based on performance and to provide long-term durability and budgetary execution. Thus, it is essential to secure basic data to be analyzed in an integrated platform and decision-marking system. This study derived the data linkage measures to secure port facility design and management information. The target of deriving the data linkage was the POMS (Port Facility Management System) currently in operation by the MOF (Ministry of Oceans and Fisheries). To derive data linkage, analyze the database of POMS and select the data required for the operation-integrated platform and decision-marking system. The final data linkage target was determined by compiling the requirements of the relevant experts and selecting the final target of three groups (port and facility information, management information, and user information). As a result, the API interface design was prepared for detailed linked data and data linkage framework between the linkage data of POMS. The provision of real-time data linkage between POMS and integrated platform is expected to improve the operational efficiency of the integrated platform.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.254-260
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• 2017

The service life of civil infrastructure needs to be maintained or extended through appropriate inspections and maintenance planning, which results from the optimization process. A multi-objective optimization process can lead to more rational and flexible trade-off solutions rather than a single-objective optimization for the service life management of civil infrastructure. Recent investigations on the service life management of civil infrastructure were generally based on minimizing the life-cycle cost analysis and maximizing the structural performance. Various objectives for service life management have been developed using novel probabilistic concepts and methods over the last few decades. On the other hand, an increase in the number of objectives in a multi-objective optimization problem can lead to difficulties in computational efficiency, visualization, and decision making. These difficulties can be overcome using the objective reduction approach to identify the redundant and essential objectives. As a result, the efficiency in computational efforts, visualization, and decision making can be improved. In this paper, the multi-objective optimization using the objective reduction approach was applied to the service life management of concrete bridges. The results showed that four initial objectives can be reduced by two objectives for the optimal service life management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.751-762
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• 2022

Welded head studs are mainly used as shear connectors to bond steel girders and concrete slabs in steel-concrete composite bridges. For welded shear connectors, environmental problems include noise and scattering dust which are generated during the removal of damaged or aged slabs. Therefore, it is necessary to develop demountable shear connectors that can easily replace aged concrete slabs for efficient maintenance and thus for better management of environmental problems and life cycle costs. The buried nut method is commonly studied in relation to bolted shear connectors, but this method is not used in civil structures such as bridges due to low rigidity, low shear resistance, and increased initial slip. In this study, in order to mitigate these problems, a demountable bolted shear connector is proposed in which the buried nut is integrated into the stud column and has a tapered shape at the bottom of an enlarged column shank. To verify the performance of the proposed demountable stud bolts in terms of static shear strength and slip displacement, a horizontal shear test was conducted, with the performance outcomes compared to those of conventional welded studs. It was confirmed that the proposed demountable bolted shear connector is capable of excellent shear performance and that it satisfies the slip displacement and ductility design criteria, meaning that it is feasible as a replacement for existing welding studs.

• Journal of the Korean Society for Environmental Technology
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• v.19 no.6
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• pp.576-585
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• 2018

Systematic management during the whole life cycle from construction to operation and maintenance is very important for the seven underground pipelines (waterworks, sewerage, electricity, telecommunications, gas, heating, oil including waterworks and sewerage). Especially, it is the construction process that affects the whole life cycle of underground buried pipeline. In order to construct a new city or to maintain different underground pipes, it is always necessary to dig the ground and carry out construction and related work. There is a possibility that secondary and tertiary breaks frequently occur in the pipeline construction process after the piping constructed first in this process. To solve this problem, a system is needed which can monitor damage in real time. However, the supply of electric power for continuous operation of the system is limited according to the environment of underground buried pipelines, so it is necessary to develop a stable electric power supply system using natural energy rather than existing electric power. In this study, we developed a system that can operate the pipeline monitoring system for long time (24 hours and 15 days) using natural energy using wind and solar light.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.262-268
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• 2017

The energy consumption of buildings is approximately 20.5% of the total energy consumption, and the interest in energy efficiency and low consumption of the building is increasing. Several studies have performed energy analysis and evaluation. Energy analysis and evaluation are effective when applied in the initial design phase. In the initial design phase, however, the energy performance is evaluated using general level information, such as glazing area and surface area. Therefore, the evaluation results of the detailed design stage, which is based on the drawings, including detailed information of the materials and facilities, will be different. Thus far, most studies have reported the analysis and evaluation at the detailed design stage, where detailed information about the materials installed in the building becomes clear. Therefore, it is possible to improve the accuracy of the energy environment analysis if the energy environment information generated during the life cycle of the building can be established and accurate information can be provided in the analysis at the initial design stage using a probability / statistical method. On the other hand, historical data on energy use has not been established in Korea. Therefore, this study performed energy environment analysis to construct the energy environment historical data. As a result of the research, information classification system, information model, and service model for acquiring and providing energy environment information that can be used for building lifecycle information of buildings are presented and used as the basic data. The results can be utilized in the historical data management system so that the reliability of analysis can be improved by supplementing the input information at the initial design stage. If the historical data is stacked, it can be used as learning data in methods, such as probability / statistics or artificial intelligence for energy environment analysis in the initial design stage.