• Steel and Composite Structures
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• v.52 no.2
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• pp.199-215
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• 2024

The Caynarachi Bridge is a 130 m long posttensioned steel-concrete composite bridge built in Peru. The structural performance of this bridge under construction loads is reviewed in this paper using numerical simulation. Hence, a numerical model using shell finite elements to trace its deformational behavior at service conditions is proposed. The geometry and boundary conditions of the superstructure are updated according to the construction schedule. Firstly, the adequacy of the proposed model is validated with the field measurements obtained from the static truck load test. Secondly, the study of other scenarios less explored in research are performed to investigate the effect of some variables on bridge performance such as time effects, sequence of execution of concrete slabs and type of supports conditions at the abutments. The obtained results show that the original sequence of execution of the superstructure better behaves mechanically in relation to the other studied scenarios, yielding smaller stresses at critical cross sections with staging. It is also demonstrated that an improper slab staging may lead to more critical stresses at the studied cross sections and that casting the concrete slab at the negative moment regions first can lead to an optimal design. Also, the long-term displacements can be accurately predicted using an equivalent composite resistance cross section defined by a steel to concrete modulus ratio equal to three. This article gives some insights into the potential shortcomings or advantages of the original design through high-fidelity finite element simulations and reinforces the understating of posttensioned composite bridges with staging.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.157-163
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• 2016

BIM is currently applied in some domestic construction firms, but it is not being actively utilized due to changes in working environments and qualms about new studies. In order to utilize a BIM model in the design phase, process information is needed during construction, but the input system and utilization method of the process information's state are not complete. Therefore, we propose a BIM template for construction progress management that can show basic BIM information as the construction progresses in an easy and convenient way. This method will facilitate the adoption of BIM and enhance the productivity of construction companies. To this end, we designed a progress explorer for step-by-step progress and work schedules, and we generated three-dimensional views and a progress list by applying unit information (primary units, part units, and detail units) of the work breakdown structure (WBS) to the parameters. To use the BIM template, work progress information is input to the BIM modeling objects through Dynamo. We also used Dynamo for quick and easy calculation of the quantity of materials needed for construction work. To test the BIM template, we applied it to an actual project and evaluated its visibility and a progress list. The results showed that the proposed BIM template facilitates progress management of a project and can thus facilitate the adoption of BIM and improve the productivity of construction companies.

• Tunnel and Underground Space
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• v.19 no.4
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• pp.275-286
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• 2009

In order to establish the causes and measures for technical risks that occur in various ground conditions when a subsea tunnel is excavated, it is important to configure expected risk scenarios. In addition, when the risk scenarios are classified because the scenario that occurs along all tunnel route and the scenario limited to some area are considered together, a logical framework with systematic and organized responses can be provided for project managements. In this research, project risk scenarios and management elements were configurated, and the project schedule was established for the management techniques to the risk scenario. The risk scenarios expected in a subsea tunnel were classified into a common risk scenario and a special risk scenario, and the concept which can combine with the project management elements was derived.

• Journal of Korea Port Economic Association
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• v.33 no.2
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• pp.83-96
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• 2017

As a way to address global warming, among the renewable energy sources, there have been heavy investments worldwide for the development of offshore wind farms. However, such development has a drawback: investment costs are higher than those for onshore wind farms due to required operations such as offshore transportation and installation. In particular, delays in installation due to adverse maritime weather conditions are factors that affect the economics of offshore wind farms' operation. Therefore, in this study, we analyze the optimal schedule of the construction of an offshore wind farm from a macro perspective by considering the weather conditions in Korea. For this purpose, we develop a mathematical model and apply it to a 2.5 GW offshore wind farm project on the southwestern coast of the country. We use data from the Korea Meteorological Agency for maritime weather conditions and attempt to reflect the actual input data based on precedent cases overseas. The results show that it takes 6 months to install 35 offshore wind turbines. More specifically, it is pointed out that it is possible to minimize costs by not working in winter.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.165-173
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• 2021

The purpose of this study was to provide directions to help enter and expand long-distance routes by analyzing the characteristics of AirAsia X's network construction with Malaysia Airlines. To this end, long-distance route data was extracted from the OAG Schedule Analyzer and the network was analyzed on a two-period basis using SNA. Since AirAsia X's entry into long-range routes, Malaysia Airlines has steadily reduced its routes across the entire region. On the other hand, it is analyzed that AirAsia X is building an expanded network by increasing its network in Northeast Asia instead of ultra-long range routes. Studies have shown that LCCs also have potential growth in the long-distance route market of less than 7,000 km. The results of this study may help LCC establish a long-distance market entry and network deployment strategy.

• Journal of Korean Library and Information Science Society
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• v.55 no.3
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• pp.23-42
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• 2024

Korean Decimal Classification (KDC) 6^th edition currently adopts a synthetic number-built methods by using schedule and tables. But this methods faces with limitations in building various subjects because of due to the mono-dimensional structure with the bias of note types, insufficient analytical-synthetic notes, and lack of notes that using tables. This research practically analyzed the structural limitations of the notes in KDC 6^th edition and proposed a multi-dimensional structure to improve the number-building methods. The note types were analyzed using 4 main classes in schedule, and the problems of the current mono-dimensional note structure were identified. Based on the analysis results, the components of notes of the KDC were identified, and a multi-dimensional and hierarchical note structure was proposed. Through this structure, it is expected that KDC can establish a foundation for effectively responding to the evolving knowledge system.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.1
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• pp.33-43
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• 2007

The pickup and delivery problem with time windows generally involves the construction of optimal routeswhich satisfy a set of transportation requests under pairing, precedence, time window, vehicle capacity, andavailability constraints. In this paper, we added some constraints to the problem and adopted an objectivefunction based on number of used vehicles, total travel distance and total schedule duration to consider morerealistic problems. A branch and price algohthm for the problem is proposed and an enumeration method is usedfor the subproblems. The algorithm was tested on randomly generated instances and computational results werereported.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1451-1459
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• 2011

Recently, low energy houses have become an essential issue globally and various subsidy programs are ongoing to penetrate. All-electric houses which are another type of low energy houses or zero carbon houses are being developed. These houses consider new & renewable energy and demand side management programs in the construction and the diffusion process because these programs are essential policies to use energy resources reasonably. This paper shows a simulation methodology to control home appliances in all-electric houses considering the electricity consumption pattern of residents. The simulation is a first step to estimate energy saving of the house in a practical manner.

• Water for future
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• v.35 no.5
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• pp.51-59
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• 2002

In recent years the human impact on the environment becomes increasing lift threatening, calls for the better management of resources. In field of water quality of river flow, the best way to conserve water quality is specific efforts to control the pollutant loadings and treat the loadings in the basin to reduce the discharge of pollutant loadings to river. But in general the water quality influenced by the dam discharge. Especially in dry season, it is more dominant way to improve the water quality which contaminated with the pollutant loadings from the basin. The dam discharge amounts of the 2 dams in the Keum River that maintain the down stream water quality were estimated for the year of 1999, 2001, 2006, 2011, in case of irrigation and non-irrigation seasons. The pollutant loadings for the basin are estimated with the planning of treatment plants construction schedule for every sub-basins. The river flow rates were considered low flow as 2.33 year low flow and 10 year low flow. The QUAL2E model was used as a tool of simulation.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.19-22
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• 2003

This study is carried out (1) checking the development of compressive strength of high flowing concrete at early age, changing water-binder ratio, curing temperature, and type of aggregate, and (2) suggesting basic date that helping cost and schedule plan in future construction. As the result of this study, we find that high curing temperature is effective for the development of compressive strength of concrete at early age on the condition of each water-binder ratio, and after making the compressive prediction formula related to the curing temperature by maturity, the result of the formular is similar to the temperature-compressive strength-age measured data