• Korean Journal of Construction Engineering and Management
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• v.7 no.1 s.29
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• pp.138-147
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• 2006

Construction companies have been interested in the construction duration which importantly affects the performance and the success of the construction projects in accordance with the systemic changes such as five days per week system, introduction of construction duration reduction bidding system and post sale system nowadays. It is also very important to estimate and forecast properly the construction duration as the construction companies compete for the projects in the situation of construction market reduction and the lowest bidding system. Recognizing the importance about the construction duration, the researches about comparing and analyzing or estiamting the construction duration have been performed. However, comparing studies about the construction duraion have been limited to the apartment and office building in domestic area. Many studies about forecasting construction duration have been performed through stochastic analysis and simulations. Little research has been addressed the comparison analysis of the real construction duration about the mix-use building and officetel building which occured according to the changes of the building requirements. Therefore, the objective of this study is to compare and analyze the real construction duration and the hypothetical construction duration about the mix-use building and officetel building of the domestic companies. Moreover, we select the most competitve construction company to get the strengths and analyze the competitive advatages of the construction companies about construction duration.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.604-605
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• 2015

To secure quality of dam construction needs appropriate construction duration. Tight construction schedule may have negative influence on infrastructure quality, work safety and maintenance cost. It is necessary to reflect proper construction duration in the planning phase. There have been standards for estimating construction duration of building and industrial complex development but dam construction have not. In order to estimate construction duration of CFRD, feasible study reports and design reports were analyzed to acquire available information. After that, considering on construction duration methods such as comparison with similar cases, approximate estimating formula, approximate quantity assumption were adapted to Critical Path items. Hence, this study present framework for construction duration estimating of CFRD in the planning phase. This framework can be applied other types of dam along the same line.

• Journal of KIBIM
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• v.6 no.4
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• pp.35-41
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• 2016

Learning effect is an observation that the more times a task is performed, the less time is required to produce the same amount of outcomes. The construction industry heavily relies on repeated tasks where the learning effect is an important measure to be used. However, most construction durations are calculated and applied in real projects without considering the learning effects in each of the repeated activities. This paper applied the learning effect to the repeated activities in a small sized apartment construction project. The result showed that there was about 10 percent of difference in duration (one approach of the total duration with learning effects in 41 days while the other without learning effect in 36.5 days). To make the comparison between the two approaches, a large number of BIM based computer simulations were generated and useful patterns were recognized using machine learning algorithm named Decision Tree (See5). Machine learning is a data-driven approach for pattern recognition based on observational evidence.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.677-685
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• 2018

In construction, schedule management is the basic but important step, for the effective schedule management, the preparation of the reasonable schedule table should be prioritized. In the design stage, the optimal construction period can be selected through comparison of various conditions and construction methods considering weather conditions and site characteristics. But, At the planning phase, it is difficult to select the effective method and calculate the proper construction period by the basic data(D/B) analysis. In this paper, the construction method considering characteristics of each type and conditions of existing city was selected. For the reasonable duration calculation, we analyzed the unit schedule for RC method for open type and Shield TBM method for tunnel type. The normal project duration of construction assuming of 1,200m of extension and every 200m of ventilation was prepared by integrating each unit schedule. It was analyzed that it took 893 days for the open type and 616 days for the tunnel type. The results of this study will help to make type selection and normal project duration more easily in the planning phase. If it is linked to the design stage, it will be easy to estimate the process and construction cost.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.3
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• pp.4750-4770
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• 1978

Under the various variations of the sample thickness, the load increment ratio and the load increment duration, this consolidation test of the clay in the Asan Bay was tried for the comparison with the standard consolidation test. The results gained are as follows; 1. The void ratio variations of the leached-clay samples were increasingly high, according as the sample thickness thinned and the load increment duration and the laod increment ratio increased. 2. The coefficient of consolidation were increased with the increment of the sample thickness, of the load increment ratio and of the load increment duration. Near the pre-consolidation load, the coefficient of secondary consolidation had the maximum value and lessened with the increment of the sample thicknss, and of the load increment duration 3. The value of the pre-consolidation load increased in proportion to the increment of the sample thickness and the decrease of the load increment ratio and the load increment duration. 4. The compression indices increased as the increment of load increased and decreased as the sample thickness increased. 5. The initial compression ratio increased as the sample thickness, the load increment ratio and the load increment duration decreased. The ratio of primary compression to the secondary decreased with the increment of the sample thickness and of the load increment ratio. 6. The time at the completion of psimary consolidation increased with the increment of the sample thickness and of the consolidation load, and with the decrease of the load increment ratio. 7. The compression indicses increaed as the sample thickness lessened and decreased as the load increment ratio increased. The coefficient of consolidation increased according as the sample thickness, the load increment ratio and the load increment duration went up. The settlement at the construction site should be calculated highly in proportion as the sample thickness lessened and the load increment ratio increased. The consolidation ratio is thought to be accelerated if the sample thickness and the load increment ratio becomes higher and the load increment duration longer.

• Journal of Construction Engineering and Project Management
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• v.2 no.3
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• pp.17-29
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• 2012

Delays are one of the biggest problems facing by the construction industry and they have significant financial and social impact in construction projects. The paper presents a framework of Delay Analysis System (DAS) with the aim of analysing the impact of delay factors in Libyan construction projects. The system has designed by integrating the possible delay factors, critical activities of a project using@risk simulator. A case study of building project was demonstrated to identify the impact of delays and the sensitivity of delay factor. The case study result showed that the project might be delayed by 97 to 103 days in comparison to the planned duration. The developed DAS is a tool for analysing and identify the impacts of delay factors and assist to construction manager to take necessary measure in reducing the delay impact. The paper provides a methodology for analysing the possible delay impact in a construction project and informing to construction manager in advance of the possible delay factors.

• Korean Journal of Construction Engineering and Management
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• v.10 no.3
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• pp.102-110
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• 2009

Although several research efforts have been directed to fast-tracking to reduce the total delivery time, few researches have been studied on concurrent engineering in construction projects. The focus of fast-tracking is primarily on overlapping independent activity pairs. In comparison, the focus of concurrent engineering is on overlapping dependent activity pairs. Dependent activities are much harder to overlap successfully. This paper presents a simulation-based Concurrent Engineering methodology to optimize the overall duration of a set of design activities in a project by modelling key factors that determine the duration of individual activities and overlap between dependent activities. This methodology involves determining how much to overlap activities, how to decide which activities to overlap and the corresponding cost and time tradeoffs using a discrete event model solution. This simulation model, therefore, can be used as a reference on decision-making to define optimum point between time and cost.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.2_2
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• pp.403-414
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• 2024

The aim of this study is to evaluate the productivity of multilayered modular housing units during the prefabrication phase. Additionally, it shows the results of productivity analysis conducted using the Web Cyclone technique. Initially, an review of literature and prior studies helped outline the comprehensive manufacturing process of laminated modular apartments, examining the range of minimum, average, and maximum work durations along with workforce size. Subsequently, the productivity of the multilayered apartments' prefabrication was assessed using the Web Cyclone technique, focusing on the workflow, duration, and personnel involved. This analysis also included a comparison of productivity against the initial plan based on the outcomes of a sensitivity analysis.

• Structural Engineering and Mechanics
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• v.20 no.6
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• pp.673-693
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• 2005

A general step-by-step simulation for the time-dependent analysis of segmentally-erected prestressed concrete box-girder bridges is presented. A three dimensional finite-element model for the balanced-cantilever construction of segmental bridges, including effects of the load history, material nonlinearity, creep, shrinkage, and aging of concrete and the relaxation of prestressing steel was developed using ABAQUS software. The models included three-dimensional shell elements to model the box-girder walls and Rebar elements representing the prestressing tendons. The step-by-step procedure allows simulating the construction stages, effects of time-dependent deformations of materials and changes in the structural system of the bridges. The structural responses during construction and throughout the service life were traced. A comparison of the developed computer simulation with available experimental results was conducted and good agreement was found. Deflection of the bridge deck, changes in stresses and strains and the redistribution of internal forces were calculated for different examples of bridges, built by the balanced-cantilever method, over thirty-year duration. Significant time-dependent effects on the bridge deflections and redistribution of internal forces and stresses were observed. The ultimate load carrying capacities of the bridges and the behavior before collapse were also determined. It was observed that the ultimate load carrying capacity of such bridges decreases with time as a result of time-dependent effects.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.377-380
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• 2007

Formwork is a very important work in the construction. Various research and development about formwork has been going on, many methods are developed. And the effort to reduce the cost has been progressed at oversea. And a lot of attempts have been in motion in domestic field. But the systematic researches to apply to field are scarced. So, some problems pointed out at the stage of application. Therefore through comparison analysis of other formwork problems are derived and it's solution were suggested in this study.