• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.119-127
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• 2005

According to the recent systemic changes such as construction market reduction, five days per week system, introduction of construction duration reduction bidding system and post-construction sale system, the bidding competition have been enhanced. However, there are many construction schedule risks which could delay construction completion. Without the proper identification of construction schedule risks and the structured construction schedule risk management, the competitive advantages of construction project could not be made. Previous researches to solve the problem have been focused on the construction schedule categorization, construction schedule management, and the system development to manage the construction schedule risk. Therefore, this study selected the reinforeced concrete construction as the studied work due to the major impact characteristics on the total construction duration and the quite accident rate, and then proposed the real construction schedule risks of reinforced concrete construction and the construction risk management method based on the previous studies, many times of expert interviews and brainstorming.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.27-37
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• 2017

In the construction sites, rush (speedy construction) work have recently been overused because of budget reductions by reducing the construction duration after the long-term economic recession and construction business stagnation with institutional change including the instruction of the duration shortening bidding system and the introduction of the post-construction sales system by the Korea Research Institute for Human Settlements. Due to this, negligent accidents have frequently occurred by forcing manpower, equipment, finance, and material procurement and pressing ahead with impractical construction wok at night according to the reduction of construction schedules. Therefore, this paper has the necessity of this study to seek for alternatives to prevent negligent accidents by finding factors related to rush work in the reality that the importance for preventing negligent accidents is more emphasized while they have not been reduced in construction sites.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.117-118
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• 2015

These days buildings have more possibilities to occur construction delay as many variables and risks are inherent in them due to the enlargement and complexity. When a project is delayed, it generates extra working expenses and this causes a dispute between the employer and the constructor. Most construction sites conduct emergency construction work to recover the delay of the project duration. When an emergency construction is carried out in the actual construction site, it's necessary to utilize and distribute the proper working groups based on the procedure of successor and predecessor. Many constructions, however, have been going only with more number of work forces and working time. This study suggests a process management optimization plan with an application of emergency construction scenario by using linear programing.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.366-370
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• 2005

The construction environment is dynamic in nature and is characterized by various degrees of uncertainties. The uncertainties such as lack of coordination, non availability of resources, condition of temporary structures and varying weather conditions have a significant impact on estimating the duration of activities. These are subjective, vague and imprecisely defined and are expressed in subjective measures rather than mathematical terms. Conventionally, various quantitative techniques such as CPM and PERT have emerged in construction industry. These techniques cannot solve the above problems and rely on human experts which may not always be possible. In such situations Artificial Intelligence tools such as fuzzy sets and neural networks handle such variables and provide global strategies. The present paper evaluates the effect of qualitative factors to identify the activity duration using new intelligent approach. The results are compared with conventional methods for effective project management. A case study is considered to demonstrate the applicability of fuzzy logic for project scheduling.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.892-896
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• 2005

This paper collected 132 schools reconstruction projects in central Taiwan, which received the most serious damage from the Chi-Chi Earthquake. Regression analysis was implemented to build the prediction model of the cost and the duration for the collected projects. It is found that the cubic regression models are capable for predicting the cost and the duration of the projects contracted by the central agency of which the contracting awarding approach was based on the most advantageous tendering (MAT) approach. On the other hand, power regression models are capable for predicting the cost and the duration of the projects contracted through the low bid tendering (LBT) approach. It is also found that the performance of the regression prediction model differs in accordance with organizations that contracted the reconstruction projects.

• Korean Journal of Construction Engineering and Management
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• v.6 no.3 s.25
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• pp.81-89
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• 2005

Delay schedule coming about duration extension is happening essentially because public construction project consist of many sub contractor. The method which can calculate delay day is suggested by many studies in case of happing delay schedule, but It is difficult to apply to real construction project because there is no mention about the control of The law of contract according to delay schedule. The law of Contract which is cost of account has more uncertain problem than FIDIC condition of contract. This study suggests method which can make extension of duration procedure clear in case of happing the reason of design change related with activity duration during carrying on construction, and a submission process of the reason of duration extension and modify schedule making way about section which is basis of calculating contract amount clear.

• Journal of Korea Water Resources Association
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• v.38 no.9 s.158
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• pp.771-778
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• 2005

In this study, flow duration analysis was conducted at the Gumbo stage gauging station due to construction of the Youngchun dam. The flow duration characteristics were $10.49\;m^3/s$ of drought flow, $13.30\;m^3/s$. of low flow, $15.65\;m^3/s$ of normal flow, and $25.00\;m^3/s$ abundant flow before construction of Youngchun dam. But after construction of Youngchun dam, the flow duration characteristics were $2.07\;m^^3/s,\;2.89\;m^3/s,\;4.0\;m^3/s,\;9.36\;m^3/s$ and they had been deteriorated. Applying the Physical Habitat Simulation Model by Instream Flow Incremental Methodology, the Weighted Usable Area(WUA)-Discharge Curve was developed for Zacco Platypus according to the growth stages. Using the WUA-Discharge Curve, the WUA Duration Curve was developed with exceedance probability of daily flow and evaluated fish habitat conditions due to the construction of Youngchun dam. As an evaluation result, the WUA was reduced and fish habitat environment was deteriorated due to the construction of Youngchun dam during the spawning and growth period of Zacco Platypus. However the exceedence probability of the $90\;\%$, irrigation water supply from the Youngchun dam improved flow duration characteristics and Weighted Usable Area as well as fish habitat.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.35-43
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• 2015

It is important to have enough design and construction duration for infrastructure projects. However, recent water resource project in Korea shows several problems caused by their fast-tract schedule. National Audit Committee report several water resource projects have quality problems caused by insufficient project duration. Especially, water resource projects such as dam and water pipeline construction should have proper time to secure their structure quality. Normal project duration for these projects should be estimated based on previous similar projects' historical data analysis. However there is no standard model which can estimate normal project duration for water resource projects in Korea. There are several normal project duration estimation models for building project developed by public(LH) and private construction companies. However, there is no proper model for water resource projects. So, this study developed normal project duration model for dam and water pipeline projects using historical data and show application of models.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.487-495
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• 2014

Shortening the construction duration of structural frame work is extremely important because the work accounts for a major percentage of all cost and duration in large projects. For this reason, new construction methods to reduce the duration of structural frame work are being continuously studied and developed. A PSRC composite column, which uses steel angles instead of H-beams, has the advantages of flexural strength and ductility. Moreover, with this PSRC technique, conventional work for reinforcing bars in columns in practice can be skipped. However, one limitation exists in which the form work is still required. This research proposes a Form-LPSRC column method that is prefabricated with the column frame that includes permanent forms attached. Feasibility was examined with mock-up specimens and finally, the technique applied to real practice. Compared to the conventional SRC column method, this study demonstrated that the proposed technique has many advantages in construction duration, cost, quality, safety and environment.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.805-808
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• 2007

Recently there are many contract claims, which are caused by duration delay, in construction industry. Many kinds of research for solving such duration delay problem are being progressed and an effective computerized system needs to improve it. This study suggests an improved methodology and necessary functions to make a time impact analysis system. This results will be useful for quantifying responsible number of days caused by duration delay.