• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.87-88
• /
• 2023

In accordance with changes in the domestic construction environment, interest in off-site construction methods (factory-manufactured construction methods) including modular construction methods is rapidly increasing. Among various off-site (OSC) construction methods, the front runner is the steel-based box-type modular construction method. Compared to the existing wet construction method, the steel modular construction method is increasing in terms of securing economic feasibility by shortening the construction period and increasing the prefabrication rate. However, due to the recent rise in raw materials and a sharp rise in the exchange rate, the economic feasibility of the wet method is deteriorating compared to the wet method. Therefore, a hybrid between 9-Matrix-based OSC construction methods is considered as a solution, away from the steel-box type combination, and a comparative study of the construction process between each construction method is being conducted. It was analyzed that the PC modular construction method shortened the construction period by 9% compared to the existing steel modular construction method. On the other hand, when comparing the construction period of the Gayang-dong demonstration complex calculated assuming that all modules are applied, it is estimated that there will be a 12% reduction in construction period compared to the steel modular method and a whopping 43% compared to the RC method.

• Journal of the Korea Institute of Building Construction
• /
• v.15 no.1
• /
• pp.73-79
• /
• 2015

Legislated in 1988, the Occupational Safety and Health Expenses Criteria, has been giving a positive impact on improving the safety of construction sites. Previous researchers have been insisting that the rate is not enough to ensure the safety and health of the construction site. However, according to Korea Gallup's survey of more than 1000 construction sites in 2012, the respondents replied that large number of them did not comply with the criteria of the Occupational Safety and Health Expenses. This study analyses the completed works cost statistics of construction projects to figure out the compliance rate of the criteria. This study confirmed that the compliance rates are substantially low in most types of clients and the result is expected to be used in future research on appropriate safety and health expenses rate and on improving compliance rate of the criteria.

• Korean Journal of Construction Engineering and Management
• /
• v.19 no.1
• /
• pp.90-102
• /
• 2018

In preparation of the increase in the domestic debts and the rise in the US interest rate, the Korean government has started to strengthen the regulation on the property market since 2017. So, it is likely that the sales in the domestic construction market would be decreased. Even in the overseas plant projects market, as there has been the continuous increase in the cost and the resulting increase in the losses, it looks hard for the large construction companies to keep their credit ratings as they are now. This study is designed to check Korean government's property policy and any possible problems caused by the overseas and domestic economic environment, which include the property market policy, interest rate, rise in the property price and lackluster sales in housing market. It showed the change in the credit ratings by finding out the sales, work capability, sales in non-governmental projects, operating profits and PF contingency liabilities. For this study, the questionnaires were sent to 30 practical experts to analyze the effect of the risk factor on the outside credit rating of large construction companies.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.10 no.1
• /
• pp.74-92
• /
• 2000

This study was performed to evaluate the working conditions In construction workers through measurements of working environments and to improve the working conditions and to design the appropriate environmental and health management system. The results of measurement for working environments in construction work are as following: 1. The excess rate of noise and dust concentration in express highway construction, road construction, building construction and interior painting was 28.6% and 24.5% respectively. 2. The excess rate of mixed organic solvents concentration in interior painting was 39.3%. 3. The chain type bulldozer has the highest level of vibration; the excess rate was 85.7%, and among the vibration instruments, the level of left hand's vibration of all vibrators exceeded the criterion and in the case of drilling all the level of vibration exceeded the criterion in both hands. On the basis of the results in this research the environmental and health management system for construction workers must be considered. Therefore, it is necessary to be introduced the special medical examination and measurement of working environments in construction industry. In defining "the working place" of Article 39 of Enforcement regulations of industrial safety and health act, the word "indoors" should be deleted. Then the eligible industry for measurement of working environment must be extended. And it is also necessary for construction industry to be performed group health management service by agencies such as other manufacturing industry.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.2
• /
• pp.667-676
• /
• 2014

This study has conducted case studies in order to suggest alternatives to the historical data-based estimate system. Price fluctuation calculation methods based on historial cost indexes, standard estimate and construction cost indexes were applied to 9 road construction sites in Jeju for an analysis. As a result, in 5 construction sites (about 56% of 9 sites), the index control rate calculated based upon historical data-based estimate system was higher than that calculated based upon standard estimate and construction cost indexes. Thus the establishment of the requirements for the adjustment of contract price due to price fluctuation delays, which leads to a significant difference in price fluctuation amount. And, in an analysis of construction cost indexes, the indexes for road construction were used for calculating index control rate which ranges from 2.0 to 9.4 percent, indicating the time of construction amount and price fluctuation application has a significant influence on index control rate.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.48-53
• /
• 2007

A project manager of construction project must analyze risks which might happen during the construction phase and prepare a restoration method against the risks in order to get the successful project's accomplishment. Insurance is a representative kind of risk transfer method and an institution which prevents damages of the insured. In spite of increasing the ratio of construction insurance policy in the construction industry, project managers have regarded the insurance as a formal action in the budget through insurance companies' guides. These aspects make them not be able to valuate the reasonableness of premium rate and the real amount of the risks. This thesis is to present an improved method of construction insurance contract. Firstly, the status of the current construction insurance system have been anlyzed and the problems have been deducted. Secondly the development direction against the problems is presented in the research. Lastly, the procedure model is proposed for acquiring the resonable premium rate of insurance.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.11a
• /
• pp.38-39
• /
• 2020

Since a lot of fugitive dust is generated at construction and civil engineering construction sites in Korea, the fine dust regulation at construction sites has been strengthened in accordance with the implementation of the Special Act on Fine Dust Reduction. In a construction site, water is generally sprayed to temporarily reduce the generation rate of scattered dust, but there is a problem that when water evaporates, it scatters again. In this study, the performance of a scattering dust inhibitor incorporating a polymer that stabilizes the ground and reduces the rate of scattering dust by forming a polymer film even when water evaporates using a polymer and a surfactant was evaluated.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.608-615
• /
• 2022

Construction projects are large-scale projects that require extensive construction costs and resources. Especially, scheduling is considered as one of the essential issues for project success. However, the schedule and resource management are challenging to conduct in high-tech construction projects including complex design of MEP and architectural finishing which has to be constructed within a limited workspace and duration. In order to deal with such a problem, this study suggests resource and sequence optimization using constraint programming in construction projects. The optimization model consists of two modules. The first module is the data structure of the schedule model, which consists of parameters for optimization such as labor, task, workspace, and the work interference rate. The second module is the optimization module, which is for optimizing resources and sequences based on Constraint Programming (CP) methodology. For model validation, actual data of plumbing works were collected from a construction project using a five-minute rate (FMR) method. By comparing actual data and optimized results, this study shows the possibility of reducing the duration of plumbing works in construction projects. This study shows decreased overall project duration by eliminating work interference by optimizing resources and sequences within limited workspaces.

• International conference on construction engineering and project management
• /
• 2005.10a
• /
• pp.1244-1249
• /
• 2005

Present PII(Private Infrastructure Investment) in Korea has increased up to 11% compared to the year 2003 and is expected to increase in the future. In spite of its rapid increase, we don't have any definite standard or system which distinctly presents the rate of return for domestic PII yet, and practical and scientific research is not sufficient compared to its necessity and importance. Hence, in this study we suggests methods to estimate the rate of return of PII to promote SOC PII to last successfully and present the proper level of rate of return of PII which is appropriate for domestic situations through diverse analysis. Therefore, to present reasonable rate of return, we have used 5 methods: previous research analysis, case study, financial index analysis, analysis of investor's rate of return, and analysis of rate of return in a real estate market. After comparing and analyzing these methods, at the end, we have presented the appropriate level of rate of return of PII, which can be applied in the domestic market.

• International conference on construction engineering and project management
• /
• 2007.03a
• /
• pp.96-105
• /
• 2007

This paper presents a study on the impact of variation of construction material prices on the feasibility of building projects in Vietnam. The paper makes use of Monte-Carlo simulation for financial risk analysis of net present Value (NPV) and internal rate of return (IRR). To well illustrate the influencing, a case study is presented. The research results show that there is a strong correlation between steel prices, gold prices, and $US exchange rate. Outputs of statistics also reveal that the concurrent variation of prices of cement, steel, sand, brick, formwork and stone has strongly negative impact on NPV and IRR of building projects. The results also indicate that the proportion of steel cost to total construction cost is 17.95% which is the cause of risks for the feasibility of building project in Vietnam. The paper stresses that feasibility study of building project must integrate the impact of construction materials prices in order to mitigate risks in developing countries as Vietnam.