Precast concrete (PC) construction method is typically preferred due to its reduced construction time, quality assurance, and cost effectiveness. Experimental studies have proven that in-situ production of PC components ensures equivalent or enhanced quality with substantial cost reductions compared to those of in-plant production, under the same production conditions. The construction method may also be environment friendly due to its relatively low CO₂ emissions. However, it is necessary to examine the degree of this method’s effectiveness via experimental studies. The purpose of this study is to evaluate the CO₂ emission reduction effect of in-situ production of PC components. Using a case project, the CO₂ emission is estimated and compared for the operations between in-situ and in-plant production. The CO₂ emission of in-situ produced PC components reduced by 14.3% or more when compared to the in-plant production. This shows that in-situ production of PC components can greatly reduce CO₂ emissions, while maintaining its cost effectiveness and quality assurance. Furthermore, this study contributes in changing the negative perception of in-situ production of PC components and in the development of algorithms that scientifically analyze the CO₂ emission reduction effect of in-situ production of PC components.

Electrical contractors encounter problems such as limited construction sites, schedule interference, and inefficient communication with other contractors when they typically subcontract with general contractors. Electrical projects require effective and systematic project management strategies to overcome these problems and achieve the desired goal. In an electrical construction project, individual tasks are interconnected at different stages, including pre-construction planning (PCP) and project execution (PE). Therefore, analyzing the effect of task strings on the project success in terms of schedule and cost performance is necessary. The main objective of this study is to perform a static analysis to compare successful and failed projects with a focus on the cost and schedule performances, using the PCP and PE task strings in electrical construction projects. To achieve this, a continuous PCP-PE task strings implementation score was calculated for each PE group in terms of cost and schedule, and successful and failed projects on unweighted and weighted values were compared and analyzed by performing an independent sample t-test. Consequently, it was confirmed that the use of most task strings had a positive effect on the cost success at a confidence level of 95%, and that only the subcontractor management group had a positive effect on the schedule success. Hence, it was derived that the usage of task strings for these groups is recommended for cost success in electrical construction, and continuous PCP-PE task strings do not have a positive effect on schedule success; therefore, it is recommended to use the PCP-PE task strings only for specific groups for schedule success in electrical construction. Demonstrating the relationship between the PCP and PE tasks, the findings of this study are expected to help electrical contractors achieve a better performance using effective project management strategies.

CO₂ emissions account for 80% of greenhouse gases, which lead to the largest contributions to climate change. As the problem of CO₂ emission becomes more and more prominent, research on sustainable technologies to reduce CO₂ emission among environmental loads is continuously being conducted. In-situ production of precast concrete members has advantages over in-plant production in reducing costs, securing equal or enhanced quality under equal conditions, and reducing CO₂ emission. When applying in-situ production to real projects, it is vital to calculate the optimal quantity. This paper presents a dynamic optimization model for estimating in-situ production quantity of precast concrete members subjected to environmental loads. After defining various factors and deriving the objective function, an optimization model is developed using system dynamics. As a result of optimizing the quantity by applying it to the case project, it was confirmed that the optimal case can save 7557 t-CO₂ in CO₂ emissions and 6,966,000 USD in cost, which resulted in 14.58% and 10.53% for environmental loads and cost, respectively. The model developed here can be used to calculate the quantity of in-situ production quickly and easily in consideration of dynamically changing field conditions.

In South Korea, industrial accidents continue to increase in frequency, with construction accidents accounting for more than a third of all industrial accidents. Specifically, by preventing fall accidents, the death rate from accidents can be reduced by 50%. Fall protection is required to prevent fall accidents, and investigating the reinforcement of the worker’s safety harness and hook fastening becomes imperative. This requires automation of computer vision confirmation of the safety harness and hook fastening. As the accident risk can be reduced by an effective safety culture in the system, it is necessary to monitor safety on site through a construction safety automation system. Therefore, the objective of this study is to develop a computer vision process for safety harness and hook for preventing fall accidents in South Korea’s construction industry. This study focuses on system scaffolds that are widely used at construction sites. The application of this methodology to sample sites and field cases established its applicability. The proposed computer vision application methodology will serve as the foundation for visualization research in the construction industry, and image recognition will help reduce the safety accident rate. Accidents caused by failure to use a safety harness and hook can be reduced in South Korea as well as globally. Additionally, this methodology is applicable to roof construction, tower crane installation and dismantling work, as well as steel tower installation and dismantling.

The precast concrete (PC) method is preferable in construction activities for its short construction time, guaranteed quality, and cost-effectiveness. Most researchers and engineers believe that these benefits are maximized if the PC components are produced at manufacturing plants. However, under similar production conditions, the in-situ production of PC components can save production costs while providing quality equal to or better than in-plant production. Several studies have described the benefits for the cost reduction effects of in-situ production. However, the verification by using case studies was not conducted. The purpose of this study is to analyze the cost reduction effects of the in-situ production of PC elements. For this study, a case project was selected to establish an in-situ production plan and PC columns were produced on site. Then, the cost reduction effects were analyzed using the actual data of the case project. The results of this study will be used as a core for the development of algorithms for in-situ production of PC components.