Sangyong Kim

Life Comparative Analysis of Energy Consumption and CO2 Emissions of Different Building Structural Frame Types

The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO2 emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (RC) or steel (S) structures. An input-output framework analysis was used to measure energy consumption and CO2 emissions of input materials for each structural frame type. In addition, the CO2 emissions cost was measured using the trading price of CO2 emissions on the International Commodity Exchange. This research revealed that both energy consumption and CO2 emissions were, on average, 26% lower with the RC structure than with the S structure, and the construction costs (including the CO2 emissions cost) of the RC structure were about 9.8% lower, compared to the S structure. This research provides insights through which the construction industry will be able to respond to the carbon market, which is expected to continue to grow in the future.

Bayesian Markov Chain Monte Carlo Model for Determining Optimum Tender Price in Multifamily Housing Projects

AbstractThis study presents a strategy model for determining the optimum tender price that reflects appropriate profit and risk contingencies in competitive tendering according to the Bayesian Markov Chain Monte Carlo (BMCMC) model. The BMCMC approach is known to be theoretically optimal for handling tender-price problems. The BMCMC model provides a practical solution that can reflect not only objective information but also subjective experience and knowledge. The BMCMC model allows contractors to estimate the tender price more accurately by reflecting the prior distribution function on key factors. Conclusively, this model was found to improve decision-making processes for setting an optimum tender price. An applied example showed that the proposed methods are feasible.

Case Study on the Determination of Building Materials Using a Support Vector Machine

AbstractFor any construction project to succeed, it is very important to select the materials accurately during the project’s initial stage. Trying to choose the best-performing materials is a crucial task for the successful completion of a construction project. The material selection process typically is performed through the information received from a highly experienced decision maker and a purchasing agent without the logical decision making; thus, the construction field gains access to various artificial intelligence (AI) techniques to support decision models in their own selection method. Through a case study, this paper proposes the application of a systematic and efficient support vector machine (SVM) model to select suitable materials. The 120 data sets of the case study have completed building projects in South Korea. These data set were divided into three groups and constructed five binary classification models in the one-against-all (OAA) multiclassification method by data classification and n...

Contractor-led critical design management factors in high-rise building projects involving multinational design teams

High-rise building projects (HRPs) are comprised of various complex design elements. The involvement of a multinational design team increases design-related issues for contractors, which must be managed during the construction stage. Thus, contractors need to understand how appropriate design management can positively affect project performance and their profit. Identification of critical design management factors (CDMFs) can provide appropriate decision-making support for contractors, including how limited resources including money, manpower, and equipment can be allocated throughout the construction stage. This study identifies and ranks the CDMFs for HRPs designed by multinational design teams. Through a questionnaire survey in South Korea, 21 design management factors were acknowledged among 40 initial factors. Then, using factor analysis, these 21 identified CDMFs were categorized into four groups: interface management, design information, production stage, and risk contribution. Based on results, this study identifies general and regional features of design management. Because these CDMFs are chosen from the contractor’s perspective, if they are used to make appropriate decisions, the overall project performance should be increased during the construction phases.

Optimizing the Mixing Proportion with Neural Networks Based on Genetic Algorithms for Recycled Aggregate Concrete

This research aims to optimize the mixing proportion of recycled aggregate concrete (RAC) using neural networks (NNs) based on genetic algorithms (GAs) for increasing the use of recycled aggregate (RA). NN and GA were used to predict the compressive strength of the concrete at 28 days. And sensitivity analysis of the NN based on GA was used to find the mixing ratio of RAC. The mixing criteria for RAC were determined and the replacement ratio of RAs was identified. This research reveal that the proposed method, which is NN based on GA, is proper for optimizing appropriate mixing proportion of RAC. Also, this method would help the construction engineers to utilize the recycled aggregate and reduce the concrete waste in construction process.

Ubiquitous Sensor Network for Construction Site Monitoring

The importance of construction monitoring trend is required rational method to take health and safety and effective maintenance control from uncertainity and associated risks. Thus, timely field monitoring can overcome the gap between the prediction and real situation through the analyzing validity for the construction. This study suggests automated monitoring system with three kinds of communication methods to achieve effective operation of the system. The example of case study helps to easily understand for practical application with use of the mobile phones.

Pile foundation design through the increased bearing capacity of extended end pile

Pretensioned spun high strength concrete (PHC) piles are a commonly used type of pile, while approximately 60% of the pile′s strength is only used in the design bearing capacity. Because of the limited support capacities of PHC piles, applying PHC piles to high-rise buildings or soft ground is inefficient. Extended end (EXT) piles are a new type of pile that can reduce the waste of pile strength and increase the ground bearing capacity. This study investigated the behavior of EXT piles through a field test and it was confirmed that the bearing capacity of the EXT pile is better than the PHC pile. The increased bearing capacity of EXT piles also influenced work duration and project cost.

Comparison of High-Strength Steel Pipe and H-Shaped Steel in the Strut of a Braced Wall System

Excavation work accounts for a high percentage of the total building construction cost. The most widely used method for excavation work in an urban area is a braced wall system with struts or rakers. H-shaped steel, which is the most commonly used component for struts in braced wall systems, has disadvantages such as cost-ineffectiveness and increased work interference associated with narrow strut spacing. Therefore, the use of high-strength steel pipe struts in braced wall systems can be an effective alternative to widening the strut spacing. In this study, the construction costs of a braced wall system using H-shaped steel and a braced wall system made with high strength steel pipe were compared by analyzing the required amounts of materials and the construction costs for four practical cases. All analyzed cases considered a change from H-shaped steel to high strength steel pipe in a design change during the construction stage. The results of this study show that the required amount of materials and the construction costs of a braced wall system with high strength steel pipe were lower than those of a braced wall system with H-shaped steel. Consequently, this study suggests that a high strength steel pipe strut is a more economical alternative than an H-shaped steel strut in braced wall systems for deep excavation work.

Decision Making Method Based on Importance-Dangerousness Analysis for the Potential Risk Behavior of Construction Laborers

Unsafe behavior contributes to 90% of the causes of construction accidents. To prevent construction accidents, studies on existing unsafe behaviors have been regularly conducted. However, existing studies generally tend to average the survey results and conduct analyses thereon, and such a method cannot consider the potential risk as regards people’s anxiety about a certain unsafe behavior. Thus, this research suggests an Importance-Dangerousness Analysis (IDA) technique so that potential risks due to unsafe behaviors of laborers working in the construction sector could be evaluated. In order to verify the applicability of the suggested technique, an actual survey was conducted, and the results of Importance-Performance Analysis (IPA) and IDA were compared with each other. It was found that, unlike IPA, unsafe behaviors that could pose potential risks were confirmed by IDA. Further, unsafe behaviors in the construction sector that should be urgently addressed were also studied. Finally, the IDA suggested in this research could contribute to effective construction safety management on-site by supporting the decisions of the safety manager based on the unsafe behavior analysis of construction laborers.

Case Study on the Maintenance of a Construction Monitoring Using USN-Based Data Acquisition

In recent years, there has been an increasing interest in the adoption of emerging ubiquitous sensor network (USN) technologies for instrumentation within a variety of sustainability systems. USN is emerging as a sensing paradigm that is being newly considered by the sustainability management field as an alternative to traditional tethered monitoring systems. Researchers have been discovering that USN is an exciting technology that should not be viewed simply as a substitute for traditional tethered monitoring systems. In this study, we investigate how a movement monitoring measurement system of a complex building is developed as a research environment for USN and related decision-supportive technologies. To address the apparent danger of building movement, agent-mediated communication concepts have been designed to autonomously manage large volumes of exchanged information. In this study, we additionally detail the design of the proposed system, including its principles, data processing algorithms, system architecture, and user interface specifics. Results of the test and case study demonstrate the effectiveness of the USN-based data acquisition system for real-time monitoring of movement operations.