Han-Guk Ryu

Probabilistic Duration Estimation Model for High-Rise Structural Work

The duration of a construction project is a key factor to consider before starting a new project, as it can determine project success or failure. Despite the high level of uncertainty and risk involved in construction, current construction planning relies on traditional deterministic scheduling methods that cannot clearly ascertain the level of uncertainty involved in a project. This, subsequently, can prolong a projects duration, particularly when that project is high-rise structural work, which is not yet a common project type in Korea. Indeed, among construction processes, structural work is notable, as it is basically performed outdoors. Thus, no matter how precisely a schedule is developed, such projects can easily fail due to unexpected events that are beyond the planners control, such as changes in weather conditions. Therefore, in this study, to cope with the uncertainties involved in high-rise building projects, a probabilistic duration estimation model is developed in which both weather conditions and work cycle time for unit work are considered to predict structural work duration. According to the proposed estimation model, weather variables are divided into two types: weather conditions that result in nonworking days and weather conditions that result in work productivity rate (WPR) change. Obtained from actual previous data, the WPR is used with relevant nonworking day weather conditions to modify the actual number of working days per calendar days. Furthermore, on the basis of previous research results, the cycle time of the unit work area is assumed to follow the β probability distribution function. Thus, the probabilistic duration model is valid for 95% probability. Finally, a case study is conducted that confirms the model can be practically used to estimate more reliable and applicable probabilistic durations of structural work. Indeed, this model can assist schedulers and site workers by alerting them, at the beginning of a project, to project uncertainties that specifically pertain to structural work and the weather. Thus, the proposed model can enable personnel to easily amend, and increase the reliability of, the construction schedule at hand.

Loss Prediction Model for Building Construction Projects Using Insurance Claim Payout

The amount of risk and the occurrence of damage in construction projects have increased as construction projects are becoming larger and more complex, increasing the demands for an effective risk assessment model. Therefore, quantitative risk analysis is needed to develop a financial risk assessment model using the risk indicators for construction projects. To address this need, authors analyzed the damage records of actual construction sites in South Korea, in order to identify the critical risk factors of damage and investigate the relationships among the risk indicators to develop a loss prediction model. Authors used claim payout records from an insurance company to reflect real financial loss as the dependent variable. As independent variables, authors adopted four risk categories based on our literature review and data analysis: natural hazards, geographic information, construction method and ability, and construction information. Our loss prediction model for construction projects, along with our findings, offers fundamental guidelines for construction companies, construction project owners, and insurance companies hoping to model and predict financial loss for building construction projects.

Assignment Buffer Control for Construction Projects

Buffer in construction management means a cushion that protects the planned project schedule from uncertainty. Traditional buffer management, however, often fails to perform its purpose, hence reducing efficiency in schedule management. Such failure has been mainly attributed to the fact that traditional buffering is based on experience rather than being made in a systemic manner. For this reason, in this paper, we investigate the inefficiencies of the traditional buffer, especially focusing on the manager’s assignments. In this study, in-depth interviews were conducted on sixteen schedule experts in twelve companies in Korea to explore their scheduling practice, and interesting facts were found. By analyzing the interview results, this research identifies three fundamental problems of the traditional buffering, based on which, Assignment Buffer Control (ABC) is proposed. ABC improves the problem by metamorphosing the buffer and incorporating manager’s assignment direction to the schedule.

Dynamic Resource Management

Excess resource idling can result in cost overruns, while low resource coverage or long leadtime in resource acquisition can delay the project schedule. Therefore, systematically managing this tradeoff is critical to ensure project delivery in time and within budget. In addition, to provide practically useful guidelines and tools, the dynamic construction process needs to be realistically represented. As an effort to address these issues, a model-based dynamic approach is proposed for construction resource management. The dynamics of construction progress and the tradeoff with resource coverage are identified. Then, the dynamic resource management model that has been developed using system dynamics is described. By simulating the model, the effect of resource coverage on project performance is quantified and policy implications are obtained for dynamic resource management. Finally, the use of the model as an automated tool is demonstrated.

Schedule Management Process Model Based on CSDM

The duration of a construction project must be an important item in construction contracts. If a contractor can work in the planned parameter, the contractor can finish the construction project in a timely manner. However, when construction industry is compared to other industries, it is difficult to complete a construction project in which many construction trades participate during the construction phase. In most cases, there are numerous impact factors that impact a construction process and hinder its timely completion. Those impact factors can be categorized construction schedule risk, productivity, constraints and so forth. The scheduler must consider the impact factors to plan the construction project schedule. But, many studies or methodologies or programs on planning the construction schedule have been focused on the result of works. So, this study proposes the schedule management process model based on CSDM (Construction Schedule Data Mart) considering data warehousing, MOLAP (and case-base reasoning.