The National Academy of Construction (NAC) will hold three Ask Me Anything (AMA) webinars for high school and college students with interest in the design & construction industry. Each AMA features one NAC member who will discuss their careers and answer questions from students. Students who submit a question are eligible to win one of three $500 scholarships.
Faculty: Please register your class using the NAC AMA Class Registration Form.
Students: Please register using the NAC AMA Student Registration Form.
Abstract: Precast concrete structures (PCs) are widely used in the construction industry to reduce project delivery times and improve quality. On-time delivery of PCs is critical for successful project completion because the processes involving precast concrete are the critical paths in most cases. However, existing models for scheduling PC production are not adequate for use in dynamic environments where construction projects have uncertain construction schedules because of various reasons such as poor labor productivity, inadequate equipment, and poor weather. This research proposes a dynamic model for PC production scheduling by adopting a discrete-time simulation method to respond to due date changes in real time and by using a new dispatching rule that considers the uncertainty of the due dates to minimize tardiness.
Authored by: Taehoon Kim, Yong-Woo Kim, and Hunhee Cho
Abstract: This study applies empowerment theory to production planning at the level of frontline managers in a construction project. Using structural equation modeling, we investigate how empowering frontline managers impacts their planning performance. In contrast to prior studies, we find that although psychological empowerment of frontline managers has no direct effect on their production planning reliability or scheduling performance, it has an indirect effect on planning reliability and scheduling performance, as long as the organization supports empowerment structurally during production planning. This implies that a project manager should provide frontline managers at the operational level with proper formal and informal authority over workflow development, shielding, and resource allocation when planning production in order to enhance job performance through psychological empowerment.
Authored by: Yong-Woo Kim and Byong-Duk Rhee
Abstract: The research investigates the relationship between the production plan reliability and the project cost performance using project data in the heavy civil construction sector. The research also investigates the attributes of a make-ready process using statistical analysis. This study shows that production planning reliability (i.e. Per cent Constraint Removal (PCR) and Per cent Plan Complete (PPC)) and project cost performance (CPI) are significantly correlated in the heavy construction projects. The findings show that there is a more significant correlation between production planning reliability and project cost performance in project-scaled data than in monthly scaled data. They suggest that there is a time-lag between when the variance of workflow occurs and when the workflow variance impacts on the project cost performance.
Authored by: Yong-Woo Kim
Funding: This study was supported by P. D. Koon Endowed Fund and Construction Industry Institute under Grant RT-271.
Project Funded by: Turner Construction
CERC Applied Research Fellowship
Faculty Advisor: Carrie Sturts Dossick
Ph.D. Canddiate: Sadra Fardhosseini
Turner Partners: Renzo DiFuria, Sean Beatty
“Digital fabrication is an emerging approach to transforming design to physical products. While a number of studies have been carried out to highlight the use of digital technologies in construction, there is still a dearth of studies focused on design-to-fabrication workflows for concrete formwork in construction projects. In response, the overarching goal of this study is to develop a design-to-fabrication workflow using digital models and Computer Numerical Control (CNC) machines with a focus on formwork fabrication. The specific objectives are to (1) develop a detailed workflow from the design phase of formwork to the fabrication phase, and (2) develop automated procedures to support the workflow without extensive manual intervention. This workflow integrates Virtual Design and Construction (VDC), trade coordination, parametric modeling, software customization, tool path development, and CNC routing in order to produce precise prefabricated formwork components. To test and validate the workflow, the research team will use a case study for the prefabrication of cast-in-place concrete structural and architectural elements. The case study shows that the use of the workflow for CNC machines supports craftsmanship to improve labor productivity, safety, and fabrication quality. The results demonstrate the advantages of using this workflow over the traditional approach to support project teams’ productivity and enable them to make informed decisions for their implementation of digital fabrication.”