College of Design-School of Building Construction-Ph.D. Dissertation Defense- Tran Duong Nguyen

Date: Friday, November 20, 2026

Time: 11:00 AM – 1:00 PM EST

Location: Georgia Tech Library Dissertation Defense Room (PG 4222)

Link to Join Presentation: https://teams.microsoft.com/meet/226087938578718?p=1C63dFt4xav1CoYvrs

Committee Members

• Dr. Pardis Pishdad – School of Building Construction, Georgia Tech (Advisor, Chair)
• Dr. Valerie M. Thomas – School of Industrial and Systems Engineering, Georgia Tech
• Dr. Ebenezer Fanijo – School of Building Construction, Georgia Tech
• Dr. Patrick Kastner – School of Architecture, Georgia Tech

• Dr. Sanjeev Adhikari – Department of Construction Management, Kennesaw State University

   

Title: Comparative Carbon, Schedule, and Cost-Parity Conditions of Conventional, Modular, and Distributed Construction: An Integrated Decision-Support Framework

Abstract:

Housing delivery in the United States faces mounting challenges associated with rising construction costs, schedule pressures, labor shortages, and increasing demands to reduce embodied carbon emissions. In response, industrialized construction approaches, including traditional modular construction (TM) and the emerging concept of distributed construction (DC), have gained attention as potential alternatives to conventional construction (CC). Although these approaches offer opportunities to improve construction efficiency and sustainability, empirical evidence supporting systematic comparisons of their schedule, cost, and environmental performance remains limited. In particular, there is a lack of integrated, evidence-based assessment frameworks that enable consistent comparisons of these construction methods under varying project conditions.

This dissertation addresses this gap by developing an integrated, Building Information Modeling (BIM)-enabled decision-support framework to systematically evaluate and compare the schedule, cost, and embodied carbon performance of CC, TM, and DC. The proposed framework integrates BIM-based quantity takeoff, Life Cycle Assessment (LCA) using Tally, parametric modeling using Rhino and Grasshopper, phase-level schedule scenarios, break-even cost analysis, multi-objective optimization (NSGA-II), and the Analytic Hierarchy Process (AHP).. This integration enables systematic generation and evaluation of alternative design and construction scenarios and supports the identification of trade-offs among project duration, construction cost, and embodied carbon emissions. Furthermore, the framework facilitates sensitivity analyses to investigate how variations in material waste, transport distance, grid emission factors, and fabrication duration influence the relative performance of each delivery method.

The framework is demonstrated through case studies at the room-unit and project levels. At the room-unit level, prototype modular units are compared with conventional guestrooms. At the project level, all three construction approaches are evaluated using a consistent building design and project scope. An actual conventional construction project serves as the baseline, providing observed project data for the CC scenario. Comparable TM and DC scenarios are developed for the same building using data derived from an actual DC prototype case study, supplemented by published empirical evidence and relevant literature on modular construction. This approach enables a controlled, scenario-based comparison while explicitly accounting for the assumptions and limitations associated with extrapolating data across different construction methods.

In the modeled scenarios, TM and DC had lower construction-stage embodied carbon than CC, by about 10% and 14%, and prototype modular units had lower emissions than conventional units. These advantages depended mostly on the conventional material waste rate and on the distance between production facilities and the site. Both TM and DC shortened the construction phase mainly when off-site fabrication overlapped site work, and the resulting schedule savings could offset only a small cost premium, below the premiums reported for offsite construction. The comparison therefore identifies the conditions under which each method performs better, not a single best method.

The dissertation contributes to the body of knowledge by establishing an integrated BIM–LCA–schedule–cost decision-support framework that connects material-level, room-unit-level, and project-level performance outcomes to their underlying design and construction assumptions. By identifying performance trade-offs and the project conditions under which alternative construction methods may offer advantages, the research provides a systematic basis for evaluating industrialized construction strategies. The resulting framework supports owners, designers, contractors, and public agencies in making more informed, project-specific decisions regarding conventional, modular, and distributed construction approaches.