Graduation Semester and Year
Spring 2026
Language
English
Document Type
Thesis
Degree Name
Master of Science in Civil Engineering
Department
Civil Engineering
First Advisor
Vinayak Kaushal, Ph.D., P.E.
Abstract
Underground sanitary sewer pipelines are essential components of urban infrastructure; however, open-cut pipeline installation requires excavation, bedding preparation, pipe placement, backfilling, embedment, and compaction activities that rely heavily on construction equipment and fuel consumption. As a result, open-cut installation can generate measurable greenhouse gas emissions during the construction phase. With increasing attention to sustainable infrastructure delivery, there is a need for a consistent approach to quantify construction-phase carbon footprint and convert those emissions into a comparable economic indicator. Accordingly, this thesis aims to create and apply a productivity rate-based calculation framework for estimating and comparing construction-phase CO₂e emissions and carbon footprint cost associated with open-cut sanitary sewer pipeline installation. The secondary objectives of this research are to define a consistent functional unit and system boundary, standardize activity-level calculations across selected case studies, estimate equipment fuel consumption using productivity-based active construction time, convert fuel use into CO₂e emissions, and monetize the resulting emissions using a consistent carbon price. This study focuses on open-cut sanitary sewer pipeline installation across four pipe-size groups: Small, Medium, Large, and Very Large. Three comprehensive industry case studies were utilized and evaluated using a common functional unit of 1,000 ft of installed pipeline, with the help of the system boundary concept. This conceptual method included construction-phase equipment fuel combustion for excavation/trenching, bedding, pipe placement, backfill/embedment, and compaction, while long-term operation and maintenance, pipe manufacturing, material transportation, traffic delay impacts, and full surface restoration were excluded because these components were not consistently reported across all case studies. The calculation framework followed a step-by-step process in which productivity rates were used to estimate active construction hours, equipment fuel consumption was calculated using active hours, fuel rates, utilization, and number of equipment units, and fuel use was converted into CO₂, CH₄, and N₂O emissions using emission factors from the United States Environmental Protection Agency (USEPA) Greenhouse Gas (GHG) Emission Factors Hub as per USEPA (2025). These emissions were then converted to CO₂e using global warming potential values, and carbon footprint cost was calculated by multiplying total CO₂e emissions by a carbon price of $0.215 per kg CO₂e. This value is equivalent to $215 per metric ton of CO₂e and was selected from the EPA social cost of greenhouse gases estimates for the 2026 emission year under the 2.0% near-term Ramsey discount-rate scenario as per USEPA (2023). Based on the selected case studies, the results showed that both CO₂e emissions and carbon footprint cost generally increased as pipe size increased from Small to Very Large. Since all results were normalized to the same 1,000-ft functional unit, this trend indicates that larger pipe sizes required greater construction effort, longer active construction time, and higher fuel consumption under the defined system boundary. The comparison also showed that the magnitude of emissions varied among the case studies because of differences in productivity rates, equipment fuel rates, active construction hours, and activity-equipment relationships. Overall, the findings indicate that pipe size controls the direction of the carbon impact trend, while productivity and equipment use strongly influence the total amount of CO₂e and carbon footprint cost. The practical application of this thesis research is that it provides a consistent framework for comparing open-cut pipeline installation projects based on construction-phase carbon impacts, allowing engineers, project owners, and decision-makers to identify how pipe size, productivity, equipment use, and activity-level fuel consumption influence carbon footprint and carbon footprint cost. Future research is recommended to expand the system boundary by including material production, hauling, surface restoration, traffic delay impacts, and long-term operation and maintenance when consistent data are available. Additional field-based case studies are also recommended to validate productivity assumptions, equipment utilization rates, and fuel consumption values, and future work may compare open-cut installation with trenchless alternatives using the same functional unit, system boundary, and carbon valuation method.
Keywords
Carbon Footprint, Cost, Productivity Rate, Open-cut Pipeline, Sanitary Sewer, Construction, System Boundary Concept
Disciplines
Construction Engineering and Management
License
This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.
Recommended Citation
Zakeri, Amir Reza, "A PRODUCTIVITY RATE-BASED COMPARATIVE CARBON FOOTPRINT COST ANALYSIS OF SMALL TO LARGE-SIZED OPEN-CUT PIPELINE INSTALLATION ACTIVITIES FOR SANITARY SEWERAGE CONSTRUCTION: A SYSTEM BOUNDARY CONCEPT" (2026). Civil Engineering Theses. 3.
https://mavmatrix.uta.edu/civilengineering_theses2/3