Doctor of Philosophy with a Major in Building Construction

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Doctor of Philosophy with a Major in Building Construction

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https://hdl.handle.net/1853/72547

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Degree Series

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School of Building Construction

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Now showing 1 - 10 of 13

Decision support system for the integration of sustainable parameters in single-family housing project delivery

(Georgia Institute of Technology, 2019-07-26) Tijo, Silvia Juliana

The implementation of sustainable practices in building construction has a direct impact on the financial, environmental, and social dimensions of sustainable development. Powering and heating buildings consumes enormous amounts of energy, and the residential and commercial building sector remains the largest end-use sector for energy in the U.S. The fact that actual energy consumption of this sector is two-fifths of the total energy consumption in the United States represents a significant economic opportunity for the country. In spite of the progress in performance and affordability of sustainable technologies, materials, and systems, the residential sector is behind in adopting these in single-family homes. Several building aspects must undergo evaluation under a holistic approach to achieving the technical and economic success of the project, but the fragmentation of the industry and the required expertise level for using existing simulating tools represent a barrier for this purpose. In residential projects, the selection of design and construction parameters occurs mostly during the early stages of the pre-construction process, while the majority of the building simulation tools require information from late stages of the process. During the early stages, the designer cannot easily predict the impact of decisions on building performance and cost. Furthermore, existing methodologies do not integrate project goals in early stages (i.e., pre-design, conceptual design, and schematic design) of the pre-construction process. Without these methodologies, selecting sustainable parameters for housing delivery and implementing sustainable principles is difficult, and consequently jeopardizes reaching sustainable goals for the building. The result of this research is a decision support system (DSS) that uses the analytic hierarchy process (AHP) and system dynamics (SD) to assist decision makers in the selection of construction parameters for sustainable housing. The proposed DSS integrates a set of project goals in the process of selecting alternatives, allowing a balance between the preferences of the decision maker and the solution that better fits those preferences. The approach focuses more on using DSS to support design exploration rather than finding optimal solutions. Given the iterative nature of the design process and the fragmentation of the construction industry, the proposed DSS provides information about costs, duration, and environmental impact of the alternatives at early stages of the project development. Therefore, an objective comparison of different design alternatives under identical conditions can take place, and the decision maker can learn from the effects of new decisions over other parameters that are interrelated. The outcomes of the research can help developers, architects, and home-owners to define sustainable parameters at early stages of the project delivery when the impact of their decisions is higher, and the cost of implementing changes is lower than in the later stages.
Sustainable energy technology, adoption, rebound, and resilience

(Georgia Institute of Technology, 2019-01-22) Hashemi Toroghi, Shahaboddin

While in the United States, centralized generation and distribution network are the basis of the current electric infrastructure, the recent surge in uptake of solar photovoltaic (PV) systems introduces a new avenue to decentralize this system. Furthermore, PV systems can substitute the grid electricity and increase the share of renewable energy sources. While by 2018, five states in the U.S. (California, Hawaii, Nevada Massachusetts, and Vermont) could reach 10% threshold for the share of solar sources in generating electricity, at the country level this share is still less than 3%; whereas in some other countries, such as Germany and Japan, it has already reached more than 6%. This dissertation examines the diffusion of PV systems from three perspectives, addressing three gaps in knowledge: an empirical study of the diffusion of PV systems in Georgia, a method to estimate renewable rebound effect, and a framework to quantify the resilience capacity of an electric infrastructure system with emergency electricity generators, including PV systems. Three studies present the primary contributions of this research. Study 1 examines the diffusion of PV systems in Georgia, identifies characteristics of adopters and patterns of adoption, and forecasts the future adoption of PV systems. Study 2 introduces a new approach to estimate the direct rebound effect, subsequent of a major adoption of PV systems. Study 3 presents a state-of-the-art framework that quantifies the resilience capacity of an electric infrastructure system with emergency electricity generators. The findings of the study 1 provides a benchmark for the future adoption of PV systems and highlights the impact of socio-economic and location-based factors in the diffusion of PV systems in Georgia. These findings can be used to shape a more effective policy, aiming to increase the share of PV systems, or evaluate the effectiveness of a policy. The finding of the study 2 opens a new avenue to compute the rebound effect and can support development of a policy to mitigate the renewable rebound effect in a targeted region. The finding of the study 3 can help system designers to customize the design of a resilient system based on its characteristics. The introduced framework can further be used to investigate improvement of the resilience capacity in an electric infrastructure system by increasing the penetration of PV systems, or other decentralized electricity generators in a region.
If these walls could talk: Automated performance measurement for building modeling decisions using data analytics

(Georgia Institute of Technology, 2018-01-10) Yarmohammadi, Saman

Building information modeling (BIM) is instrumental in documenting design, enhancing customer experience, and improving product functionality in capital projects. However, high-quality building models do not happen by accident, but rather because of a managed process that involves several participants from different disciplines and backgrounds. Throughout this process, the different priorities of design modelers often result in conflicts that can negatively impact project outcomes. There is a need for effective management of the modeling process to prevent such unwanted outcomes. Effective management of this process requires an ability to closely monitor the modeling process and correctly measure the modelers' performance. Nevertheless, existing methods of performance monitoring in building design practices lack an objective measurement system to quantify modeling progress. The widespread utilization of BIM tools presents a unique opportunity to retrieve granular design process data and conduct accurate performance measurements. This research improves upon previous efforts by presenting a novel application programming interface (API)-enabled approach to automatically collect detailed design development data directly from BIM software packages and efficiently calculate several modeling performance measures. The primary objective of this research is to create and examine the feasibility of a proposed automated design performance monitoring framework. The proposed framework provides the following capabilities: (a) non-intrusive and cost-effective data acquisition for capturing design development events in real time, (b) scalable and high-speed ingestion for the storage of design modeling data, (c) objective measurement of designer performance and estimating levels of effort required to complete design tasks, and (d) identifying optimal design teams using empirical performance information. In chapter 3, the utilization of modeling development information embedded in design log files that are produced by Autodesk Revit is proposed as a rich source of performance data. To this end, generalized suffix tree (GST) data structures are utilized to find common, frequent command sequences among Revit users. In addition to identifying the common command execution patterns, the average time it takes the selected modelers to execute command sequences is calculated. The obtained results demonstrate that there is a statistically significant difference between the modelers in terms of the time it takes them to conduct similar modeling tasks. Chapter 4 utilizes modeling software solution’s APIs to automatically collect and store timestamped design development information. The proposed passive data recording approach allows for the real-time capture of comprehensive user interface (UI) interaction and model element modification events. The proposed framework is also implemented as an Autodesk Revit plugin. An experiment is then conducted to verify the accuracy of this plugin. Throughout this experiment, manual recordings of model development events were compared against the automatically generated plugin output. Chapter 5 outlines the details of an approach to identify the optimal design modeling team configuration based on automatically collected performance data. To this end, an experiment is conducted to capture data using the developed Revit plugin. Experiment participants’ individual production rates are estimated to establish the validity of the proposed approach to identify the optimal design team configurations. The presented approach uses the earliest due date (EDD) sequencing rule in combination with the critical path method (CPM) to calculate the maximum lateness for different design team arrangements. The primary contributions of this study to the state of knowledge are as follows: (a) proposing a tailored string mining algorithm that is capable of extracting meaningful information from timestamped design development data, (b) developing a framework based on APIs to automatically collect design modeling data, and (c) creating a mathematical model to estimate design modeling project completion times based on individual performance data and project requirements. This study contributes to the state of practice by (a) allowing design project managers to gain an unprecedented insight into the evolution of a building model using the information embedded in design log files, (b) helping design managers to acquire progress information without the need to manually record and report data, and (c) enabling design managers to identify an optimal modeling team arrangement based on automatically captured, quantitative performance information.
The effect of military construction transformation on project cost and schedule within the United States Army Corps of Engineers South Atlantic Division

(Georgia Institute of Technology, 2017-11-07) Westcott, Matthew

The United States Corps of Engineers (USACE) has been the primary Construction Agent of the United States Army and Air Force. Its members are considered the experts in project delivery for the Department of Defense (DoD). In 2006, the Base Realignment and Closure Program (BRAC) and the Global War on Terrorism (GWOT) led to increased workload which caused the USACE to adopt the Design-Build project delivery process as a primary means of project delivery in an effort to leverage the method’s ability to deliver projects at a lower cost and faster delivery time as compared to conventional methods. The focused use of the Design-Build process was to become the primary business practice of USACE after the BRAC/GWOT period, replacing the traditional Design-Bid-Build process that had dominated the USACE landscape for 50 years. The USACE Commander’s intent behind the Design-Build incorporation was to realize a 15% cost savings and a 30% reduction in delivery time over the traditional method. This measure of success would serve as a guide to the USACE for future business practices. Military Construction Transformation, or MILCON Transformation, was the name designated to the Design-Build process when it was approved as the primary form of project delivery in the USACE in 2006. Since then, the four-year spike in project workload brought about during the BRAC and initial GWOT period has been diminished, and the business practice has taken some time to incorporate refinements based on lessons learned during the BRAC/GWOT period. In 2009 the Engineer Inspector General (EIG) was commissioned to measure the performance standards given by the USACE Commander, but after conducting only interviews of district chiefs across the USACE, the EIG was unable to quantify any project data that was relatable to the Commander’s metric (EIG, 2009). Independent studies evaluating the performance of Design-Build in various domains of the public sector have been conducted in the past, however a measurement of this specificity has yet to be conducted. The scope of this thesis is to evaluate the MILCON Transformation performance of the of the South Atlantic Division during 2002-2014. Project data was gathered from the USACE-internal automated information system, Enterprise Data Warehouse (EDW). Only MILCON, vertical construction project data was collected from EDW, and four hypothesis based off cost and time were developed for testing. Five project milestones for 304 projects that qualified for evaluation were evaluated using 180 separate Welch’s T-tests to test for a statistically significant difference between Design-Bid-Build and Design-Build. Of the 180 T-tests conducted, 37 were in support of the alternate hypothesis, which stated that there was a statistically significant difference with 95% confidence between the two project delivery models. Projects were analyzed in three different ways. First, projects were distributed between the two project delivery populations and all performance metrics regarding cost and time were analyzed from the Division level. Next, projects were analyzed by building type, to find out if there were any specific types of buildings where Design-Build performed better than Design-Bid-Build. Finally, projects were analyzed by District, where projects from each of the 5 Districts within the South Atlantic Division were analyzed to determine if any one District executed Design-Build more successfully than another District. From this analysis, it was found that the 15% reduction of cost by use of Design-Build was realized from a Division level. However, in no circumstance was the target 30% reduction in time realized for the Division, any District, or any specific building type. Results were then presented to a focus group of leaders within the USACE South Atlantic Division to gather insight on why the USACE Commanders goals were not completely met. Since literature pointed to Design-Build as being a source of lower cost and time in the public sector, data results warranted further insight as to why the USACE struggled to gain full value from the Design-Build delivery model. The focus group validated the data and findings while attributing discovered performance metrics to operational tempo, manpower, and conservative management. From these results, the researcher submits recommendations on how the USACE can realize greater value from the use of Design-Build.
Analyzing uncertainty in the price of materials and financial risk management strategies

(Georgia Institute of Technology, 2017-05-11) Ilbeigi, Mohammad

Significant volatility and unprecedented uncertainty in the price of asphalt cement is a serious challenge for both contractors and state DOTs with regards to proper cost estimating and budgeting of transportation projects. Previous studies indicate that owner organizations often overpay for projects under fixed-price contracts that transfer the material price risk to contractors due to increased risk premiums and hidden contingencies in contractors’ submitted bid prices. A common method widely used by state DOTs for handling the issue of extra risk premiums in submitted bid prices and avoiding overpayment to contractors is to offer price adjustment clauses (PACs) in contracts. A PAC is a risk sharing contractual mechanism that guarantees an adjustment in payment to contractors based on the size and direction of the material price change. Although uncertainty in the price of asphalt cement is a serious challenge for both contractors and state DOTs and many transportation agencies utilize PACs to control consequences of material price volatility, there is little knowledge about analyzing uncertainties in the price of asphalt cement and actual performance of PACs. This dissertation aims to analyze uncertainty in the price of asphalt cement and examine performance of PACs in highway construction projects. After a comprehensive review of the existing body of knowledge about uncertainties in the price of critical materials in transportation projects and PACs, time series analysis is conducted and four univariate time series forecasting models are created to forecast future price of asphalt cement. The results of the time series forecasting show that all four time series models can predict the future values of asphalt cement price with proper accuracy but among the four models, the ARIMA and Holt Exponential Smoothing models are the most accurate prediction models with less than 2% error. Then, ARCH/GARCH time series analysis is conducted to quantify and forecast level of uncertainties in the price of asphalt cement. The results of this step can help transportation agencies systematically measure, analyze and forecast the uncertainties in the price of asphalt cement and implement their risk management strategies at the right time. In next step, impacts of offering PACs on submitted bid prices for major asphalt line items are analyzed using multivariate regression analysis. Finally, effects of offering PACs on dispersion of submitted bid prices and number of bidders are analyzed using system monitoring processes.
Stakeholder alignment strategies for highway infrastructure public-private partnerships

(Georgia Institute of Technology, 2017-03-31) Mostaan, Kia

The U.S. Department of Transportation (U.S. DOT) and state DOTs across the nation seek private investments to leverage their shrinking financial resources. Involvement of the private sector in financing and delivery of highway public-private partnerships (P3s) in the United States has experienced various limitations and challenges. The lack of standard approaches for P3 project delivery as well as public agencies’ varying levels of maturity in P3 implementation have negative impacts on successful project delivery. There is a need for research to determine the variability in public sector’s project delivery practice, due to its negative impacts that lead to market inefficiency and unpredictability. It is necessary to evaluate and analyze improvement strategies that can standardize P3 project delivery and enhance partnership alignment between the public and private sectors. The overarching objective of this study is to propose recommendations and enablers for improving alignment of public and private sectors in P3s. This study employs a three-phase combinatory research approach to achieve the research objectives. At first, a national survey of state DOTs is conducted to determine the degree of variability in public sector’s P3 practice. Following the public sector survey, twenty-five P3 experts are identified and selected from organizations that are active in the U.S. P3 market. A structured interview protocol is utilized to conduct interviews consistent with study questions and document the results. The third and final phase of the study methodology prior to concluding the analysis and providing recommendations is to conduct case studies of three mature P3 programs (Florida, Texas, and Virginia DOTs). The final phase of the research methodology aims to demonstrate best practices for P3 implementation and sustainment through case studies of agencies in the United States. While there is ample research on P3s in general, this study focuses on the alignment of public and private sectors in highway P3s. This study identifies the leading factors and issues that affect P3 decision-making by the public sector and the inconsistency in P3 implementation across project phases. This study also determines and evaluates the factors that can influence the public and private sector alignment in U.S. P3s and compares them with international best practices. Finally, by identifying recommended strategies and enabling mechanisms, this research aims to mitigate the lack of alignment between the public and private sectors in the U.S. P3 market. This study also demonstrates how mature P3 programs in the U.S. have achieved sustained partnerships. The final contribution of this study is a set of detailed recommendations for alignment of public and private sectors in U.S. P3s. The findings of this study are relevant for the U.S. P3 market, but may also be useful for planners and policy-makers in other countries. The major stakeholders impacted by this research involve public sector agencies, such as state DOTs, state and national infrastructure banks, metropolitan planning organizations (MPOs), permitting agencies and private sector stakeholders, such as multinational development companies, contractors, investments banks, procurement, financial and legal advisors.
Change order insurance policy (COIP) in the U.S. design and construction industry: Is there any likelihood of acceptance?

(Georgia Institute of Technology, 2016-11-15) Ghaziri, Louay

Throughout the construction industry and for a long period of time, the issue of change orders poses as an undesirable problem in maintaining the efficiency and cost of construction projects. This research study will investigate a new mechanism for dealing with such problems. Accordingly, it will propose sharing the risk of cost overrun as a consequence of change orders, with a third-party insurance company, which can also be known as Change Order Insurance Policy (COIP). In order to check for the possibility of implementing such a policy in the U.S. market, this study will primarily test for the acceptance rate of design and construction professionals spanning the industry. Accordingly, participants were chosen from a list of 25 top construction firms found in The Atlanta Business Chronicle. Two anonymous surveys were then administered to assess the extent to which construction-affiliated professionals accept the concept of using COIP. Accordingly, results showed that the majority of participants do not accept the idea of using such a policy. However, program managers and owners did portray higher acceptance rates, as opposed to architects and contractors.
Assessing the effects of augmented reality on the spatial skills of postsecondary construction management students in the U.S.

(Georgia Institute of Technology, 2016-04-18) Kim, Jeff

There is a continual challenge within the construction industry to meet schedule, budget, and quality expectations. At the same time, there is an underlying problem where the older and more experienced workforce is retiring from industry at a faster rate than the newer workforce can replace them. As the more experienced workforce departs from the industry, they are taking with them much-needed skills and experience that fail to get transitioned to the newer and less experienced workforce. Among these skills are spatial skills. The construction industry has already caught on that this is a serious problem that they must contend with, and so, they have looked to the postsecondary institutions to help resolve it. However, the postsecondary institutions have a problem of their own, whereby they commonly default to passive teaching techniques that are not well suited to teaching spatial skills. So, therefore, there is a need to graduate construction management students with better spatial skills in order to meet the necessities of industry. Along with this, is the need for academia to reconsider teaching styles to better train spatial skills. Spatial skills, it has been found, are better retained when active and collaborative teaching engagements are arranged. Therefore, identifying and testing a practical and non-interfering classroom tool that students can easily use, would be the most favorable way to overcome academia’s tendency towards passive teaching. Spatial skills are needed in every part of the construction industry. In fact, everyday simple tasks require spatial skills and while these skills are honed over time, more refined skills, capable of interpreting abstract space, are required to assemble a complex construction project. Construction projects are getting more complex and often the design involves some measure of abstract thinking. Teaching these abstract-based spatial skills in postsecondary institutions has typically been done through drafting and plan reading courses, with some success. However, the need from industry is not being fully met with these skills and so an alternative solution is recommended. While Building Information Modeling (BIM) has become an adequate solution to aid in the understanding and planning of highly abstract designs, successfully using it requires excellent spatial skills. Consequently, it would be advantageous if those spatial skills were developed before students were introduced to BIM. Augmented reality is a collection of technologies that allows a user to view the “real” world with additional information that is intended to provide a better understanding of what is being observed. Augmented reality already has applications in many industries and is fast becoming a proven technology. With the availability of smaller and more powerful consumer mobile devices, augmented reality has the potential of becoming a more ubiquitous and practical tool. Recognizing that this technology can be practical, non-interfering, and known by the masses makes it an excellent solution for the classroom. Therefore, this research will study the use of an augmented reality tool to determine if there is an improvement of spatial skills in terms of accuracy, time to execute, and the retention of concepts over time. Furthermore, a separate analysis will be conducted to determine if the teaching tool is a benefit or disruption to the overall learning experience.
Decision support system for masonry labor planning and allocation considering productivity and social sustainability

(Georgia Institute of Technology, 2015-11-16) Florez, Laura

Masonry construction is labor-intensive. Processes involve little to no mechanization and require a large number of crews made up of workers with diverse skills, capabilities, and personalities. Relationships among crews are tight and very dependent. Often crews are re-assembled and the superintendent is responsible for assigning workers to crews and allocating crews to different tasks to maximize workflow. This dynamic environment can influence the motivation of workers and impose pressure and stress on them. Workers, unlike other resources, have their own needs and requirements beyond the financial compensation for their work. Workers place a great value on requirements such as certainty about work assignments, matching assignments to career development goals, and work satisfaction. If managed properly, workers may bring considerable benefits to both the project and the contractor. A project that links workers to career goals not only allows contractors to develop more qualified staff for its future projects, but also gives the worker opportunities for career growth and development. Additionally, job satisfaction and efficiency increases from suitable worker assignment and consideration of tasks. Therefore, the study of sustainable labor management practices is of interest in masonry construction and other labor-intensive industries. A mixed-integer programming (MIP) model enables the integration of workers needs and contractor requirements into the process of labor allocation. Furthermore, the model can be used to quantify strategies that maximize productivity, quality of work, and the well-being of workers. Developing such a model is a necessary task. To plan and manage masonry construction, the contractor has to take into account not only multiple workers with different characteristics but also rules for crew design and makeup and project requirements in terms of personnel needs. Providing an analytical description of all the needs and requirements is challenging. Therefore, to determine labor management practices that indeed maximize production and maximize workers satisfaction, the model needs to realistically represent the realities in masonry construction sites and staffing practices, while remaining computationally manageable such that optimization models can be derived. This dissertation proposes a decision support system (DSS) for sustainable labor management in masonry construction that takes into consideration information on workers and job characteristics with the intention of assisting decision makers in allocating crews. Firstly, semi-structured interviews were conducted with masonry practitioners to gather perspectives on labor requirements, rules for crew design, and drivers for crew makeup. Secondly, a model that incorporates realities was implemented. The model supports masonry contractors and superintendent in the challenging process of managing crews, that is, to determine the composition of each crew and the allocation of crews to maximize productivity and workflow while considering workers’ preferences and well-being. With the DSS, project managers and superintendents are not only able to identify working patterns for each of the workers but also optimal crew formation and investment and labor costs. Data from real case study is used to compare the schedule and allocation on the site with the one proposed by the model. The comparison shows the model can optimize the allocation of crews to reduce the completion time to build the walls while maximizing the utilization of masons and outlining opportunities for concurrent work. It is expected that the DSS will help contractors improve productivity and quality while efficiently managing masonry workers in a more sustainable way. The contributions for the masonry industry are two-fold. Firstly, the proposed model considers a set of rules that masonry practitioners typically use to design crews of masons and analytically captures the realities of masonry construction jobsites when managing labor. Secondly, it attempts to quantify and mathematically model the practices that contractors use for crew makeup and evaluate labor management allocation both in terms of contractor requirements and worker needs. Literature review indicates that the existing models for labor allocation have not taken into consideration masonry site realities. An optimization framework, which combines masonry site realities from the semi-structured interviews is proposed. The framework results in a MIP model that is used to solve a crew scheduling and allocation problem. The model is formulated to determine which masons are in a crew and to assign crews to the different walls in a project. Additionally, it is used to evaluate crew design strategies that maximize productivity.
Feasibility of implementing prefabricated U.S. products and methods for residential construction in Thailand

(Georgia Institute of Technology, 2014-06-24) Ngoenchuklin, Chawin

Prefabricated construction has been a common construction method for American construction for more than a century. The concept of build it fast in the most economical way has not changed since the beginning; however, the new technologies have been developed to suit the modern world prefabricated construction. The new technologies are not only help contractors and owners get their building faster and more economical but they also help reduce construction waste and produce high energy efficiency buildings which result in a long term benefit to projects. On the other hand, prefabrication for residential construction has been used in Thailand for only less than two decades. However, the prefabrication construction in Thailand has grown rapidly from the past five years. Recently, there are many new developers, and contractors who have switched from a traditional construction to prefabrication to keep up the rising in Thai residential market. Moreover, the new minimum wage policy from Thai government has hit Thai construction business very hard. The labor cost has raised more than 40% in some area (Thai Department of labor, 2013) since 2012. Thai developers see prefabrication as a future and ready to invest more in this type of construction. (Krunthep Thurakit, 2013) Currently, there are many construction products from the U.S. which have been using in Thai construction. Thai people are familiar with American product, therefore, U.S. prefabricated products and methods can easily make a quick transition to Thai prefabricated construction. The intention of this research is to find the prefabricated residential construction products or method from the U.S. that can be used for developing the new or similar products that compatible with Thai market. There are a lot of strong potential prefabricated construction products and method in the U.S. which can be very useful in Thailand. Those can be benefit to both American investors and Thai construction. The selected products or method will be review and investigate in the categories such as performance, compatibility, availability, price and ability to adapt to Thai market.