VTechWorks Repository :: Browsing by Author "Beliveau, Yvan J."

Browsing by Author "Beliveau, Yvan J."

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Analysis of Means and Methods of Construction Improvement in Single Family Housing in Mid-Atlantic Rural University Towns
Obiso, Melissa Lynn (Virginia Tech, 1997-05-07)
The goal of this study was to determine if innovative building methods and materials have the potential to lead to better productivity. Furthermore, this study endeavored to establish the premise that builders who use pre-fabrication, pre-assembly, and modular materials and building methods will perform more productively than those builders who don't. These ideas were pursued by first reviewing the history of home building in the United States to determine trends and patterns in innovation. The experimental phase of the study was accomplished by interviewing local and regional builders about their actual methods of construction used for residential construction. These methods were then analyzed to determine the contribution of these methods to the builder's productivity. Not surprisingly, builders choose one specific type of construction to build a majority of their projects. They use these methods because they are comfortable with them and confident in them; they know they work, and they believe that they are an efficient means of producing a house. It was determined that residential builders in these rural university towns tend to use traditional wood framing construction methods above all of the other available methods. However, there are builders who do use less-conventional methods including: wall panels, pole construction, and modular unit construction. The actual building methods used by builders are somewhat determined by several factors, including: project type, company size and structure, and area of the country. Furthermore, the builders who choose to use non-traditional construction methods with regularity tend to have higher rates of productivity as well as the ability to take on more projects. Higher rates of productivity and the ability to take on more projects have the potential to give builders a competitive advantage over their competition.
Analysis of Thermal Energy Collection from Precast Concrete Roof Assemblies
Abbott, Ashley Burnett (Virginia Tech, 2004-08-11)
The development of precast concrete housing systems provides an opportunity to easily and inexpensively incorporate solar energy collection by casting collector tubes into the roof structure. A design is presented for a precast solar water heating system used to aid in meeting the space and domestic water heating loads of a single family residence. A three-dimensional transient collector model is developed to characterize the precast solar collector's performance throughout the day. The model describes the collector as a series of segments in the axial direction connected by a fluid flowing through an embedded tube. Each segment is represented by a two-dimensional solid model with top boundary conditions determined using a traditional flat plate solar collector model for convection and radiation from the collector cover plate. The precast collector is coupled to a series solar assisted heat pump system and used to meet the heating needs of the residence. The performance of the proposed system is compared to the performance of a typical air to air heat pump. The combined collector and heat pump model is solved using Matlab in conjunction with the finite element solver, Femlab. Using the system model, various non-dimensional design and operating parameters were analyzed to determine a set of near optimal design and operating values. The annual performance of the near optimal system was evaluated to determine the energy and cost savings for applications in Atlanta, GA and Chicago, IL. In addition, a life cycle cost study of the system was completed to determine the economic feasibility of the proposed system. The results of the annual study show that capturing solar energy using the precast collector and applying the energy through a solar assisted heat pump can reduce the electricity required for heating by more than 50% in regions with long heating seasons. The life cycle cost analysis shows that the energy savings justifies the increase in initial cost in locations with long heating seasons but that the system is not economically attractive in locations with shorter heating seasons.
Analytical Framework to Study Energy Efficiency Policy Portfolios across Countries/States
Bhattacharjee, Suchismita (Virginia Tech, 2010-07-22)
Energy conservation and implementation of effective energy efficiency policies have become imperative to curbing the escalating consumption of energy. The imbalance in the supply and demand of a country's energy has increased the importance of implementing energy efficiency policies. Proper replication of strategic energy efficiency policies that are known to be successful in one country, along with development of new approaches, can be helpful in developing the energy policy portfolio of another country. Some OECD (Organization of Economic Cooperation and Development) countries like Denmark, Finland, France, Germany, Italy, the United Kingdom and the United States have benefited from their energy policies during the most recent energy crisis. The motivation of this research is to provide a tool for developing countries, which are still in the stage of formulating their energy efficiency policies, to compare energy efficiency policy portfolios across countries. These countries can improve their energy efficiency policy portfolios based on lessons learned from the developed countries. The research develops a framework to compare energy efficiency policy portfolios across countries / states. Although this framework can be adopted for any type of energy policy, targeting any sector with few modifications, the current focus is on policies that target the residential building sector to reduce energy consumption. The research begins with identification of the functional domains that influence human behavior–people, economy, environment and technology–followed by identification of the factors affecting household energy consumption. It uses the four functional domains as the evaluation framework's four axes. The various factors affecting household energy consumption are positioned in the framework based on association with the functional domains. The energy efficiency policies implemented in a country are positioned in the same framework based on the pattern of diffusion of each type of policy. In addition, a prototype method is developed to identify the factors targeted by each energy efficiency policy implemented in a country. This evaluation method allows for a uniform assessment process of how energy efficiency policies target specific socio-economic factors that are known to affect energy consumption. The proposed framework will facilitate the work of policy makers and other decision makers with a powerful tool for evaluating and comparing their individual policies, or their complete portfolio of energy efficiency policies, to those from other states or countries, and to benefit from the lessons learned.
An application of the hyperbolic navigation radio system for automated position and control
Purdy, Daniel S. (Virginia Tech, 1989-08-05)
As automation in the construction site of the future becomes a reality, position location systems are necessary to provide real-time data to an operator. This thesis addresses problems associated with development of a real time automated position location system using a method similar to hyperbolic navigation methods. The Automated Position and Control (APAC) project is a joint effort between the Civil and Electrical Engineering departments at Virginia Polytechnic and State University and Bechtel Eastern Power Corporation.
An Approach to Organizational Intelligence Management (A Framework for Analyzing Organizational Intelligence Within the Construction Process)
Jung, Younghan (Virginia Tech, 2009-07-31)
The construction industry is inherently multidisciplinary and has adopted many intellectual and technical business improvements from other industries in an effort to optimize productivity. In construction, management inactivity is the root cause of 30% of non-productive time. This has created an opportunity and need for standardized and structured repeatable procedures for new managerial strategies. A theoretical framework for Organizational Intelligence (OI), which encompasses the procedural ability of an organization to efficiently process, support, measure and reason through management issues, is proposed. The elements of organizational intelligence are divided into three types of intellectual capital: Human Capital, Organizational Capital, and Relational Capital. The performance of an organizational activity depends on the quality of these capitals that are available within an organization. An organization's Human Capital (HC) is the human resources within the organization that can be deployed to acquire and apply its knowledge to perform, respond, or control designated work with available organizational assets. Organizational Capital (OC) refers to the assets available to the organization to support the performance of organizational activities Relational Capital (RC), which combines human capital and organizational capital to perform, is needed specific organizational activities. In addition, the research uses human cognitive abilities as the basis of a fundamental structure from which to form new organizational cognitive abilities that are capable of presenting management processes as critical value creations. Organizational cognitive ability is suggested to define appropriate organizational resources in order to integrate and determine a rational selection of applicable technologies and improvements. This ability can develop knowledge with interconnected variables, namely intellectual capital, managerial process, and performance, all of which support organizational intelligence. From the theoretical framework for OI, a prototype (Intelligibility Learning Model), which determines the role of relationships in an organization's operation and use of resources, is formulated. A case based research then applies the prototype to a managerial process in the construction industry. The case research demonstrates that the Intelligibility Learning Model (ILM) could be use effectively by industry decision makers to improve performance of organizational activities. The identification and application of a theoretical framework constitutes the foundation of a new managerial theory, Organizational Intelligence Management. It thus provides a fundamental foundation that explains how the construction processes, knowledge, skills, and resources used for managerial activities function. This theory contributes and establishes a better understanding of management, from organizational resources through to final production.
The Automated Laser Position System - ALPS
Lundberg, Eric J. (Virginia Tech, 1989-09-15)
The construction industry needs an accurate real-time positioning system. Such a system, if successfully implemented, would lead to significant increases in the performance of many construction operations. This thesis presents the Automated Laser Position System (ALPS) for accurate real-time positioning. ALPS is a spin-off of the Automated Position And Control System (APAC) research, sponsored by the National Science Foundation under grant DMC-8717476. The ALPS concept has three primary components: a rotation laser, laser detectors and a central processing unit. ALPS generates both horizontal (X,Y) and vertical (Z) position information. It is mathematically predicted that ALPS could produce accuracies of ± 17 mm in the horizontal and ± 5,9 mm in the vertical, at a range of 400 m. Position measurements would be updated 50 times a second.
Case studies of employee participation programs in construction and their effects on absenteeism
Cox, Robert F. (Virginia Tech, 1994-11-05)
In recent years, the construction industry has shown a steady decline in productivity and worker morale, while experiencing an increase in absenteeism (Maloney, 1991; CII, 1982). This has had a tremendous economic and motivational impact. This dilemma coupled with the fast-paced growth of competition has led many construction companies to look for new ways to improve overall performance and reduce absenteeism. For over twenty years construction researchers have proposed various employee participation programs (EPP’s) as a possible management method to counter the decline in productivity. The suggested modern styles of management included applications such as: quality circles, goal setting, participative decision making, work crew selection, work teams, and more recently, Total Quality Management / Continuous Improvement Programs. While these past research efforts proposed such approaches, they are still not considered standard practices for the industry. Some leading edge contractors are working towards adaptation of these new management methods in hopes of leading their competition. This research studies four construction firms and their efforts to implement Employee Participation Programs (EPP’s) as part of their movement towards improving quality management. Each of the four cases utilized a “top-down” implementation approach which began with the management, executive, office staff, and supervisory personnel (company level). At the time of this study, the case companies had not established EPP’s at the field level of their organizations. The research investigates employee participation programs and their effects on absenteeism. The research utilized F-Tests (analysis of variance), factor analyses, T-tests, and regression analyses in support of its findings. The overall results show that EPP’s can have a negative influence on the variation in absenteeism behaviors. The findings indicate that the EPP’s affects over time increase as the program matures. The study concluded that employee perception of their significance and their proximity to the participation played a major role in the overall effects on absenteeism. The study found that the decision / problem environment was the single best predictor of changes in absence behaviors. Significant absenteeism trends were identified in Post-EPP measurement periods. The outcomes of this study were secured through the development and pilot use of the Employee Participation Program Profile Classification System (EPP-PCS).
Case-based Study and Analysis of Integrated Project Delivery (IPD) Approach and Trust-Building Attributes
Pishdad-Bozorgi, Pardis (Virginia Tech, 2012-07-06)
The goal of this Ph.D. research is to explore the IPD contractual strategies, to highlight the elements that distinguish IPD from a traditional delivery approach, to analyze how trust-based relationships are established and promoted, and to demonstrate if/how trust and IPD contractual principles correlate. The result of this research will promote the understanding of the industry on the strategies that promote trust and integration through real world case studies. The significance of the subject becomes more evident when reflecting on the current industry's crisis: productivity loss, fragmented delivery process, and lack of trust and collaboration. Through a literature review a Project Delivery and Contracting Strategies (PDCS) framework, an IPD traits framework, and a trust-Building framework are developed. The frameworks are used as the organizational tools to structure and inquire relevant information on the two IPD projects. An expert panel is assembled to discuss the frameworks and the findings of literature analysis and to seek the industry's insight on the units of analysis for contract, and the units of measure for trust. The units of analysis for contract are elements, such as strategies for risks/rewards sharing, liability considerations, decision making authority, and governance. The units of measure for trust are the individuals' perception, and the trust-building attributes as outlined in table 4-1. Two IPD projects were selected and their contract agreements were studied. A questionnaire including both open-ended questions and multiple choice questions was developed based on the information collected through: 1. the IPD agreements in each case study, 2. the literature-based frameworks on trust and project delivery contracting strategies. Accordingly, two IPD case studies are developed following the analysis of their IPD agreements and the individual one-on-one interviews with their key IPD players. The trust-building framework presented in this work includes a series of techniques that the contracting parties can follow when establishing their contractual and managerial strategies and also when interacting with each other.
Characterizing Virtual Prototype Constructability Programming for the Pictographic Instruction of Procedure
Johnston, Brendan Ashley (Virginia Tech, 2012-10-08)
The modern design-construction boundary is facing an unprecedented moment of evaluation. Global applications of building information modeling, including virtual prototyping, factory-based component procurement and industrialized site production are only a few of the forces that threaten to engulf the established façades of architecture, engineering and construction practice. Those professional identities that are unable or unwilling to reach deeply into this oncoming torrent of interoperability, integrated delivery, and infinite domains will be lost. It is even possible that the language of building culture will be washed away forever. Preparations should be made. This research proposes to strengthen available built-project communications. It does so by examining the natural architectonic relationships which exists at the most primitive level of production — about the assembly task. A work and its procedures are investigated through the programming interface of a Virtual Prototype (VP) modeling system. With visualized constructability as its goal, this study highlights the character of VP programming as it translates between design and production information with digital specificity. The results of that investigation fashion a test of a new production communications language with the potential to enrich and refresh the insulate expressions and hollow specification of traditional design communications.
Commercialization for Innovative Products in the Residential Construction Industry
McCoy, Andrew P. (Virginia Tech, 2008-07-25)
This work presents the development of a new framework for the commercialization of innovative products in the residential construction industry. It is the aim of this work to identify commercialization decisions, actions, risks, barriers and accelerators specific to the residential construction industry market that will increase the acceptance of product innovations for those developing them. Commercialization is broadly defined as the process of developing a business enterprise from an idea, through feasibility and implementation, to its acceptance into a market (USDOE 1999, Goldsmith 2003). Commercialization frameworks describe the concurrent decisions and actions along the innovation development process, optimizing all of the technical and business decisions required for a successful introduction to the marketplace. Successful commercialization frameworks serve as a form of development plan, promoting solutions to questions and problems that arise along the development path. This research derives such a framework for the commercialization of innovative products and makes it specific to residential construction through the following tasks: 1. Understanding standard terminology: defining innovation and commercialization as they relate to this work. 2. Creating a lens for the unique nature of commercialization in this industry: deriving a commercialization framework (matrix) from the research literature in business, construction, and concurrent engineering, capable of accepting later alterations. 3. Understanding the manufacturer's role and risks: conducting case study interviews for fifteen innovative residential construction products that specify important tasks, risks and benefits for commercialization. 4. Understanding the role, risks and benefits of builders, as users of innovation: comparing case studies and workshop surveys of many residential construction industry players that focus on the builder to establish parameters for the innovation commercialization matrix. 5. Linking both manufacturer and builder: comparing manufacturer commercialization best-practices with builder adoption patterns for innovative products over time.
A Common Taxonomy for Modeling Construction Operations
Al-Masalha, Sami (Virginia Tech, 2004-08-02)
The construction industry continues to strive for new ways to improve construction operations. This requires better understanding and analysis of these operations, which necessitates a way to systematically capture and analyze the diverse elements involved. The dynamic nature of construction is very difficult to describe using existing computer simulation and modeling systems. What is needed is rather a common construction language and a comprehensive modeling system that can be used to capture and analyze construction operations and potentially lead to improvements. A new taxonomy and its use for modeling construction operations are developed here. This taxonomy identifies a hierarchical representation of construction projects based on operational considerations. The hierarchy consists of seven levels: product, assemblies and subassemblies, components, operations, processes, physics, and control. The hierarchical levels were established by looking in the ways that construction field operations are being carried out. The new modeling system successfully accounts for the geometric and physical representations of not only the product but also the processes involved in shaping the product. Six major blocks of construction knowledge are described and information about the interaction processes required to model construction operations in a logical way is provided. An overview of the current state of modeling and simulation techniques that are used to develop and evaluate construction operations is presented. The advantages and limitations of physical-based modeling, 4D-CAD, and virtual modeling techniques as an integral part of the developed taxonomy are identified. The potential uses of robotics and automation opportunities in construction are described. Also, distribution of work between humans and tools and equipment based on their physical and information contributions are reviewed and analyzed. Classifications of construction work at different levels of detail are described to identify which operations can be usefully modeled and the appropriate level of the model. Two practical case studies are discussed that show the capabilities and potential uses of the developed taxonomy. The first case study describes the modeling process of the fabrication, assembly, and erection of steel structures. The second exploratory case study shows the potential use of the developed modeling in improving the heat recovery system generator's (HRSG) erection process. Also, prototype models and 3D models of the HRSG assemblies are developed. Both case studies validate with great confidence the use of the developed taxonomy as a direct support tool that captures the diverse elements and enhances the modeling and analysis to improve construction operations.
Controlling the cost of workers' compensation in construction: making the pieces fit
Decker, Lisa (Virginia Tech, 1995-05-03)
The costs related to workers compensation in the construction industry are rising every year, with no end in sight. Construction professionals can no longer afford to wait for others to solve the problem through new legislation or rate control. Controlling workers’ compensation costs is a puzzle that can be solved by contractors if they have all of the “pieces” and a guide. This thesis supplies the “pieces” by educating the reader on the terminology, intricacies, and problems of the workers’ compensation system. It also serves as the guide to solving the puzzle by discussing management techniques that are currently being used to control workers’ compensation costs, and their effectiveness. Costs are not the only concern of construction professionals as they turn their attention to workers’ compensation. It is mandatory that every company that is eligible have an Experience Modification Rating (EMR) that is applied to its premiums to adjust for its actual insurance performance. The EMR has gained a new function, however. Owners are using the EMR as a prequalifier in bidding, suggesting that the EMR is an accurate predictor of a contractor’s safety performance. This assertion is not entirely true. This thesis addresses the inadequacy of the EMR as an indicator of safety performance and suggests alternative measures of a contractor’s safety. The management techniques cited, and the assertions made with regard to the EMR, in this thesis are based on the opinions of the forty-two (42) contractors and over one thousand six hundred (1600) construction workers who participated in a study conducted by the Construction Industry Institute’s (CII) Workers Compensation Task Force. The findings of this thesis were made a part of the task force’s CII Source Document.
Cost tracking and productivity reporting
Husson, David Edward (Virginia Tech, 1987-08-05)
The objective of this report is to examine the need for an on-site computerized cost control system in the construction industry. The background of the construction industry leading to the need for such a system is discussed. The report then covers the technologies available for cost tracking and productivity reporting. Finally, a solution to the problem involving the reports and information required for the compilation of the reports as well as a model cost tracking and productivity reporting system are discussed.
Decision-Making Framework for the Selection and Design of Shading Devices
Olbina, Svetlana (Virginia Tech, 2005-02-11)
Most shading device systems installed in windows or glass walls are used only for protection from overheating and glare, neglecting other possible functions, such as increasing the daylight level in the space or collecting solar energy. The blinds are usually made of opaque or translucent materials, and if they are partially open/closed or completely closed, a direct view to the outside is blocked. A balance between a sufficient amount of daylight and protection from overheating of the space in summer is not often achieved due to inappropriate control of the blinds’ tilt angle. There is also a need for specific guidance for the selection and design of shading device systems in the windows. This research develops a general decision-making framework (DMF) that can be used by architects and manufacturers of shading devices. The general DMF is a guide for the user in analyzing shading device performance in the process of selection/design of the shading device. This research also develops a specific DMF to better understand and validate the general DMF. The specific DMF, based on illuminance and luminance, is used for an analysis of daylighting performance of shading devices to select the best possible existing system or new system among several alternatives. Architects or manufacturers of shading devices, as the users of the DMF, analyze various systems of blinds applied on a particular building and at a given location. The users of the DMF can apply either an experimental procedure or computer simulation that provides information about illuminance and luminance levels in the space. Based on the analysis of the results of the experiments or simulations, the user of the DMF decides which blinds to select. The specific DMF proposes a methodology for both the analysis of the daylighting performance and for the process for making a decision based on the results of the analysis. A case study is conducted in order to validate the DMF. Three types of shading devices are tested: an existing system, a patented system, and a new system, proposed by this research. The shading devices are installed in an office space located in Roanoke, Virginia. The software Autodesk VIZ 4 is used to simulate daylighting performance. The output information, such as illuminance and luminance levels in the space, is used as a basis for making the decision about which type of blinds to apply. A new system of shading device, which has a triangular cross section and is made of clear plastic with a silver coating on one side, shows better performance than the existing shading device and the patented shading device, given the research limitations. By using the specific decision-making framework, a shading device manufacturer/designer is able to understand the shading device daylighting performance from his design-imposed criteria. Selection of the shading device, given the designer's daylighting objectives, is better achieved. Existing shading devices are also able to be analyzed from a building designer's perspective. This analysis is based on the designer-imposed daylighting criteria. The specific decision-making framework helps the designers of the buildings, together with the clients, select the most appropriate shading device based on daylighting performance. The decision-making framework is a model for development of decision-making software that will help designers of buildings, facades, and shading device systems in the selection/design of shading device systems in all phases of the design.
A Design Framework for Integrated Design and Control Strategies in Energy Efficient Buildings
Abaza, Hussein Fuad (Virginia Tech, 2002-04-22)
This research proposes a computer evaluation model that assists architects and designers in producing buildings with low energy consumption. The model is based on computer-designer interaction. Here, the designer suggests a range of design alternatives, and, in turn, the computer evaluation model generates a matrix of design solutions and performs various environmental simulations. The performances of the various design solutions then analyzed by a statistical analysis package that derives relationships. These relationships explain the impact that the different building components have on energy consumption. The relationships are represented in the form of statistical relations and interactive data charts. The evaluation model was tested and used to support new ventilation strategies for the Beliveau House in Blacksburg, Virginia. The designer of this house implemented strategies for integrating solar radiation, thermal mass, thermal insulation, and air ventilation to conserve energy. A field study and computer simulation were conducted to monitor the actual performance of the house and to validate the evaluation model results. Based on the evaluation model results, this research suggests new direct and indirect ventilation control strategies to reduce cooling energy and to improve comfort. The research also suggests general design guidelines to improve the energy performance of buildings and to enhance thermal comfort. These design guidelines are based on a holistic view of integrating the building components that has significant impact on buildings thermal performance.
The design of column base anchorages for shear and tension
Applegate, Steven M. (Virginia Tech, 1991-07-03)
A unified and consistent design procedure is proposed for column base anchorages loaded in shear and tension. A literature review of previous work was done to identify discrepancies. A design procedure for anchorages loaded in shear, tension and combined shear and tension was developed which attempted to coordinate c;lnd resolve the discrepancies in previous work. A design methodology utilizing shear lugs was developed. The overall design procedure is for column bases loaded in shear and tension and uses two design methods: Method 1: Headed anchor bolts are used to resist both shear and tension Loads. Method 2: A shear lug welded to the bottom of the base plate resists shear loads and the headed anchor bolts resist only tension loads. The proposed design method differs form the design method used by Shipp and Haninger (Reference 23) as follows: 1. The proposed procedure incorporates both shear and tension design stress based on the ultimate strength of the anchor bolts times a reduction factor. 2. Separate capacity reduction factors are introduced for shear and tension. 3. The use of shear lugs is incorporated in the proposed design. 4. The incorrect use of the "shear-friction" concept is noted and not used in the design. 5. The safety factor for the required embedment depth is applied to the projected area of the failure cone not the embedment depth of the bolt. Several design examples are presented using the two methods. A computer program (using Microsoft QuickBasic 4.0) has also been developed using the proposed design procedure.
Developing a Framework for Historic Restoration Projects: A Case Study of the Catawba Farm Dairy Barn
Rigby, Ellen Troland (Virginia Tech, 2009-07-17)
As the national building stock ages and society needs for public facilities evolve, communities undertake revitalization projects to restore or repurpose existing structures to suit current needs. Community-based restoration projects involve a variety of stakeholders: owners, community members, and visitors to the community. Because some restoration projects involve derelict or at-risk structures, communities need a framework for prioritizing construction tasks and undertaking short term rehabilitation procedures in order to save the building in the short term while the community negotiates its appropriate use. Several frameworks exist to help communities prioritize tasks in terms of the building's structure or the long term energy efficiency of the building, but communities need a framework that provides the additional construct of allowing project stakeholders to begin baseline restoration tasks to prolong the immediate life of the facility.This research aims to develop a multi-step, straightforward framework for communities to approach restoration projects, conduct analyses, identify potential future use alternatives, and prioritize tasks for reconstruction. The paper first details the methodology used to develop the framework by presenting a case study of a historic dairy barn facility in Catawba, Virginia. The research uses the case study approach as a baseline for developing the framework, and then applies the framework back to the dairy barn restoration project in order to prioritize construction tasks and develop a path forward for the facility. In addition to the case study framework development, the research offers procedures and estimates specifically for the case study facility restoration. Finally, the paper offers recommendations for application and testing of the framework and offers areas for future examination.
Developing Prefabricated, Light-weight CLT Exterior Wall Panels for Mid-rise Buildings
Sharifniay Dizboni, Houri (Virginia Tech, 2024-06-10)
The building construction industry has seen the emergence of Cross Laminated Timber (CLT) as a renewable replacement for structural application of steel, concrete, and masonry. However, CLT has not been researched extensively as a nonstructural component of the building envelope/facade. In the presented research, the application of CLT is introduced in the form of lightweight CLT (CLT-L) panels and presents a framework to evaluate the opportunities and application of CLT-L panels as an alternative construction method for non-load-bearing exterior wall systems. Since exterior walls as part of the enclosure system have a significant role in energy consumption and human comfort level, the research evaluates application opportunities of the CLT panels for US climates, by conducting a life cycle environmental analysis, and a thermal evaluation of CLT-L systems for Phoenix, Arizona, and Minneapolis, Minnesota. The life cycle analysis was conducted to assess the environmental impact of a typical CLT wall system as compared to three conventional panelized wall systems. The results of the analysis have shown that CLT wall systems exhibit the lowest cumulative life cycle environmental impact indicators, including acidification potential, fossil fuel consumption, global warming potential, and human health particulate when compared to other wall systems. These results suggest that CLT wall systems could be a viable alternative to conventional panelized exterior wall systems from an environmental impact perspective. In the next step, a parametric study was conducted to determine the optimal configuration of a CLT-L wall system for enhanced thermal performance. This was achieved through dynamic thermal simulations by employing the conduction transfer algorithm and analyzing various thicknesses and locations of the thermal insulation layer. Through analysis of the annual thermal transmission load and decrement factor, the optimum insulation thicknesses for CLT wall systems in two climate regions were determined. The results showed that the exterior insulation location yields better thermal efficiency. The results of this phase were employed in the development of the CLT wall system model and conduction of a comparative parametric study on the thermal mass behavior of CLT and CMU wall systems via finite difference algorithm. One significant outcome of the simulation data analysis was the heat transfer dynamics within the CLT and CMU wall system when exterior insulation is applied. The analysis revealed that in the presence of exterior insulation, the CLT layer continues to be the primary contributor to the reduced thermal transmission of the wall. However, in the CMU mass wall configuration, the insulation layer assumes a dominant role in the reduced thermal transmission of the wall. The findings of this research present CLT as a potential environmentally efficient envelope alternative for framed buildings and provide insights into the thermal performance of CLT wall systems, which can lead to the opening of a new market for CLT panel application in the U.S.
The development and deployment of a submersible ROV for the underwater inspection of hydroelectric station tunnels
Heffron, Ronald E. (Virginia Tech, 1990-08-15)
The inspection of deep and long, water-filled tunnels at pumped storage hydroelectric stations has posed a challenge to the electric utility industry. Virginia Power and its partner, Allegheny Power System, faced this challenge at its Bath County Pumped Storage Station in western Virginia. 2100 megawatts. The station consists of six pump/turbines and three large tunnels, each 28.5 feet in diameter and approximately two miles long, which link the upper and lower reservoirs. After reviewing the alternatives of using divers, manned submersibles and dewatering of the tunnels, the owners decided to use a submersible remotely operated vehicle (ROV) for the inspection task. A study was performed which determined that the owners could save approximately $677,000 by performing the work in-house versus hiring a specialty contractor. An ROV system was developed and equipped specifically for tunnel inspection work. Three video cameras, a stereo photo camera, dye release system, dual head sonar, and a 7000 foot umbilical provided the inspection capabilities. The overall condition of the tunnels was very good, particularly in the upper and lower horizontal sections. The vertical flow shaft of the tunnel had two predominant longitudinal cracks with the east wall crack showing evidence of water egress. The ROV system proved to be a very safe, economical, and reliable means of conducting inspections of this type. The vehicle successfully completed the 6100 foot excursion at a maximum depth of 1350 feet, representing the longest tunnel excursion performed to date. It is probable that inspections of this type will become the norm at hydroelectric stations as well as other facilities with similar tunnel systems requiring inspection. This report will describe the background of the project, discuss the evaluation of inspection alternatives. and provide a complete description of the HYDROVER system and its development. A brief discussion of the results of the inspection of the first of the three tunnels will be presented. Although portions of the remaining two tunnels have now been inspected, these results are not within the scope of this paper. Following the discussion of the system development and inspection results, conclusions will be presented regarding the viability and future role of this advanced underwater technology.
Development of a computer-understandable representation of design rationale to support value engineering
Alcantara, Primo T. (Virginia Tech, 1996-07-14)
The life span of facilities produced by the Architecture-Engineering-Construction industry is typically 25 years or more Several distinct phases characterize the life span of a facility. Each of these phases involve numerous participants from different professional disciplines. These participants generate and use a lot of information about the facility. Current methods used by the industry to convey this information are drawings and specifications. However. these drawings and specifications reflect only a summary of the information generated and used by the project participants This summarized information only describes the product. Information about the process of generating these information becomes implicit in the drawings and specifications. Rationale is the collective term for this set of implicit process information. The main issue addressed by this dissertation is the need to communicate design rationale information. Design rationale is a subset of the entire rationale generated for a facility Design rationale refers to information about the design process. Explicitly stating design rationale information reduces the chance of misinterpreting design drawings and specifications. The primary objective of this dissertation is to determine a data structure capable of representing design rationale information. This data structure also allows a computer system to perform analytical tasks on the design rationale data. Examples of analytical tasks a computer system can perform on design rationale data include: generating a parameter dependency network and resolving data conflicts. This dissertation defines this data structure as two separate but complementary modules. The Knowledge Representation Module assists in gathering project-specific product information. The Rationale Storage Module assists in capturing project-specific process information. This dissertation discusses each of these two modules in detail. The secondary objectives of this dissertation include: (1) defining a computer program architecture, (2) creating a computer program interface, and (3) verifying the appropriateness of the data structure in representing design rationale. A proof-of-concept computer program, DRIVE, applied to an actual value engineering study project accomplishes these objectives.

Browsing by Author "Beliveau, Yvan J."

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