Browsing by Author "Hildreth, John C."

Now showing 1 - 5 of 5
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    The Development of Mathematical Models for Preliminary Prediction of Highway Construction Duration
    Williams, Robert C. (Virginia Tech, 2008-11-04)
    Knowledge of construction duration is pertinent to a number of project planning functions prior to detailed design development. Funding, financing, and resource allocation decisions take place early in project design development and are significantly influenced by the construction duration. Currently, there is not an understanding of the project factors having a statistically significant relationship with highway construction duration. Other industry sectors have successfully used statistical regression analysis to identify and model the project parameters related to construction duration. While the need is seen for such work in highway construction, there are very few studies which attempt to identify duration-influential parameters and their relationship with the highway construction duration. This research identifies the project factors, known early in design development, which influence highway construction duration. The factors identified are specific to their respective project types and are those factors which demonstrate a statistically-significant relationship with construction duration. This work also quantifies the relationship between the duration-influential factors and highway construction duration. The quantity, magnitude, and sign of the factor coefficient yields evidence regarding the importance of the project factor to highway construction duration. Finally, the research incorporates the duration-influential project factors and their relationship with highway construction duration into mathematical models which assist in the prediction of construction duration. Full and condensed models are presented for Full-Depth Section and Highway Improvement project types. This research uses statistical regression analysis to identify, quantify, and model these early-known, duration-influential project factors. The results of this research contribute to the body of knowledge of the sponsoring organization (Virginia Department of Transportation), the highway construction industry, and the general construction industry at large.
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    A Development of Performance Metrics for Forecasting Schedule Slippage
    Arcuri, Frank John (Virginia Tech, 2007-04-30)
    Project schedules should mirror the project, as the project takes place. Accurate project schedules, when updated and revised, reflect the actual progress of construction as performed in the field. Various methods for monitoring progress of construction are successful in their representation of actual construction as it takes place. Progress monitoring techniques clearly identify when we are behind schedule, yet it is less obvious to recognize when we are going to slip behind schedule. This research explores how schedule performance measurement mechanisms are used to recognize construction projects that may potentially slip behind schedule, as well as what type of early warning they provide in order to take corrective action. Such early warning systems help prevent situations where the contractor and/or owner are in denial for a number of months that a possible catastrophe of a project is going to finish on time. This research develops the intellectual framework for schedule control systems, based on a review of control systems in the construction industry. The framework forms the foundation for the development of a schedule control technique for forecasting schedule slippage — the Required Performance Method (RPM). The RPM forecasts the required performance needed for timely project completion, and is based on the contractor's ability to expand future work. The RPM is a paradigm shift from control based on scheduled completion date to control based on required performance. This shift enables forecasts to express concern in terms that are more tangible. Furthermore, the shift represents a focus on what needs to be done to achieve a target completion date, as opposed to the traditional focus on what has been done. The RPM is demonstrated through a case study, revealing its ability to forecast impending schedule slippage.
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    Evaluation of SiteManager as a Tool to Collect Performance Time Data
    Rich, Daniel William (Virginia Tech, 2006-05-26)
    This work evaluates SiteManager, the construction documentation system used by VDOT, as a tool for collecting the daily installed quantity and active crew days necessary to populate the operations level of the database. This evaluation first sought to determine if SiteManager was a feasible option for collecting performance data. This was done by establishing data collection methods to enable SiteManager to have the ability to collect performance data, implementing the methods on select projects, resolving issues, and developing recommendations to cause SiteManager to be a more practical option. Secondly, a statistical analysis was performed to determine if the data collected from SiteManager was reasonably accurate. Thirdly, the technical issues of transferring performance data from SiteManager into the performance time database were resolved. It was found SiteManager could not be used in its current format to collect performance data and some modifications are required.
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    The Framework of a Multi-Level Database of Highway Construction Performance Times
    Williams, Robert Charles (Virginia Tech, 2006-04-28)
    Accurate and reasonable contract time is important to all aspects of a highway construction project. Unreasonably short contract times can raise the bid price, restrict qualified bidders from submitting bids, reduce the quality of the work, and increase the potential for legal disputes. Conversely, unreasonably long contract times encourage less qualified contractors to submit a bid and are a general inconvenience to the traveling public. The Federal Highway Administration (FHWA) recognizes this, and has recommended that all state highway agencies develop a standardized method for estimating contract performance time. To date, the Virginia Department of Transportation (VDOT) does not have an established method. One major portion of this work is the development of the framework for a multi-level time estimating system to aid in the establishment of contract performance times. This system parallels the VDOT cost estimating process, refining estimates as design details become available along the Project Development Concurrent Engineering Process (PDCEP). Three distinct stages exist along the PDCEP that will facilitate the use of a tool for estimating contract time. Sufficient information to begin the conceptual estimate is known as the project enters the six year plan. The parametric estimate may commence as the project enters the scoping phase. Finally, details for the pre-advertisement time estimate are available upon project field inspection. The second major component of this work, the pre-advertisement estimating database system (BIDDS – Bid Item Duration Data System) was constructed during this work. BIDDS uses project information and characteristics to filter through historical performance time data, returning production data from similar projects. Production data is returned at the bid item level to assist in the estimation of production rates, for calculating activity durations.
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    The Use of Short-Interval GPS Data for Construction Operations Analysis
    Hildreth, John C. (Virginia Tech, 2003-01-29)
    The global positioning system (GPS) makes use of extremely accurate measures of the time to determine position. The times required for electronic signals to travel at the speed of light from at least four orbiting satellites to a receiver on earth is measured precisely and used to calculate the distances from the satellites to the receiver. The calculated distances are used to determine the position of the receiver through triangulation. This research takes an approach opposite the original GPS research, focusing on the use of position to determine the time at which events occur. Specifically, this work addresses the question: Can the information pertaining to position and speed contained in a GPS record be used to autonomously identify the times at which critical events occur within a production cycle? The research question was answered by determining the hardware needs for collecting the desired data in a useable format an developing a unique data collection tool to meet those needs. The tool was field evaluated and the data collected was used to determine the software needs for automated reduction of the data to the times at which key events occurred. The software tools were developed in the form of Time Identification Modules (TIMs). The TIMs were used to reduce data collected from a load and haul earthmoving operation to duration measures for the load, haul, dump, and return activities. The value of the developed system was demonstrated by investigating correlations between performance times in construction operations and by using field data to verify the results obtained from productivity estimating tools. Use of the system was shown to improve knowledge and provide additional insight into operations analysis studies.