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- All Subjects: Civil Engineering
- Genre: Doctoral Dissertation
- Creators: El Asmar, Mounir
- Creators: Zapata, Claudia E
This study presents the results of one of the first attempts to characterize the pore water pressure response of soils subjected to traffic loading under saturated and unsaturated conditions. It is widely known that pore water pressure develops within the soil pores as a response to external stimulus. Also, it has been recognized that the development of pores water pressure contributes to the degradation of the resilient modulus of unbound materials. In the last decades several efforts have been directed to model the effect of air and water pore pressures upon resilient modulus. However, none of them consider dynamic variations in pressures but rather are based on equilibrium values corresponding to initial conditions. The measurement of this response is challenging especially in soils under unsaturated conditions. Models are needed not only to overcome testing limitations but also to understand the dynamic behavior of internal pore pressures that under critical conditions may even lead to failure. A testing program was conducted to characterize the pore water pressure response of a low plasticity fine clayey sand subjected to dynamic loading. The bulk stress, initial matric suction and dwelling time parameters were controlled and their effects were analyzed. The results were used to attempt models capable of predicting the accumulated excess pore pressure at any given time during the traffic loading and unloading phases. Important findings regarding the influence of the controlled variables challenge common beliefs. The accumulated excess pore water pressure was found to be higher for unsaturated soil specimens than for saturated soil specimens. The maximum pore water pressure always increased when the high bulk stress level was applied. Higher dwelling time was found to decelerate the accumulation of pore water pressure. In addition, it was found that the higher the dwelling time, the lower the maximum pore water pressure. It was concluded that upon further research, the proposed models may become a powerful tool not only to overcome testing limitations but also to enhance current design practices and to prevent soil failure due to excessive development of pore water pressure.
This dissertation fills the crucial knowledge gap in contract administration functions and tools for DB and CM/GC highway project delivery. First, this research identifies and models contract administration functions in DBB, CM/GC, and DB using integrated definition modeling (IDEF0). Second, this research identifies and analyzes DB and CM/GC tools for contract administration by conducting 30 ACM project case studies involving over 90 ACM practitioners. Recommendations on appropriate use regarding project phase, complexity, and size were gathered from 16 ACM practitioners. Third, the alternative technical concepts tool was studied. Data from 30 DB projects was analyzed to explore the timing of DB procurement and DB initial award performance in relation to the project influence curve. Types of innovations derived from ATCs are discussed. Considerable industry input at multiple stages grounds this research in professional practice.
Results indicate that the involvement of the contractor during the design phase for both DB and CM/GC delivery creates unique contract administration functions that need unique tools. Thirty-six DB and CM/GC tools for contract administration are identified with recommendations for effective implementation. While strong initial award performance is achievable in DB projects, initial award performance in this sample of projects is only loosely tied to the level of percent base design at procurement. Cost savings typically come from multiple ATCs, and innovations tend to be incremental rather than systemic, disruptive, or radical. Opportunity for innovation on DB highway projects is influenced by project characteristics and engaging the DB entity after pre-project planning.
as front end planning (FEP), have a large impact on project success and significant
influence on the configuration of the final project. As a key component of FEP, front end
engineering design (FEED) plays an essential role in the overall success of large industrial
projects. The primary objective of this dissertation focuses on FEED maturity and accuracy
and its impact on project performance. The author was a member of the Construction
Industry Institute (CII) Research Team (RT) 331, which was tasked to develop the FEED
Maturity and Accuracy Total Rating System (FEED MATRS), pronounced “feed matters.”
This dissertation provides the motivation, methodology, data analysis, research findings
(which include significant correlations between the maturity and accuracy of FEED and
project performance), applicability and contributions to academia and industry. A scientific
research methodology was employed in this dissertation that included a literature review,
focus groups, an industry survey, data collection workshops, in-progress projects testing,
and statistical analysis of project performance. The results presented in this dissertation are
based on input from 128 experts in 57 organizations and a data sample of 33 completed
and 11 on-going large industrial projects representing over $13.9 billion of total installed
cost. The contributions of this work include: (1) developing a tested FEED definition for
the large industrial projects sector, (2) determining the industry’s state of practice for
measuring FEED deliverables, (3) developing an objective and scalable two-dimensional
method to measure FEED maturity and accuracy, and (4) quantifying that projects with
high FEED maturity and accuracy outperformed projects with low FEED maturity and
accuracy by 24 percent in terms of cost growth, in relation to the approved budget.
There is a growing need to quantify the project performance and financial benefits of PPP. This dissertation fills this gap in knowledge by performing a comprehensive quantitative analysis of PPP project performance and financial sources for transportation projects in the U.S. This study’s specific research objectives are:
(1) Develop a solid baseline for comparison, comprised of non-PPP projects;
(2) Quantify PPP project cost and schedule performance; and
(3) Quantify private versus public financing sources of PPP.
A thorough literature review led to the development of a structured data collection process for PPP and comparable non-PPP projects. Financing data was collected and verified for a total of 133 ongoing and completed projects; while performance data was verified for a subset of 81 completed projects. Data analysis included regression analysis, descriptive statistics, inferential statistics and non-parametric statistical tests.
The results provide benchmarks for PPP project performance and financing sources. For the performance results, non-PPP projects have an average cost change of 8.46 percent and an average schedule change of -0.22 percent. PPP projects have an average cost change of 3.04 percent and average schedule change of 1.38 percent. Statistical analysis showed cost change for PPP projects were superior to that of non-PPP; however, schedule change differences were not significant. For the financing results, private financing totaled 44.5 percent while public financing totaled 55.5 percent. This result shows private financing can be used to leverage public financing with close to a one-to-one ratio and that PPP has the potential to double the amount of infrastructure delivered to the public.
The author hypothesized that there are specific practices that, if properly implemented, can lead to instantaneous controls of capital projects. It is also hypothesized that instantaneous project controls pose benefits to project performance. This research aims to find practices and identify benefits and barriers to achieving a real-time mode of control. To achieve these objectives, several lines of inquiry had to be pursued. A panel of 13 industry professionals and three academics collaborated on this research project. Two surveys were completed to map the current state of project control practices and to identify state-of-the-art or ideal processes. Ten case studies were conducted within and outside of the capital projects industry to identify practices for achieving real-time project controls. Also, statistical analyses were completed on retrospective data for completed capital projects in order to quantify the benefits of IPC. In conclusion, this research presents a framework for implementing IPC across the capital projects industry. The ultimate output from this research is procedures and recommendations that improve project controls processes.