Houston, we have a problem.‖ The national average graduation rate for undergraduate engineering students in the United States is around 55%. The average graduation rate for LeTourneau University's (LETU) School of Engineering and Engineering Technology (SEET) for the five-year period of this study was 42%, substantially below the national average. In addition to the SEET's low five-year average, the most recent graduation years show a definite decline, reaching a level of just 33% for the final year of this study. It was in light of our low and declining graduation rates that this study was conducted in the summer of 2009. In order to determine our (the SEET) current standing with respect to graduation and retention rates, we examined internal LETU data and compared it to that of other universities' engineering programs at large. We also attempted to answer the-Why are they leaving?‖ question by probing our own data and by surveying those who had left the SEET over the previous three years. Again, we compared our internal findings with those of other universities. An extensive literature study was also conducted in order to determine what other engineering programs are doing across the nation to increase their graduation and retention rates. The most successful of these efforts were identified and are highlighted in this study. After examining the improvements made by other universities that led to increased retention and graduation rates, and by looking at the current state of our school, we recommended that initial improvements be made in our freshman year. These should focus on an early introduction to the engineering field and the creation of first-year interest groups with significant faculty and peer mentor interactions. The development of a new first-semester course to provide experiences in engineering practice was also recommended. This report details our findings and supports our recommendations.

This work responds to a need to obtain statistically adequate quantities of input data for probabilistic assessments of girth welded pipelines. It is desirable to limit the data collection efforts to that warranted by overall reliability and confidence requirements. This is motivated by the challenge of limited and/or high-cost access to in-service pipelines for property measurement and flaw inspection. The goal of this work is to develop a methodology for specifying the minimum, cost-optimized sampling frequency for each of the model input parameters in a multiple girth weld fitness-for-service (FFS) assessment. The sampling frequency specifies the number of samples for each of the model variables to minimize the given cost function. The methodology is based on a user-specified confidence level for the computed reliability of a given pipeline segment (or segments), as well as the estimated per-sample cost of obtaining data for each parameter. The methodology is implemented as an add-on module in the GirthRel computer program. By expressing FFS in the language of risk-based inspection and maintenance, tools such as the one developed here will be invaluable to the development of a pipeline risk management system.

Requirements for the fabrication and inspection of transmission pipeline girth welds are given in national codes such as API 1104, CSA Z662, and BS 4515. Their objective is to ensure an acceptable level of quality, and implicitly, operational safety. They seek to achieve this by imposing workmanship standards which prescribe the allowable size and frequency of various discontinuities. These standards are largely arbitrary and thus highly conservative in most situations. However, the potential for economic benefit, an increasing demand for safety, and the development of fracture mechanics technology have motivated the inclusion of optional fitness-for-service (FFS)-based flaw acceptance criteria. Two major objectives of the present work were to educate those unfamiliar with structural reliability concepts, particularly as they apply to pipeline integrity, and review the worldwide codification of LRFD for industries that fabricate and maintain welded structures. The final objective was to develop a library of PSFs for pipeline girth weld flaw assessment thereby aligning girth weld fitness-for-service assessment procedures with emerging LRFD codes for transmission pipelines.

This paper presents an assessment case study on several segments of buried natural gas pipeline constructed in 1936 with ‘bell-bell-chill ring’ (BBCR) style girth weld joints, and currently operating in a seismically active region of North America. Seismic vulnerability was evaluated in terms of girth weld fracture and plastic collapse probabilities for specified hazards of varying severity and likelihood. Monte Carlo simulations performed in NESSUS® provided failure probability estimates from distributed inputs based on PIPLIN deformation analyses, nondestructive and destructive flaw sizing, residual stress measurements, weld metal tensile and CTOD tests, and limit state functions based on published stress intensity and collapse solutions.