The U.S. military requires the ability to rapidly deploy troops, equipment, and materials anywhere in the world. Recent operations have brought attention to the need to utilize austere, unsurfaced, and sometimes sub-standard airfields within a theater of interest. These airfields may require additional taxiways and aprons. One option for the rapid construction of such is airfield matting systems. The focus of the work for this thesis was commercially available airfield matting systems to support large military transport aircraft, such as the C 17. Several test sections with differing strength soils were built with chosen mats tested in an elimination method, using a load cart that simulates contingency loading of one main gear of the C 17. Matting systems were evaluated based on logistical and assembly requirements, and deformation and damage sustained during traffic. A modeling effort was performed to investigate the potential of a simple model to predict the response of these matting systems under full-scale testing.

No description available.

Steel moment frames are a popular seismic-force resisting system, but it is believed that they are susceptible to early fracture if there is a stress concentration in the plastic hinge region, also known as the protected zone. If a defect is present in this area, it may be repaired by grinding and/or welding, but little research has investigated how the repairs affect the performance of full-scale moment connections subjected to inelastic rotations. Thus, the goals of this research were to establish the performance of full-scale moment connections with repairs and defects, then develop a method for predicting fracture of the full-scale specimens using more economical cyclic bend tests. To do this, six full-scale reduced beam section (RBS) connections were tested having arrays of repairs or defects applied to the flanges. The repairs were 0.125 in. deep notches ground to a smooth taper and 0.25 in. deep notches ground to a smooth taper, welded, and ground smooth. The defects were sharp 0.25 in. and 0.375 in. notches. In addition, 54 bend tests were conducted on beam flange and bar stock coupons having the same repairs and defects, power actuated fasteners, puddle welds, and no artifacts. Finally, Coffin-Manson low-cycle fatigue relationships were calibrated using results from the cyclic bend tests with each artifact (repair, defect, or attachment method) and used in conjunction with estimates of full-scale plastic strain amplitudes to predict fracture of full-scale specimens. All four of the full-scale moment connections with repairs satisfied special moment frame qualification criteria (SMF). One full-scale specimen with sharp 0.25 in. notches satisfied SMF qualification criteria, but the flexural resistance dropped rapidly after the qualification cycle. On the other hand, the specimen with sharp 0.375 in. notches did not satisfy SMF qualification criteria due to ductile fractures propagating from the notches. The proposed method for predicting fracture of full-scale connections was validated using the six current and six previous full-scale RBS specimens. This method underpredicted fracture for eleven of the twelve specimens. The ratio of the actual to predicted cumulative story drift at fracture had a mean of 1.13 and a standard deviation of 0.19. / M.S. / Moment connections in steel structures resist earthquake loads by permanently deforming the material near the connection. This area is called the protected zone and is critical to the safety of the structure in an earthquake. Due to this importance, no defects are allowed near the connection, which can include gouges or notches. If a defect does occur, it must repaired by a grinding or welding. These are the required repair methods, but there have be no tests to determine how the repairs affect the strength and ductility of the connection. This research tested six full-scale moment connections with defects repaired by grinding and welding, as well as unrepaired defects. A correlation was also developed and validated between the full-scale tests and small-scale bend tests of steel bars with the same defects and repairs. This relationship is valuable because the small-scale tests are quicker and less expensive to conduct than the full-scale tests, meaning other defects or repairs could be easily tested in the future. All but one of the six full-scale specimens met the strength requirements and had adequate ductility. The one test specimen that failed had an unrepaired defect. The relationship between the full-scale and small-scale tests underpredicted fracture (a conservative estimate) for the five of the full-scale tests and overpredicted fracture (unconservative estimate) for one test.

Three end-plate moment connection configurations are prequalified for special moment frames for seismic applications in AISC 358-10. The eight bolt extended stiffened connection is the strongest of the three configurations, but it can only develop approximately 30 percent of currently available hot-rolled beam sections. The strength of this configuration is limited by bolt strength. There is a need for a stronger end-plate moment connection, hence the reason for the development and validation of a twelve bolt configuration. Equations were developed for the design procedure using various analytical methods, which included yield line analysis and an effective tee stub model. An experimental program was conducted, which consisted of the full-scale cyclic testing of four end-plate moment connections. The intention of the testing was to develop and validate the design procedure, and prequalify a new twelve bolt configuration. A displacement-controlled loading protocol was applied according to AISC 341-10. The experimental results showed that the model for thick end-plate behavior is conservative by 6.7%, the model for end-plate yielding is conservative by 8.8%, and the model for bolt tension rupture with prying conservatively predicts by 18.5%. The specimens that were designed to form a plastic hinge in the beam fractured in a brittle manner. The deep beam specimen fractured in the first 2% story drift cycle, and the shallow beam specimen fractured in the second 3% story drift cycle. The fracture of the prequalification specimens was determined to have been caused by stiffeners of high yield stress relative to the beam yield stress. / Master of Science

To analyze the system development, manufacturing practices and system evaluation procedures of representative PPES manufacturers, two companies (i.e., one "small", referred to here as "simple manufacturer (SM)", and one "large", referred here as "complex manufacturer (CM)" — in terms of workforce, market presence, and capital) that develop first responder PPES, which voluntarily agreed to participate in the research were chosen. The complex PPES is an Air-Pak, a self contained breathing apparatus (SCBA) used by first responders for artificial breathing in life-threatening scenarios and the simple PPES is the Fire-Eye device, a thermal sensor that attaches to the visor of the firefighter in order to convey the visual warning of the ambient thermal environment. In order to differentiate the two distinct methodological approaches, the dissertation has been split into two different parts. The first methodology is a "case study" type of empirical investigation which follows a triangulation approach utilizing surveys, structured interviews, process and system observations, and examination of archival records. The second type of methodology is an experimental empirical research one, which involves laboratory-scale and full-scale real-life fire scenarios to conduct product evaluation. The research goals of the case study research were to identify the problems faced by the manufacturers of PPES and to formulate guidelines with regards to manufacturing, compliance, design and development processes, etc., for the PPES manufacturers. The investigation sought answer to the following key questions: a) How do PPES manufacturers currently approach the systems design and development process and what best practices in manufacturing and quality control have they adopted? b) What human factors and ergonomic measures are adopted by these companies while designing their products and what human testing is conducted by companies? c)What safety measures are considered by the safety designer while designing the product? The recommendations also include modifications to the product design process taking into account the market trends in the product design processes, involvement of ergonomics and safety aspects. The research goals for the experimental part of this dissertation were to identify appropriate evaluation methods and conduct the PPES evaluation in simulated fire environments. The Fire-Eye device primarily functions in hot environments and warns the firefighters of the ambient temperature. Therefore, the laboratory-scale evaluation was conducted using test methods such as the Static Oven, Fire Equipment Evaluator, and Radiant Panel, methods which represent controlled environment test conditions. The Fire-Eye device was also evaluated in realistic fire environment created in an ISO burn room by conducting several tests using different types of fuels such as Heptane, Natural Gas, and Living-room set-up (i.e., furniture as fuel). The Fire-Eye device was tested for repeatability and reproducibility of its performance in both of the experimental settings. Statistical data analysis was conducted to determine any differences in performance of the Fire-Eye device among each laboratory-scale methods as well as to compare the performance of the device between laboratory-scale and full-scale fire environments in identical heat locations. The results suggest that a dual approach (laboratory-scale and full-scale fire environment) for evaluating the performance of PPES is more effective than is testing the device in either one of the methods. / Ph. D.

Phytoremediation is an attractive remediation technology due to its relative low cost and maintenance requirement. Acceptance of phytoremediation requires that the contaminant removal mechanisms are characterized and demonstrated in the field. Quantification of contributions from each mechanism to the overall remediation rate is crucial for optimization of phytoremediation systems, risk management and prediction of the total remediation time. The objective of this research was to characterize and quantify removal mechanisms for naphthalene at a creosote-contaminated site with poplar trees in Oneida, Tennessee. Groundwater monitoring for seven years in the surficial aquifer at this site demonstrated a reduction in polycyclic aromatic hydrocarbons (PAHs) with selective removal of naphthalene and three-ring compounds. Naphthalene mass loss mechanisms investigated at this site are biodegradation in the saturated zone, volatilization and biodegradation in the vadose zone and phytovolatilization. This is probably the most comprehensive field study of PAH phytoremediation mechanisms conducted to date. The significance of this research is to contribute to predictions of remediation time and end result for phytoremediation of PAHs. The understanding of in situ factors controlling each mechanism can facilitate future optimization of phytoremediation systems as well as improve risk assessment and monitoring strategies. Biodegradation rates were determined for different conditions at this site with in situ respiration tests, laboratory soil microcosms and laboratory soil columns. The combined remediation mechanisms of volatilization and biodegradation in the vadose zone were investigated in the field and in laboratory columns. Field measurements show that lower groundwater elevations in the summer and early fall lead to elevated groundwater concentrations of naphthalene and increased volatilization. The increase in the fraction of the porespace occupied by gas (gas saturation) in the unsaturated zone during the summer and fall further enhances the volatilization by increasing effective diffusion rates. Water consumption and interception by the phytoremediation system are believed to enhance mass transfer to the vadose zone. Column experiments and field measurements show that more than 90% of the naphthalene vapors are biodegraded within 5-10 cm above the groundwater table. The data indicate that biodegradation increases the overall volatilization flux out of the source by 10-300 times, when the source is exposed directly to the gas phase. In situ the naphthalene is generally dissolved from the source into the groundwater and then volatilezed from the groundwater to the gas phase. Under these conditions biodegradation in the vadose zone will still indirectly have an enhancing effect on the flux out of the source. This is the result of removal naphthalene from the soil gas by biodegrdation driving removal from the groundwater by volatilization, which in turn drives dissolution form the source into the groundwater. Phytovolatilization was quantified in flux chambers mounted on trees and calculated from transpiration rates. A laboratory uptake study and analysis of tree cores from the site provided supplementary evidence for naphthalene uptake by poplar trees. Phytovolatilization was detected throughout the year and was highest in the summer and fall when the groundwater concentrations were highest and transpiration was active. The role of biodegradation relative to physical removal mechanisms was compared for a year, for winter and summer conditions and with and without the impact of phytoremediation. Biodegradation of naphthalene in the saturated zone dominates by orders of magnitude over the removal by volatilization and phytovolatilization of naphthalene at this site. The removal of the total residual naphthalene mass was estimated to require up to 100 years with phytoremediation, but more than twice as long without phytoremediation. The estimated removal of naphthalene was three times larger in the summer than in the winter due to slower biodegradation in the saturated zone and smaller rates of volatilization to the vadose zone in the winter. The research shows that phytoremediation enhances the overall naphthalene removal, mainly by stimulating faster biodegradation in the rhizosphere and promoting mass transfer of naphthalene to the vadose zone followed by rapid vadose zone biodegradation. In the future, phytoremediation research focusing on the capillary zone is desirable. / Ph. D.

Both the identification and validation of expedient portland cement concrete (PCC) repair technologies have been the focus of the pavements research community for decades due to ever decreasing construction timelines. Precast concrete panel technology offers a potential repair alternative to conventional cast-in-place PCC because the panel is fully cured and has gained full strength prior to its use. This repaired surface may be trafficked immediately, thus eliminating the need for long curing durations required for conventional PCC. The literature reveals a number of precast PCC panel investigations in the past 50 years; however precast technology has only recently gained acceptance and increased use in the US for highway pavements. Furthermore, only limited information regarding performance of airfield applications is available. Following a review of the available technologies, an existing panel prototype was redesigned to allow for both single- and multiple-panel repairs. A series of various sized repairs were conducted in a full-scale airfield PCC test section. Results of accelerated testing indicated that precast panels were suitable for airfield repairs, withstanding between 5,000 and 10,000 passes of C-17 aircraft traffic prior to failure. Failure was due to spalling of the transverse doweled joints. The load transfer characteristics of the transverse joint were studied to determine if the joint load test could be used to predict failure. Results showed that the load transfer efficiency calculations from the joint load test data were not useful for predicting failure; however differential deflections could possibly be applied. Additionally, the practice of filling the joints with rapid-setting grout may have resulted in higher measurements of load transfer efficiency. To determine the stresses generated in the doweled joint, three-dimensional finite element analyses were conducted. Results indicated that the dowel diameter should be increased to reduce stresses and to improve repair performance. Finally, the precast repair technology was compared to other expedient repair techniques in terms of repair speed, performance, and cost. Compared to other methods, the precast panel repair alternative provided similar return-to-service timelines and traffic performance at a slightly higher cost. Costs can be minimized through modification to the panel design and by fabricating panels in a precast facility. Modifications to the system design and placement procedures are also recommended to improve the field performance of the panels. / Ph. D.

Fan system efficiency for modern aircraft engine design is increasing to the point that bypass duct geometry is becoming a significant contributor and could ultimately become a limiting factor. To investigate this, a number of methods are available to provide qualitative and quantitative analysis of the flow around the loss mechanisms present in the duct. Particle image velocimetry (PIV) is a strong candidate among experimental techniques to address this challenge. Its use has been documented in many other locations within the engine and it can provide high spatial resolution data over large fields of view. In this work it is shown that these characteristics allow the PIV user to reduce the spatial sampling error associated with sparsely spaced point measurements in a large measurement region with high order gradients and small spatial scale flow phenomena. A synthetic flow featuring such attributes was generated by computational fluid dynamics (CFD) and was sampled by a virtual PIV system and a virtual generic point measurement system. The PIV sampling technique estimated the average integrated velocity field about five times more accurately than the point measurement sampling due to the large errors that existed between each point measurement location. Despite its advantages, implementation of PIV can be a significant challenge, especially for internal measurement where optical access is limited. To reduce the time and cost associated with iterating through experiment designs, a software package was developed which incorporates basic optics principles and fundamental PIV relationships, and calculates experimental output parameters of interest such as camera field of view and the amount of scattered light which reaches the camera sensor. The program can be used to judge the likelihood of success of a proposed PIV experiment design by comparing the output parameters with those calculated from benchmark experiments. The primary experiment in this work focused on the Pratt and Whitney Canada JT15D-1 aft support strut wake structure in the bypass duct and was comprised of three parts: a simulated engine environment was created to provide a proof of concept of the PIV experiment design; the PIV experiment was repeated in the full scale engine at four fan speeds ranging from engine idle up to 80% of the maximum corrected fan speed; and, finally, a CFD simulation was performed with simplifying assumptions to provide insight and perspective into the formation of the wake structures observed in the PIV data. Both computational and experimental results illustrate a non-uniform wake structure downstream of the support strut and support the hypothesis that the junction of the strut and the engine core wall is creating a separate wake structure from that created by the strut main body. The PIV data also shows that the wake structure moves in the circumferential direction at higher fan speeds, possibly due to bulk swirl present in the engine or a pressure differential created by the support strut. The experiment highlights the advantages of using PIV, but also illustrates a number of the implementation challenges present, most notably, those associated with consistently providing a sufficient number of seeding particles in the measurement region. Also, the experiment is the first to the author's knowledge to document the use of PIV in a full scale turbofan engine bypass duct. / Master of Science

Wave energy converters of point absorber type have been developed and constructed. Full scale experiments have been carried out at sea and electricity has been successfully delivered. Linear permanent magnet generators together with a subsea substation and buoys of various geometric shapes have been investigated theoretically and experimentally. The design has in large extent an electronic approach, keeping the mechanical part of it as simple as possible, due to the long life span and reliability of electric components. Because of the nature of a linear generator, the internal translator with permanent magnets has a limited stroke length which will be reached when the buoy is exposed to large wave heights. Internal springs at the top and bottom of the generator prevent the translator from hitting the generator hull. Inertial forces due to the mass and velocity of the translator and the buoy and its heave added mass compresses the spring. The added mass is a rather large part of the total moving mass. Simulations of a converter with a vertical cylindrical buoy and with a toroidal buoy were conducted, as well as real sea experiments with converters with cylindrical buoys of two different sizes and a toroidal buoy. The overloads are likely to affect the design and service life of the generator, the buoy and the wire which interconnects them. Buoy shapes with as much excitation force as possible and as little heave added mass as possible were sought. A toroidal buoy caused less overloads on the generator at sea states with short wave periods and relatively large wave height, but for sea states with very long wave periods or extremely high waves, the magnitude of the overloads was mainly determined by the maximum displacement of the buoy. Snap loads on the interconnecting wire, as the slack wire tensed up after a very deep wave trough, were found to be greater but of the same order of magnitude as forces during the rest of the wave cycle. During a 4 day period at various wave conditions, two converters with cylindrical buoys proved efficiency between 11.1 % and 24.4 %. The larger buoy had 78 % larger water plane area than the other buoy which resulted in 11 % more power production. Short wave period was beneficial for the power production. Infinite frequency heave added mass was measured for a cylindrical buoy at real sea and found to be greater than the linearly calculated theoretical added mass.

Deep foundations, including driven piles, are used to support vertical loads of structures and applied lateral forces. Many pile supported structures, including bridges, are subjected to large lateral loads in the form of wind, wave, seismic, and traffic impact loads. In many practical situations, structures subjected to lateral loading are located near or in excavated and fill slopes or embankments. Full-scale research to examine the effects of soil slope on lateral pile capacity is limited. The purpose of this study is to examine the effects on lateral capacity of piles located in or near cohesionless soil slopes. A full-scale lateral load testing program was undertaken on pipe piles in a cohesionless soil at Oregon State University. Five piles were tested near a 2H:1V test slope and located between 0D to 8D behind the slope crest, where D is the pile diameter. Two vertical baseline piles and three battered piles were also tested in level ground conditions. The cohesionless backfill soil was a well-graded material with a fines content of less than 10% and a relative compaction of 95%, meeting the Caltrans specification for structural backfill. Data collected from the instrumented piles was used to back calculate p-y curves, load-displacement curves, reduction factors, and load resistance ratios for each pile. The effects of slope on lateral pile capacity are insignificant at displacements of less than 2.0 inches for piles located 2D and further from the crest. For pile located at 4D or greater from the slope crest, the effect of slope is insignificant on p-y curves. A simplified p-multiplier design procedure derived from back-calculated p-y curves is proposed to account for the effects of soil slope. Comparisons of the full-scale results were made using proposed recommendations from the available literature. Lateral resistance ratios obtained by computer, centrifuge, and small scale-models tend to be conservative and overestimate the effects of slope on lateral capacities. Standard cohesionless p-y curve methods slightly over predict the soil resistance at very low displacements but significantly under predict the ultimate soil resistance. Available reduction factors from the literature, or p-multipliers, are slightly conservative and compare well with the back-calculated p-y curves from this study. / Graduation date: 2012