The research presented in this thesis focuses on the quantification of the effect of limited site investigations on the design and performance of pile foundations. Limited site investigation is one of the main causes of structural foundation failures. Over the last 30 years, most site investigations conducted for infrastructure projects have been dictated by minimum cost and time of completion, rather than meeting the need to appropriately characterise soil properties (Institution of Civil Engineers 1991; Jaksa et al. 2003). As a result, limited site investigations remain common, resulting in a higher risk of structural foundation failure, unforeseen additional construction, and/or repair costs. Also, limited site investigations can result in over-designing foundations, leading to increased and unnecessary cost (ASFE 1996). Based on the reliability examination method for site investigations introduced by Jaksa et al. (2003) and performed by Goldsworthy (2006), this research investigated the effect of limited site investigations on the design of pile foundations. This was achieved by generating three-dimensional random fields to obtain a virtual site consisting of soil properties at certain levels of variability, and by simulating various numbers of cone penetration tests (CPTs) and pile foundations on the generated site. Once the site and the CPTs were simulated, the cone tip resistance (qc) was profiled along the vertical and horizontal axes. The simulated qc profiles yielded by the CPTs were then used to compute axial pile load capacity termed the pile foundation design based on site investigations (SI). In parallel, the axial pile load capacity of the simulated pile foundation utilising the “true” cone tip resistance along the simulated pile was also determined. This is termed “the true” design, or the benchmark pile foundation design, and referred to as pile foundation design based on complete knowledge (CK). At the end of this process, the research compared the pile foundation designs based on SI and those based on CK. The reliability of the foundation design based on SI was analysed with a probabilistic approach, using the Monte Carlo technique. The results indicated that limited site investigations have a significant impact on the design of pile foundations. The results showed that minimum sampling efforts result in a high risk of over- or under-designing piles. More intensive sampling efforts, in contrast, led to a low risk of under- or over-design. The results also indicated that the levels of spatial variability of the soil are notable factors that affect the effectiveness of site investigations. These results will assist geotechnical engineers in planning a site investigation in a more rational manner with knowledge of the associated risks. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375097 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Civil, Environmental and Mining Engineering, 2009

The research presented in this thesis focuses on the quantification of the effect of limited site investigations on the design and performance of pile foundations. Limited site investigation is one of the main causes of structural foundation failures. Over the last 30 years, most site investigations conducted for infrastructure projects have been dictated by minimum cost and time of completion, rather than meeting the need to appropriately characterise soil properties (Institution of Civil Engineers 1991; Jaksa et al. 2003). As a result, limited site investigations remain common, resulting in a higher risk of structural foundation failure, unforeseen additional construction, and/or repair costs. Also, limited site investigations can result in over-designing foundations, leading to increased and unnecessary cost (ASFE 1996). Based on the reliability examination method for site investigations introduced by Jaksa et al. (2003) and performed by Goldsworthy (2006), this research investigated the effect of limited site investigations on the design of pile foundations. This was achieved by generating three-dimensional random fields to obtain a virtual site consisting of soil properties at certain levels of variability, and by simulating various numbers of cone penetration tests (CPTs) and pile foundations on the generated site. Once the site and the CPTs were simulated, the cone tip resistance (qc) was profiled along the vertical and horizontal axes. The simulated qc profiles yielded by the CPTs were then used to compute axial pile load capacity termed the pile foundation design based on site investigations (SI). In parallel, the axial pile load capacity of the simulated pile foundation utilising the “true” cone tip resistance along the simulated pile was also determined. This is termed “the true” design, or the benchmark pile foundation design, and referred to as pile foundation design based on complete knowledge (CK). At the end of this process, the research compared the pile foundation designs based on SI and those based on CK. The reliability of the foundation design based on SI was analysed with a probabilistic approach, using the Monte Carlo technique. The results indicated that limited site investigations have a significant impact on the design of pile foundations. The results showed that minimum sampling efforts result in a high risk of over- or under-designing piles. More intensive sampling efforts, in contrast, led to a low risk of under- or over-design. The results also indicated that the levels of spatial variability of the soil are notable factors that affect the effectiveness of site investigations. These results will assist geotechnical engineers in planning a site investigation in a more rational manner with knowledge of the associated risks. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375097 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Civil, Environmental and Mining Engineering, 2009

Thesis (M.S.)--Auburn University, 2008. / Abstract. Includes bibliographical references (p. 187-189).

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references (p.114).

In this research, extensive use has been made of limit equilibrium methods of analysis for studying the stability of slopes. For the determination of the factor of safety (FOS) of slopes, the usual two-step process has been adopted; (a) assuming a slip surface for the soil mass, and (b) using the appropriate limit equilibrium equation(s). Eight wellknown limit equilibrium methods have been programmed to calculate different FOS values. The comparative performance of the various analyses has been carried out successfully using case studies. The innovative use of Gauss quadrature to calculate the FOS values has been shown to reducet he iterative sequencesd ramatically with no loss of accuracy. A visco-plastic flow model has been proposed to estimate lateral forces on piles used for slope stabilisation. The present research data occupies an "in-between" position to the previously reported values, with the variation trend being confirmed satisfactorily in all cases. Slope stabilisation due to the presence of a row of piles has been investigated using two distinct lateral load estimations. These include theories of plastic deformation and the proposed visco-plastic flow which are modelled and implemented in a computer program. Eight well-known methods of slope stability analyses have been adopted and computer coded to re-calculate FOS values for a slope reinforced by a row of piles. A Finite Element computer program has been developed to evaluate the displacement, bending moment and shear force along the pile axis. The pile is analysed at two levels above and below the slip failure surface.

This dissertation presents findings from three separate investigations, a laboratory study and two field studies that evaluated the durability of the Fiber Reinforced Polymer (FRP)-concrete bond. The laboratory study explored the role of porosity on CFRP-concrete bond following immersion in warm water. Two disparate field studies measured residual bond after 20 years outdoor exposure of FRP repairs of full-size masonry walls and after 12 years for partially submerged piles supporting the Friendship Trail Bridge, Tampa Bay. The ACI 440 code requires the same surface preparation for all externally bonded FRP concrete repairs. This disregards the role of porosity that is a function of the water / cementitious (w/c) ratio. Concretes with high w/c ratios are low strength concretes, have large voids and a more elaborate capillary pore network compared to low w/c, high strength concretes. Epoxies will therefore penetrate deeper into high porosity concretes. As a result, the performance of low strength, high porosity concrete under moisture exposure can be anticipated to be superior. The laboratory study was intended to determine whether this hypothesis was correct or not. Three different concrete mixes with water / cementitious ratios of 0.73, 0.44 and 0.25 representing high, medium and low porosities were used for the study. The corresponding target compressive strengths were 2,500 psi, 5,000 psi and 7,500 psi respectively. A total of eighteen, 9 in. x 9 in. x 2.5 in. thick slabs, three for each concrete porosity were tested. Slabs were allowed to cure for over 90 days before surfaces were lightly sand blasted to provide the required concrete surface profile (CSP 3). Specimens were then pre-conditioned in an oven for 48 hours to ensure uniform drying. Concrete porosity was characterized using mercury porosimetry, SEM, 3D surface scanning and images obtained using a portable microscope. Two commercially available CFRP materials were bonded to the oven-dried prepared slab surfaces and the epoxy allowed to cure at room temperature for 4 weeks. Twelve FRP bonded slabs were completely submerged in potable water at 30 oC (86 oF) as part of the aging program. The six remaining slabs were used for establishing baseline bond values through destructive pull-off tests. The twelve exposed slabs were similarly tested following 15 weeks of exposure. Results showed minimal degradation in the high porosity, low strength concrete but over 20% reduction in the low porosity, higher strength concrete. Analysis of the failure plane indicated that the lower porosity of the high strength concrete had limited the depth to which the epoxy could penetrate. This was confirmed from magnified images of the bond line taken using a microscope and from a careful assessment of the failure mode. Findings also suggest that the CSP 3 surface profile (light sand blasting) may be adequate for lower strength concrete but not so for higher strength concrete. For applications where FRP concrete repairs of higher strength concrete are permanently or intermittently exposed to moisture, alternative surface preparation may be needed to allow epoxy to penetrate deeper into the concrete substrate. The viscosity of the resin hitherto not considered may be a critical parameter. In 1995, two full-scale concrete masonry walls were repaired using three horizontally aligned 20 in. (508 mm) wide uni-directional carbon fiber sheets using different commercially available epoxies. Twenty years later the CFRP-CMU bond was determined through selective pull-off tests that were preceded by detailed non-destructive evaluation. Results showed that despite superficial damage to the top epoxy coating and debonding along masonry joints, the residual CFRP-CMU bond was largely unaffected by prolonged exposure to Florida’s harsh environment. Therein, 99% of samples exhibited in cohesive failure of the CMU or mortar. Pull-off strength was poorer at mortar joints but because the CFRP was well bonded to the masonry surface, its impact on structural performance of the repair was expected to be minimal. Overall, the repairs proved to be durable with both epoxy systems performing well. The Friendship Trail Bridge linking St. Petersburg to Tampa FL was demolished in 2016. This was the site of three disparate demonstration projects in which 13 corroding reinforced concrete piles were repaired using fiber reinforced polymer (FRP) in 2003-04, 2006, and 2008. The repairs were undertaken using combinations of carbon and glass fiber, pre-preg and wet layup, epoxy and polyurethane resin, and were installed using either shrink wrap or pressure bagging. Residual FRP-concrete bond was evaluated after up to 12 years of exposure through 120 pull-off tests conducted on 10 representative repaired piles. Results showed a wide variation in the measured pull-off strength depending on the type of resin, the number of FRP layers, the prevailing conditions at the time the epoxy was mixed and the method of installation. Epoxy-based systems were found to be sensitive to ambient conditions at installation. Pressure bagging improved performance. The highest residual bond was recorded in pressure bagged piles repaired in 2008. The findings suggest that in marine environments epoxy-based systems installed using pressure bagging can lead to durable repairs.

Le réseau de capteurs sans fil (WSN) est un des protagonistes contribuant à l’évolution et au développement de l’Internet des objets (IoT). Plusieurs cas d’usage peuvent être trouvés dans les différents domaines comme l’industrie du transport maritime où le fret conteneurisé compte environ pour 60% du commerce mondial. Dans ce contexte, la société TRAXENS a développé un dispositif radio alimenté par batterie appelé TRAX-BOX et conçu pour être fixé aux containeurs dans l’objectif de les traquer et les surveiller tout au long de la chaine logistique. Dans cette thèse, je vais présenter une nouvelle pile protocolaire WSN appelée TRAX-NET et conçue pour permettre aux TRAX-BOX de s’auto-organiser dans un réseau sans fil et coopérer pour délivrer les données acquises au serveur TRAXENS d’une façon énergiquement efficiente. Les résultats des simulations et des tests sur le terrain montrent que TRAX-NET est bien optimisé pour les différents scenarios pour lesquels il a été développé et satisfait les exigences de l’application concernée mieux que les autres solutions étudiées dans la littérature. TRAX-NET est une solution complète et adaptée au suivi des conteneurs de fret de par le monde. / Wireless Sensor Networks (WSN) is one of the protagonists contributing to the evolution and the development of the Internet of Things (IoT). Several use cases can be found today in the different fields of the modern technology including the container shipping industry where containerized cargo accounts for about 60 percent of all world seaborne trade. In this context, TRAXENS developed a battery-powered device named TRAX-BOX designed to be attached to the freight containers in order to track and monitor the shipping goods along the whole supply chain. In this thesis, we present a new energy-efficient self-organizing WSN protocol stack named TRAX-NET designed to allow the TRAX-BOX devices to cooperate to deliver the sensed data to the TRAXENS platform.The results of simulations and field tests show that TRAX-NET well perform in the different scenarios in which it is supposed to operate and better fulfil the requirements of the assumed application in comparison with the existing schemes.

No description available.

No description available.

Geothermal heat exchangers are a growing energy technology that improve the energy efficiency of heating and cooling systems in buildings. Vertical borehole heat exchangers (BHE) coupled with ground source heat pumps have been widely developed and researched in the past century. The major disadvantage of BHEs is the initial capital cost required to drill the boreholes. Geothermal energy piles (GEP) were developed to help offset the high initial cost of these systems. A GEP combines ground source heat pump technology with deep earth structural foundations of buildings. GEPs are relatively new technology and robust standards and guidelines have not yet been developed for the design of these systems. The main operational difference between GEPs and conventional BHEs is the length and diameter of the below ground heat exchangers. The diameter of a GEP is much larger and the length is typically shorter than BHEs. Computational fluid dynamics (CFD) analysis is used in this study to investigate and better understand how structural piles perform as geothermal heat exchangers. The CFD analysis is used to simulate an existing experimental energy pile test. The experimental test is modeled as built including fluid modeling to provide additional detail into the behavior of the circulation fluid within the pile. Two comparisons of large diameter GEPs are made using CFD analysis to gain knowledge of the effects of varying pile diameter and loop configuration. The thermal response test was successfully modeled using the CFD model. The CFD results closely match the results of the field test. The large diameter comparisons show that the performance of an energy pile will increase as the diameter increases with a constant loop density. Multiple numbers of loops were tested in a constant diameter pile and the results show that with symmetrically placed loops the performance will increase with a greater number of loops in the pile. / Master of Science