Behavior of lap splices formed by CFRP rolls has been studied. CFRP rolls have been prepared by using CFRP sheets of a certain width. Strengthening methods that use CFRP rolls as reinforcement may require an epoxy anchored lap splice due to the conditions at the strengthening regions. It may not always be possible to strengthen the region by using only one roll fan anchored at both ends, but using two rolls from opposite faces of the member and lap splicing them at the middle so that they act as a single roll. Lap splice behavior can be studied best by using flexural beam bond specimens if the reinforcing material is steel. Therefore, it has initially been suggested that flexural beam specimens reinforced for flexure with CFRP rolls as tension reinforcement can be used in studying the lap splice behavior. However, due to the difficulties encountered in the beam tests, another type of test specimen was introduced, which was a direct pull-out specimen. In this type of test specimen, lap spliced CFRP rolls have been tested under direct tension, in which the tension has been applied by making use of concrete end blocks that transfer the tension to the rolls. Eleven tests have been made in total. Full material capacity of the rolls could not be achieved due to premature failures. However, important conclusions and recommendations have been made for future studies.

The problem of passive earth pressure is one of the important topics in Geotechnical engineering. At attempt is made in this thesis to generate passive earth pressure coefficients for general c-Φ soils using logarithmic spiral failure surface by limit equilibrium approach. Method of slices for the determination of passive force in c-Φsoils is presented and the method is extended to a typical problem of two layered soil system. The application of passive earth pressure coefficients has been demonstrated for pullout capacity of inclined strip anchors in sloping ground. A semi-empirical approach for the determination of displacement-related passive earth pressure is presented. The thesis is organized in seven chapters. In Ch.2, a brief summary of relevant literature is presented along with the scope of the thesis. In Ch. 3, limit equilibrium approach for the determination of the passive earth pressure in soils is presented. The passive earth pressure coefficients are developed for δ/Φ= - 1, - ¾ , -2/3, - ½, 0, ½, ¾ 1; ψ = -60º, -45º, -30º, -20º, -10º, 0º,10º,20º,30º and 45º; i= -30º, -20º, -10º,0º,10º,20º and 30º where δ is the wall friction angle, Φ is the angle of internal friction, Ψ is the inclination of the wall with the vertical and i is the ground inclination with the horizontal. Ch.4 deals with the method of slices. Satisfying all the three equilibrium conditions and using interstice friction as a variable, passive earth pressure coefficients are obtained for soils. Extension of the method to a two layered soil system is demonstrated by an illustrative example. A generalised approach for the determination of uplift capacity of inclined strip anchors in sloping ground subjected to surcharge is presented in Ch. 5. Expressions are provided for the determination of pullout capacity of deep anchors. Displacement-related passive earth pressure is discussed in Ch. 6. Using the earlier experimental observations on the passive earth pressure measurements with displacements, expressions have been fitted for the determination of displacement-related passive earth pressure for the three modes of rigid body movements viz., translation, rotation about the top and rotation about the bottom. The conclusions drawn from the present investigations are listed in Ch 7. (Pl see the original document for abstract)

Severe corrosion damage and even complete failure was recently discovered in external post-tensioned (PT) tendons of three Florida's pre-cast, segmental bridges over seawater. A key deterioration factor was the formation of large bleed water grout voids at or near the anchorages. Steel corrosion may occur at the grout-void interface or in the air space of the void itself. Since the tendons are critical to the structural integrity of the bridges, reliable and non-intrusive damage detection methods are desirable to manage or prevent future occurrences. In recent years several indirect non-destructive methods have been developed or improved to evaluate the conditions of the tendons. One of those methods is vibration-based tension measurements, consisting of detecting tendon tension loss by analyzing the tendon's natural frequencies. Until recently, vibration-based tension measurements were costly and laborious since they required several operators to conduct the tests and complicated analysis through different programs. The first objective of this research is to provide a practical, simplified, user-friendly testing and analysis method for screening tendons by vibration measurements. Electrochemical Impedance Spectroscopy, Linear Polarization, and Electrical Resistance are alternative methods that could nondestructively detect or monitor corrosion before strand failures occur. The reliability and sensitivity of these conventional monitoring methods in solid or liquid media are well proven. However, few investigations exist on applying these methods to air-space corrosion as it may occur in tendon anchors. The second objective of this research is to establish the feasibility of using the above conventional monitoring methods for detecting air-space corrosion. In this investigation, two different types of Electrical Resistance probes were designed and evaluated. Also, electrochemical probes were constructed simulating strands conditions in the grout-void interface. Electrochemical Impedance Spectroscopy and Linear Polarization measurements were conducted in the electrochemical probes to calculate their instantaneous corrosion rates. Electrical Resistance and Electrochemical probes results indicate that both methods provide sufficient sensibility to determine the ongoing damage.

This thesis focuses on the forensic analysis of ten full-scale post-tensioned beam specimens after four years of aggressive exposure testing. The research was funded by FHWA and TxDOT. Post-tensioned structures have been under scrutiny due to their vulnerability to corrosion damage. Recent corrosion failures have been traced to inadequate materials and construction procedures. The purpose of this research project is to evaluate the corrosion performance of new and upcoming post-tensioning materials and systems and to determine their suitability for preventing durability issues which were found in older structures. The following variables were tested in the full-scale beam specimens: strand type, duct type, duct coupler type, anchorage type, tendon encapsulation. Non-destructive and destructive testing methods for evaluating corrosion damage were examined. Cost analysis of each material was conducted using tendon quantities from a typical post-tensioned bridge for comparison. Galvanized steel ducts performed poorly, showing substantial pitting and area loss. Plastic ducts were intact, but elevated grout chloride levels indicate that moisture was able to enter the ducts at the locations of couplers and grout vents. Strand corrosion was minor and uniform for all the types which were examined, suggesting that chloride traveled the length of the tendons through strand interstices. Stainless steel strands were nearly corrosion-free. Pourback quality was found to protect anchorages more than galvanization of bearing plates. The electrically isolated tendon did not completely prevent strand corrosion, but the system resulted in much lower chloride concentrations along the tendon than the conventional systems. / text

We applied single-molecule fluorescence (SMF) methods to probe the properties of individual fluorescent probes, and to characterize the proteins of interest to which these probes were attached. One remarkable advantage of SMF spectroscopy is the ability to investigate heterogeneous subpopulations of the ensemble, which are buried in ensemble averaging in other measurements. Other advantages include the ability to probe the entire dynamic sequences of a single molecule transitioning between different conformational states. For the purpose of having an extended observation of single molecules, while maintaining the native nanoscale surroundings, we developed an improved vesicle preparation method for encapsulating scarce biological samples. SMF investigations revealed that molecules trapped in vesicles exhibit nearly ideal single-emitter behavior, which therefore recommends the vesicle encapsulation for reproducible and reliable SMF studies. Hyperactive Signal-Transducer-and-Activator-of-Transcription 3 (STAT3) protein contributes significantly to human cancers, such as leukemia and lymphoma. We have proposed a novel therapeutic strategy by designing a cholesterol-based protein membrane anchor (PMA), to tether STAT3 to the cell membrane and thus inhibit unwanted transcription at the cell nucleus. We designed in vitro proof-of-concept experiments by encapsulating STAT3 and PMAs in phospholipid vesicles. The efficiency and the stability of STAT3 anchoring in the lipid membrane were interrogated via quantitative fluorescence imaging and multiparameter SMF spectroscopy. Our in vitro data paved the way for the in vivo demonstration of STAT3 inhibition in live cells, thus demonstrating that PMA-induced protein localization is a conceptually viable therapeutic strategy. The recent discovery of intrinsically disordered proteins (IDPs) highlights important exceptions to the traditional structure-function paradigm. SMF methods are very suited for probing the properties of such highly heterogeneous systems. We studied in detail the effects of electrostatics on the conformational disorder of an IDP protein, Sic1 from yeast, and found that the electrostatic repulsion is a major factor controlling the dimensions of Sic1. Based on our data we also conclude that a rod-like shape seems a better candidate than a random Gaussian chain to describe and predict the behavior of Sic1.

We applied single-molecule fluorescence (SMF) methods to probe the properties of individual fluorescent probes, and to characterize the proteins of interest to which these probes were attached. One remarkable advantage of SMF spectroscopy is the ability to investigate heterogeneous subpopulations of the ensemble, which are buried in ensemble averaging in other measurements. Other advantages include the ability to probe the entire dynamic sequences of a single molecule transitioning between different conformational states. For the purpose of having an extended observation of single molecules, while maintaining the native nanoscale surroundings, we developed an improved vesicle preparation method for encapsulating scarce biological samples. SMF investigations revealed that molecules trapped in vesicles exhibit nearly ideal single-emitter behavior, which therefore recommends the vesicle encapsulation for reproducible and reliable SMF studies. Hyperactive Signal-Transducer-and-Activator-of-Transcription 3 (STAT3) protein contributes significantly to human cancers, such as leukemia and lymphoma. We have proposed a novel therapeutic strategy by designing a cholesterol-based protein membrane anchor (PMA), to tether STAT3 to the cell membrane and thus inhibit unwanted transcription at the cell nucleus. We designed in vitro proof-of-concept experiments by encapsulating STAT3 and PMAs in phospholipid vesicles. The efficiency and the stability of STAT3 anchoring in the lipid membrane were interrogated via quantitative fluorescence imaging and multiparameter SMF spectroscopy. Our in vitro data paved the way for the in vivo demonstration of STAT3 inhibition in live cells, thus demonstrating that PMA-induced protein localization is a conceptually viable therapeutic strategy. The recent discovery of intrinsically disordered proteins (IDPs) highlights important exceptions to the traditional structure-function paradigm. SMF methods are very suited for probing the properties of such highly heterogeneous systems. We studied in detail the effects of electrostatics on the conformational disorder of an IDP protein, Sic1 from yeast, and found that the electrostatic repulsion is a major factor controlling the dimensions of Sic1. Based on our data we also conclude that a rod-like shape seems a better candidate than a random Gaussian chain to describe and predict the behavior of Sic1.

The Fully Encapsulated Resin Bolt (FERB) is widely utilised for strata control and ground support in civil and mining applications worldwide, with approximately 6 million installed per annum by the Australian coal mining industry. Independent studies have concluded that 30-35% of these rockbolts, which represents an annual expenditure of $40 million, are ineffective. The anchorage and failure mechanisms of FERB are yet to be quantified, and support systems are designed primarily from empirical rather than scientific methods. There are no standardised methods of assessing FERB components, installation techniques and support behaviour. The majority of research into FERB support systems remains commercial intellectual property, with little information released into the public domain. This thesis investigated several variables of FERB support systems, and also examined differences between field and laboratory pull-out test load distributions. This research was conducted in two phases, with Phase 1 seeking standardised methodology and repeatability in results, while Phase 2 further refined Phase 1 methods and extended the range of tests. The results in both phases were encouraging, with reasonable repeatability attained in all testing series. The findings included: ??? Annulus Thickness: There was little change in load capacity with small annulus thickness, however the maximum peak load (MPL) significantly reduced once annulus thickness exceeded 4mm ??? Resin Installation Spin Time: Underspinning of cartridge resin was found to have an insignificant effect on rockbolt load/deformation characteristics. Overspinning, however, led to a dramatic reduction in anchorage performance with a lessening in both MPL and stiffness ??? Rockbolt Load Transfer: The magnitude of an applied load reduced to zero along the length of the rockbolt, being greatest nearest the rock free surface (the point of load application). An exponential reduction was found when tested in the manner of laboratory tests, with the loading jack reacting against the free surface. This reduction was linear when the load was applied as in the field, with no load placed on the free surface This basic investigation into FERB support systems has validated many empirical understandings of rockbolts, while highlighting the need for further testing into several key areas.

Thesis (M. E.)--University of New South Wales, 2003. / "The precursor to this thesis was an industry-sponsored project, completed in 2000 by C. Offner at the School of Mining Engineering, UNSW ; this project is referred to as the Stage 1 project"--summary. Also available online.

Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 184-188). Also available in electronic format on the Internet.

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed June 2, 2008). Includes bibliographical references.