Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 97 for “"prestressing"”.
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Prestressing Concrete with Shape Memory Alloy Fibers
… which increases the overall size of the member. Prestressing concrete remedies this problem by inducing a compressive stress in the concrete thereby reducing the net tension in the member and increasing the load required to crack the member. Traditional prestressing is generally limited to large, …
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Column Footings Strengthened with External Prestressing and External Wrapping Systems
… in this dissertation:</p> <p>• Circular external prestressing system (CEP);</p> <p>• Circular external regular reinforcement system (CERR);</p> <p>• Circular external BFRP wrapping system (CEBW);</p> <p>• Circular external CFRP wrapping system (CECW);</p> <p>• Circular external steel jacketing …
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Adaptive prestressing system for concrete structures using shape memory alloys
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01
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Innovative method of prestressing structures with externally bonded FRP composites
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1991.
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Grade 300 Prestressing Strand and the Effect of Vertical Casting Position
The purpose of this study was to investigate the influence an increase in strand strength and the effect the as-cast vertical location had on transfer length, development length, and flexural strength and to resolve the discrepancies regarding the definition of the top-bar/strand effect. Two types …
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Bond and Material Properties of Grade 270 and Grade 300 Prestressing Strands
… material properties of grade 270 and grade 300 prestressing strand of various sizes. Tension tests were performed on each type of strand. The data from these tests was used to determine modulus of elasticity, yield stress, ultimate stress, and ultimate elongation for each strand. The yield …
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Seismic retrofit of existing reinforced concrete moment resisting frame structures using diagonal prestressing
… to explore the possibilities of using diagonal prestressing, in various configurations, to increase structural stiffness and decrease lateral drift demands under seismic loading. Shallouf (2005) successfully demonstrated experimentally that a 1 bay, 1 storey R/C frame with masonry infill panels, …
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Characterization of UHPFRC Materials for Bridge Construction: An Opportunity to Offset the Need for Prestressing in Bridge Decks
… alternatives for large bridge spans without prestressing (Lee et al. 2017). To quantify the global effects on the response of the structural components comprising UHPFRC materials, design parameters affecting the flexural response of UHPFRC girders were studied.
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Material Properties of the Grade 300 and Grade 270 Prestressing Strands and their Impact on the Design of Bridges
… properties of the new Grade 300, low-relaxation prestressing strand. The purpose of this testing was to verify the advertised breaking strengths and relaxation properties of the Grade 300 strand. Additional properties, such as yield strength, modulus of elasticity, and elongation, were also …
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Strengthening prestressed beams using parafil ropes as external tendons
… methods can be used, one of them is the external prestressing. Also, to avoid corrosion problem that faced this type of strengthening, Fibre Reinforced Plastics (FRP) can be used instead of steel tendons. Within the different types of FRP, Parafil rope was established to be well suited for …
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Design of prestressed, fabric-formed concrete beams
Fabric forms and prestressing are both technologies for concrete structures that allow for less material to do more work. This thesis seeks to assess the feasibility and performance of fabric formed, prestressed beams with a keyhole cross-section, while varying parameters such as concrete strength, …
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A study of the complete design for circular prestressed concrete tank and its dynamic analysis
… tank structure. A proposed method of circular prestressing is presented and the comparative study of the prevailing circular prestressing system is also included. The thesis is divided into four parts. The first part is a study of the structural analysis using the theory of the thin shell as an …
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Partially prestressed concrete internal square panel
… floor structure, under the influence of various prestressing tendon arrangements. The prestressing effects are studied with the help of a finite element package (PAFEC), representing the prestressing forces by equivalent vertical loads. From a variety of possible spacing arrangements, the …
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Development and Characterization of a Self-Stressing Shape Memory Alloy (SMA)-Fiber Reinforced Polymers (FRP) Composite Patch for Repair of Cracked Steel Structures
… and civil infrastructure. However, existing prestressing methods require the use of heavy and complex fixtures to apply prestressing forces, which is impractical in many applications. In this research a self-stressing shape memory alloy (SMA)-fiber reinforced polymer patch is presented that …
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Developing a prism qualification test to ensure adequate splitting resistance in pretensioned concrete railroad ties
… of wire indentation on bond performance between prestressing steel and concrete when using different concrete mixtures. The bond between prestressing wires and concrete is crucial for transferring the stresses between the two materials in a pretensioned concrete member. Furthermore, bond can be …
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Residual flexural strength of corroded AASHTO TYPE II pretensioned concrete girder-deck system
… were considered: 1) span-depth ratio, 2) prestressing reinforcement ratio, 3) corrosion level, 4) number of corroded strands, and 5) corrosion length. Results from the FEA model were used to develop a detailed analytical model to study the residual flexural strength of the girder-deck …
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Rehabilitation of concrete girders with distressed end regions using innovative materials
… phenomenon offers significant ease when applying prestressing in very localized regions where conventional prestressing technique is not feasible. This research utilizes experimental and numerical approaches to explore the effectiveness of using FRP laminates and precast prestressing plate (PPP) …
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Prestressed cable domes: structural behavior and design
… vulnerable to wind uplift were recognized and prestressing force levels were increased accordingly. As such, the findings from the influence surface analysis proved to be a good indicator of the adequacy of prestressing forces assigned to a dome. Further, the results revealed that additional …
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Development of a Magnetic Field Sensor System for Nondestructive Evaluation of Reinforcing Steel in Prestressed Concrete Bridge Members
… includes inspection of the condition of the prestressing strands for load rating. This thesis presents a magnetic inspection system to measure main magnetic flux (MMF) and magnetic leakage flux (MFL) signals, to evaluate the condition of prestressing stands. A proof-of-concept has been …
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Flexural Behavior of CFRP-Pretensioned Girders
… to environmental exposure. The corrosion of the prestressing steel reduces the beams’ load-carrying capacity and may result in catastrophic failures. Carbon fiber reinforced polymers (CFRP), as an emerging material, have potential to replace prestressing steel and provide corrosion-free …
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