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Showing 1 to 19 of 19 for “"prestress losses"”.
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Time-Dependent Prestress Losses in Pretensioned Concrete Construction
Made available in DSpace on 2014-12-13T19:31:17Z (GMT). No. of bitstreams: 1 7524318.pdf: 5500784 bytes, checksum: b7563a77f1dac06b42b69502c58ce938 (MD5) Previous issue date: 1975
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Investigation of Long-Term Prestress Losses in Pretensioned High Performance Concrete Girders
Effective determination of long-term prestress losses is important in the design of prestressed concrete bridges. Over-predicting prestress losses results in an overly conservative design for service load stresses, and under-predicting prestress losses, can result in cracking at service loads. …
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Effective Prestress Evaluation of the Varina-Enon Bridge Using a Long-Term Monitoring System and Finite Element Model
… 2012 that prompted concerns regarding long-term prestress losses in the structure. Prestress losses could impact the future performance, serviceability, and flexural strength of the bridge. Accurately quantifying prestress losses is critical for understanding and maintaining the structure during …
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Long-Term Monitoring and Evaluation of the Varina-Enon Bridge
… of a structure, the precise calculation of the prestress losses is very important. In post-tensioned structures, the prestress losses due to creep and shrinkage can cause serviceability issues and can reduce flexural capacity. The Varina-Enon Bridge is a cable-stayed, precast, segmental, …
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Transfer Length, Development Length, Flexural Strength, and Prestress Loss Evaluation in Pretensioned Self-Consolidating Concrete Members
… development lengths, and flexural strengths of prestressed members. Three small rectangular members were made, two cast with SCC mixes and one cast with a conventional mix, to determine the transfer length of each mix. Transfer lengths of both ends of each member were determined by measuring the …
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Top Strand Effect and Evaluation of Effective Prestress in Prestressed Concrete Beams
… orientation on bond strength in pretensioned prestressed concrete members. The "top strand effect" was evaluated through transfer and development length tests of prestressed concrete beams. Eight beams were cast with normal orientation, while four beams were cast with inverted orientation so …
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Shear Strength of a PCBT-53 Girder Fabricated with Lightweight, Self-Consolidating Concrete
… The second goal was to monitor the change in prestress over time (and hence the prestress loss) occurring in the PCBT-53 girder. Prestress losses were experimentally measured by vibrating wire gages (measured changes in concrete strain) and flexural load testing. Measured prestress losses were …
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Time-dependent losses in post-tensioned prestressed concrete
… affecting the time-dependent deformations, prestress losses and deflections of Class 1 uncracked prestressed concrete beams. The main influencing factors considered were environmental conditions, loading conditions,size and shape of members and concrete mix composition. Twenty seven beams …
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Self-Compacting Concrete for Prestressed Bridge Girders
… materials for the construction of precast prestressed SCC girders in the State of Minnesota. The primary objective of the research was to determine both short-term and long-term properties of SCC bridge girders, evaluate the applicability and accuracy of available test procedures, design …
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Behavior and temporal-based effects of sustainable self-consolidating concrete in bridge structures
… part of this dissertation presents the total prestress losses and thermal behavior of Bridge A7957 constructed with HS-SCC. A health monitoring system was established on this bridge to monitor the time-dependent behavior of bridge girders using VWSGs and a data acquisition system. HS-SCC …
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Analysis of time-dependent effects on segmental prestressed concrete curved box-girder bridges
… analysis of segmentally erected curved prestressed box-girder bridges and other structures. The program is capable of predicting the response of such structures throughout their various stages of construction and service load history. The analysis accounts for the effects of concrete …
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Macro and nanocreep of self-consolidating concrete
… growing interest in using SCC in precast and prestressed applications. These applications are known to be sensitive to time-dependent phenomena such as creep and shrinkage. Therefore, it is important to understand the creep and shrinkage behavior of SCC compared with other types of concrete. …
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Compressive Creep of a Lightweight, High Strength Concrete Mixture
… deformation is referred to as total strain. The prestressed concrete beams in the Chickahominy River Bridge have been fabricated with a lightweight, high strength concrete mixture (LTHSC). Laboratory test specimens have been cast using the concrete materials and mixture proportions used in the …
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Investigation of Transfer Length, Development Length, Flexural Strength and Prestress Loss Trend in Fully Bonded High Strength Lightweight Prestressed Girders
… conducted on two AASHTO Type IV HSLWC prestressed girders, resulted in an average transfer length of 17 inches, well below the AASHTO and ACI guidance. Two girders composed of HSLWC AASHTO Type II girders and a 48" x 8" normal weight 4000-psi concrete deck were produced. The HSLWC Type …
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Refined Evaluation of Effective Prestress in the Varina-Enon Bridge
… of the bridge. Particular focus has been put on prestress losses which have a significant impact on the strength and serviceability of the bridge. Previous work has been conducted to monitor the behavior of the bridge and to back-calculate effective prestress. This was done using field data from …
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Variations in low-grade wood modification and stress lamination
… buildings, primarily due to concerns regarding losses in prestress levels from creep and the moisture-related movement and shrinkage of wood. Scale models and testing emphasise the technique’s potential for both standard and bespoke structural elements for buildings. Full-scale detailing, …
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A Compilation of Research on Self-Consolidating Concrete for Prestressed Bridge Girders
… can be utilized to improve fabrication of prestressed girders. SCC has been used in the precast industry with a satisfactory performance. This was achieved by reducing fabrication time, decreasing health hazards due to excessive noise, and a much better finishing on the surface of the …
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Investigation of Time-Dependent Deflection in Long Span, High Strength, Prestressed Concrete Bridge Beams
Accurate camber prediction in prestressed concrete bridge beams is important to all parties involved in bridge design and construction. Many current prestress loss prediction methods, necessary for proper camber calculation, were developed many years ago and are predicated on assumptions that may …
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Recommendations for Longitudinal Post-Tensioning in Full-Depth Precast Concrete Bridge Deck Panels
… and shrinkage in concrete and relaxation of prestressing steel complicate bridge behavior, making the existing recommendations for post-tensioning in precast deck panels invalid for all bridges with differing girder types, sizes, spacings, and span lengths. Therefore, the development of …