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Book Cracking and Shear Capacity of High Strength Concrete Bridge Girders

Download or read book Cracking and Shear Capacity of High Strength Concrete Bridge Girders written by Kamal S. Tawfiq and published by . This book was released on 1995 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Strength and Durability of Near surface Mounted CFRP Bars for Shear Strengthening Reinforced Concrete Bridge Girders

Download or read book Strength and Durability of Near surface Mounted CFRP Bars for Shear Strengthening Reinforced Concrete Bridge Girders written by Jacob Hans Goebel and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candidates for shear strengthening to extend their useful life. Carbon fiber reinforced polymers (CFRP) are emerging as effective materials for strengthening and rehabilitating such bridges. Near surface mounting (NSM) is a newer technique for application of CFRP for retrofitting bridge members that provides advantages over other strengthening techniques. The technique is still new and uncertainties remain regarding strength, long-term durability, and design including the influence of member proportions, flexural reinforcing steel, and CFRP spacing. Bridge girders retrofitted with NSM-CFRP may be exposed to millions of load cycles and environmental conditions and the influence of these exposures on performance are not established. To address these issues, laboratory tests were performed on ten full-size reinforced concrete girders, representative of in-situ bridge members, to determine the performance of NSM-CFRP retrofitting for shear strengthening. One of the specimens was exposed to fatigue loading, two were subjected to environmental exposures, and one was subjected to combined environmental exposure and fatigue loading. Results indicated that NSM-CFRP retrofitting provided significant shear capacity increases, and the high-cycle fatigue and environmental exposures considered did not adversely affect the strength or behavior of the girders. Environmental exposures of some of the adhesives considered did show somewhat reduced performance; therefore, careful selection of materials is important to ensure performance over the expected lifetime. Recommendations for shear strength design with NSM-CFRP are made.

Book Shear Reinforcement Requirements for High Strength Concrete Bridge Girders

Download or read book Shear Reinforcement Requirements for High Strength Concrete Bridge Girders written by J.A. Ramirez and published by . This book was released on 2005-07-15 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Strength and Durability of Near surface Mounted CFRP Bars for Shear Strengthening Reinforced Concrete Bridge Girders

Download or read book Strength and Durability of Near surface Mounted CFRP Bars for Shear Strengthening Reinforced Concrete Bridge Girders written by Jacob Hans Goebel and published by . This book was released on 2012 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candidates for shear strengthening to extend their useful life. Carbon fiber reinforced polymers (CFRP) are emerging as effective materials for strengthening and rehabilitating such bridges. Near surface mounting (NSM) is a newer technique for application of CFRP for retrofitting bridge members that provides advantages over other strengthening techniques. The technique is still new and uncertainties remain regarding strength, long-term durability, and design including the influence of member proportions, flexural reinforcing steel, and CFRP spacing. Bridge girders retrofitted with NSM-CFRP may be exposed to millions of load cycles and environmental conditions and the influence of these exposures on performance are not established. To address these issues, laboratory tests were performed on ten full-size reinforced concrete girders, representative of in-situ bridge members, to determine the performance of NSM-CFRP retrofitting for shear strengthening. One of the specimens was exposed to fatigue loading, two were subjected to environmental exposures, and one was subjected to combined environmental exposure and fatigue loading. Results indicated that NSM-CFRP retrofitting provided significant shear capacity increases, and the high-cycle fatigue and environmental exposures considered did not adversely affect the strength or behavior of the girders. Environmental exposures of some of the adhesives considered did show somewhat reduced performance; therefore, careful selection of materials is important to ensure performance over the expected lifetime. Recommendations for shear strength design with NSM-CFRP are made.

Book Shear Capacity of in Service Prestressed Concrete Bridge Girders

Download or read book Shear Capacity of in Service Prestressed Concrete Bridge Girders written by Paul Barr and published by . This book was released on 2010 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design procedure to calculate the shear capacity of bridge girders that was used forty years ago is very different than those procedures that are recommended in the current AASHTO LRFD Specifications. As a result, many bridge girders that were built forty years ago do not meet current design standards, and in some cases warrant replacement due to insufficient calculated shear capacity. However despite this insufficient calculated capacity, these bridge girders have been found to function adequately in service with minimal signs of distress. The objective of this research was to investigate the actual in service capacity of prestressed concrete girders that have been in service over an extended period of time.

Book Shear Capacity of High Strength Prestressed Concrete Girders

Download or read book Shear Capacity of High Strength Prestressed Concrete Girders written by David L. Hartmann and published by . This book was released on 1988 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Prestress Losses in Pretensioned High strength Concrete Bridge Girders

Download or read book Prestress Losses in Pretensioned High strength Concrete Bridge Girders written by Maher K. Tadros and published by Transportation Research Board. This book was released on 2003 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The HCM includes three printed volumes (Volumes 1-3) that can be purchased from the Transportation Research Board in print and electronic formats. Volume 4 is a free online resource that supports the rest of the manual. It includes: Supplemental chapters 25-38, providing additional details of the methodologies described in the Volume 1-3 chapters, example problems, and other resources; A technical reference library providing access to a significant portion of the research supporting HCM methods; Two applications guides demonstrating how the HCM can be applied to planning-level analysis and a variety of traffic operations applications; Interpretations, updates, and errata for the HCM (as they are developed);A discussion forum allowing HCM users to ask questions and collaborate on HCM-related matters; and Notifications of chapter updates, active discussions, and more via an optional e-mail notification feature."--Publisher.

Book High Strength Prestressed Concrete Bridge Girders

Download or read book High Strength Prestressed Concrete Bridge Girders written by Theresa Marie Ahlborn and published by . This book was released on 1998 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Shear and Flexural Capacity of High Strength Prestressed Concrete Bridge Girders

Download or read book Shear and Flexural Capacity of High Strength Prestressed Concrete Bridge Girders written by Arek Tilmann Higgs and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Shear Behavior of High Strength Self consolidating Concrete in Nebraska University Bridge Girders

Download or read book Shear Behavior of High Strength Self consolidating Concrete in Nebraska University Bridge Girders written by Alexander Michael Griffin and published by . This book was released on 2014 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: "As the nation's infrastructure continues to age, advanced concrete technologies have been developed to both reduce a structure's costs and increase its life expectancy. Since the early 1990's, self-consolidating concrete (SCC) has been one of these technologies. Many, however, have been reluctant to implement SCC in highway girders due to the mixture constituents. One of these concerns is the reduced content and size of the coarse aggregate. These differences in the concrete potentially hinder SCC's mechanical properties and shear resistance. Additionally, for high strength concretes (HSC) with weaker aggregates, shear cracks tend to propagate through the coarse aggregate, reducing the aggregate interlock component of the shear resistance. This study aimed at assessing the web-shear strength both with and without web reinforcement of two precast-prestressed Nebraska University (NU) 53 girders fabricated with high strength self-consolidating concrete (HS-SCC). The results were compared to the ACI 318 (2011) and AASHTO LRFD (2012) code estimates, and a finite element model (FEM) package, Response 2000. ATENA Engineering, a finite element analysis (FEA) program, was also used to evaluate the qualitative results, specifically crack patterns and the effect of the coarse aggregate content and size. A prestressed concrete database was also constructed to assess the effect of the reduced coarse aggregate content on the shear capacity of HS-SCC in prestressed concrete members. The mechanical properties of the HS-SCC mix were also tested and compared to relevant empirical equations. The HS-SCC mix investigated in this study proves to be a viable cost-saving alternative for bridge superstructure elements"--Abstract, page iii.

Book On the Fatigue of Headed Shear Studs in Steel concrete Composite Bridge Girders

Download or read book On the Fatigue of Headed Shear Studs in Steel concrete Composite Bridge Girders written by Brianna Laurene Ovuoba and published by . This book was released on 2017 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shear connectors are commonly used in steel bridges to join the concrete deck and steel superstructure, providing a mechanism for shear transfer across the steel-concrete interface. The most common shear connector is the headed shear stud. In the current AASHTO LRFD Bridge Specifications on composite design, shear stud fatigue often governs over static strength, and a large number of shear connectors often result. This dissertation investigates headed shear stud fatigue capacities and demands, and provides insight into conservancies in existing design specifications through examination of existing high-traffic bridge performance. To investigate stud capacity, a total of six high-cycle fatigue tests are conducted on stud pushout specimens at low stress ranges and combined with existing experimental data to develop probabilistic S-N fatigue capacity curves. Results from composite push-out specimens tested at stress ranges between 4.4 and 8.7 ksi suggest a fatigue limit of 6.5 ksi, which is near the existing limit of 7 ksi. Recommendations for modification of the existing AASHTO finite-life shear stud S-N fatigue capacity curve are proposed. In addition to experimental testing, a finite element parametric study considers the effects of stud pitch, girder depth, and girder span on shear flow demands. Results from the parametric study indicate that the shear forces within stud clusters are not captured by current AASHTO shear flow demand estimations. A new design method and updated formulation for predicting stud demands are presented. To examine high-traffic bridge performance, residual fatigue life is investigated by further fatigue testing, as well as magnetic particle inspection and dye penetrant testing on two existing bridges. The lack of discovered fatigue cracks within the studs of the bridges investigated suggests that the shear stress range estimation in AASHTO specification is higher than what is actually experienced. This discrepancy is likely due to shear transfer through adhesion and friction, which are not considered in AASHTO design calculations. Fatigue tests from sections of the decommissioned bridge exceeded the design life expectancy of approximately 850,000 cycles (at 11.6 ksi) by over 2,500,000 cycles. This evidence further indicates that stud fatigue is an unlikely failure mode during service loading.

Book Design of Concrete Structures Using High strength Steel Reinforcement

Download or read book Design of Concrete Structures Using High strength Steel Reinforcement written by Bahram M. Shahrooz and published by Transportation Research Board. This book was released on 2011 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 679: Design of Concrete Structures Using High-Strength Steel Reinforcement evaluates the existing American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications relevant to the use of high-strength reinforcing steel and other grades of reinforcing steel having no discernible yield plateau. The report also includes recommended language to the AASHTO LRFD Bridge Design Specifications that will permit the use of high-strength reinforcing steel with specified yield strengths not greater than 100 ksi. The Appendixes to NCHRP Report 679 were published online.