Cracking and Shear Capacity of High Strength Concrete Bridge Girders Under Fatigue Loading (phase II) PDF Download

Author: Kamal Tawfiq
Publisher:
ISBN:
Category : Concrete beams
Languages : en
Pages : 254

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Author: Kamal Tawfiq
Publisher:
ISBN:
Category : Concrete bridges
Languages : en
Pages : 127

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Book Description

Author: Kamal Tawfiq
Publisher:
ISBN:
Category : Concrete beams
Languages : en
Pages : 254

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Book Description

Author: Kamal S. Tawfiq
Publisher:
ISBN:
Category : Concrete bridges
Languages : en
Pages : 152

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Book Description

Author: Jacob Hans Goebel
Publisher:
ISBN:
Category : Carbon fiber-reinforced plastics
Languages : en
Pages : 0

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Book Description
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.

Author: J.A. Ramirez
Publisher:
ISBN: 9781622601844
Category :
Languages : en
Pages :

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Book Description

Author: Jacob Hans Goebel
Publisher:
ISBN:
Category : Carbon fiber-reinforced plastics
Languages : en
Pages : 119

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Book Description
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.

Author: David L. Hartmann
Publisher:
ISBN:
Category : Concrete beams
Languages : en
Pages : 278

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Book Description

Author: Paul Barr
Publisher:
ISBN:
Category : Girders
Languages : en
Pages : 244

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Book Description
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.

Author: John Poulson
Publisher:
ISBN:
Category : Prestressed concrete beams
Languages : en
Pages : 602

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