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Polyethylene duct cracking in post-tensioning tendons of Florida segmental bridges
Title
Polyethylene duct cracking in post-tensioning tendons of Florida segmental bridges.
Creator
Suarez, Jorge Alejandro, Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
For the purpose of investigating the cause of duct cracking in post-tensioning tendons and improving the durability of this type of structure, a series of experiments was performed. These were divided in two groups, the first to simulate the state of stress inside the tendon ducts and the second to compare the properties of new materials approved according to new regulations on the subject and those used in the construction of the structures. A proposed mechanism of cracking was studied and...
Show moreFor the purpose of investigating the cause of duct cracking in post-tensioning tendons and improving the durability of this type of structure, a series of experiments was performed. These were divided in two groups, the first to simulate the state of stress inside the tendon ducts and the second to compare the properties of new materials approved according to new regulations on the subject and those used in the construction of the structures. A proposed mechanism of cracking was studied and its validity verified. According to simulations performed on specimens that were fabricated and others developed by the finite element method, new major factors were found to explain the duct failure. Finally, a comparison of mechanical properties indicated a difference between virgin and aged materials.
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Date Issued
2003
PURL
http://purl.flvc.org/fcla/dt/13071
Subject Headings
Post-tensioned prestressed concrete construction, Bridges--Florida, Polyethylene
Format
Document (PDF)
Knowledge based expert system for the analysis and rating of Florida bridges
Title
Knowledge based expert system for the analysis and rating of Florida bridges.
Creator
Sawka, Mark Joseph., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The automation of bridge strength evaluation by utilizing artificial intelligence tools is presented herein. The study involved the development of a microcomputer based expert system, REX (Rating EXpert). REX is an interactive menu-driven system combining the expert system shell EXSYS, the Grillage program 'BRIDGES', and various other pre- and post- processing devices. The system is capable of analyzing and assessing the load carrying capacity of solid and voided slab, and AASHTO girder and...
Show moreThe automation of bridge strength evaluation by utilizing artificial intelligence tools is presented herein. The study involved the development of a microcomputer based expert system, REX (Rating EXpert). REX is an interactive menu-driven system combining the expert system shell EXSYS, the Grillage program 'BRIDGES', and various other pre- and post- processing devices. The system is capable of analyzing and assessing the load carrying capacity of solid and voided slab, and AASHTO girder and slab bridges.
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Date Issued
1992
PURL
http://purl.flvc.org/fcla/dt/14841
Subject Headings
Bridges--Florida, Bridges--Testing, Expert systems (Computer science)
Format
Document (PDF)
Thermal modeling and field temperature measurement of segmental box girder bridges in Florida
Title
Thermal modeling and field temperature measurement of segmental box girder bridges in Florida.
Creator
Basole, Milind Madhukar., Florida Atlantic University, Reddy, Dronnadula V.
Abstract/Description
Temperature and thermal stress variations in a segmental box girder bridge arc studied. A finite element model using the general finite element software MARC is used to predict temperature and thermal stress variation, for segmental box girder bridges. The predictions are compared with actual measured temperature data of two segmental box girder bridges, instrumented with thermocouples and vibrating wire strain gages, in Davie, Florida. Continuous monitoring was carried out for two months in...
Show moreTemperature and thermal stress variations in a segmental box girder bridge arc studied. A finite element model using the general finite element software MARC is used to predict temperature and thermal stress variation, for segmental box girder bridges. The predictions are compared with actual measured temperature data of two segmental box girder bridges, instrumented with thermocouples and vibrating wire strain gages, in Davie, Florida. Continuous monitoring was carried out for two months in July-August, 1991, and for one month in January-February, 1992. Comparison are also made with the NCHRP suggested profiles. A Monte Carlo analysis is performed to accommodate the probabilistic variation of ambient temperature conditions.
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Date Issued
1992
PURL
http://purl.flvc.org/fcla/dt/14840
Subject Headings
Bridges, Box girder, Bridges--Florida, Thermal stresses
Format
Document (PDF)
role of polyethylene duct cracking in the failure of post-tensioned cables in Florida segmental bridges
Title
The role of polyethylene duct cracking in the failure of post-tensioned cables in Florida segmental bridges.
Creator
David, Florent Martin., Florida Atlantic University, Hartt, William H.
Abstract/Description
During the past several decades, segmental construction using precast sections has evolved as a preferred design and construction method for bridges. The tendons used to hold the precast sections together are comprised of cables surrounded by a plastic duct filled with grout. Cracking of the tendon's protective plastic duct has been observed in several Florida bridges. An experimental investigation was performed to characterize the material properties of the high density polyethylene ducts...
Show moreDuring the past several decades, segmental construction using precast sections has evolved as a preferred design and construction method for bridges. The tendons used to hold the precast sections together are comprised of cables surrounded by a plastic duct filled with grout. Cracking of the tendon's protective plastic duct has been observed in several Florida bridges. An experimental investigation was performed to characterize the material properties of the high density polyethylene ducts used in the past and those being specified nowadays. The degree of cure of the resin, the results of three-point bending tests for unnotched and notched specimens, the coefficient of thermal expansion, and the deformation of a tendon as a function of temperature changes were studied. The effects of the grouting pressure and the void presence in the grout were quantified and the pressurization period was shown to affect significantly the pipe strain.
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Date Issued
2003
PURL
http://purl.flvc.org/fcla/dt/12999
Subject Headings
Pipe, Plastic--Testing, Bridges--Florida, Post-tensioned prestressed concrete construction
Format
Document (PDF)