The Experts below are selected from a list of 475131 Experts worldwide ranked by ideXlab platform
Petros Sideris - One of the best experts on this subject based on the ideXlab platform.
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low damage posttensioned segmental bridge columns with flexible end joints for seismic accelerated bridge Construction
Transportation Research Record, 2016Co-Authors: M T Nikoukalam, Petros SiderisAbstract:A computational parametric study leading toward the development of a new type of low-damage precast concrete segmental column for accelerated bridge Construction in seismic areas is outlined. In contrast to conventional monolithic concrete Construction, accelerated bridge Construction significantly reduces On-Site Construction Time, total project delivery Time, weather-related Construction delays, and environmental impact, and it provides improved work zone safety for the traveling public and contractor personnel and high product quality and durability. Low-damage systems provide significantly reduced postearthquake downTimes, repair costs, and casualties. The proposed column design will incorporate internal unbonded posttensioning and flexible joints at the column ends, where large flexural demands occur. These joints will be (flexurally) deformable enough to accommodate large column lateral deformations (drift ratios of 10% or higher) without damage, and (axially) stiff enough to limit initial axial def...
M T Nikoukalam - One of the best experts on this subject based on the ideXlab platform.
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low damage posttensioned segmental bridge columns with flexible end joints for seismic accelerated bridge Construction
Transportation Research Record, 2016Co-Authors: M T Nikoukalam, Petros SiderisAbstract:A computational parametric study leading toward the development of a new type of low-damage precast concrete segmental column for accelerated bridge Construction in seismic areas is outlined. In contrast to conventional monolithic concrete Construction, accelerated bridge Construction significantly reduces On-Site Construction Time, total project delivery Time, weather-related Construction delays, and environmental impact, and it provides improved work zone safety for the traveling public and contractor personnel and high product quality and durability. Low-damage systems provide significantly reduced postearthquake downTimes, repair costs, and casualties. The proposed column design will incorporate internal unbonded posttensioning and flexible joints at the column ends, where large flexural demands occur. These joints will be (flexurally) deformable enough to accommodate large column lateral deformations (drift ratios of 10% or higher) without damage, and (axially) stiff enough to limit initial axial def...
Travis Thonstad - One of the best experts on this subject based on the ideXlab platform.
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A Pre-Tensioned, Rocking Bridge System for Accelerated Construction and Enhanced Seismic Performance
2016Co-Authors: Travis ThonstadAbstract:A new bridge bent system has been developed to reduce On-Site Construction Time, minimize residual displacements even after a large earthquake, and reduce seismic damage in comparison with conventional cast-in-place Construction. Precast connections used in the system have been tested successfully under quasi-static conditions and found to perform exceptionally well, re-centering with essentially no concrete damage or residual drift after being loaded cyclically to drift ratios of up to 10%. The seismic performance of the new system was evaluated with shaking table tests of a quarter-scale, two-span bridge. The maximum displacements of the bents were similar to those expected for a conventional bridge through the Design Level event (PGA=0.75g). Damage to the column concrete was negligible; the columns would not need any repair after being subjected to the Design Level motion. Residual drift ratios never exceeded 0.2% up to the 221% Design Level motion (PGA = 1.66g). The only structural damage to the bridge was the eventual fracture of the column’s longitudinal reinforcement and bulging of the column’s confining tubes placed at the ends of the columns, both of which occurred at drift ratios of approximately 6%. Results from the subassembly and shaking table tests were used to develop a design methodology for the new system that aligns with the displacement-based procedure outlined in the AASHTO Guide Specifications for LRFD Seismic Bridge Design (2015). The modifications to this procedure necessary to align with the objectives of the new system are straightforward and could be implemented within current design practice. A modeling strategy for the pre-tensioned bent system is also proposed and specific aspects of this approach are validated against the subassembly and shaking table test results.
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Seismic Performance of Precast, Pretensioned, and Cast-in-Place Bridges: Shake Table Test Comparison
Journal of Bridge Engineering, 2016Co-Authors: Islam M. Mantawy, Travis Thonstad, David Sanders, John F. Stanton, Marc O. EberhardAbstract:AbstractA new bridge system has been developed to (1) reduce On-Site Construction Time by using precast components, (2) eliminate major earthquake damage by utilizing column rocking and confinement of the column ends with a steel tube, and (3) maintain the system functionality after a strong earthquake by minimizing residual drift through the use of pretensioned strands in the columns. Furthermore, it uses only conventional materials. This paper compares the shaking table performance of a quarter-scale, two-span bridge constructed through the use of the new system with that of a conventional cast-in-place bridge with similar geometry tested in 2005. The new bridge system was constructed in approximately 20% of the Time needed for the conventional cast-in-place system. In tests, the conventional bridge suffered major concrete cracking and spalling, whereas in the new system, damage to the concrete was only cosmetic. In the conventional bridge, the longitudinal bars buckled, and both the longitudinal and sp...
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Shaking Table Performance of a New Bridge System with Pretensioned Rocking Columns
Journal of Bridge Engineering, 2016Co-Authors: Travis Thonstad, Islam M. Mantawy, John F. Stanton, Marc O. Eberhard, David SandersAbstract:AbstractA new bridge bent system has been developed to reduce On-Site Construction Time, minimize residual displacements even after a large earthquake, and reduce seismic damage in comparison with conventional cast-in-place Construction. Accelerated Construction is achieved through the use of precast columns and cap beams that can be assembled quickly. Postearthquake residual displacements are reduced by pretensioning the columns with partially unbonded tendons. Damage in the columns is nearly eliminated by concentrating flexural deformations to specially detailed regions at the top and bottom of the columns. In this study, the seismic performance of the new system was evaluated with a multi-shaking table test of a quarter scale, two-span bridge at the Network for Earthquake Engineering Simulation (NEES) Earthquake Engineering Laboratory at the University of Nevada, Reno. The maximum displacements of the bents were similar to those expected for a conventional bridge through the 100% design-level event [pe...
Islam M. Mantawy - One of the best experts on this subject based on the ideXlab platform.
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Durable Bridge Columns using Stay-In-Place UHPC Shells for Accelerated Bridge Construction
Infrastructures, 2019Co-Authors: Nerma Caluk, Islam M. Mantawy, Atorod AzizinaminiAbstract:Ultra-high performance concrete (UHPC) is a durable material that allows the Construction of innovative structural elements and conforms with accelerated bridge Construction (ABC) goals. The main idea of this research is to utilize UHPC to prefabricate a shell that acts as a stay-in-place form for bridge columns. The prefabricated shell eliminates the conventional formwork while reducing the On-Site Construction Time and acting as a durable protective layer for the normal concrete inside the shell against environmental attacks. In addition, the UHPC shell provides additional confinement to the column concrete, which improves the column’s structural performance. During Construction and after completing the column reinforcement work onsite, based on the conventional Construction methods, the prefabricated UHPC shell is placed around the column reinforcement, followed by casting a portion of UHPC for a column-to-footing connection, which improves the capacity of the connection and shifts the plastic hinge zone above the connection. Once the UHPC portion hardens, normal concrete is placed inside the shell, forming a permanent concrete-filled UHPC shell. The Construction process is finalized by placing and connecting a prefabricated cap beam to the column through the same developed connection as that in this research. This technical note presents the development of two test specimens using an UHPC shell in lieu of a conventional formwork with the advantage of improving the column performance and durability.
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Seismic Performance of Precast, Pretensioned, and Cast-in-Place Bridges: Shake Table Test Comparison
Journal of Bridge Engineering, 2016Co-Authors: Islam M. Mantawy, Travis Thonstad, David Sanders, John F. Stanton, Marc O. EberhardAbstract:AbstractA new bridge system has been developed to (1) reduce On-Site Construction Time by using precast components, (2) eliminate major earthquake damage by utilizing column rocking and confinement of the column ends with a steel tube, and (3) maintain the system functionality after a strong earthquake by minimizing residual drift through the use of pretensioned strands in the columns. Furthermore, it uses only conventional materials. This paper compares the shaking table performance of a quarter-scale, two-span bridge constructed through the use of the new system with that of a conventional cast-in-place bridge with similar geometry tested in 2005. The new bridge system was constructed in approximately 20% of the Time needed for the conventional cast-in-place system. In tests, the conventional bridge suffered major concrete cracking and spalling, whereas in the new system, damage to the concrete was only cosmetic. In the conventional bridge, the longitudinal bars buckled, and both the longitudinal and sp...
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Shaking Table Performance of a New Bridge System with Pretensioned Rocking Columns
Journal of Bridge Engineering, 2016Co-Authors: Travis Thonstad, Islam M. Mantawy, John F. Stanton, Marc O. Eberhard, David SandersAbstract:AbstractA new bridge bent system has been developed to reduce On-Site Construction Time, minimize residual displacements even after a large earthquake, and reduce seismic damage in comparison with conventional cast-in-place Construction. Accelerated Construction is achieved through the use of precast columns and cap beams that can be assembled quickly. Postearthquake residual displacements are reduced by pretensioning the columns with partially unbonded tendons. Damage in the columns is nearly eliminated by concentrating flexural deformations to specially detailed regions at the top and bottom of the columns. In this study, the seismic performance of the new system was evaluated with a multi-shaking table test of a quarter scale, two-span bridge at the Network for Earthquake Engineering Simulation (NEES) Earthquake Engineering Laboratory at the University of Nevada, Reno. The maximum displacements of the bents were similar to those expected for a conventional bridge through the 100% design-level event [pe...
Joseph Servos - One of the best experts on this subject based on the ideXlab platform.
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Prefabricated/Precast Bridge Elements and Systems (PBES) for O-System Bridges
2012Co-Authors: Michelle Roddenberry, Joseph ServosAbstract:The Federal Highway Administration's (FHWA) "Every Day Counts" initiative aims to shorten the overall project delivery Time, enhance safety, and protect the environment both on and around Construction projects. Using innovative planning, design, and Construction methods, Accelerated Bridge Construction (ABC) techniques reduce On-Site Construction Time for new or replacement bridges. One aspect of ABC is Prefabricated Bridge Elements and Systems (PBES), where bridge components are fabricated off site to reduce On-Site Construction activities. Many state departments of transportation (DOTs) are currently making efforts to implement PBES for Construction of their off-system bridges. The purpose of this research project was to investigate other states' standards and to evaluate them for possible implementation in Florida. An exhaustive search was made, and new literature was reviewed, to learn about current DOT standards and practices. The search revealed that the states with the most prefabricated bridge standards or activities are as follows: Utah, Alabama, Texas, Minnesota, and a collaboration of Northeastern states. These standards were reviewed for details such as the presence of post-tensioning, joint types, design load, and inspectability. The two standard bridge types that show the most promise for adoption by Florida Department of Transportation (FDOT) are Minnesota's Inverted-tee Beam, and PCI's "Northeastern Extreme Tee" (NEXT) Beam. A summary of the findings, including advantages and disadvantages of the bridge systems, is included in this report. Also included is a comprehensive list of Web links to standard drawings from all state DOTs, as well as more information on ABC and PBES, which could also be helpful to expedite other research that involves standards and bridge Construction/design practices.
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prefabricated precast bridge elements and systems pbes for o system bridges
2012Co-Authors: Michelle Roddenberry, Joseph ServosAbstract:The Federal Highway Administration's (FHWA) "Every Day Counts" initiative aims to shorten the overall project delivery Time, enhance safety, and protect the environment both on and around Construction projects. Using innovative planning, design, and Construction methods, Accelerated Bridge Construction (ABC) techniques reduce On-Site Construction Time for new or replacement bridges. One aspect of ABC is Prefabricated Bridge Elements and Systems (PBES), where bridge components are fabricated off site to reduce On-Site Construction activities. Many state departments of transportation (DOTs) are currently making efforts to implement PBES for Construction of their off-system bridges. The purpose of this research project was to investigate other states' standards and to evaluate them for possible implementation in Florida. An exhaustive search was made, and new literature was reviewed, to learn about current DOT standards and practices. The search revealed that the states with the most prefabricated bridge standards or activities are as follows: Utah, Alabama, Texas, Minnesota, and a collaboration of Northeastern states. These standards were reviewed for details such as the presence of post-tensioning, joint types, design load, and inspectability. The two standard bridge types that show the most promise for adoption by Florida Department of Transportation (FDOT) are Minnesota's Inverted-tee Beam, and PCI's "Northeastern Extreme Tee" (NEXT) Beam. A summary of the findings, including advantages and disadvantages of the bridge systems, is included in this report. Also included is a comprehensive list of Web links to standard drawings from all state DOTs, as well as more information on ABC and PBES, which could also be helpful to expedite other research that involves standards and bridge Construction/design practices.
