The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform

Catherine E French - One of the best experts on this subject based on the ideXlab platform.

  • cast in place concrete connections for precast deck Systems
    NCHRP Web Document, 2011
    Co-Authors: Catherine E French, Carol K. Shield, D Klaseus, M D Smith, W Eriksson, Zhongguo John, Samuel Lewis, Cheryl E Chapman
    Abstract:

    This report contains recommended design specifications, construction specifications, and five illustrative examples of durable cast-in-place (CIP) reinforced concrete connections for precast deck Systems that emulate monolithic construction, considering issues including speed of construction, durability, and fatigue. Included in the report is the supporting research that led to these recommendations. This research focused on Systems that reduce the need to place and remove formwork thus accelerating on-site construction and improving safety. The three Systems considered to accomplish these objectives were: (1) a precast composite slab Span System (PCSSS) for short to moderate Span structures, (2) full-depth prefabricated concrete decks, and (3) deck joint closure details (e.g., decked-bulb-tee (DBT) flange connections) for precast prestressed concrete girder Systems for long Span structures. Depending on the System, the connections are either transverse (i.e., across the width of the bridge) or longitudinal (i.e., along the length of the bridge). The first System, PCSSS, is an entire bridge System; whereas the other two Systems investigated in the project represented transverse and longitudinal joint details to transfer moment and shear in precast deck panels and flanges of decked bulb tees. Two types of connection concepts were explored with these details, looped bar details and two layers of headed bar details.

  • Field and Laboratory Study of Precast Composite Slab Span System (PCSSS)
    2010
    Co-Authors: Catherine E French, Carol K. Shield, Matthew Smith, Whitney Eriksson, Dave Klaseus
    Abstract:

    This paper describes a field and laboratory investigation of a Precast Composite Slab Span System (PCSSS) implemented for short to moderate Span bridges (20-50ft. range). Advantages of the System include accelerated construction, improved quality control, and reduced impact on the environment compared to cast-in-place (CIP) slab Span Systems. In addition, the PCSSS is a viable alternative used by maintenance crews in retrofitting existing bridges. The field study was conducted on one of the early Minnesota Department of Transportation (Mn/DOT) implementations over a period of 24 months to investigate the performance of the System relative to design assumptions and the susceptibility of the System to developing reflective cracking. As part of the NCHRP 10-71 Cast-in-Place Connections project, the University of Minnesota is developing design recommendations for these Systems. Numerical studies and experiments on large-scale bridge specimens were conducted in the laboratory environment to investigate the effects of a number of parameters including variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, flange surface treatment, and crack control reinforcement.

  • Monitoring and Analysis of Mn/DOT Precast Composite Slab Span System (PCSSS)
    2008
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    University of Minnesota Master of Science thesis. January 2010. Major: Civil Engineering. Advisors: Catherine French and Carol Shield. 1 computer file (PDF); viii, 227 pages.

  • Field and Laboratory Study of the Mn/DOT Slab Span System
    2007
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    The Minnesota Department of Transportation (MN DOT) Precast Slab Span System was initially designed by MN DOT with input from University of Minnesota researchers and local fabricators. The bridge System consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One of the MN DOT implementations, located in Center City, MN, was instrumented. The bridge has been monitored for reflective cracking and continuity over the piers since the deck was cast. Transverse load distribution was evaluated with a static truck test. In addition, a two-Span test specimen was constructed to investigate effects of variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, and flange surface treatment. The data obtained from the field study indicated that cracking had initiated in the bridge at the locations of some of the gages at midSpan and near the support. The cracking was determined to be the result of environmental loads and shrinkage rather than due to vehicular loads. The data from the truck tests indicated that the design assumption of a monolithic slab System was valid for the determination of load distribution factors. The results of the laboratory study showed that positive restraint moments developed in the precast System for which continuity was made at a young age (i.e., seven days), and that these moments could be reasonably well predicted by existing models. It has also been found that current American Association of State Highway and Transportation Officials bursting requirements require unnecessary transverse reinforcement in the end zones of slab Span Systems.

Sandy Kennedy - One of the best experts on this subject based on the ideXlab platform.

  • GPS/INS Integration in Real-time and Post- processing with NovAtel's Span System
    2007
    Co-Authors: Sandy Kennedy, Darren Cosandier
    Abstract:

    NovAtel offers a GPS/INS solution with a uniquely robust architecture. The Span (Synchronized Position Attitude Navigation) System builds on the OEMV receiver, by integrating inertial measurements to provide a high-rate, continuous navigation solution. The integration is tightly coupled with access to the GPS receiver core, with both the GPS and inertial processing benefiting from the integration. Typically, GPS measurements are used to aid the inertial solution, providing update measurements to model IMU errors and control error growth during GPS outages. With Span, GPS performance is also improved. A Span enabled receiver features rapid signal requisition and a faster return to fixed integer carrier phase status (RTK) after signal outages. By improving the quality and availability of the GPS signals, the INS solution is also improved since there are more updates available. Post-processing functionality comes with Inertial Explorer, a software package featuring a fixed interval smoother to minimize errors during GPS outages. To demonstrate the performance of the Span (real-time) and Inertial Explorer (post-processed), results from real world applications will be presented. Data sets collected in an aircraft and in a land vehicle will be presented. The airborne data set illustrates how Span can be incorporated

  • gps ins integration in real time and post processing with novatel s Span System
    2007
    Co-Authors: Sandy Kennedy, Darren Cosandier
    Abstract:

    NovAtel offers a GPS/INS solution with a uniquely robust architecture. The Span (Synchronized Position Attitude Navigation) System builds on the OEMV receiver, by integrating inertial measurements to provide a high-rate, continuous navigation solution. The integration is tightly coupled with access to the GPS receiver core, with both the GPS and inertial processing benefiting from the integration. Typically, GPS measurements are used to aid the inertial solution, providing update measurements to model IMU errors and control error growth during GPS outages. With Span, GPS performance is also improved. A Span enabled receiver features rapid signal requisition and a faster return to fixed integer carrier phase status (RTK) after signal outages. By improving the quality and availability of the GPS signals, the INS solution is also improved since there are more updates available. Post-processing functionality comes with Inertial Explorer, a software package featuring a fixed interval smoother to minimize errors during GPS outages. To demonstrate the performance of the Span (real-time) and Inertial Explorer (post-processed), results from real world applications will be presented. Data sets collected in an aircraft and in a land vehicle will be presented. The airborne data set illustrates how Span can be incorporated

  • architecture and System performance of Span novatel s gps ins solution
    IEEE ION Position Location and Navigation Symposium, 2006
    Co-Authors: Sandy Kennedy, J Hamilton, H Martell
    Abstract:

    As a GPS receiver manufacturer, NovAtel is in a unique position to build a GPS/INS navigation System. The Synchronized Position Attitude Navigation (Span) System is based on OEM4 receiver technology combined with an Inertial Measurement Unit (IMU). The IMU integration is tightly coupled with access to the GPS receiver core. The integrated System provides real time position, velocity and attitude. GPS outages can be seamlessly bridged, enabling more reliable navigation through challenging environments like urban canyons. Additionally, GPS performance is improved with the integration of inertial measurements, allowing for faster signal reacquisition and faster return to a fixed integer carrier phase solution after signal outage. The real time solution is computed on board the receiver and raw data can be simultaneously logged for post-processing. Post processing is performed by NovAtel’s Waypoint Inertial Explorer package. This paper discusses NovAtel's approach to INS/GPS System architecture. To demonstrate the performance of the Span System, data will be collected under real world conditions in a land vehicle. Test results will show System performance with various levels of GPS aiding and with wheel sensor aiding. The real time solution will be compared to the post-processed solution. Methods to deal with the constraints of real time will be discussed. The accuracy benefits of a post-processed solution will be demonstrated as well.

  • Architecture and System Performance of Span -NovAtel's GPS/INS Solution
    2006 IEEE ION Position Location And Navigation Symposium, 1
    Co-Authors: Sandy Kennedy, J Hamilton, H Martell
    Abstract:

    As a GPS receiver manufacturer, NovAtel is in a unique position to build a GPS/INS navigation System. The Synchronized Position Attitude Navigation (Span) System is based on OEM4 receiver technology combined with an Inertial Measurement Unit (IMU). The IMU integration is tightly coupled with access to the GPS receiver core. The integrated System provides real time position, velocity and attitude. GPS outages can be seamlessly bridged, enabling more reliable navigation through challenging environments like urban canyons. Additionally, GPS performance is improved with the integration of inertial measurements, allowing for faster signal reacquisition and faster return to a fixed integer carrier phase solution after signal outage. The real time solution is computed on board the receiver and raw data can be simultaneously logged for post-processing. Post processing is performed by NovAtel’s Waypoint Inertial Explorer package. This paper discusses NovAtel's approach to INS/GPS System architecture. To demonstrate the performance of the Span System, data will be collected under real world conditions in a land vehicle. Test results will show System performance with various levels of GPS aiding and with wheel sensor aiding. The real time solution will be compared to the post-processed solution. Methods to deal with the constraints of real time will be discussed. The accuracy benefits of a post-processed solution will be demonstrated as well.

Carol K. Shield - One of the best experts on this subject based on the ideXlab platform.

  • cast in place concrete connections for precast deck Systems
    NCHRP Web Document, 2011
    Co-Authors: Catherine E French, Carol K. Shield, D Klaseus, M D Smith, W Eriksson, Zhongguo John, Samuel Lewis, Cheryl E Chapman
    Abstract:

    This report contains recommended design specifications, construction specifications, and five illustrative examples of durable cast-in-place (CIP) reinforced concrete connections for precast deck Systems that emulate monolithic construction, considering issues including speed of construction, durability, and fatigue. Included in the report is the supporting research that led to these recommendations. This research focused on Systems that reduce the need to place and remove formwork thus accelerating on-site construction and improving safety. The three Systems considered to accomplish these objectives were: (1) a precast composite slab Span System (PCSSS) for short to moderate Span structures, (2) full-depth prefabricated concrete decks, and (3) deck joint closure details (e.g., decked-bulb-tee (DBT) flange connections) for precast prestressed concrete girder Systems for long Span structures. Depending on the System, the connections are either transverse (i.e., across the width of the bridge) or longitudinal (i.e., along the length of the bridge). The first System, PCSSS, is an entire bridge System; whereas the other two Systems investigated in the project represented transverse and longitudinal joint details to transfer moment and shear in precast deck panels and flanges of decked bulb tees. Two types of connection concepts were explored with these details, looped bar details and two layers of headed bar details.

  • Field and Laboratory Study of Precast Composite Slab Span System (PCSSS)
    2010
    Co-Authors: Catherine E French, Carol K. Shield, Matthew Smith, Whitney Eriksson, Dave Klaseus
    Abstract:

    This paper describes a field and laboratory investigation of a Precast Composite Slab Span System (PCSSS) implemented for short to moderate Span bridges (20-50ft. range). Advantages of the System include accelerated construction, improved quality control, and reduced impact on the environment compared to cast-in-place (CIP) slab Span Systems. In addition, the PCSSS is a viable alternative used by maintenance crews in retrofitting existing bridges. The field study was conducted on one of the early Minnesota Department of Transportation (Mn/DOT) implementations over a period of 24 months to investigate the performance of the System relative to design assumptions and the susceptibility of the System to developing reflective cracking. As part of the NCHRP 10-71 Cast-in-Place Connections project, the University of Minnesota is developing design recommendations for these Systems. Numerical studies and experiments on large-scale bridge specimens were conducted in the laboratory environment to investigate the effects of a number of parameters including variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, flange surface treatment, and crack control reinforcement.

  • Monitoring and Analysis of Mn/DOT Precast Composite Slab Span System (PCSSS)
    2008
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    University of Minnesota Master of Science thesis. January 2010. Major: Civil Engineering. Advisors: Catherine French and Carol Shield. 1 computer file (PDF); viii, 227 pages.

  • Field and Laboratory Study of the Mn/DOT Slab Span System
    2007
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    The Minnesota Department of Transportation (MN DOT) Precast Slab Span System was initially designed by MN DOT with input from University of Minnesota researchers and local fabricators. The bridge System consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One of the MN DOT implementations, located in Center City, MN, was instrumented. The bridge has been monitored for reflective cracking and continuity over the piers since the deck was cast. Transverse load distribution was evaluated with a static truck test. In addition, a two-Span test specimen was constructed to investigate effects of variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, and flange surface treatment. The data obtained from the field study indicated that cracking had initiated in the bridge at the locations of some of the gages at midSpan and near the support. The cracking was determined to be the result of environmental loads and shrinkage rather than due to vehicular loads. The data from the truck tests indicated that the design assumption of a monolithic slab System was valid for the determination of load distribution factors. The results of the laboratory study showed that positive restraint moments developed in the precast System for which continuity was made at a young age (i.e., seven days), and that these moments could be reasonably well predicted by existing models. It has also been found that current American Association of State Highway and Transportation Officials bursting requirements require unnecessary transverse reinforcement in the end zones of slab Span Systems.

  • Field and Laboratory Study of the Mn/DOT Precast Slab Span System
    2007
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine W. French
    Abstract:

    The Minnesota Department of Transportation (Mn/DOT) Precast Slab Span System was initially designed by Mn/DOT with input from University of Minnesota researchers and local fabricators. The bridge System consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One of the Mn/DOT implementations, located in Center City, MN, was instrumented. The bridge has been monitored for reflective cracking and continuity over the piers since the deck was cast. Transverse load distribution was evaluated with a static truck test. In addition, a two-Span test specimen was constructed to investigate effects of variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, and flange surface treatment. The data obtained from the field study indicated that cracking had initiated in the bridge at the locations of some of the gages at midSpan and near the support. The cracking was determined to be the result of environmental loads and shrinkage rather than due to vehicular loads. The data from the truck tests indicated that the design assumption of a monolithic slab System was valid for the determination of load distribution factors. The results of the laboratory study showed that positive restraint moments developed in the precast System for which continuity was made at a young age (i.e., seven days), and that these moments could be reasonably well predicted by existing models. It has also been found that current American Association of State Highway and Transportation Officials bursting requirements require unnecessary transverse reinforcement in the end zones of slab Span Systems.

Matthew Smith - One of the best experts on this subject based on the ideXlab platform.

  • Field and Laboratory Study of Precast Composite Slab Span System (PCSSS)
    2010
    Co-Authors: Catherine E French, Carol K. Shield, Matthew Smith, Whitney Eriksson, Dave Klaseus
    Abstract:

    This paper describes a field and laboratory investigation of a Precast Composite Slab Span System (PCSSS) implemented for short to moderate Span bridges (20-50ft. range). Advantages of the System include accelerated construction, improved quality control, and reduced impact on the environment compared to cast-in-place (CIP) slab Span Systems. In addition, the PCSSS is a viable alternative used by maintenance crews in retrofitting existing bridges. The field study was conducted on one of the early Minnesota Department of Transportation (Mn/DOT) implementations over a period of 24 months to investigate the performance of the System relative to design assumptions and the susceptibility of the System to developing reflective cracking. As part of the NCHRP 10-71 Cast-in-Place Connections project, the University of Minnesota is developing design recommendations for these Systems. Numerical studies and experiments on large-scale bridge specimens were conducted in the laboratory environment to investigate the effects of a number of parameters including variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, flange surface treatment, and crack control reinforcement.

  • Monitoring and Analysis of Mn/DOT Precast Composite Slab Span System (PCSSS)
    2008
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    University of Minnesota Master of Science thesis. January 2010. Major: Civil Engineering. Advisors: Catherine French and Carol Shield. 1 computer file (PDF); viii, 227 pages.

  • Field and Laboratory Study of the Mn/DOT Slab Span System
    2007
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    The Minnesota Department of Transportation (MN DOT) Precast Slab Span System was initially designed by MN DOT with input from University of Minnesota researchers and local fabricators. The bridge System consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One of the MN DOT implementations, located in Center City, MN, was instrumented. The bridge has been monitored for reflective cracking and continuity over the piers since the deck was cast. Transverse load distribution was evaluated with a static truck test. In addition, a two-Span test specimen was constructed to investigate effects of variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, and flange surface treatment. The data obtained from the field study indicated that cracking had initiated in the bridge at the locations of some of the gages at midSpan and near the support. The cracking was determined to be the result of environmental loads and shrinkage rather than due to vehicular loads. The data from the truck tests indicated that the design assumption of a monolithic slab System was valid for the determination of load distribution factors. The results of the laboratory study showed that positive restraint moments developed in the precast System for which continuity was made at a young age (i.e., seven days), and that these moments could be reasonably well predicted by existing models. It has also been found that current American Association of State Highway and Transportation Officials bursting requirements require unnecessary transverse reinforcement in the end zones of slab Span Systems.

  • Field and Laboratory Study of the Mn/DOT Precast Slab Span System
    2007
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine W. French
    Abstract:

    The Minnesota Department of Transportation (Mn/DOT) Precast Slab Span System was initially designed by Mn/DOT with input from University of Minnesota researchers and local fabricators. The bridge System consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One of the Mn/DOT implementations, located in Center City, MN, was instrumented. The bridge has been monitored for reflective cracking and continuity over the piers since the deck was cast. Transverse load distribution was evaluated with a static truck test. In addition, a two-Span test specimen was constructed to investigate effects of variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, and flange surface treatment. The data obtained from the field study indicated that cracking had initiated in the bridge at the locations of some of the gages at midSpan and near the support. The cracking was determined to be the result of environmental loads and shrinkage rather than due to vehicular loads. The data from the truck tests indicated that the design assumption of a monolithic slab System was valid for the determination of load distribution factors. The results of the laboratory study showed that positive restraint moments developed in the precast System for which continuity was made at a young age (i.e., seven days), and that these moments could be reasonably well predicted by existing models. It has also been found that current American Association of State Highway and Transportation Officials bursting requirements require unnecessary transverse reinforcement in the end zones of slab Span Systems.

Whitney Eriksson - One of the best experts on this subject based on the ideXlab platform.

  • Field and Laboratory Study of Precast Composite Slab Span System (PCSSS)
    2010
    Co-Authors: Catherine E French, Carol K. Shield, Matthew Smith, Whitney Eriksson, Dave Klaseus
    Abstract:

    This paper describes a field and laboratory investigation of a Precast Composite Slab Span System (PCSSS) implemented for short to moderate Span bridges (20-50ft. range). Advantages of the System include accelerated construction, improved quality control, and reduced impact on the environment compared to cast-in-place (CIP) slab Span Systems. In addition, the PCSSS is a viable alternative used by maintenance crews in retrofitting existing bridges. The field study was conducted on one of the early Minnesota Department of Transportation (Mn/DOT) implementations over a period of 24 months to investigate the performance of the System relative to design assumptions and the susceptibility of the System to developing reflective cracking. As part of the NCHRP 10-71 Cast-in-Place Connections project, the University of Minnesota is developing design recommendations for these Systems. Numerical studies and experiments on large-scale bridge specimens were conducted in the laboratory environment to investigate the effects of a number of parameters including variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, flange surface treatment, and crack control reinforcement.

  • Monitoring and Analysis of Mn/DOT Precast Composite Slab Span System (PCSSS)
    2008
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    University of Minnesota Master of Science thesis. January 2010. Major: Civil Engineering. Advisors: Catherine French and Carol Shield. 1 computer file (PDF); viii, 227 pages.

  • Field and Laboratory Study of the Mn/DOT Slab Span System
    2007
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine E French
    Abstract:

    The Minnesota Department of Transportation (MN DOT) Precast Slab Span System was initially designed by MN DOT with input from University of Minnesota researchers and local fabricators. The bridge System consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One of the MN DOT implementations, located in Center City, MN, was instrumented. The bridge has been monitored for reflective cracking and continuity over the piers since the deck was cast. Transverse load distribution was evaluated with a static truck test. In addition, a two-Span test specimen was constructed to investigate effects of variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, and flange surface treatment. The data obtained from the field study indicated that cracking had initiated in the bridge at the locations of some of the gages at midSpan and near the support. The cracking was determined to be the result of environmental loads and shrinkage rather than due to vehicular loads. The data from the truck tests indicated that the design assumption of a monolithic slab System was valid for the determination of load distribution factors. The results of the laboratory study showed that positive restraint moments developed in the precast System for which continuity was made at a young age (i.e., seven days), and that these moments could be reasonably well predicted by existing models. It has also been found that current American Association of State Highway and Transportation Officials bursting requirements require unnecessary transverse reinforcement in the end zones of slab Span Systems.

  • Field and Laboratory Study of the Mn/DOT Precast Slab Span System
    2007
    Co-Authors: Matthew Smith, Carol K. Shield, Whitney Eriksson, Catherine W. French
    Abstract:

    The Minnesota Department of Transportation (Mn/DOT) Precast Slab Span System was initially designed by Mn/DOT with input from University of Minnesota researchers and local fabricators. The bridge System consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One of the Mn/DOT implementations, located in Center City, MN, was instrumented. The bridge has been monitored for reflective cracking and continuity over the piers since the deck was cast. Transverse load distribution was evaluated with a static truck test. In addition, a two-Span test specimen was constructed to investigate effects of variations in flange thickness, bursting reinforcement, horizontal shear reinforcement, and flange surface treatment. The data obtained from the field study indicated that cracking had initiated in the bridge at the locations of some of the gages at midSpan and near the support. The cracking was determined to be the result of environmental loads and shrinkage rather than due to vehicular loads. The data from the truck tests indicated that the design assumption of a monolithic slab System was valid for the determination of load distribution factors. The results of the laboratory study showed that positive restraint moments developed in the precast System for which continuity was made at a young age (i.e., seven days), and that these moments could be reasonably well predicted by existing models. It has also been found that current American Association of State Highway and Transportation Officials bursting requirements require unnecessary transverse reinforcement in the end zones of slab Span Systems.