The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform

Michalis F Vassiliou - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Response and Stability of the Rocking Frame
    Computational Methods Seismic Protection Hybrid Testing and Resilience in Earthquake Engineering, 2014
    Co-Authors: Nicos Makris, Michalis F Vassiliou
    Abstract:

    This paper investigates the planar rocking response of an array of free-standing columns capped with a freely supported rigid beam in an effort to explain the appreciable seismic stability of ancient free-standing columns which support heavy epistyles together with the even heavier frieze atop. Following a variational formulation the paper concludes to the remarkable result that the dynamic rocking response of an array of free-standing columns capped with a rigid beam is identical to the rocking response of a single free-standing column with the same slenderness; yet with larger size – that is a more stable configuration. Most importantly, the study shows that the heavier the freely supported cap-beam is (epistyles with frieze atop), the more stable is the rocking frame regardless the rise of the center of gravity of the cap-beam; concluding that top-heavy rocking frames are more stable than when they are top-light. This “counter intuitive” finding renders rocking isolation a most attractive alternative for the seismic protection of Bridges with tall piers; while its potential implementation shall remove several of the concerns associated with the seismic connections of Prefabricated Bridges.

  • planar rocking response and stability analysis of an array of free standing columns capped with a freely supported rigid beam
    Earthquake Engineering & Structural Dynamics, 2013
    Co-Authors: Nicos Makris, Michalis F Vassiliou
    Abstract:

    SUMMARY This paper investigates the planar rocking response of an array of free-standing columns capped with a freely supported rigid beam in an effort to explain the appreciable seismic stability of ancient free-standing columns that support heavy epistyles together with the even heavier frieze atop. Following a variational formulation, the paper concludes to the remarkable result that the dynamic rocking response of an array of free-standing columns capped with a rigid beam is identical to the rocking response of a single free-standing column with the same slenderness yet with larger size, that is a more stable configuration. Most importantly, the study shows that the heavier the freely supported cap beam is (epistyles with frieze atop), the more stable is the rocking frame regardless of the rise of the center of gravity of the cap beam, concluding that top-heavy rocking frames are more stable than when they are top light. This ‘counter intuitive’ finding renders rocking isolation a most attractive alternative for the seismic protection of Bridges with tall piers, whereas its potential implementation shall remove several of the concerns associated with the seismic connections of Prefabricated Bridges. Copyright © 2012 John Wiley & Sons, Ltd.

  • Planar rocking response and stability analysis of an array of free‐standing columns capped with a freely supported rigid beam
    Earthquake Engineering & Structural Dynamics, 2012
    Co-Authors: Nicos Makris, Michalis F Vassiliou
    Abstract:

    SUMMARY This paper investigates the planar rocking response of an array of free-standing columns capped with a freely supported rigid beam in an effort to explain the appreciable seismic stability of ancient free-standing columns that support heavy epistyles together with the even heavier frieze atop. Following a variational formulation, the paper concludes to the remarkable result that the dynamic rocking response of an array of free-standing columns capped with a rigid beam is identical to the rocking response of a single free-standing column with the same slenderness yet with larger size, that is a more stable configuration. Most importantly, the study shows that the heavier the freely supported cap beam is (epistyles with frieze atop), the more stable is the rocking frame regardless of the rise of the center of gravity of the cap beam, concluding that top-heavy rocking frames are more stable than when they are top light. This ‘counter intuitive’ finding renders rocking isolation a most attractive alternative for the seismic protection of Bridges with tall piers, whereas its potential implementation shall remove several of the concerns associated with the seismic connections of Prefabricated Bridges. Copyright © 2012 John Wiley & Sons, Ltd.

Nicos Makris - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Response and Stability of the Rocking Frame
    Computational Methods Seismic Protection Hybrid Testing and Resilience in Earthquake Engineering, 2014
    Co-Authors: Nicos Makris, Michalis F Vassiliou
    Abstract:

    This paper investigates the planar rocking response of an array of free-standing columns capped with a freely supported rigid beam in an effort to explain the appreciable seismic stability of ancient free-standing columns which support heavy epistyles together with the even heavier frieze atop. Following a variational formulation the paper concludes to the remarkable result that the dynamic rocking response of an array of free-standing columns capped with a rigid beam is identical to the rocking response of a single free-standing column with the same slenderness; yet with larger size – that is a more stable configuration. Most importantly, the study shows that the heavier the freely supported cap-beam is (epistyles with frieze atop), the more stable is the rocking frame regardless the rise of the center of gravity of the cap-beam; concluding that top-heavy rocking frames are more stable than when they are top-light. This “counter intuitive” finding renders rocking isolation a most attractive alternative for the seismic protection of Bridges with tall piers; while its potential implementation shall remove several of the concerns associated with the seismic connections of Prefabricated Bridges.

  • planar rocking response and stability analysis of an array of free standing columns capped with a freely supported rigid beam
    Earthquake Engineering & Structural Dynamics, 2013
    Co-Authors: Nicos Makris, Michalis F Vassiliou
    Abstract:

    SUMMARY This paper investigates the planar rocking response of an array of free-standing columns capped with a freely supported rigid beam in an effort to explain the appreciable seismic stability of ancient free-standing columns that support heavy epistyles together with the even heavier frieze atop. Following a variational formulation, the paper concludes to the remarkable result that the dynamic rocking response of an array of free-standing columns capped with a rigid beam is identical to the rocking response of a single free-standing column with the same slenderness yet with larger size, that is a more stable configuration. Most importantly, the study shows that the heavier the freely supported cap beam is (epistyles with frieze atop), the more stable is the rocking frame regardless of the rise of the center of gravity of the cap beam, concluding that top-heavy rocking frames are more stable than when they are top light. This ‘counter intuitive’ finding renders rocking isolation a most attractive alternative for the seismic protection of Bridges with tall piers, whereas its potential implementation shall remove several of the concerns associated with the seismic connections of Prefabricated Bridges. Copyright © 2012 John Wiley & Sons, Ltd.

  • Planar rocking response and stability analysis of an array of free‐standing columns capped with a freely supported rigid beam
    Earthquake Engineering & Structural Dynamics, 2012
    Co-Authors: Nicos Makris, Michalis F Vassiliou
    Abstract:

    SUMMARY This paper investigates the planar rocking response of an array of free-standing columns capped with a freely supported rigid beam in an effort to explain the appreciable seismic stability of ancient free-standing columns that support heavy epistyles together with the even heavier frieze atop. Following a variational formulation, the paper concludes to the remarkable result that the dynamic rocking response of an array of free-standing columns capped with a rigid beam is identical to the rocking response of a single free-standing column with the same slenderness yet with larger size, that is a more stable configuration. Most importantly, the study shows that the heavier the freely supported cap beam is (epistyles with frieze atop), the more stable is the rocking frame regardless of the rise of the center of gravity of the cap beam, concluding that top-heavy rocking frames are more stable than when they are top light. This ‘counter intuitive’ finding renders rocking isolation a most attractive alternative for the seismic protection of Bridges with tall piers, whereas its potential implementation shall remove several of the concerns associated with the seismic connections of Prefabricated Bridges. Copyright © 2012 John Wiley & Sons, Ltd.

Bijan Khaleghi - One of the best experts on this subject based on the ideXlab platform.

  • Innovative Bridge Design and Construction in Washington State
    2010
    Co-Authors: Bijan Khaleghi
    Abstract:

    Bridge construction with prefabrication of modular components offers an attractive alternative to conventional Bridges. Prefabricated bridge components are in increasing demand for accelerated bridge construction. Prefabricating eliminates the need for forming, casting, and curing of concrete in the work zones, making bridge construction safer while improving quality and durability. Prefabricated Bridges consisting of pretensioned girders, post-tensioned spliced girders, trapezoidal open box girders, and other types of superstructure members are often used for accelerated bridge construction; however, bridge engineers are concerned with the durability and performance of Bridges made of Prefabricated members in areas of high or moderate seismicity. This paper presents the latest Accelerated Bridge Construction (ABC) research in Washington and its implementation to a bridge construction project. The discussion expands to the ongoing Highways For Life (HFL) project benefitting the latest research data available for ABC implementation.

  • Use of Precast Bridge Members in Areas of High or Moderate Seismicity
    Transportation Research Record, 2009
    Co-Authors: Jugesh Kapur, Bijan Khaleghi
    Abstract:

    Prefabricated bridge components are in increasing demand for accelerated bridge construction. Precasting eliminates the need for forming, casting, and curing concrete in work zones and makes bridge construction safer while improving quality and durability. Precast Bridges consisting of pretensioned girders, posttensioned spliced girders, trapezoidal open box girders, and other types of superstructure members are often used for accelerated bridge construction; however, bridge engineers are concerned with the durability and performance of Bridges made of precast members in areas of high or moderate seismicity. The applicability of the AASHTO load and resistance factor design specifications to precast Prefabricated Bridges in areas of high or moderate seismicity was examined. The different seismic design methodologies were reviewed and guidance in their application to precast Bridges is provided. The Washington State Department of Transportation design criteria and recent research and bridge projects using the accelerated bridge construction technique in Washington State are reviewed.

  • Use of Precast Bridge Members in Areas of High or Moderate Seismicity
    2008
    Co-Authors: Jugesh Kapur, Bijan Khaleghi
    Abstract:

    Prefabricated bridge components are in increasing demand for accelerated bridge construction. Precasting eliminates the need for forming, casting, and curing concrete in work zones and makes bridge construction safer while improving quality and durability. Precast Bridges consisting of pretensioned girders, posttensioned spliced girders, trapezoidal open box girders, and other types of superstructure members are often used for accelerated bridge construction; however, bridge engineers are concerned with the durability and performance of Bridges made of precast members in areas of high or moderate seismicity. The applicability of the American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design specifications to precast Prefabricated Bridges in areas of high or moderate seismicity was examined. The different seismic design methodologies were reviewed and guidance in their application to precast Bridges is provided. The Washington State Department of Transportation design criteria and recent research and bridge projects using the accelerated bridge construction technique in Washington State are reviewed.

Jugesh Kapur - One of the best experts on this subject based on the ideXlab platform.

  • Use of Precast Bridge Members in Areas of High or Moderate Seismicity
    Transportation Research Record, 2009
    Co-Authors: Jugesh Kapur, Bijan Khaleghi
    Abstract:

    Prefabricated bridge components are in increasing demand for accelerated bridge construction. Precasting eliminates the need for forming, casting, and curing concrete in work zones and makes bridge construction safer while improving quality and durability. Precast Bridges consisting of pretensioned girders, posttensioned spliced girders, trapezoidal open box girders, and other types of superstructure members are often used for accelerated bridge construction; however, bridge engineers are concerned with the durability and performance of Bridges made of precast members in areas of high or moderate seismicity. The applicability of the AASHTO load and resistance factor design specifications to precast Prefabricated Bridges in areas of high or moderate seismicity was examined. The different seismic design methodologies were reviewed and guidance in their application to precast Bridges is provided. The Washington State Department of Transportation design criteria and recent research and bridge projects using the accelerated bridge construction technique in Washington State are reviewed.

  • Use of Precast Bridge Members in Areas of High or Moderate Seismicity
    2008
    Co-Authors: Jugesh Kapur, Bijan Khaleghi
    Abstract:

    Prefabricated bridge components are in increasing demand for accelerated bridge construction. Precasting eliminates the need for forming, casting, and curing concrete in work zones and makes bridge construction safer while improving quality and durability. Precast Bridges consisting of pretensioned girders, posttensioned spliced girders, trapezoidal open box girders, and other types of superstructure members are often used for accelerated bridge construction; however, bridge engineers are concerned with the durability and performance of Bridges made of precast members in areas of high or moderate seismicity. The applicability of the American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design specifications to precast Prefabricated Bridges in areas of high or moderate seismicity was examined. The different seismic design methodologies were reviewed and guidance in their application to precast Bridges is provided. The Washington State Department of Transportation design criteria and recent research and bridge projects using the accelerated bridge construction technique in Washington State are reviewed.

Benjamin M. Tang - One of the best experts on this subject based on the ideXlab platform.

  • Prefabricated Bridges or Rapid Construction
    HPC Bridge Views, 2005
    Co-Authors: Mary Lou Ralls, Benjamin M. Tang
    Abstract:

    This paper describes how transportation agencies today face significant challenges to restore highway capacity while enhancing safety through construction work zones. About one-third of our Nation’s Bridges are in need of repair or replacement. During the summer road work season, 20 percent of the National Highway System is typically under construction. This translates into 6,400 highway work zones with a corresponding loss of 6,200 lane-miles (10,000 lane-km) in capacity. On a road construction project with a high volume of traffic, the cost of traffic control can be 30 to 50 percent of the construction cost. These costs can be reduced and work zone safety enhanced through the use of accelerated construction methods. Limited available funding and significant construction needs have resulted in initial cost controlling bridge design and construction. In addition to managing costs, owners are now responding to the need to “get in, get out, and stay out” as the advancing age of our highway infrastructure necessitates increased reconstruction. Prefabricated bridge elements and systems, in combination with HPC and accelerated construction requirements in the contracts, help meet the need for rapid bridge construction.