The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

D G Manning - One of the best experts on this subject based on the ideXlab platform.

  • friction in Bridge Bearings with contaminated tfe slide surface
    Journal of Structural Engineering-asce, 1993
    Co-Authors: T I Campbell, M J Fatemi, D G Manning
    Abstract:

    Tetrafluoroethylene (TFE) is commonly used as a slide surface mating with polished stainless steel in Bridge Bearings that accommodate translation and rotation of the superstructure relative to the substructure. The primary requirement of the slide surface is a low coefficient of friction that is maintained throughout the service life of the bearing. The paper reports on a laboratory investigation comprising 14 tests undertaken at room temperature under simulated field conditions that was performed to determine the effect of contamination on the coefficient of friction in a lubricated TFE/stainless steel interface. It is shown that the friction of a lubricated surface increases significantly with a relatively low amount of contamination in the form of unhydrated portland cement in the interface, emphasizing the need for assembling Bearings in a dust-free environment and avoiding disassembling of Bearings on site. The influences of the degree of contamination on the coefficient of friction at initial movement and after 200 cycles of movement, as well as on the peak value of the coefficient of friction recorded during a test, are discussed.

  • MOVEMENTS IN Bridge Bearings
    1990
    Co-Authors: T Masliwec, D G Manning
    Abstract:

    The paper reports the results of a program to identify suitable equipment and to measure, under service conditions, the displacements and velocities of Bridge Bearings incorporating TFE stainless steel slide surface.

John L Tassoulas - One of the best experts on this subject based on the ideXlab platform.

  • behavior of elastomeric Bridge Bearings computational results
    Journal of Bridge Engineering, 1998
    Co-Authors: O Hamzeh, John L Tassoulas, Eric B Becker
    Abstract:

    A p-version, two-dimensional (2D) finite-element model incorporating both material and geometric nonlinearities and a consistent frictional contact algorithm is utilized to analyze elastomeric Bridge Bearings. Stresses and strains are examined and factors affecting them are discussed. In particular, tapered Bearings, used to support inclined girders, are analyzed. The shear stiffness of both flat and tapered pads is investigated. It is shown that deforming a tapered pad vertically results in a horizontal reaction that should be considered for proper bearing design. Comparisons with some recent experimental findings are shown.

  • model for viscous walking of elastomeric Bridge Bearings
    Journal of Engineering Mechanics-asce, 1998
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings have been occasionally observed to move out of their original position. A simple model for this gradual displacement, also known as walking, is developed. The model, through a regularized Coulomb law, incorporates viscous frictional interfaces between the bearing and the girder, abutment, or pier. It is concluded that viscous interfaces, introduced by a layer of wax, are the main factor causing the walking of pads.

  • MODEL FOR VISCOUS "WALKING" OF ELASTOMERIC Bridge Bearings. TECHNICAL NOTE
    Journal of Engineering Mechanics-asce, 1998
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings have been occasionally observed to move out of their original position. A simple model for this gradual displacement, also known as "walking," is developed. The model, through a regularized Coulomb law, incorporates viscous frictional interfaces between the bearing and the girder, abutment, or pier. It is concluded that viscous interfaces, introduced by a layer of wax, are the main factor causing the "walking" of pads.

  • ANALYTICAL MODEL FOR ELASTOMERIC Bridge Bearings
    1997
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings are analyzed using a nonlinear finite element method. In a plane-strain setting, the rubber is modeled as a hyper elastic incompressible material. A frictional-contact algorithm is incorporated to account for the interaction of the bearing with the girder and the abutment. In this paper, the results of a study conducted to examine the effects of several design parameters on bearing performance are presented. The overall behavior of the bearing, with emphasis on its hear and compressive stiffness, is examined. In addition, stresses and strains in the bearing are discussed. Response of tapered Bearings is investigated. Comparisons with experimental findings are shown.

  • ANALYSIS OF ELASTOMERIC Bridge Bearings. INTERIM REPORT
    1995
    Co-Authors: O Hamzeh, John L Tassoulas, E. B. Becker
    Abstract:

    A two-dimensional nonlinear p-version finite element method is developed for the analysis of boundary value problems relevant to elastomeric Bridge Bearings. The method incorporates polynomial shape functions of the hierarchic type for the modeling of large-deformations rubber elasticity. In addition, a frictional-contact algorithm based on a penalty formulation and suitable for the interaction of the pad with rigid flat surfaces is derived and implemented. The J sub 2 flow theory with isotropic hardening is utilized to model the reinforcing steel as a bilinear elastoplastic material. Examples are presented to illustrate the performance of the element and some guidelines for the selection of appropriate orders of interpolation and integration rules. The results of a study performed to examine the effects of several design parameters of the bearing are presented. Comparisons with experimental findings are shown. A dynamic lumped model for the walking of the bearing is developed. Viscous frictional interfaces with the girder and the abutment are included. Several cases are analyzed to investigate the factors that affect this phenomenon.

O Hamzeh - One of the best experts on this subject based on the ideXlab platform.

  • behavior of elastomeric Bridge Bearings computational results
    Journal of Bridge Engineering, 1998
    Co-Authors: O Hamzeh, John L Tassoulas, Eric B Becker
    Abstract:

    A p-version, two-dimensional (2D) finite-element model incorporating both material and geometric nonlinearities and a consistent frictional contact algorithm is utilized to analyze elastomeric Bridge Bearings. Stresses and strains are examined and factors affecting them are discussed. In particular, tapered Bearings, used to support inclined girders, are analyzed. The shear stiffness of both flat and tapered pads is investigated. It is shown that deforming a tapered pad vertically results in a horizontal reaction that should be considered for proper bearing design. Comparisons with some recent experimental findings are shown.

  • model for viscous walking of elastomeric Bridge Bearings
    Journal of Engineering Mechanics-asce, 1998
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings have been occasionally observed to move out of their original position. A simple model for this gradual displacement, also known as walking, is developed. The model, through a regularized Coulomb law, incorporates viscous frictional interfaces between the bearing and the girder, abutment, or pier. It is concluded that viscous interfaces, introduced by a layer of wax, are the main factor causing the walking of pads.

  • MODEL FOR VISCOUS "WALKING" OF ELASTOMERIC Bridge Bearings. TECHNICAL NOTE
    Journal of Engineering Mechanics-asce, 1998
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings have been occasionally observed to move out of their original position. A simple model for this gradual displacement, also known as "walking," is developed. The model, through a regularized Coulomb law, incorporates viscous frictional interfaces between the bearing and the girder, abutment, or pier. It is concluded that viscous interfaces, introduced by a layer of wax, are the main factor causing the "walking" of pads.

  • ANALYTICAL MODEL FOR ELASTOMERIC Bridge Bearings
    1997
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings are analyzed using a nonlinear finite element method. In a plane-strain setting, the rubber is modeled as a hyper elastic incompressible material. A frictional-contact algorithm is incorporated to account for the interaction of the bearing with the girder and the abutment. In this paper, the results of a study conducted to examine the effects of several design parameters on bearing performance are presented. The overall behavior of the bearing, with emphasis on its hear and compressive stiffness, is examined. In addition, stresses and strains in the bearing are discussed. Response of tapered Bearings is investigated. Comparisons with experimental findings are shown.

  • ANALYSIS OF ELASTOMERIC Bridge Bearings. INTERIM REPORT
    1995
    Co-Authors: O Hamzeh, John L Tassoulas, E. B. Becker
    Abstract:

    A two-dimensional nonlinear p-version finite element method is developed for the analysis of boundary value problems relevant to elastomeric Bridge Bearings. The method incorporates polynomial shape functions of the hierarchic type for the modeling of large-deformations rubber elasticity. In addition, a frictional-contact algorithm based on a penalty formulation and suitable for the interaction of the pad with rigid flat surfaces is derived and implemented. The J sub 2 flow theory with isotropic hardening is utilized to model the reinforcing steel as a bilinear elastoplastic material. Examples are presented to illustrate the performance of the element and some guidelines for the selection of appropriate orders of interpolation and integration rules. The results of a study performed to examine the effects of several design parameters of the bearing are presented. Comparisons with experimental findings are shown. A dynamic lumped model for the walking of the bearing is developed. Viscous frictional interfaces with the girder and the abutment are included. Several cases are analyzed to investigate the factors that affect this phenomenon.

T I Campbell - One of the best experts on this subject based on the ideXlab platform.

  • high load multi rotational Bridge Bearings
    NCHRP Report, 1999
    Co-Authors: John F Stanton, Charles W Roeder, T I Campbell
    Abstract:

    This report contains the results of a study on high-load multi-rotational Bridge Bearings. Information on various bearing types, including pot Bearings, disk Bearings, and polytetrafluoroethylene (PTFE) sliding surfaces is included. Design and selection guidance is provided. The contents of this report will be of immediate interest to Bridge and structural engineers, materials engineers, and manufacturers of Bridge Bearings.

  • DESIGN CONSIDERATIONS FOR SPHERICAL Bridge Bearings UNDER HORIZONTAL LOADS
    1996
    Co-Authors: T I Campbell, M. F. Green, N. C. Koppens, A. C. Agarwal
    Abstract:

    The mechanics of load transfer in the curved sliding compression-only surface of a spherical bearing, containing a layer of polytetrafluoroethylene (PTFE), under external applied horizontal load, and the implications for design of such a bearing are the topic of this paper. Relevant literature indicates that the critical parameters are the ratio of horizontal to vertical load, and the ratio of the radius of curvature to the plan diameter of the interfacing spherical surfaces. An experimental program to measure the stress-displacement relationship of confined PTFE discs, under uniaxial and eccentric compressive loading, is described and a bilinear stress-displacement is proposed.

  • friction in Bridge Bearings with contaminated tfe slide surface
    Journal of Structural Engineering-asce, 1993
    Co-Authors: T I Campbell, M J Fatemi, D G Manning
    Abstract:

    Tetrafluoroethylene (TFE) is commonly used as a slide surface mating with polished stainless steel in Bridge Bearings that accommodate translation and rotation of the superstructure relative to the substructure. The primary requirement of the slide surface is a low coefficient of friction that is maintained throughout the service life of the bearing. The paper reports on a laboratory investigation comprising 14 tests undertaken at room temperature under simulated field conditions that was performed to determine the effect of contamination on the coefficient of friction in a lubricated TFE/stainless steel interface. It is shown that the friction of a lubricated surface increases significantly with a relatively low amount of contamination in the form of unhydrated portland cement in the interface, emphasizing the need for assembling Bearings in a dust-free environment and avoiding disassembling of Bearings on site. The influences of the degree of contamination on the coefficient of friction at initial movement and after 200 cycles of movement, as well as on the peak value of the coefficient of friction recorded during a test, are discussed.

Eric B Becker - One of the best experts on this subject based on the ideXlab platform.

  • behavior of elastomeric Bridge Bearings computational results
    Journal of Bridge Engineering, 1998
    Co-Authors: O Hamzeh, John L Tassoulas, Eric B Becker
    Abstract:

    A p-version, two-dimensional (2D) finite-element model incorporating both material and geometric nonlinearities and a consistent frictional contact algorithm is utilized to analyze elastomeric Bridge Bearings. Stresses and strains are examined and factors affecting them are discussed. In particular, tapered Bearings, used to support inclined girders, are analyzed. The shear stiffness of both flat and tapered pads is investigated. It is shown that deforming a tapered pad vertically results in a horizontal reaction that should be considered for proper bearing design. Comparisons with some recent experimental findings are shown.

  • model for viscous walking of elastomeric Bridge Bearings
    Journal of Engineering Mechanics-asce, 1998
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings have been occasionally observed to move out of their original position. A simple model for this gradual displacement, also known as walking, is developed. The model, through a regularized Coulomb law, incorporates viscous frictional interfaces between the bearing and the girder, abutment, or pier. It is concluded that viscous interfaces, introduced by a layer of wax, are the main factor causing the walking of pads.

  • MODEL FOR VISCOUS "WALKING" OF ELASTOMERIC Bridge Bearings. TECHNICAL NOTE
    Journal of Engineering Mechanics-asce, 1998
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings have been occasionally observed to move out of their original position. A simple model for this gradual displacement, also known as "walking," is developed. The model, through a regularized Coulomb law, incorporates viscous frictional interfaces between the bearing and the girder, abutment, or pier. It is concluded that viscous interfaces, introduced by a layer of wax, are the main factor causing the "walking" of pads.

  • ANALYTICAL MODEL FOR ELASTOMERIC Bridge Bearings
    1997
    Co-Authors: O Hamzeh, Eric B Becker, John L Tassoulas
    Abstract:

    Elastomeric Bridge Bearings are analyzed using a nonlinear finite element method. In a plane-strain setting, the rubber is modeled as a hyper elastic incompressible material. A frictional-contact algorithm is incorporated to account for the interaction of the bearing with the girder and the abutment. In this paper, the results of a study conducted to examine the effects of several design parameters on bearing performance are presented. The overall behavior of the bearing, with emphasis on its hear and compressive stiffness, is examined. In addition, stresses and strains in the bearing are discussed. Response of tapered Bearings is investigated. Comparisons with experimental findings are shown.