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Jeong-tae Kim - One of the best experts on this subject based on the ideXlab platform.

  • hybrid structural health monitoring of steel Plate Girder Bridges using acceleration impedance features
    Journal of The Korean Society of Civil Engineers, 2009
    Co-Authors: Dongsoo Hong, Jeong-tae Kim
    Abstract:

    In this paper, hybrid health monitoring techniques using acceleration-impedance features are newly proposed to detect two damage-type in steel Plate-Girder Bridges, which are Girder's stiffness-loss and support perturbation. The hybrid techniques mainly consists of three sequential phases: 1) to alarm the occurrence of damage in global manner, 2) to classify the alarmed damage into subsystems of the structure, and 3) to estimate the classified damage in detail using methods suitable for the subsystems. In the first phase, the global occurrence of damage is alarmed by monitoring changes in acceleration features. In the second phase, the alarmed damage is classified into subsystems by recognizing patterns of impedance features. In the final phase, the location and the extent of damage are estimated by using modal strain energy-based damage index method and root mean square deviation (RMSD) method. The feasibility of the proposed hybrid technique is evaluated on a laboratory-scaled steel Plate-Girder bridge model for which hybrid acceleration-impedance signatures were measured for several damage scenarios. Also, the effect of temperature on the accuracy of the impedance-based damage monitoring results are experimentally examined from combined scenarios of support damage cases and temperature changes.

  • hybrid vibration impedance approaches for damage detection in Plate Girder Bridges
    The 15th International Symposium on: Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring, 2008
    Co-Authors: Dongsoo Hong, Jeong-tae Kim, Hyunman Cho
    Abstract:

    In this paper, a hybrid vibration-impedance approaches is newly proposed to detect the occurrence of damage, the location of damage, and extent of damage in steel Plate-Girder Bridges. Firstly, theoretical backgrounds of the hybrid structural health monitoring are described. The hybrid scheme mainly consists of three sequential phases: 1) to alarm the occurrence of damage in global manner, 2) to classify the alarmed damage into subsystems of the structure, and 3) to estimate the classified damage in detail using methods suitable for the subsystems. Damage types of interest include flexural stiffness-loss in Girder and perturbation in supports. In the first phase, the global occurrence of damage is alarmed by monitoring changes in acceleration features. In the second phase, the alarmed damage is classified into subsystems by recognizing patterns of impedance features. In the final phase, the location and the extent of damage are estimated by using modal strain energy-based damage index methods. The feasibility of the proposed system is evaluated on a laboratory-scaled steel Plate-Girder bridge model for which hybrid vibration-impedance signatures were measured for several damage scenarios.

  • vibration based damage monitoring in model Plate Girder Bridges under uncertain temperature conditions
    Engineering Structures, 2007
    Co-Authors: Jeong-tae Kim, Jaehyung Park, Byungjun Lee
    Abstract:

    Dynamic modal parameters are appealing features for a prompt diagnosis of structural conditions, since they are relatively simple to measure and utilize. The feasibility of using them for damage detection, however, is limited when their changes go undisclosed due to uncertain temperature conditions, particularly for large structures. In this paper, a vibration-based damage monitoring scheme to give warning of the occurrence, the location, and the severity of damage under temperature-induced uncertainty conditions is proposed. Firstly, experiments on a model Plate-Girder bridge, for which a set of modal parameters were measured under uncertain temperature conditions, are described. Secondly, a damage warning model is selected to statistically identify the occurrence of damage, by recognizing the patterns of damage-driven changes in natural frequencies of the test structure, and by distinguishing temperature-induced off-limits. Thirdly, a frequency-based damage index method based on the concept of modal strain energy is implemented into the test structure to predict the location and the severity of damage. In order to adjust the temperature-induced changes in natural frequencies that are used for damage detection, a set of empirical frequency correction formulae are derived from the relationship between temperature and frequency ratio.

  • structural health monitoring and risk alarming in Plate Girder Bridges under uncertain temperature condition
    Smart Structures and Materials 2005: Sensors and Smart Structures Technologies for Civil Mechanical and Aerospace Systems, 2005
    Co-Authors: Jeong-tae Kim, Jaehyung Park, Jungsuk Lee
    Abstract:

    Even significant damage may cause very small changes in structural characteristics, particularly for large structures. Furthermore, these changes may go undetected due to changes in environmental and operational conditions. In this paper, the temperature-driven variability on a combined structural health monitoring (SHM) system is examined in a model Plate-Girder bridge. The combined SHM system consists of global vibration-based technique and local electro-mechanical impedance (EMI) based technique. First, dynamic modal parameters of the test structure are measured before and after the occurrence of flexural cracks at various temperatures. Also, EMI signatures are sensed before and after the changes in support systems at various temperatures. Next, the risk of damage-occurrence in the structure is alarmed by statistical pattern recognition of the signals. Damage-induced changes in the signals are distinguished from temperature-driven uncertainty. The effect of temperature variability is also assessed to estimate the accuracy of damage detection.

  • Thermal affects on modal properties and frequency-based damage detection in Plate-Girder Bridges
    Smart Structures and Materials 2004: Sensors and Smart Structures Technologies for Civil Mechanical and Aerospace Systems, 2004
    Co-Authors: Jeong-tae Kim, Chung-bang Yun, Jae-hyeong Park
    Abstract:

    The variation of modal properties caused by temperature effects is assessed to correct modal data used for damage detection in Plate-Girder Bridges. First, experiments on model Plate-Girder Bridges are described. Next, the relationship between temperature and natural frequencies is estimated and a set of empirical frequency-correction formula are analyzed for the test structure. Finally, a frequency-based method is used to locate and estimate severity of damage in the test structure using experimental modal data which are adjusted by the frequency-correction formula. Here, local damage in beam-type structures is detected by using measured frequencies and analytical mode shapes.

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

  • Seismic Modeling and Analysis of Curved Steel Plate Girder Bridges
    9999
    Co-Authors: Monzon Eric, Itani, Ahmad M., Buckle, Ian G.
    Abstract:

    Report No. CCEER-13-05This report presents the analytical investigations into the seismic response of curved steel Plate Girder Bridges. Three levels of modeling techniques – spine beam, grillage (traditional grillage and Plate-and-beam), and 3D finite element – of curved steel Plate Girder Bridges were discussed. Guidelines for the development of these models were presented. Spine beam model is where the superstructure is modeled as a 3D singe beam with equivalent section properties. Traditional grillage model is where the superstructure is modeled as a grid of longitudinal and transverse beam in one plane. Plate-and-beam model is where the deck is modeled using shell elements while the Girders are modeled as beam elements. 3D finite element is where the deck and Girders are modeled using shell elements. Guidelines for modeling the bearings and substructure components were also presented. The effects of the different modeling techniques on the seismic response were investigated and limitations on their application were identified. The spine beam model was able to capture the global seismic response of the bridge and give reasonable estimates of the column forces. However, this model was unable to capture the response of local components such as bearings and cross-frames. The response of the Plate-and-beam model was comparable to the 3D finite element model. This model may be used to design local components such as bearings and cross-frames. In addition, 3D finite element models of the curved steel Plate Girder bridge were developed to determine the influence of the stiffness of the cross-frames, Girders, shear connectors, and reinforced concrete deck on the distribution of seismic forces between the Girders and the cross-frames. It was found that the cross-frames were most effective in transferring the seismic forces to the bearings when the cross-frame-to-Girder stiffness ratio was about 3.0. The shear connector stiffness had negligible effect on the framing action between the deck and Girders. The number and spacing of shear connectors required for service loads, according to AASHTO Specifications, is sufficient to achieve this framing action

  • Proposed Seismic Provisions and Commentary for Steel Plate Girder Superstructures
    9999
    Co-Authors: Itani, Ahmad M., Grubb, Michael A., Monzon Eric
    Abstract:

    Report No. CCEER-10-03The seismic provisions of the current AASHTO LRFD Specifications (AASHTO, 2007) are based on the NCHRP Project 20-7/45. These provisions were updated in 2008 to include the 2006 USGS 1000-year maps and several revisions to keep the specifications current with the recent advances in the seismic analysis and design. However, none of these changes reflected the new information that was gained in the seismic analysis and design of steel Plate Girder superstructures. In an effort, to bridge this gap in the specifications, the American Iron and Steel Institute commissioned this report to propose updates for the seismic design of steel Plate Girder superstructures to AASHTO LRFD Specifications. The objectives of this study are to: 1. Present the state-of-the art summary of research related to the seismic analysis and design of steel Plate Girder Bridges 2. Develop code language and commentary that can be adopted in the AASHTO LRFD Specifications 3. Develop design examples that show how the proposed language can be used in the seismic analysis and design of steel Plate Girder Bridges To achieve these objectives, Chapter 1 of this report discusses related research to the seismic behavior and design of steel Plate Girder Bridges. Chapter 2 presents the proposed language and commentary for the seismic design of steel Plate Girder Bridges. Chapter 3 presents detailed seismic analysis and design examples for a single span and a two span continuous steel Plate Girder bridge with a single column bent and a dropped cap. Appendix 1 presents a summary of all existing seismic specifications that are related to steel Plate Girder Bridges

  • Seismic Performance of Steel Plate Girder Bridges with Integral Abutments
    9999
    Co-Authors: Monzon Eric
    Abstract:

    Report No. CCEER-10-08This report presents the results of a pilot study on the seismic behavior and response of steel Bridges with integral abutments. Analytical investigations were conducted on computational models of steel Bridges with integral abutments to determine their seismic behavior as a system and to develop seismic design guidelines. The effect of the superstructure flexibility due to inadequate embedment length was investigated using 3D finite element models. This flexibility, modeled as translational and rotational springs, proved to have significant effect on the overall bridge dynamic characteristics in terms of periods and critical mode shapes. Lateral and longitudinal load paths and the seismic response were investigated using modal pushover and nonlinear time history analyses. A limited investigation on the effect of skew was conducted on a single-span integral abutment bridge. A procedure for incorporating the system level damping due to the yielding and inelastic responses of various components was proposed for use in the seismic analysis. Based on the analytical investigations and available experimental research, guidelines for the seismic analysis and design of integral abutment Bridges were developed

  • Seismic Performance of Curved Steel Plate Girder Bridges with Seismic Isolation
    9999
    Co-Authors: Monzon Eric, Buckle, Ian G., Itani, Ahmad M.
    Abstract:

    Report No. CCEER-13-06In a federally-funded project on the seismic performance of curved highway Bridges at the University of Nevada Reno, a 2/5th scale model of a 3-span, curved steel Plate Girder bridge was tested on multiple shake tables with an isolation system comprising 12 lead-rubber isolators. The purpose of this experiment was three-fold: (1) confirm that elastic performance of the columns could be achieved during the Design Earthquake using isolation, (2) study the effect of curvature on the seismic response of an isolated bridge, and (3) identify the limit states for an isolated curved bridge and, in particular, determine the nature and consequences of isolator instability during extreme input motions. Elastic performance was indeed achieved during the Design Earthquake with no concrete spalling in potential plastic hinge zones and minor cracking on face of the columns. In fact, essentially elastic behavior was observed up to three times the Design Earthquake. Even though this bridge was highly curved (subtended angle was 1.8 radians), curvature had little effect on the response of the isolators. It did cause asymmetry in response and the abutment isolators were subject to higher displacements than those over the piers, but at the Design Earthquake these differences were small and the results of the AASHTO Simplified Method of analysis were adequate for design purposes. However, at three times the Design Earthquake, instability occurred in the isolators at one of the abutments due to excessive displacement. Bridge collapse did not however occur because the isolators at other supports remained stable. Full recovery of the unstable isolators was observed. In fact subsequent seismic excitation applied to the bridge after the instability occurred showed the experience of instability had minimal effect on the isolator stiffness properties

  • Nonlinear Evaluation of the Proposed Seismic Design Procedure for Steel Bridges with Ductile End Cross Frames
    9999
    Co-Authors: Monzon Eric, Itani, Ahmad M., Grubb, Michael A.
    Abstract:

    Report No. CCEER-14-04Neither the current AASHTO LRFD Bridge Design Specifications nor the AASHTO Guide Specification for LRFD Seismic Bridge Design provides a design procedure to achieve the desired performance of essentially elastic substructure and ductile superstructure. This design strategy that is termed Type 2 Design Strategy in the Guide Specifications limits the inelastic activity to the superstructure of steel Plate Girder Bridges. Due to the lack of this information, bridge engineers have been reluctant of using this strategy which will limit the damage to the support cross frames in steel Plate Girder bridge. This will also keep the substructure essentially elastic and thus limit the repair of the substructure after a design level earthquake. This report presents a proposed force-base design procedure that will achieve an ‘essentially' elastic substructure and ductile superstructure. The reinforced concrete (R/C) substructure flexural resistance is designed for the combined effect of seismic forces similar to conventional seismic design with a force reduction factor equal to 1.5. Meanwhile, the shear resistance and the confinement requirements are similar to the conventional seismic design. To achieve ductile superstructure, the horizontal resistance of the support cross frames is based on the nominal shear resistance of the substructure divided by a proposed response modification factor equal to 4. This will ensure that the superstructure will act as a ‘fuse' and will not subject the substructure to forces that may cause nonlinear response in that direction. In order to achieve a ductile response of pier cross frames, the diagonal members, which are expected to undergo inelastic response, are detailed to have limits on width-to-thickness and slenderness ratios. The diagonal member connections and other cross frame members are designed for fully yielded and strain hardened diagonal members. The shear resistance of the substructure is also checked based on the expected lateral resistance of fully yielded and strain hardened pier cross frames. Three Bridges were selected to illustrate the proposed design procedure for Type 2 design strategy. The substructure of these Bridges included single-column pier, two-column pier, and wall piers. Examples showing the design of these Bridges using Type 1 design strategy with Critical and other Operational Categories are also shown. Thus, a total of eight bridge design examples are shown in this report. The design and performance of these Bridges were then compared. The performance was evaluated through nonlinear response history analysis using seven ground motions representing the design and maximum considered earthquakes. The proposed design strategy for Type 2 design showed an increase in the size of the substructure when compared to Other bridge operation category. However, it also showed a decrease in in the size of the substructure when compared to Critical bridge operation category. The nonlinear evaluation showed the Type 2 design strategy has indeed achieved an essentially elastic substructure and ductile superstructure. In bridge with stiff substructures such as pier walls designed using Type 1 strategy, inelastic activity was observed in the support cross frames. This will subject the superstructure connections and bearings to seismic forces that they are not designed for, which may result in undesirable seismic performance

Jaeho Song - One of the best experts on this subject based on the ideXlab platform.

  • Girder wheel load distribution factor of skew Plate Girder Bridges
    Journal of the Korea institute for structural maintenance and inspection, 2005
    Co-Authors: Changbum Seo, Jaeho Song
    Abstract:

    The Girder wheel load distribution factors stated in the Korean Bridge Specification and AASHTO Standard Specifications do not account for the effect of skewness of Plate Girders, and very little research has been conducted on Girder wheel load distribution factors. The purpose of the study is to propose load distribution factor formulas for skew Plate Girder Bridges which comprise various parameters through structural analysis. To comprise the validity of finite element models used in this study analytic values are compared with the field test results. From the results it should be noted that span length is not such a dominant parameter compared with others. In view of better load distribution of interior Girders, skew arranged cross beams or bracing are preferable, furthemore bracing system is more effective than cross beam system. By means of regression analysis on the basis of analytic results wheel load distribution factor formulas are proposed and compared with current codes.

  • Wheel Load Distribution Factor for Girder Moment and Shear Force of Skew Plate Girder Bridges
    2005
    Co-Authors: Changbum Seo, Jaeho Song
    Abstract:

    The Girder wheel load distribution factors stated in the Korean Bridge Specification and AASHTO Standard Specifications do not account for the effect of skewness of Plate Girders, and very little research has been conducted on Girder wheel load distribution factors. The purpose of the study is to propose load distribution factor formulas for skew Plate Girder Bridges which comprise various parameters through structural analysis. To confirm the validity of finite element models used in this study analytic values are compared with the field test results. From the results it should be noted that span length is not such a dominant parameter compared with others. In view of better load distribution of interior Girders, skew arranged cross beams or bracing are preferable, furthemore bracing system is more effective than cross beam system. By means of regression analysis on the basis of analytic results wheel load distribution factor formulas are proposed and compared with current codes.

Itani, Ahmad M. - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Performance of Steel Girder Bridge Superstructures with Ductile End Cross Frames and Seismic Isolation
    9999
    Co-Authors: Carden, Lyle P., Itani, Ahmad M., Buckle, Ian G.
    Abstract:

    Report No. CCEER-05-4As the end cross frames of steel Plate Girder Bridges are critical in the transverse seismic load path they may be designed to deform in a ductile manner to reduce the elastic base shear in a bridge. From experimental results and analytical studies using ductile single angle X-braces, and buckling restrained braces in the end cross frames, the base shear in a bridge model was reduced to as low as 40% of the elastic base shear. The buckling restrained braces resulted in 20% to 30% smaller drifts than the X-braces at a given level of base shear, a result that is attributed to better energy dissipation. However, the displacement capacity of the single angle X-braces is larger than that for the buckling restrained braces. Removing some shear studs near the supports of the Girders, and allowing the shear to be transferred into the end cross frames using a top chord, allows the Girders to "rock" enabling considerable transverse drifts in the Girders. Reinforced elastomeric bearings allow large rotations at the base of the Girders. The maximum drift measured in the Girders during experiments was 7% of the Girder height, with no damage observed in the Girders and minimal distress to the deck slab. Despite significant reductions using the ductile end cross frames, the elastic base shear in the bridge model was reduced further using seismic isolation. The capacity of the bearings was limited by the their stability, with buckling observed in the bearings at a displacement close to the expected buckling displacement. Despite this critical state, the isolation system did not fail because dynamic inertial effects in the bridge were able to restore stability to the system

  • Seismic Modeling and Analysis of Curved Steel Plate Girder Bridges
    9999
    Co-Authors: Monzon Eric, Itani, Ahmad M., Buckle, Ian G.
    Abstract:

    Report No. CCEER-13-05This report presents the analytical investigations into the seismic response of curved steel Plate Girder Bridges. Three levels of modeling techniques – spine beam, grillage (traditional grillage and Plate-and-beam), and 3D finite element – of curved steel Plate Girder Bridges were discussed. Guidelines for the development of these models were presented. Spine beam model is where the superstructure is modeled as a 3D singe beam with equivalent section properties. Traditional grillage model is where the superstructure is modeled as a grid of longitudinal and transverse beam in one plane. Plate-and-beam model is where the deck is modeled using shell elements while the Girders are modeled as beam elements. 3D finite element is where the deck and Girders are modeled using shell elements. Guidelines for modeling the bearings and substructure components were also presented. The effects of the different modeling techniques on the seismic response were investigated and limitations on their application were identified. The spine beam model was able to capture the global seismic response of the bridge and give reasonable estimates of the column forces. However, this model was unable to capture the response of local components such as bearings and cross-frames. The response of the Plate-and-beam model was comparable to the 3D finite element model. This model may be used to design local components such as bearings and cross-frames. In addition, 3D finite element models of the curved steel Plate Girder bridge were developed to determine the influence of the stiffness of the cross-frames, Girders, shear connectors, and reinforced concrete deck on the distribution of seismic forces between the Girders and the cross-frames. It was found that the cross-frames were most effective in transferring the seismic forces to the bearings when the cross-frame-to-Girder stiffness ratio was about 3.0. The shear connector stiffness had negligible effect on the framing action between the deck and Girders. The number and spacing of shear connectors required for service loads, according to AASHTO Specifications, is sufficient to achieve this framing action

  • Proposed Seismic Provisions and Commentary for Steel Plate Girder Superstructures
    9999
    Co-Authors: Itani, Ahmad M., Grubb, Michael A., Monzon Eric
    Abstract:

    Report No. CCEER-10-03The seismic provisions of the current AASHTO LRFD Specifications (AASHTO, 2007) are based on the NCHRP Project 20-7/45. These provisions were updated in 2008 to include the 2006 USGS 1000-year maps and several revisions to keep the specifications current with the recent advances in the seismic analysis and design. However, none of these changes reflected the new information that was gained in the seismic analysis and design of steel Plate Girder superstructures. In an effort, to bridge this gap in the specifications, the American Iron and Steel Institute commissioned this report to propose updates for the seismic design of steel Plate Girder superstructures to AASHTO LRFD Specifications. The objectives of this study are to: 1. Present the state-of-the art summary of research related to the seismic analysis and design of steel Plate Girder Bridges 2. Develop code language and commentary that can be adopted in the AASHTO LRFD Specifications 3. Develop design examples that show how the proposed language can be used in the seismic analysis and design of steel Plate Girder Bridges To achieve these objectives, Chapter 1 of this report discusses related research to the seismic behavior and design of steel Plate Girder Bridges. Chapter 2 presents the proposed language and commentary for the seismic design of steel Plate Girder Bridges. Chapter 3 presents detailed seismic analysis and design examples for a single span and a two span continuous steel Plate Girder bridge with a single column bent and a dropped cap. Appendix 1 presents a summary of all existing seismic specifications that are related to steel Plate Girder Bridges

  • Seismic Performance of Curved Steel Plate Girder Bridges with Seismic Isolation
    9999
    Co-Authors: Monzon Eric, Buckle, Ian G., Itani, Ahmad M.
    Abstract:

    Report No. CCEER-13-06In a federally-funded project on the seismic performance of curved highway Bridges at the University of Nevada Reno, a 2/5th scale model of a 3-span, curved steel Plate Girder bridge was tested on multiple shake tables with an isolation system comprising 12 lead-rubber isolators. The purpose of this experiment was three-fold: (1) confirm that elastic performance of the columns could be achieved during the Design Earthquake using isolation, (2) study the effect of curvature on the seismic response of an isolated bridge, and (3) identify the limit states for an isolated curved bridge and, in particular, determine the nature and consequences of isolator instability during extreme input motions. Elastic performance was indeed achieved during the Design Earthquake with no concrete spalling in potential plastic hinge zones and minor cracking on face of the columns. In fact, essentially elastic behavior was observed up to three times the Design Earthquake. Even though this bridge was highly curved (subtended angle was 1.8 radians), curvature had little effect on the response of the isolators. It did cause asymmetry in response and the abutment isolators were subject to higher displacements than those over the piers, but at the Design Earthquake these differences were small and the results of the AASHTO Simplified Method of analysis were adequate for design purposes. However, at three times the Design Earthquake, instability occurred in the isolators at one of the abutments due to excessive displacement. Bridge collapse did not however occur because the isolators at other supports remained stable. Full recovery of the unstable isolators was observed. In fact subsequent seismic excitation applied to the bridge after the instability occurred showed the experience of instability had minimal effect on the isolator stiffness properties

  • Nonlinear Evaluation of the Proposed Seismic Design Procedure for Steel Bridges with Ductile End Cross Frames
    9999
    Co-Authors: Monzon Eric, Itani, Ahmad M., Grubb, Michael A.
    Abstract:

    Report No. CCEER-14-04Neither the current AASHTO LRFD Bridge Design Specifications nor the AASHTO Guide Specification for LRFD Seismic Bridge Design provides a design procedure to achieve the desired performance of essentially elastic substructure and ductile superstructure. This design strategy that is termed Type 2 Design Strategy in the Guide Specifications limits the inelastic activity to the superstructure of steel Plate Girder Bridges. Due to the lack of this information, bridge engineers have been reluctant of using this strategy which will limit the damage to the support cross frames in steel Plate Girder bridge. This will also keep the substructure essentially elastic and thus limit the repair of the substructure after a design level earthquake. This report presents a proposed force-base design procedure that will achieve an ‘essentially' elastic substructure and ductile superstructure. The reinforced concrete (R/C) substructure flexural resistance is designed for the combined effect of seismic forces similar to conventional seismic design with a force reduction factor equal to 1.5. Meanwhile, the shear resistance and the confinement requirements are similar to the conventional seismic design. To achieve ductile superstructure, the horizontal resistance of the support cross frames is based on the nominal shear resistance of the substructure divided by a proposed response modification factor equal to 4. This will ensure that the superstructure will act as a ‘fuse' and will not subject the substructure to forces that may cause nonlinear response in that direction. In order to achieve a ductile response of pier cross frames, the diagonal members, which are expected to undergo inelastic response, are detailed to have limits on width-to-thickness and slenderness ratios. The diagonal member connections and other cross frame members are designed for fully yielded and strain hardened diagonal members. The shear resistance of the substructure is also checked based on the expected lateral resistance of fully yielded and strain hardened pier cross frames. Three Bridges were selected to illustrate the proposed design procedure for Type 2 design strategy. The substructure of these Bridges included single-column pier, two-column pier, and wall piers. Examples showing the design of these Bridges using Type 1 design strategy with Critical and other Operational Categories are also shown. Thus, a total of eight bridge design examples are shown in this report. The design and performance of these Bridges were then compared. The performance was evaluated through nonlinear response history analysis using seven ground motions representing the design and maximum considered earthquakes. The proposed design strategy for Type 2 design showed an increase in the size of the substructure when compared to Other bridge operation category. However, it also showed a decrease in in the size of the substructure when compared to Critical bridge operation category. The nonlinear evaluation showed the Type 2 design strategy has indeed achieved an essentially elastic substructure and ductile superstructure. In bridge with stiff substructures such as pier walls designed using Type 1 strategy, inelastic activity was observed in the support cross frames. This will subject the superstructure connections and bearings to seismic forces that they are not designed for, which may result in undesirable seismic performance

Changbum Seo - One of the best experts on this subject based on the ideXlab platform.

  • Girder wheel load distribution factor of skew Plate Girder Bridges
    Journal of the Korea institute for structural maintenance and inspection, 2005
    Co-Authors: Changbum Seo, Jaeho Song
    Abstract:

    The Girder wheel load distribution factors stated in the Korean Bridge Specification and AASHTO Standard Specifications do not account for the effect of skewness of Plate Girders, and very little research has been conducted on Girder wheel load distribution factors. The purpose of the study is to propose load distribution factor formulas for skew Plate Girder Bridges which comprise various parameters through structural analysis. To comprise the validity of finite element models used in this study analytic values are compared with the field test results. From the results it should be noted that span length is not such a dominant parameter compared with others. In view of better load distribution of interior Girders, skew arranged cross beams or bracing are preferable, furthemore bracing system is more effective than cross beam system. By means of regression analysis on the basis of analytic results wheel load distribution factor formulas are proposed and compared with current codes.

  • Wheel Load Distribution Factor for Girder Moment and Shear Force of Skew Plate Girder Bridges
    2005
    Co-Authors: Changbum Seo, Jaeho Song
    Abstract:

    The Girder wheel load distribution factors stated in the Korean Bridge Specification and AASHTO Standard Specifications do not account for the effect of skewness of Plate Girders, and very little research has been conducted on Girder wheel load distribution factors. The purpose of the study is to propose load distribution factor formulas for skew Plate Girder Bridges which comprise various parameters through structural analysis. To confirm the validity of finite element models used in this study analytic values are compared with the field test results. From the results it should be noted that span length is not such a dominant parameter compared with others. In view of better load distribution of interior Girders, skew arranged cross beams or bracing are preferable, furthemore bracing system is more effective than cross beam system. By means of regression analysis on the basis of analytic results wheel load distribution factor formulas are proposed and compared with current codes.