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| Malone,S. | WA-RD 602.1 | Information Tools to Improve Post-Earthquake Prioritization of WSDOT Bridge Inspections | 2005 | TRAC/UW |
Abstract:
University of Washington researchers developed information tools to increase the speed and efficiency of Washington State Department of Transportation (WSDOT) post-earthquake response and recovery efforts. The researchers upgraded the Pacific Northwest Seismograph Network (PNSN) ground-motion processing software to rapidly generate and disseminate "ShakeMaps," which are maps of earthquake intensity. The researchers also implemented two procedures to estimate the likelihood of slight (or greater) bridge damage; these procedures are based on the intensity of earthquake shaking (obtained from the ShakeMaps) and on each bridge's location, year of construction, and bridge type (obtained from the Washington State Bridge Inventory). The first procedure, developed at the University of Washington, is based on observations of bridge damage from the 2001 Nisqually earthquake. The second procedure is contained in the Federal Emergency Management Agency HAZUS software for predicting the lowest level of damage. Shortly following an earthquake, e-mail and pager alert messages will be sent to WSDOT personnel notifying them of the preliminary earthquake magnitude and epicenter. ShakeMaps and a prioritized list of bridges (ranked by likelihood of bridge damage) will be available on a Web server at the University of Washington and will be pushed to a WSDOT FTP server.
Authors:
Malone,S., Eberhard,M. O., LaBelle,J., Ranf,T.
Keywords:
bridges, damage, earthquakes, fragilities, inspection, ShakeMap, Washington, speed, Washington state, transportation, WSDOT, software, earthquake, bridge, construction, management
University of Washington researchers developed information tools to increase the speed and efficiency of Washington State Department of Transportation (WSDOT) post-earthquake response and recovery efforts. The researchers upgraded the Pacific Northwest Seismograph Network (PNSN) ground-motion processing software to rapidly generate and disseminate "ShakeMaps," which are maps of earthquake intensity. The researchers also implemented two procedures to estimate the likelihood of slight (or greater) bridge damage; these procedures are based on the intensity of earthquake shaking (obtained from the ShakeMaps) and on each bridge's location, year of construction, and bridge type (obtained from the Washington State Bridge Inventory). The first procedure, developed at the University of Washington, is based on observations of bridge damage from the 2001 Nisqually earthquake. The second procedure is contained in the Federal Emergency Management Agency HAZUS software for predicting the lowest level of damage. Shortly following an earthquake, e-mail and pager alert messages will be sent to WSDOT personnel notifying them of the preliminary earthquake magnitude and epicenter. ShakeMaps and a prioritized list of bridges (ranked by likelihood of bridge damage) will be available on a Web server at the University of Washington and will be pushed to a WSDOT FTP server.
Authors:
Malone,S., Eberhard,M. O., LaBelle,J., Ranf,T.
Keywords:
bridges, damage, earthquakes, fragilities, inspection, ShakeMap, Washington, speed, Washington state, transportation, WSDOT, software, earthquake, bridge, construction, management
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http://www.wsdot.wa.gov/research/reports/fullreports/602.1.pdf http://wsdot.wa.gov/Research/Reports/600/602.1.htm |
| Hieber,D. G. | WA-RD 594.1 | State-of-the-Art Report on Precast Concrete Systems for Rapid Construction of Bridges | 2004 | TRAC/UW |
Abstract:
More extensive use of precast concrete components, which are fabricated off-site and then connected on-site, could allow bridges to be constructed more rapidly. The increased use of precast components in bridges also promises to increase work-zone safety and reduce environmental impacts for bridges that span waterways. This report discusses precast concrete systems that have been used for rapid bridge construction outside of Washington State and evaluates whether they are suitable for use within Western Washington. The report also identifies key features that are important for successful precast concrete system applications. Information on previously used systems was gathered through an extensive review of published literature. Washington State Department of Transportation (WSDOT) design and construction engineers, precast concrete producers, and bridge contractors were also consulted to obtain their input on the positive and negative aspects of applied systems. Most applications have been used in areas of low seismic potential. By contrast, Western Washington is subject to strong earthquakes. Because precast systems contain connections, and connections are typically vulnerable to seismic loading, a qualitative evaluation of the expected seismic performance of each system was deemed necessary. The researchers identified four types of precast concrete superstructure systems: full-depth precast concrete panels, partial-depth precast concrete panels, prestressed concrete multibeam superstructures, and preconstructed composite units. The four systems appear to have acceptable seismic behavior, but there are concerns associated with constructability and durability. Precast concrete substructure systems have received much less attention than have superstructure systems. The use of precast substructure components can provide significant time savings by eliminating the time needed to erect formwork, fix steel, and cure concrete in the substructure. The success of the system depends strongly on the connections, which must hae good seismic resistance, have tolerances that allow easy assembly, and be suitable for rapid construction.
Authors:
Hieber,D. G., Wacker,J. M., Eberhard,M. O., Stanton,J. F.
Keywords:
bridge, bridges, concrete, construction, multibeam superstructures, precast concrete, precast substructures, prestressed concrete, Rapid construction, state-of-the-art, systems, safety, environmental, environmental impact, impacts, span, Washington, Washington state, applications, transportation, WSDOT, design, seismic, earthquake, seismic loading, evaluation, performance, superstructure, prestressed, seismic behavior, constructability, durability, steel, resistance
More extensive use of precast concrete components, which are fabricated off-site and then connected on-site, could allow bridges to be constructed more rapidly. The increased use of precast components in bridges also promises to increase work-zone safety and reduce environmental impacts for bridges that span waterways. This report discusses precast concrete systems that have been used for rapid bridge construction outside of Washington State and evaluates whether they are suitable for use within Western Washington. The report also identifies key features that are important for successful precast concrete system applications. Information on previously used systems was gathered through an extensive review of published literature. Washington State Department of Transportation (WSDOT) design and construction engineers, precast concrete producers, and bridge contractors were also consulted to obtain their input on the positive and negative aspects of applied systems. Most applications have been used in areas of low seismic potential. By contrast, Western Washington is subject to strong earthquakes. Because precast systems contain connections, and connections are typically vulnerable to seismic loading, a qualitative evaluation of the expected seismic performance of each system was deemed necessary. The researchers identified four types of precast concrete superstructure systems: full-depth precast concrete panels, partial-depth precast concrete panels, prestressed concrete multibeam superstructures, and preconstructed composite units. The four systems appear to have acceptable seismic behavior, but there are concerns associated with constructability and durability. Precast concrete substructure systems have received much less attention than have superstructure systems. The use of precast substructure components can provide significant time savings by eliminating the time needed to erect formwork, fix steel, and cure concrete in the substructure. The success of the system depends strongly on the connections, which must hae good seismic resistance, have tolerances that allow easy assembly, and be suitable for rapid construction.
Authors:
Hieber,D. G., Wacker,J. M., Eberhard,M. O., Stanton,J. F.
Keywords:
bridge, bridges, concrete, construction, multibeam superstructures, precast concrete, precast substructures, prestressed concrete, Rapid construction, state-of-the-art, systems, safety, environmental, environmental impact, impacts, span, Washington, Washington state, applications, transportation, WSDOT, design, seismic, earthquake, seismic loading, evaluation, performance, superstructure, prestressed, seismic behavior, constructability, durability, steel, resistance
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http://www.wsdot.wa.gov/research/reports/fullreports/594.1.pdf http://wsdot.wa.gov/Research/Reports/500/594.1.htm |
| Symans,M. D. | WA-RD 553.1 | Evaluation of Displacement-Based Methods and Computer Software for Seismic Analysis of Highway Bridges | 2003 | TRAC/WSU |
Abstract:
The response of bridges when subjected to seismic excitation can be evaluated by a number of analysis methods. The traditional approach to seismic analysis focuses on forces (so-called force-based methods of analysis) while current design practice is moving towards an increased emphasis on displacements (so-called displacement-based methods of analysis). The primary objective of this research project was to evaluate the effectiveness of various commerically-available computer programs for performing practical displacement-based seismic analysis of highway bridges. A secondary objective was to identify the fundamental differences between force-based and displacement-based methods of analysis, particularly as they apply to highway bridges. The objectives of the project were met by utilizing four different computer programs to evaluate the seismic response of a simple two-span highway bridge. The seismic response was evaluated using two force-based methods of analysis (response spectrum and time-history) and two displacement-based methods (capacity spectrum and inelastic demand spectrum). Furthermore, the effects of two differnent abutment and bent foundation support conditions were evaluated. The experience gained by utilizing the computer software revealed that some programs were well suited to displacement-based analysis, both from the point-of-view of being efficient and providing insight into the behavior of plastic hinges. The results of the seismic analyses demonstrated that force-based methods of analysis may be conveniently used to prioritize cases under which displacement-based methods of analysis should be applied. Furthermore, the displacement-based methods of analysis that were used produced different predictions of nonlinear response with neither method being regarded as producing accurate results due to a number of simplifications inherent in the methods. Finally, the displacement-based methods of analysis appear to be attractive to practicing engineers in the sense that they emphasize a graphical evaluation of seismic performance.
Authors:
Symans,M. D., Shattarat,N. K., McLean,D. I., Cofer,W. F.
Keywords:
displacement-based seismic analysis, force-based seismic analysis, pushover analysis, nonlinear static analysis, capacity spectrum analysis, bridge design, earthquake, research
The response of bridges when subjected to seismic excitation can be evaluated by a number of analysis methods. The traditional approach to seismic analysis focuses on forces (so-called force-based methods of analysis) while current design practice is moving towards an increased emphasis on displacements (so-called displacement-based methods of analysis). The primary objective of this research project was to evaluate the effectiveness of various commerically-available computer programs for performing practical displacement-based seismic analysis of highway bridges. A secondary objective was to identify the fundamental differences between force-based and displacement-based methods of analysis, particularly as they apply to highway bridges. The objectives of the project were met by utilizing four different computer programs to evaluate the seismic response of a simple two-span highway bridge. The seismic response was evaluated using two force-based methods of analysis (response spectrum and time-history) and two displacement-based methods (capacity spectrum and inelastic demand spectrum). Furthermore, the effects of two differnent abutment and bent foundation support conditions were evaluated. The experience gained by utilizing the computer software revealed that some programs were well suited to displacement-based analysis, both from the point-of-view of being efficient and providing insight into the behavior of plastic hinges. The results of the seismic analyses demonstrated that force-based methods of analysis may be conveniently used to prioritize cases under which displacement-based methods of analysis should be applied. Furthermore, the displacement-based methods of analysis that were used produced different predictions of nonlinear response with neither method being regarded as producing accurate results due to a number of simplifications inherent in the methods. Finally, the displacement-based methods of analysis appear to be attractive to practicing engineers in the sense that they emphasize a graphical evaluation of seismic performance.
Authors:
Symans,M. D., Shattarat,N. K., McLean,D. I., Cofer,W. F.
Keywords:
displacement-based seismic analysis, force-based seismic analysis, pushover analysis, nonlinear static analysis, capacity spectrum analysis, bridge design, earthquake, research
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http://www.wsdot.wa.gov/research/reports/fullreports/553.1.pdf http://wsdot.wa.gov/Research/Reports/500/553.1.htm |
| Itani,R. | WA-RD 542.2 | Rapid Repair Design of Temporary Support Systems for Bridges Damaged by Earthquakes in the State of Washington. Appendix... | 2002 | TRAC/WSU |
Abstract:
The scope of this project is to provide designs for the rapid construction of shoring systems for damaged bridges due to earthquakes in the state of Washington. Using a broad range of loading criteria and established bridge geometries, several shoring systems were developed for 75% of the bridge types in Washington that are encountered in typical field scenarios. Using materials commonly available in the Puget Sound stockyards, steel and a wood/steel combination shoring system were developed to shore standardized concrete pre-stressed girder bridges, concrete box girder bridges, or steel plate girder bridges. The temporary shoring can span a height of 15 to 40-feet. A handbook, with a flowchart and detailed construction drawings, was developed to provide WSDOT inspection engineers with tools to administer the full, appropriate completion of the shoring systems to allow the public and emergency crews to traverse damaged bridges.
Authors:
Itani,R., Fridley,K., Heath,L.
Keywords:
shoring systems, bridges, earthquake, pre-engineered plans
The scope of this project is to provide designs for the rapid construction of shoring systems for damaged bridges due to earthquakes in the state of Washington. Using a broad range of loading criteria and established bridge geometries, several shoring systems were developed for 75% of the bridge types in Washington that are encountered in typical field scenarios. Using materials commonly available in the Puget Sound stockyards, steel and a wood/steel combination shoring system were developed to shore standardized concrete pre-stressed girder bridges, concrete box girder bridges, or steel plate girder bridges. The temporary shoring can span a height of 15 to 40-feet. A handbook, with a flowchart and detailed construction drawings, was developed to provide WSDOT inspection engineers with tools to administer the full, appropriate completion of the shoring systems to allow the public and emergency crews to traverse damaged bridges.
Authors:
Itani,R., Fridley,K., Heath,L.
Keywords:
shoring systems, bridges, earthquake, pre-engineered plans
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http://www.wsdot.wa.gov/research/reports/fullreports/542.2.pdf http://wsdot.wa.gov/Research/Reports/500/542.2.htm |
| Kramer,S. L. | WA-RD 450.1 | Ground Motions Due to Large Magnitude Subduction Zone Earthquakes | 1998 | TRAC/UW |
Abstract:
The notion that the Cascadia, subduction zone (CSZ) has produced very large earthquakes in the past, and that it can be expected to produce very large earthquakes again, is now widely accepted in the seismological and engineering communities. Because no records of ground shaking or damage exist for historical CSZ earthquakes, it is difficult to evaluate their potential effects on bridges, buildings, embankments, and other structures. However, recent advances in engineering seismology now allow the numerical simulation of earthquakes, including fault rupture, the propagation of seismic waves from the fault to the site of interest, and amplification of the resulting rock motions by shallow soil and rock layers beneath the site.Rock outcrop motions were simulated for three CSZ earthquake scenarios: magnitude 8.0, 8.5, and 9.0 earthquakes. The magnitude.8.0 earthquake was assumed to result from rupture of the portion of the CSZ adjacent to the northern part of the state; the larger magnitude earthquakes were associated with rupture on a portion of the CSZ extending along the entire length of the state. Thirty different simulations of each earthquake scenario were analyzed. For each, rock outcrop motions were computed at each of 13 locations within Washington state. Site response analyses were then performed for 15 soil profiles at the 13 locations.The rock outcrop motions showed amplitudes, frequency contents, and durations that were significantly different than the ground motions that civil structures are commonly designed for in Washington state. Peak accelerations and spectral acceleration at T=0.3 sec, were all considerably lower than the values on which most current design procedures are based. Spectral accelerations for T=1.0 sec were less than those on which current design procedures are based for Mw=8.0 earthquakes, but they were comparable for Mw=9.0 earthquakes and, at some sites, for Mw=8.5 earthquakes. CSZ ground motions have strong long-period (low frequency) components and thus should be more damaging to structures with long natural periods.. Finally, the durations of CSZ ground motions are much longer than those of the motions on which current design procedures are based. This aspect of CSZ motions may be quite significant for reinforced concrete structures and potentially liquefiable soil deposits in which the accumulation of damage depends on the number of load or stress reversals that occur during earthquake shaking.
Authors:
Kramer,S. L., Silva,W. J., Baska,D. A.
Keywords:
earthquake, response spectra, cascadia subduction zone, green's function, seismic design, research
The notion that the Cascadia, subduction zone (CSZ) has produced very large earthquakes in the past, and that it can be expected to produce very large earthquakes again, is now widely accepted in the seismological and engineering communities. Because no records of ground shaking or damage exist for historical CSZ earthquakes, it is difficult to evaluate their potential effects on bridges, buildings, embankments, and other structures. However, recent advances in engineering seismology now allow the numerical simulation of earthquakes, including fault rupture, the propagation of seismic waves from the fault to the site of interest, and amplification of the resulting rock motions by shallow soil and rock layers beneath the site.Rock outcrop motions were simulated for three CSZ earthquake scenarios: magnitude 8.0, 8.5, and 9.0 earthquakes. The magnitude.8.0 earthquake was assumed to result from rupture of the portion of the CSZ adjacent to the northern part of the state; the larger magnitude earthquakes were associated with rupture on a portion of the CSZ extending along the entire length of the state. Thirty different simulations of each earthquake scenario were analyzed. For each, rock outcrop motions were computed at each of 13 locations within Washington state. Site response analyses were then performed for 15 soil profiles at the 13 locations.The rock outcrop motions showed amplitudes, frequency contents, and durations that were significantly different than the ground motions that civil structures are commonly designed for in Washington state. Peak accelerations and spectral acceleration at T=0.3 sec, were all considerably lower than the values on which most current design procedures are based. Spectral accelerations for T=1.0 sec were less than those on which current design procedures are based for Mw=8.0 earthquakes, but they were comparable for Mw=9.0 earthquakes and, at some sites, for Mw=8.5 earthquakes. CSZ ground motions have strong long-period (low frequency) components and thus should be more damaging to structures with long natural periods.. Finally, the durations of CSZ ground motions are much longer than those of the motions on which current design procedures are based. This aspect of CSZ motions may be quite significant for reinforced concrete structures and potentially liquefiable soil deposits in which the accumulation of damage depends on the number of load or stress reversals that occur during earthquake shaking.
Authors:
Kramer,S. L., Silva,W. J., Baska,D. A.
Keywords:
earthquake, response spectra, cascadia subduction zone, green's function, seismic design, research
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| Modak,S. | WA-RD 406.1 | Determination of Rheological Parameters of Pile Foundations for Bridges for Earthquake Analysis | 1997 | TRAC/WSU |
Abstract:
Current seismic design criteria for highway bridges generally require that the effects of earthquake loading be evaluated using either an equivalent static load approach for simple bridges or a dynamic analysis for more complex bridges. These provisions usually provide detailed explanations and commentaries on techniques which are judged to be suitable for static and dynamic modeling of the bridge superstructure and supporting columns or piers. There is, however, a significant lack of guidance on exactly how the boundary conditions and soil-structure-interaction should be incorporated into the model.The purpose of this study is to present a simple analytical model of pile and pile group foundations for use as boundary conditions in a numerical model for seismic analysis of highway bridges. Both the axial and lateral response are considered. This simple model consists of a set of springs, dashpots, and masses for each degree-of-freedom on a pile, and it is based upon the Winkler hypothesis. The spring behavior is established by using the finite element method for static load conditions. The lumped dashpot constants and masses are based on realistic approximations. The effect of a sliding interface, nonlinearity of the soil and geometric, hysteresis, and viscous damping of the soil have been considered.The p-y curves for lateral and axial vibration of single piles of 0.457m (18") and 0.610m (24") diameter based on plane analysis for different depths have been presented. Similar curves for direct lateral, shear-lateral, and axial vibrations have also been presented for two-pile groups with three different spacings.Using these p-y curves, pile responses have been obtained which have been compared with those obtained from a rigorous analysis. Good agreement has been observed for a single pile response. The comparison justifies the use of this simple model.
Authors:
Modak,S., Cofer,W. F.
Keywords:
bridge, earthquake, piles, group, finite element
Current seismic design criteria for highway bridges generally require that the effects of earthquake loading be evaluated using either an equivalent static load approach for simple bridges or a dynamic analysis for more complex bridges. These provisions usually provide detailed explanations and commentaries on techniques which are judged to be suitable for static and dynamic modeling of the bridge superstructure and supporting columns or piers. There is, however, a significant lack of guidance on exactly how the boundary conditions and soil-structure-interaction should be incorporated into the model.The purpose of this study is to present a simple analytical model of pile and pile group foundations for use as boundary conditions in a numerical model for seismic analysis of highway bridges. Both the axial and lateral response are considered. This simple model consists of a set of springs, dashpots, and masses for each degree-of-freedom on a pile, and it is based upon the Winkler hypothesis. The spring behavior is established by using the finite element method for static load conditions. The lumped dashpot constants and masses are based on realistic approximations. The effect of a sliding interface, nonlinearity of the soil and geometric, hysteresis, and viscous damping of the soil have been considered.The p-y curves for lateral and axial vibration of single piles of 0.457m (18") and 0.610m (24") diameter based on plane analysis for different depths have been presented. Similar curves for direct lateral, shear-lateral, and axial vibrations have also been presented for two-pile groups with three different spacings.Using these p-y curves, pile responses have been obtained which have been compared with those obtained from a rigorous analysis. Good agreement has been observed for a single pile response. The comparison justifies the use of this simple model.
Authors:
Modak,S., Cofer,W. F.
Keywords:
bridge, earthquake, piles, group, finite element
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| Cofer,W. F. | WA-RD 406.2 | Determination of Rheological Parameters of Pile Foundations for Bridges for Earthquake Analysis | 1997 | TRAC/WSU |
Abstract:
In the seismic design criteria for highway bridges, there is a significant lack of guidance on ways to incorporate the effect of soil-structure interaction in determining seismic response. For this study, a simple analytical model for pile and pile group foundations is presented for use in dynamic modeling of bridge superstructures. Both the axial and lateral pile response is considered. This simple model consists of a set of nonlinear springs, dampers, and masses for each degree-of-freedom of the pile, and it is based on the Winkler hypothesis. The spring behavior was established by using the finite element method for static load conditions and a typical soil from Washington state. The lumped damping constants and masses were based on realistic approximations. The p-y and t-z curves for single piles and two-pile groups were presented for two pile diameters. Using these curves as near-field Winkler elements, combined with established far-field elements, the dynamic response of a single pile when subjected to a half-sine impulse load was compared to that of a more rigorous, nonlinear, three-dimensional finite element analysis. Close agreement was observed. For design, suggestions were made on ways to develop an approximately equivalent foundation model consisting of a single mass, spring, and damper.
Authors:
Cofer,W. F., Modak,S.
Keywords:
bridge, earthquake, piles, group, finite element
In the seismic design criteria for highway bridges, there is a significant lack of guidance on ways to incorporate the effect of soil-structure interaction in determining seismic response. For this study, a simple analytical model for pile and pile group foundations is presented for use in dynamic modeling of bridge superstructures. Both the axial and lateral pile response is considered. This simple model consists of a set of nonlinear springs, dampers, and masses for each degree-of-freedom of the pile, and it is based on the Winkler hypothesis. The spring behavior was established by using the finite element method for static load conditions and a typical soil from Washington state. The lumped damping constants and masses were based on realistic approximations. The p-y and t-z curves for single piles and two-pile groups were presented for two pile diameters. Using these curves as near-field Winkler elements, combined with established far-field elements, the dynamic response of a single pile when subjected to a half-sine impulse load was compared to that of a more rigorous, nonlinear, three-dimensional finite element analysis. Close agreement was observed. For design, suggestions were made on ways to develop an approximately equivalent foundation model consisting of a single mass, spring, and damper.
Authors:
Cofer,W. F., Modak,S.
Keywords:
bridge, earthquake, piles, group, finite element
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| Cofer,W. F. | WA-RD 427.1 | Analytical Evaluation of Retrofit Strategies for Multi-Column Bridges | 1997 | TRAC/WSU |
Abstract:
Many retrofit measures have been proposed and then implemented into existing highway bridges. The goal of seismic strengthening is not intended to retrofit a bridge to be "earthquake-proof", but to minimize the likelihood of a structural collapse. An amount of acceptable damage may occur during a design level earthquake. The combination of retrofit measures and the acceptable damage greatly complicates the structural properties for a bridge. It is necesary to use analytical and experimental means to verify the effectiveness of various retrofit combinations.The objectives of this research are: (1) to investigate analytically the feasibility and advantages of applying the retrofit measures developed for single-column bent bridges to multi-column bend bridges; (2) to evaluate analytically the effects and benefits of current column retrofit strategies for multi-column bridges and propose the most effective measures for strengthening bridges; (3) to evaluate the performance of earthquake restrainers and find the change of seismic load and displacements cause by their installation.To achieve the objectives, an existing nonlinear dynamic bridge analysis program with elastic-perfectly plastic column behavior and a conventional hysteresis model was modified in order to include softening behavior and a more realistic hysteresis rule for cyclic loading.Both two- and three-dimensional structural models for two actual bridges from Washington were analyzed by inputting a typical seismic record. The two-dimensional models were used to evaluate column retrofitting measures, and the three-dimensional model was used to evaluate the performance of longitudinal earthquake restrainers. Both artial and full column retrofit stratgies were shown to result in decreased maximum earthquake response and decreased plastic deformation of columns for the bridge bent compared to the case without retrofitting. Therefore, it was concluded that the partial column retrofit strategies were feasible after a ductility capacity of the bridge is exactly defined. The opening displacements at expansion joint hinges were decreased due to the installation of longitudinal restrainers. Additionally, the redistribution of earthquake forces caused by their installation was not significant. Many retrofit measures have been proposed and then implemented into existing highway bridges. The goal of seismic strengthening is not intended to retrofit a bridge to be "earthquake-proof", but to minimize the likelihood of a structural collapse. An amount of acceptable damage may occur during a design level earthquake. The combination of retrofit measures and the acceptable damage greatly complicates the structural properties for a bridge. It is necessary to use analytical and experimental means to verify the effectiveness of various retrofit combinations.
Authors:
Cofer,W. F., McLean,D. I., Zhang,Y.
Keywords:
bridge, earthquake, retrofit, analysis, columns
Many retrofit measures have been proposed and then implemented into existing highway bridges. The goal of seismic strengthening is not intended to retrofit a bridge to be "earthquake-proof", but to minimize the likelihood of a structural collapse. An amount of acceptable damage may occur during a design level earthquake. The combination of retrofit measures and the acceptable damage greatly complicates the structural properties for a bridge. It is necesary to use analytical and experimental means to verify the effectiveness of various retrofit combinations.The objectives of this research are: (1) to investigate analytically the feasibility and advantages of applying the retrofit measures developed for single-column bent bridges to multi-column bend bridges; (2) to evaluate analytically the effects and benefits of current column retrofit strategies for multi-column bridges and propose the most effective measures for strengthening bridges; (3) to evaluate the performance of earthquake restrainers and find the change of seismic load and displacements cause by their installation.To achieve the objectives, an existing nonlinear dynamic bridge analysis program with elastic-perfectly plastic column behavior and a conventional hysteresis model was modified in order to include softening behavior and a more realistic hysteresis rule for cyclic loading.Both two- and three-dimensional structural models for two actual bridges from Washington were analyzed by inputting a typical seismic record. The two-dimensional models were used to evaluate column retrofitting measures, and the three-dimensional model was used to evaluate the performance of longitudinal earthquake restrainers. Both artial and full column retrofit stratgies were shown to result in decreased maximum earthquake response and decreased plastic deformation of columns for the bridge bent compared to the case without retrofitting. Therefore, it was concluded that the partial column retrofit strategies were feasible after a ductility capacity of the bridge is exactly defined. The opening displacements at expansion joint hinges were decreased due to the installation of longitudinal restrainers. Additionally, the redistribution of earthquake forces caused by their installation was not significant. Many retrofit measures have been proposed and then implemented into existing highway bridges. The goal of seismic strengthening is not intended to retrofit a bridge to be "earthquake-proof", but to minimize the likelihood of a structural collapse. An amount of acceptable damage may occur during a design level earthquake. The combination of retrofit measures and the acceptable damage greatly complicates the structural properties for a bridge. It is necessary to use analytical and experimental means to verify the effectiveness of various retrofit combinations.
Authors:
Cofer,W. F., McLean,D. I., Zhang,Y.
Keywords:
bridge, earthquake, retrofit, analysis, columns
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| Trochalakis,P. | WA-RD 387.1 | Design Of Seismic Restrainers For In-Span Hinges | 1996 |
Abstract:
Currently, two commonly used restrainer design methods are those mandated by the American Association of State and Highway Transportation Officials (AASHTO) and the California Department of Transportation (CALTRANS). To evaluate these methods and perhaps develop a new method, the Washington State Department of Transportation (WSDOT) sponsored this study.Using sample WSDOT designs and seismic retrofitting guidelines from WSDOT and CALTRANS, the researchers developed a model of a two-frame bridge with a single in-span hinge. The nonlinear response of the bridge was studied to determine the maximum opening experienced at the in-span hinge and the maximum relative displacements at the abutments.To identify the parameters most important in restrainer design and in predicting the unrestrained maximum relative abutment displacements, the researchers varied eleven parameters. The parametric study identified the parameters that significantly influenced the maximum relative hinge displacement (MRHD) and the maximum relative abutment displacements (MRAD). Currently, two commonly used restrainer design methods are those mandated by the American Association of State and Highway Transportation Officials (AASHTO) and the California Department of Transportation (CALTRANS). To evaluate these methods and perhaps develop a new method, the Washington State Department of Transportation (WSDOT) sponsored this study.Using sample WSDOT designs and seismic retrofitting guidelines from WSDOT and CALTRANS, the researchers developed a model of a two-frame bridge with a single in-span hinge. The nonlinear response of the bridge was studied to determine the maximum opening experienced at the in-span hinge and the maximum relative displacements at the abutments.The AASHTO empirical seat width equation and the CALTRANS restrainer design method were compared with the results of nonlinear time history analysis. The empirical seat width equation produced conservative results while the CALTRANS method produced inconsistent results, a large amount of scatter and some significantly unconservative values.Using the results of the parametric study, the researchers developed a new restrainer design method that predicted the MRHD much more accurately than the CALTRANS method. The researchers also developed a method for estimating the unrestrained MRAD.
Authors:
Trochalakis,P., Eberhard,M. O., Stanton,J. F.
Keywords:
bridge, design, hinge, earthquake, evaluation, restrainers
Currently, two commonly used restrainer design methods are those mandated by the American Association of State and Highway Transportation Officials (AASHTO) and the California Department of Transportation (CALTRANS). To evaluate these methods and perhaps develop a new method, the Washington State Department of Transportation (WSDOT) sponsored this study.Using sample WSDOT designs and seismic retrofitting guidelines from WSDOT and CALTRANS, the researchers developed a model of a two-frame bridge with a single in-span hinge. The nonlinear response of the bridge was studied to determine the maximum opening experienced at the in-span hinge and the maximum relative displacements at the abutments.To identify the parameters most important in restrainer design and in predicting the unrestrained maximum relative abutment displacements, the researchers varied eleven parameters. The parametric study identified the parameters that significantly influenced the maximum relative hinge displacement (MRHD) and the maximum relative abutment displacements (MRAD). Currently, two commonly used restrainer design methods are those mandated by the American Association of State and Highway Transportation Officials (AASHTO) and the California Department of Transportation (CALTRANS). To evaluate these methods and perhaps develop a new method, the Washington State Department of Transportation (WSDOT) sponsored this study.Using sample WSDOT designs and seismic retrofitting guidelines from WSDOT and CALTRANS, the researchers developed a model of a two-frame bridge with a single in-span hinge. The nonlinear response of the bridge was studied to determine the maximum opening experienced at the in-span hinge and the maximum relative displacements at the abutments.The AASHTO empirical seat width equation and the CALTRANS restrainer design method were compared with the results of nonlinear time history analysis. The empirical seat width equation produced conservative results while the CALTRANS method produced inconsistent results, a large amount of scatter and some significantly unconservative values.Using the results of the parametric study, the researchers developed a new restrainer design method that predicted the MRHD much more accurately than the CALTRANS method. The researchers also developed a method for estimating the unrestrained MRAD.
Authors:
Trochalakis,P., Eberhard,M. O., Stanton,J. F.
Keywords:
bridge, design, hinge, earthquake, evaluation, restrainers
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| Trochalakis,P. | WA-RD 387.2 | Unseating of Simply Supported Spans During Earthquakes | 1996 | TRAC/UW |
Abstract:
The Washington State Department of Transportation (WSDOT) is currently retrofitting many older bridges to prevent their superstructures from unseating during earthquakes. In bridges whose simply supported spans have inadequate bearing lengths, WSDOT most frequently connects adjacent spans with high-strength rod restrainers. The study described in this report was undertaken to determine whether restrainers in this manner are effective in preventing span unseating and to develop a method for identifying vulnerable simply supported spans. A companion report considered the design of seismic restrainers for in-span hinges.The researchers developed a nonlinear analytical model of a four-span, simply supported, prestressed concrete bridge. Variations of this model were subjected to four ground motions to determine the maximum relative displacements between the simply supported spans and their supports. The maximum relative displacements at the piers depended most on the bearing friction resistance, the earthquake motion, and the size of the joints in the deck. The maximum relative displacements at the abutments depended most on the bearing resistance and the earthquake motion.Based on the results of the parametric study, the researchers developed a new method to estimate the susceptibility of bridges to unseating of simply supported spans. The researchers also found that restrainers connecting adjacent spans are ineffective in reducing the relative displacements between the superstructure spans and their supports.
Authors:
Trochalakis,P., Eberhard,M. O., Stanton,J. F.
Keywords:
bridge, design, span, unseating, earthquake, evaluation
The Washington State Department of Transportation (WSDOT) is currently retrofitting many older bridges to prevent their superstructures from unseating during earthquakes. In bridges whose simply supported spans have inadequate bearing lengths, WSDOT most frequently connects adjacent spans with high-strength rod restrainers. The study described in this report was undertaken to determine whether restrainers in this manner are effective in preventing span unseating and to develop a method for identifying vulnerable simply supported spans. A companion report considered the design of seismic restrainers for in-span hinges.The researchers developed a nonlinear analytical model of a four-span, simply supported, prestressed concrete bridge. Variations of this model were subjected to four ground motions to determine the maximum relative displacements between the simply supported spans and their supports. The maximum relative displacements at the piers depended most on the bearing friction resistance, the earthquake motion, and the size of the joints in the deck. The maximum relative displacements at the abutments depended most on the bearing resistance and the earthquake motion.Based on the results of the parametric study, the researchers developed a new method to estimate the susceptibility of bridges to unseating of simply supported spans. The researchers also found that restrainers connecting adjacent spans are ineffective in reducing the relative displacements between the superstructure spans and their supports.
Authors:
Trochalakis,P., Eberhard,M. O., Stanton,J. F.
Keywords:
bridge, design, span, unseating, earthquake, evaluation
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| Knaebel,P. | WA-RD 363.3 | Seismic Vulnerability of the Alaskan Way Viaduct: SED Typical Unit | 1995 | TRAC/UW |
Abstract:
An engineering team from the University of Washington (UW) evaluated the seismic vulnerability of the Alaskan Way Viaduct, located in Seattle, Washington. This report presents the evaluation of a typical three-bay unit that was designed by The City of Seattle Engineering Department (SED). The evaluation team performed response-spectrum analyses and nonlinear analyses for the fixed-base condition. The team considered a widely used soft-soil spectrum and worst-case, site-specific spectra. Wherever possible, the UW team evaluated the vulnerability for each failure mode following procedures proposed; by the Applied Technology Council; and by researchers at the University of California, San Diego.The evaluation team found that the vulnerability of the Alaskan Way Viaduct exceeds that of bridges built to current standards. The vulnerability is a result of a combination of two factors: (1) the design ground motion would strongly excite the viaduct; and (2) many of the structural components lack the ductility required by current standards. The following deficiencies were identified as the most critical.*The lower-story columns have inadequate transverse reinforcement, and could fail in shear before they develop their flexural capacity.*The first- and second-story joints have inadequate confinement reinforcement, and during strong ground motions, they could experience a diagonal-tension failure.*If the base of the lower-story columns develop their flexural capacity, the footings could fail in shear.
Authors:
Knaebel,P., Eberhard,M. O., de la Colina,J.
Keywords:
bridge, earthquake, evaluation, reinforced concrete
An engineering team from the University of Washington (UW) evaluated the seismic vulnerability of the Alaskan Way Viaduct, located in Seattle, Washington. This report presents the evaluation of a typical three-bay unit that was designed by The City of Seattle Engineering Department (SED). The evaluation team performed response-spectrum analyses and nonlinear analyses for the fixed-base condition. The team considered a widely used soft-soil spectrum and worst-case, site-specific spectra. Wherever possible, the UW team evaluated the vulnerability for each failure mode following procedures proposed; by the Applied Technology Council; and by researchers at the University of California, San Diego.The evaluation team found that the vulnerability of the Alaskan Way Viaduct exceeds that of bridges built to current standards. The vulnerability is a result of a combination of two factors: (1) the design ground motion would strongly excite the viaduct; and (2) many of the structural components lack the ductility required by current standards. The following deficiencies were identified as the most critical.*The lower-story columns have inadequate transverse reinforcement, and could fail in shear before they develop their flexural capacity.*The first- and second-story joints have inadequate confinement reinforcement, and during strong ground motions, they could experience a diagonal-tension failure.*If the base of the lower-story columns develop their flexural capacity, the footings could fail in shear.
Authors:
Knaebel,P., Eberhard,M. O., de la Colina,J.
Keywords:
bridge, earthquake, evaluation, reinforced concrete
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| Eberhard,M. O. | WA-RD 363.1 | Seismic Vulnerability of the Alaskan Way Viaduct: WSDOT Typical Unit | 1995 | TRAC/UW |
Abstract:
An engineering team from the University of Washington (UW) evaluated the seismic vulnerability of the Alaskan Way Viaduct, located in Seattle, Washington. This report presents the evaluation of a typical three-bay unit that was designed by WSDOT. The evaluation team performed response-spectrum analyses and nonlinear analyses for both fixed-base and pinned-base conditions. The team considered a widely used soft-soil spectrum and worst-case, site-specific spectra. Wherever possible, the UW team evaluated the vulnerability to each failure node following two or three procedures, including those proposed by the Applied Technology Council (1983) and Priestley, Seible, and Chai (1992).The evaluation team found that the vulnerability of the Alaskan Way Viaduct exceeds that of bridges built to current standards. The vulnerability is a result of a combination of two factors: (1) the ground motion is likely to strongly excite the viaduct; and (2) many of the WSDOT unit's structural components are likely to behave in a brittle manner. The following deficiencies were identified as the most critical.*The first-story column-reinforcement splices are too short, they have too little confinement reinforcement, and they are located in regions likely to experience large ductility demands.*The column/beam joints have inadequate confinement reinforcement, and during strong ground motions, they could experience a diagonal tension failure.*The shear strength of the first-story columns is marginal.*If the first-story columns develop their flexural capacity during an earthquake, the pile-supported footings could fail in shear.
Authors:
Eberhard,M. O., de la Colina,J., Ryter,S.
Keywords:
bridge, earthquake, evaluation, reinforced concrete
An engineering team from the University of Washington (UW) evaluated the seismic vulnerability of the Alaskan Way Viaduct, located in Seattle, Washington. This report presents the evaluation of a typical three-bay unit that was designed by WSDOT. The evaluation team performed response-spectrum analyses and nonlinear analyses for both fixed-base and pinned-base conditions. The team considered a widely used soft-soil spectrum and worst-case, site-specific spectra. Wherever possible, the UW team evaluated the vulnerability to each failure node following two or three procedures, including those proposed by the Applied Technology Council (1983) and Priestley, Seible, and Chai (1992).The evaluation team found that the vulnerability of the Alaskan Way Viaduct exceeds that of bridges built to current standards. The vulnerability is a result of a combination of two factors: (1) the ground motion is likely to strongly excite the viaduct; and (2) many of the WSDOT unit's structural components are likely to behave in a brittle manner. The following deficiencies were identified as the most critical.*The first-story column-reinforcement splices are too short, they have too little confinement reinforcement, and they are located in regions likely to experience large ductility demands.*The column/beam joints have inadequate confinement reinforcement, and during strong ground motions, they could experience a diagonal tension failure.*The shear strength of the first-story columns is marginal.*If the first-story columns develop their flexural capacity during an earthquake, the pile-supported footings could fail in shear.
Authors:
Eberhard,M. O., de la Colina,J., Ryter,S.
Keywords:
bridge, earthquake, evaluation, reinforced concrete
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| O'Donovan,T. | WA-RD 305.3 | Lateral-Load Response Of Two Reinforced Concrete Piers | 1994 | TRAC/UW |
Abstract:
This study was part of a Washington State Department of Transportation (WSDOT) program to assess the vulnerability of multiple-span highway bridges built before 1984. During the first series of static tests (Phase I), discussed in a previous report, a three-span, reinforced concrete bridge was subjected to large lateral loads. In Phase II, described in this report, the researchers greatly reduced the resistance that the abutments provided so that they could evaluate the lateral-load resistance of the piers. The researchers then subjected the piers to large, transverse cyclic displacements with drift ratios of 0.5, 1.0, 2.0, and 3.0 percent.The piers resisted repeated loadings to a force equal to one third of the bridge's weight. The envelope to the pier's hysteretic response indicated that the system yielded at a drift ratio of 0.7 percent. Whereas the top of the columns spalled at large drift ratios, the damage to the bottom of the columns was limited to flexural cracks. The pier's measured response was compared to that calculated by the researchers, the California Department of Transportation, and the WSDOT. The calculated responses were found to be strongly sensitive to the assumed steel and soil properties. On the basis of the experience gained in performing the tests, the researchers made recommendations for those planning to perform future tests of large structures. In -addition, while acknowledging the limitations of a single series of static tests, the researchers concluded that (1) the tests should serve as a benchmark against which to evaluate proposed analytical models, (2) at an effective acceleration of 0.2g, the seismic damage to the isolated bridge would probably be minor, (3) at an effective acceleration of 0.4g, the piers would likely sustain heavy damage, and (4) the WSDOT should investigate the influence of soil properties on column damage to determine when geotechnical tests are warranted.
Authors:
O'Donovan,T., Eberhard,M. O., MacLardy,J. A., Marsh,M. L.
Keywords:
bridge, earthquake, piers, reinforced concrete, tests, modeling, lateral loads
This study was part of a Washington State Department of Transportation (WSDOT) program to assess the vulnerability of multiple-span highway bridges built before 1984. During the first series of static tests (Phase I), discussed in a previous report, a three-span, reinforced concrete bridge was subjected to large lateral loads. In Phase II, described in this report, the researchers greatly reduced the resistance that the abutments provided so that they could evaluate the lateral-load resistance of the piers. The researchers then subjected the piers to large, transverse cyclic displacements with drift ratios of 0.5, 1.0, 2.0, and 3.0 percent.The piers resisted repeated loadings to a force equal to one third of the bridge's weight. The envelope to the pier's hysteretic response indicated that the system yielded at a drift ratio of 0.7 percent. Whereas the top of the columns spalled at large drift ratios, the damage to the bottom of the columns was limited to flexural cracks. The pier's measured response was compared to that calculated by the researchers, the California Department of Transportation, and the WSDOT. The calculated responses were found to be strongly sensitive to the assumed steel and soil properties. On the basis of the experience gained in performing the tests, the researchers made recommendations for those planning to perform future tests of large structures. In -addition, while acknowledging the limitations of a single series of static tests, the researchers concluded that (1) the tests should serve as a benchmark against which to evaluate proposed analytical models, (2) at an effective acceleration of 0.2g, the seismic damage to the isolated bridge would probably be minor, (3) at an effective acceleration of 0.4g, the piers would likely sustain heavy damage, and (4) the WSDOT should investigate the influence of soil properties on column damage to determine when geotechnical tests are warranted.
Authors:
O'Donovan,T., Eberhard,M. O., MacLardy,J. A., Marsh,M. L.
Keywords:
bridge, earthquake, piers, reinforced concrete, tests, modeling, lateral loads
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| McLean,D. I. | WA-RD 299.1/NTIS No. PB94-178860 | Seismic Analysis of the Westbound Lanes of the I-90 Bridges Crossing Mercer Slough | 1994 | TRAC/UW |
Abstract:
This study investigated the seismic response of the westbound lanes of I-90 crossing Mercer Slough. Mercer Slough is filled with a very soft, thick peat deposit. Both linear and nonlinear dynamic analyses were performed, including special analyses, linear time-history analyses and nonlinear time-history analyses. Variables considered in the analyses included different column and foundation stiffness, different seismic input, different simultaneous seismic input, and non-linear joint behavior. The response of the bridge was found to be extremely sensitive to seismic input and, to a lesser extent, foundation stiffness. Consideration of nonlinear effects tended to lessen the bridge response. The analyses also indicated that a long, loosely connected bridge, such as that crossing the Mercer Slough, can be adequately analyzed using a fairly short section of the bridge. All of the different analyses indicated that elements in the bridge would probably be close to or exceed their capacity during an earthquake. Problem areas which were identified included the inability of the expansion joints to sustain large relative displacements and the possible overloading of the columns in flexure.
Authors:
McLean,D. I., Cannon,I. B. S.
Keywords:
bridge and construction, bridge, seismic responses, peat, dynamic wheel loadings analysis, earthquake
This study investigated the seismic response of the westbound lanes of I-90 crossing Mercer Slough. Mercer Slough is filled with a very soft, thick peat deposit. Both linear and nonlinear dynamic analyses were performed, including special analyses, linear time-history analyses and nonlinear time-history analyses. Variables considered in the analyses included different column and foundation stiffness, different seismic input, different simultaneous seismic input, and non-linear joint behavior. The response of the bridge was found to be extremely sensitive to seismic input and, to a lesser extent, foundation stiffness. Consideration of nonlinear effects tended to lessen the bridge response. The analyses also indicated that a long, loosely connected bridge, such as that crossing the Mercer Slough, can be adequately analyzed using a fairly short section of the bridge. All of the different analyses indicated that elements in the bridge would probably be close to or exceed their capacity during an earthquake. Problem areas which were identified included the inability of the expansion joints to sustain large relative displacements and the possible overloading of the columns in flexure.
Authors:
McLean,D. I., Cannon,I. B. S.
Keywords:
bridge and construction, bridge, seismic responses, peat, dynamic wheel loadings analysis, earthquake
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| Marsh,M. L. | WA-RD 340.1 | Structural Response to Long-Duration Earthquakes | 1994 | TRAC/WSU |
Abstract:
The effects of postulated Cascadia subduction zone earthquakes on inelastic structural response have been quantified. The earthquakes studied ranged in size from those previously recorded to the largest plausible event, a magnitude 9.5, 240 second duration earthquake. Artificial acceleration records attenuated to epicentral distances corresponding to coastal range sites and Puget Sound sites were generated. These records were used as input for inelastic response history analyses of single-degree-of-freedom systems with either bilinear or degrading stiffness hysteric relationships. The results indicate that the maximum displacements are not significantly greater that those produced by previously recorded events or by records that are compatible with current design code response spectra. However, the inelastic energy dissipated and the numbers of displacement cycles are somewhat greater for the largest events, although the energy demands and cyclic demands are similar to those from previous events for magnitudes up to 8.5. Since, the maximum credible event is not well established at this time, no changes to the current design procedures are recommended.
Authors:
Marsh,M. L., Gianotti,C. M.
Keywords:
earthquake, subduction zone, duration effects, inelastic response, damage demands, response spectra, inelastic energy, cyclic loading
The effects of postulated Cascadia subduction zone earthquakes on inelastic structural response have been quantified. The earthquakes studied ranged in size from those previously recorded to the largest plausible event, a magnitude 9.5, 240 second duration earthquake. Artificial acceleration records attenuated to epicentral distances corresponding to coastal range sites and Puget Sound sites were generated. These records were used as input for inelastic response history analyses of single-degree-of-freedom systems with either bilinear or degrading stiffness hysteric relationships. The results indicate that the maximum displacements are not significantly greater that those produced by previously recorded events or by records that are compatible with current design code response spectra. However, the inelastic energy dissipated and the numbers of displacement cycles are somewhat greater for the largest events, although the energy demands and cyclic demands are similar to those from previous events for magnitudes up to 8.5. Since, the maximum credible event is not well established at this time, no changes to the current design procedures are recommended.
Authors:
Marsh,M. L., Gianotti,C. M.
Keywords:
earthquake, subduction zone, duration effects, inelastic response, damage demands, response spectra, inelastic energy, cyclic loading
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| Marsh,M. L. | WA-RD 340.2 | Structural Response to Long-Duration Earthquakes | 1994 | TRAC/WSU |
Abstract:
The effects of postulated Cascadia subduction zone earthquakes on inelastic structural response have been quantified. The earthquakes studied ranged in size from those previously recorded to the largest plausible event, a magnitude 9.5, 240 second duration earthquake. Artificial acceleration records attenuated to epicentral distances corresponding to coastal range sites and Puget Sound sites were generated. These records were used as input for inelastic response history analyses of single-degree-of-freedom systems with either bilinear or degrading stiffness hysteric relationships. The results indicate that the maximum displacements are not significantly greater that those produced by previously recorded events or by records that are compatible with current design code response spectra. However, the inelastic energy dissipated and the numbers of displacement cycles are somewhat greater for the largest events, although the energy demands and cyclic demands are similar to those from previous events for magnitudes up to 8.5. Since, the maximum credible event is not well established at this time, no changes to the current design procedures are recommended.
Authors:
Marsh,M. L., Gianotti,C. M.
Keywords:
structures, seismic, earthquake, subduction zone, duration effects, inelastic response, damage demands, response spectra, inelastic energy, cyclic loading
The effects of postulated Cascadia subduction zone earthquakes on inelastic structural response have been quantified. The earthquakes studied ranged in size from those previously recorded to the largest plausible event, a magnitude 9.5, 240 second duration earthquake. Artificial acceleration records attenuated to epicentral distances corresponding to coastal range sites and Puget Sound sites were generated. These records were used as input for inelastic response history analyses of single-degree-of-freedom systems with either bilinear or degrading stiffness hysteric relationships. The results indicate that the maximum displacements are not significantly greater that those produced by previously recorded events or by records that are compatible with current design code response spectra. However, the inelastic energy dissipated and the numbers of displacement cycles are somewhat greater for the largest events, although the energy demands and cyclic demands are similar to those from previous events for magnitudes up to 8.5. Since, the maximum credible event is not well established at this time, no changes to the current design procedures are recommended.
Authors:
Marsh,M. L., Gianotti,C. M.
Keywords:
structures, seismic, earthquake, subduction zone, duration effects, inelastic response, damage demands, response spectra, inelastic energy, cyclic loading
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| Ho,C. | WA-RD 333.1 | Seismic Response Spectra | 1994 |
Abstract:
Design response spectra were developed for the Washington State Department of Transportation (WSDOT) for nine soil groups representative of deposits that can be found in Washington State. These response spectra differ from the spectra developed for and adopted by the Applied Technology Council (ATC). Unlike the ATC spectra, the WSDOT spectra are based on the subduction zone setting that dominates Pacific Northwest seismicity. Both sets of spectra are based on numerical studies using SHAKE. The new response spectra were developed using new dynamic moduli curves for cohesive soils which have been accepted as more representative of the properties of the soils in the region. SHAKE tends to attenuate high frequencies. SHAKE based analysis compared well with analysis based on a nonlinear finite element code. The basis of most recent ATC attenuation maps is outlined, and found to be based on similar assumptions and methodology as the original ATC attenuation maps and not compatible with Washington State seismicity.
Authors:
Ho,C., Shawish,K. M.
Keywords:
response spectra, earthquake, seismic, subduction zone, attenuation
Design response spectra were developed for the Washington State Department of Transportation (WSDOT) for nine soil groups representative of deposits that can be found in Washington State. These response spectra differ from the spectra developed for and adopted by the Applied Technology Council (ATC). Unlike the ATC spectra, the WSDOT spectra are based on the subduction zone setting that dominates Pacific Northwest seismicity. Both sets of spectra are based on numerical studies using SHAKE. The new response spectra were developed using new dynamic moduli curves for cohesive soils which have been accepted as more representative of the properties of the soils in the region. SHAKE tends to attenuate high frequencies. SHAKE based analysis compared well with analysis based on a nonlinear finite element code. The basis of most recent ATC attenuation maps is outlined, and found to be based on similar assumptions and methodology as the original ATC attenuation maps and not compatible with Washington State seismicity.
Authors:
Ho,C., Shawish,K. M.
Keywords:
response spectra, earthquake, seismic, subduction zone, attenuation
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| Cofer,W. F. | WA-RD 328.1 | Analytical Modeling of Foundations for Seismic Analysis of Bridges | 1994 |
Abstract:
The response of bridges when subjected to seismic excitation may be significantly influenced by the dynamic properties of their foundations. With current design practice, foundation elements are typically considered as elastic springs without consideration of material and radiation damping. The objectives of this research were to identify general foundation models that are suitable for modeling soil-structure interaction in seismic bridge analysis, to modify an existing nonlinear seismic bridge analysis computer program to include a new element capable of representing such models, and to conduct a parametric study to assess the effect of the nacres energy dissipation mechanisms on the response of bridge substructures. For spread footing foundations, three different models were identified and applied to a typical two-column bridge bent. The seismic response for each model was compared with conventional elastic and fixed-base models. Several soil stiffness values and earthquake records were considered for analysis. Maximum values of displacement, plastic hinge rotation, and cumulative plastic hinge rotations were noted and compared. It was concluded that the use of the foundation models can produce an important change in the bridge response when compared to that of the fixed-based models, depending on the frequency and content of the earthquake and the stiffness of the soil. The effects of radiation damping were observed to be insignificant for foundations on stiff soil, but important for those on soft soil. In addition, the performance of the simpler damped foundation models was found to be quite similar to that of more complex models.
Authors:
Cofer,W. F., McLean,D. I., McGuire,J. W.
Keywords:
structures, seismic, bridge, earthquake, soil-structure interaction, foundation, analysis, modeling
The response of bridges when subjected to seismic excitation may be significantly influenced by the dynamic properties of their foundations. With current design practice, foundation elements are typically considered as elastic springs without consideration of material and radiation damping. The objectives of this research were to identify general foundation models that are suitable for modeling soil-structure interaction in seismic bridge analysis, to modify an existing nonlinear seismic bridge analysis computer program to include a new element capable of representing such models, and to conduct a parametric study to assess the effect of the nacres energy dissipation mechanisms on the response of bridge substructures. For spread footing foundations, three different models were identified and applied to a typical two-column bridge bent. The seismic response for each model was compared with conventional elastic and fixed-base models. Several soil stiffness values and earthquake records were considered for analysis. Maximum values of displacement, plastic hinge rotation, and cumulative plastic hinge rotations were noted and compared. It was concluded that the use of the foundation models can produce an important change in the bridge response when compared to that of the fixed-based models, depending on the frequency and content of the earthquake and the stiffness of the soil. The effects of radiation damping were observed to be insignificant for foundations on stiff soil, but important for those on soft soil. In addition, the performance of the simpler damped foundation models was found to be quite similar to that of more complex models.
Authors:
Cofer,W. F., McLean,D. I., McGuire,J. W.
Keywords:
structures, seismic, bridge, earthquake, soil-structure interaction, foundation, analysis, modeling
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| Cofer,W. F. | WA-RD 328.2/NTIS No. PB940181799 | Analytical Modeling of Foundations for Seismic Analysis of Bridges | 1994 | TRAC/WSU |
Abstract:
The response of bridges when subjected to seismic excitation may be significantly influenced by the dynamic properties of their foundations. With current design practice, foundation elements are typically considered as elastic springs without consideration of material and radiation damping. The objectives of this research were to identify general foundation models that are suitable for modeling soil-structure interaction in seismic bridge analysis, to modify an existing nonlinear seismic bridge analysis computer program to include a new element capable of representing such models, and to conduct a parametric study to assess the effect of the increased energy dissipation mechanisms on the response of bridge substructures. For spread footing foundations, three different models were identified and applied to a typical two-column bridge bent. The seismic response for each model was compared with conventional elastic and fixed-base models. Several soil stiffness values and earthquake records were considered for analysis. Maximum values of displacement, plastic hinge rotation, and cumulative plastic hinge rotations were noted and compared. It was concluded that the use of the foundation models can produce an important change in the bridge response when compared to that of the fixed -based models, depending on the frequency and content of the earthquake and the stiffness of the soil. The effects of radiation damping were observed to be insignificant for foundations on stiff soil, but important for those on soft soil. In addition, the performance of the simpler damped foundation models was found to be quite similar to that of more complex models.
Authors:
Cofer,W. F., McLean,D. I., McGuire,J. W.
Keywords:
bridge, earthquake, soil-structure interaction, foundation, analysis, modeling
The response of bridges when subjected to seismic excitation may be significantly influenced by the dynamic properties of their foundations. With current design practice, foundation elements are typically considered as elastic springs without consideration of material and radiation damping. The objectives of this research were to identify general foundation models that are suitable for modeling soil-structure interaction in seismic bridge analysis, to modify an existing nonlinear seismic bridge analysis computer program to include a new element capable of representing such models, and to conduct a parametric study to assess the effect of the increased energy dissipation mechanisms on the response of bridge substructures. For spread footing foundations, three different models were identified and applied to a typical two-column bridge bent. The seismic response for each model was compared with conventional elastic and fixed-base models. Several soil stiffness values and earthquake records were considered for analysis. Maximum values of displacement, plastic hinge rotation, and cumulative plastic hinge rotations were noted and compared. It was concluded that the use of the foundation models can produce an important change in the bridge response when compared to that of the fixed -based models, depending on the frequency and content of the earthquake and the stiffness of the soil. The effects of radiation damping were observed to be insignificant for foundations on stiff soil, but important for those on soft soil. In addition, the performance of the simpler damped foundation models was found to be quite similar to that of more complex models.
Authors:
Cofer,W. F., McLean,D. I., McGuire,J. W.
Keywords:
bridge, earthquake, soil-structure interaction, foundation, analysis, modeling
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| Reed,D. | WA-RD 289.1 | An Emergency Response Plan for Bridge Management | 1993 |
Abstract:
The major objective of this project was to develop a post-earthquake emergency response plan to WSDOT bridge management. Three types of seismic events was considered in the development of the plan. Inspection forms were developed for the three-stage inspection process. For events other than minor earthquakes under favorable weather and lighting conditions, existing resources appear to be inadequate. Recommendations for improving the readiness of the WSDOT bridge management are provided.
Authors:
Reed,D., Wang,J.
Keywords:
traffic surveillance and control, earthquake, emergency response planning, bridge
The major objective of this project was to develop a post-earthquake emergency response plan to WSDOT bridge management. Three types of seismic events was considered in the development of the plan. Inspection forms were developed for the three-stage inspection process. For events other than minor earthquakes under favorable weather and lighting conditions, existing resources appear to be inadequate. Recommendations for improving the readiness of the WSDOT bridge management are provided.
Authors:
Reed,D., Wang,J.
Keywords:
traffic surveillance and control, earthquake, emergency response planning, bridge
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| Eberhard,M. O. | WA-RD 305.2 | Lateral-Load Response of a Reinforced Concrete Bridge | 1993 | TRAC/UW |
Abstract:
This study was part of a Washington State Department of Transportation (WSDOT) program to assess the vulnerability of highway bridges built before 1984. Researchers applied slowly-varying transverse loads to a three-span, reinforced concrete bridge, including the superstructure, piers, and abutments. The purpose of the test was to measure the transverse stiffness of the bridge and to estimate each support's contribution to stiffness. The researchers also evaluated analytical models by comparing the calculated and observed responses. The bridge was extremely stiff and strong. In two cycles to a load equal to 45 percent of the bridge's weight, the maximum bridge displacement was 0.15 inch. During these cycles damage was minimal. At a load equal to 65 percent of the bridge's weight, the pier displacement was 0.30 inch. After the bridge had been excavated, the stiffness decreased to 15 percent of its original stiffness. The stiffness further decreased to 8 percent of the initial stiffness after the superstructure had been isolated from the abutments. The University of Washington (UW), California Department of Transportation (CALTRANS) and WSDOT models underestimated the stiffness of the bridge in its initial state. The UW model probably overestimated the resistance of the polystyrene at the abutments and underestimated the stiffness of the soil at the wingwalls. The CALTRANS model was too flexible because it neglected the resistance of the bearing pads and polysterene, and underestimated the soil stiffness. The researchers concluded that (1) the test can serve as a valuable benchmark against which to evaluate proposed seismic-evaluation procedures and models, (2) bridges that are similar to the test bridge are not highly vulnerable to transverse motions, (3) complex soil modeling is not justified if soil test data are not available, and (4) nonlinear analysis was necessary to reproduce the details of the observed response.
Authors:
Eberhard,M. O., MacLardy,J. A., Marsh,M. L., Hjartarson,G.
Keywords:
bridge and construction, bridge, earthquake, reinforced concrete, tests, modeling, lateral loads
This study was part of a Washington State Department of Transportation (WSDOT) program to assess the vulnerability of highway bridges built before 1984. Researchers applied slowly-varying transverse loads to a three-span, reinforced concrete bridge, including the superstructure, piers, and abutments. The purpose of the test was to measure the transverse stiffness of the bridge and to estimate each support's contribution to stiffness. The researchers also evaluated analytical models by comparing the calculated and observed responses. The bridge was extremely stiff and strong. In two cycles to a load equal to 45 percent of the bridge's weight, the maximum bridge displacement was 0.15 inch. During these cycles damage was minimal. At a load equal to 65 percent of the bridge's weight, the pier displacement was 0.30 inch. After the bridge had been excavated, the stiffness decreased to 15 percent of its original stiffness. The stiffness further decreased to 8 percent of the initial stiffness after the superstructure had been isolated from the abutments. The University of Washington (UW), California Department of Transportation (CALTRANS) and WSDOT models underestimated the stiffness of the bridge in its initial state. The UW model probably overestimated the resistance of the polystyrene at the abutments and underestimated the stiffness of the soil at the wingwalls. The CALTRANS model was too flexible because it neglected the resistance of the bearing pads and polysterene, and underestimated the soil stiffness. The researchers concluded that (1) the test can serve as a valuable benchmark against which to evaluate proposed seismic-evaluation procedures and models, (2) bridges that are similar to the test bridge are not highly vulnerable to transverse motions, (3) complex soil modeling is not justified if soil test data are not available, and (4) nonlinear analysis was necessary to reproduce the details of the observed response.
Authors:
Eberhard,M. O., MacLardy,J. A., Marsh,M. L., Hjartarson,G.
Keywords:
bridge and construction, bridge, earthquake, reinforced concrete, tests, modeling, lateral loads
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| Brown,C. | WA-RD 265.1 | Preliminary Investigation of the Seismic Vulnerability of the Alaskan Way Viaduct | 1992 |
Abstract:
The University of Washington (UW) team reviewed the Washington State Department of Transportation (WSDOT) report titled 'Earthquake Analyses of the Alaskan Way Viaduct' and performed an independent assessment of two typical sections of the structure. Additional analyses were performed to investigate the influence of some factors that were not considered in the WSDOT report. The input motion and geotechnical characteristics assumed in the WSDOT report were consistent with the information available to the WSDOT and the UW. However, the paucity of information available regarding the seismological risk and the subsoil conditions precluded the possibility of reliability estimating the input motion, foundations stiffness, foundation capacities, and potential for liquefaction. Inspection of the structural plans suggested that timber-concrete spliced piles in the section of the structure built by WSDOT might be particularly vulnerable. The elastic dynamic models generated by WSDOT and those constructed for this study were found to give comparable natural periods in the first three modes. Those in the higher modes differed because of the disparate ways in which the structures were modeled. However, the higher modes provided only a small portion of the total response, so the differences in calculated response were small. For the WSDOT designed part of the structure, g-ratings and dynamic code ratios were established by assuming that the reinforcement would reach its yield strength. The present study found the structure to be generally weaker than did the WSDOT study. Some of the ratings showed a consistent relationship with those given by the WSDOT study, while others showed considerable scatter. Regardless of the resolution of the discrepancies, both analyses indicated that the demands on structural members would be likely to greatly exceed their capacities. The main shortcomings in the structure appeared to be inadequate confinement steel and development lengths that were too short. Because no distress was observed after the 1965 Seattle earthquake, these calculations are undoubtedly conservative. However, the response of those brittle details cannot be predicted reliably without further investigation. The University of Washington team is proposing further study to verify seismic safety of the structure.
Authors:
Brown,C., Eberhard,M. O., Kramer,S. L., Roeder,C. W., Stanton,J. F.
Keywords:
bridge, reinforced concrete, earthquake, foundation
The University of Washington (UW) team reviewed the Washington State Department of Transportation (WSDOT) report titled 'Earthquake Analyses of the Alaskan Way Viaduct' and performed an independent assessment of two typical sections of the structure. Additional analyses were performed to investigate the influence of some factors that were not considered in the WSDOT report. The input motion and geotechnical characteristics assumed in the WSDOT report were consistent with the information available to the WSDOT and the UW. However, the paucity of information available regarding the seismological risk and the subsoil conditions precluded the possibility of reliability estimating the input motion, foundations stiffness, foundation capacities, and potential for liquefaction. Inspection of the structural plans suggested that timber-concrete spliced piles in the section of the structure built by WSDOT might be particularly vulnerable. The elastic dynamic models generated by WSDOT and those constructed for this study were found to give comparable natural periods in the first three modes. Those in the higher modes differed because of the disparate ways in which the structures were modeled. However, the higher modes provided only a small portion of the total response, so the differences in calculated response were small. For the WSDOT designed part of the structure, g-ratings and dynamic code ratios were established by assuming that the reinforcement would reach its yield strength. The present study found the structure to be generally weaker than did the WSDOT study. Some of the ratings showed a consistent relationship with those given by the WSDOT study, while others showed considerable scatter. Regardless of the resolution of the discrepancies, both analyses indicated that the demands on structural members would be likely to greatly exceed their capacities. The main shortcomings in the structure appeared to be inadequate confinement steel and development lengths that were too short. Because no distress was observed after the 1965 Seattle earthquake, these calculations are undoubtedly conservative. However, the response of those brittle details cannot be predicted reliably without further investigation. The University of Washington team is proposing further study to verify seismic safety of the structure.
Authors:
Brown,C., Eberhard,M. O., Kramer,S. L., Roeder,C. W., Stanton,J. F.
Keywords:
bridge, reinforced concrete, earthquake, foundation
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| Babaei,K. | WA-RD 217.1 | Bridge Seismic Retrofit Planning Program | 1991 |
Abstract:
This report documents a study that determined the effectiveness and cost of both previously used and proposed bridge superstructure seismic retrofit methods, including longitudinal joint restraining, transverse bearing restraining, bearing seat extension, replacement of vulnerable bearings with conventional bearings, and replacement with base isolation bearings. In addition, a procedure was developed for systematically prioritizing the state's bridges for seismic retrofitting on the basis of their importance as lifelines and their vulnerability to collapse.
Authors:
Babaei,K., Hawkins,N. M.
Keywords:
bridge and construction, bridge, earthquake, retrofitting, superstructure, prioritizing, costs
This report documents a study that determined the effectiveness and cost of both previously used and proposed bridge superstructure seismic retrofit methods, including longitudinal joint restraining, transverse bearing restraining, bearing seat extension, replacement of vulnerable bearings with conventional bearings, and replacement with base isolation bearings. In addition, a procedure was developed for systematically prioritizing the state's bridges for seismic retrofitting on the basis of their importance as lifelines and their vulnerability to collapse.
Authors:
Babaei,K., Hawkins,N. M.
Keywords:
bridge and construction, bridge, earthquake, retrofitting, superstructure, prioritizing, costs
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| Tsiatas,G. | WA-RD 233.1 | Design Response Spectra for Washington State Bridges | 1989 |
Abstract:
This report presents site-dependent design response spectra which account for the effects of the soils and earthquakes that occur in Washington State. A base spectrum and soil amplification spectra are developed that are correlated with a mapped severity coefficient. The base spectrum is selected with consideration given to the special characteristics of the subduction zone earthquakes likely to occur in this area. The computer program SHAKE is used to develop the soil amplification spectra. Soil profiles from 123 boring logs from actual bridge sites in Washington are used in this research. The results are intended to replace corresponding sections of currently used AASHTO guidelines.
Authors:
Tsiatas,G., Fragaszy,R. J., Ho,C., Kornher,K.
Keywords:
response spectrum, seismic design, earthquake
This report presents site-dependent design response spectra which account for the effects of the soils and earthquakes that occur in Washington State. A base spectrum and soil amplification spectra are developed that are correlated with a mapped severity coefficient. The base spectrum is selected with consideration given to the special characteristics of the subduction zone earthquakes likely to occur in this area. The computer program SHAKE is used to develop the soil amplification spectra. Soil profiles from 123 boring logs from actual bridge sites in Washington are used in this research. The results are intended to replace corresponding sections of currently used AASHTO guidelines.
Authors:
Tsiatas,G., Fragaszy,R. J., Ho,C., Kornher,K.
Keywords:
response spectrum, seismic design, earthquake
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| Stanton,J. F. | WA-RD 158.1 | Shaking Table Tests on Piles | 1988 |
Abstract:
This research was undertaken to explore the interaction behavior of soil-pile systems subjected to static and dynamic lateral loads. The principal objective of the study was to access the applicability and accuracy of one of the prominent methods of analysis by comparing the predicted responses with the measured responses. Presented in this report are a brief survey of the related literature on the existing analysis techniques and previous experimental studies, the details of the experimental work performed under the current study, and the appraisal of the performance of a finite element program adopted for making theoretical predictions of the experimental responses.In the present study, both static and dynamic experiments were conducted to obtain experimental data against which the analytical predictions could be verified. The experiments included laboratory simulation of the response of piles subjected to static and dynamic lateral loads applied at the pile-head and of piles embedded in a soil deposit subjected to bedrock motions. Finite element analyses of the model systems were carried out using reasonable estimates of the system parameters. No attempts were made to establish the model parameters through rigorous identification procedures. It is shown that the agreement between the predicted and measured responses can be excellent even of the properties and parameters of the soil-pile system are only roughly estimated.
Authors:
Stanton,J. F., Banerjee,S., Izzat,H.
Keywords:
piless, shaking table, lateral loads, seismic behavior, earthquake, earthquake simulator, dynamic load test, bridge and construction
This research was undertaken to explore the interaction behavior of soil-pile systems subjected to static and dynamic lateral loads. The principal objective of the study was to access the applicability and accuracy of one of the prominent methods of analysis by comparing the predicted responses with the measured responses. Presented in this report are a brief survey of the related literature on the existing analysis techniques and previous experimental studies, the details of the experimental work performed under the current study, and the appraisal of the performance of a finite element program adopted for making theoretical predictions of the experimental responses.In the present study, both static and dynamic experiments were conducted to obtain experimental data against which the analytical predictions could be verified. The experiments included laboratory simulation of the response of piles subjected to static and dynamic lateral loads applied at the pile-head and of piles embedded in a soil deposit subjected to bedrock motions. Finite element analyses of the model systems were carried out using reasonable estimates of the system parameters. No attempts were made to establish the model parameters through rigorous identification procedures. It is shown that the agreement between the predicted and measured responses can be excellent even of the properties and parameters of the soil-pile system are only roughly estimated.
Authors:
Stanton,J. F., Banerjee,S., Izzat,H.
Keywords:
piless, shaking table, lateral loads, seismic behavior, earthquake, earthquake simulator, dynamic load test, bridge and construction
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| Fragaszy,R. J. | WA-RD 138.1 | Seismic Response of Tieback Retaining Walls, Phase I | 1987 |
Abstract:
The current design practice used by WSDOT for the design of permanent tieback walls is to assume that the static design of a tieback wall retaining clayey soils provides an adequate reserve of strength to prevent failure during seismic loading. This design procedure is based largely on the assumption that the soil and the wall move together ground shaking and that significant loads are not produced. For tieback walls retaining sandy soils, it is assumed that dynamic loads are produced. Mononobe-Okabe dynamic soil pressures are added to the design pressure to account for the dynamic load. The validity of these assumptions and the resultant design practices is evaluated in this study. A pilot numerical study was conducted on a forty foot high wall with three levels of tiebacks using the program FLUSH. It was found that the wall and the soil tend to move in-phase and only negligible dynamic tie forces are generated. However, the soil above and below the excavation level tends to move out-of-phase, leading to significant dynamic pressures and bending moments in the wall and near the excavation level. It appears that in least some cases, tieback walls with an adequate static safety factor may suffer significant damage or fail during seismic loading and that the use of Mononobe-Okabe dynamic pressures may be conservative.
Authors:
Fragaszy,R. J., Denby,G., Higgins,J. D., Ali,Nmjad
Keywords:
account, bending, damage, design, earthquake, forces, loads, pressure, program, retaining wall, retaining walls, safety, Sandy soils, seismic, seismic loading, seismic response, soil, soil pressure, strength, Tieback Walls, tiebacks, walls, WSDOT
The current design practice used by WSDOT for the design of permanent tieback walls is to assume that the static design of a tieback wall retaining clayey soils provides an adequate reserve of strength to prevent failure during seismic loading. This design procedure is based largely on the assumption that the soil and the wall move together ground shaking and that significant loads are not produced. For tieback walls retaining sandy soils, it is assumed that dynamic loads are produced. Mononobe-Okabe dynamic soil pressures are added to the design pressure to account for the dynamic load. The validity of these assumptions and the resultant design practices is evaluated in this study. A pilot numerical study was conducted on a forty foot high wall with three levels of tiebacks using the program FLUSH. It was found that the wall and the soil tend to move in-phase and only negligible dynamic tie forces are generated. However, the soil above and below the excavation level tends to move out-of-phase, leading to significant dynamic pressures and bending moments in the wall and near the excavation level. It appears that in least some cases, tieback walls with an adequate static safety factor may suffer significant damage or fail during seismic loading and that the use of Mononobe-Okabe dynamic pressures may be conservative.
Authors:
Fragaszy,R. J., Denby,G., Higgins,J. D., Ali,Nmjad
Keywords:
account, bending, damage, design, earthquake, forces, loads, pressure, program, retaining wall, retaining walls, safety, Sandy soils, seismic, seismic loading, seismic response, soil, soil pressure, strength, Tieback Walls, tiebacks, walls, WSDOT
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| Kramer,S. L. | WA-RD 079.1 | Pavement Management System: Demonstration for Washington Counties | 1986 |
Abstract:
The pavement management system developed by the State of Washington was modified to meet the needs of the counties in the State of Washington within the constraints of available data and resources. The modified system, called the Washington County Pavement Management System (WCPMS), was tested for Thurston and Benton counties. Results of this testing show that; (1) The WCPMS can be operated using the existing data in the county road log in combination with collected pavement condition survey data; (2) computer resources are available to most counties to access the State computer to execute the various programs in the WCPMS; and (3) routine usage of the WCPMS for a network of 1000 miles will require a level of effort of about 150 person-days and a computer cost of $1,000.
Authors:
Kramer,S. L., Sivaneswaran,N., Tucker,K., Kulkarni,R. B., Finn,F. N.
Keywords:
bridge, design, hinge, earthquake, evaluation restrainers, pavement management, pavement management systems, counties
The pavement management system developed by the State of Washington was modified to meet the needs of the counties in the State of Washington within the constraints of available data and resources. The modified system, called the Washington County Pavement Management System (WCPMS), was tested for Thurston and Benton counties. Results of this testing show that; (1) The WCPMS can be operated using the existing data in the county road log in combination with collected pavement condition survey data; (2) computer resources are available to most counties to access the State computer to execute the various programs in the WCPMS; and (3) routine usage of the WCPMS for a network of 1000 miles will require a level of effort of about 150 person-days and a computer cost of $1,000.
Authors:
Kramer,S. L., Sivaneswaran,N., Tucker,K., Kulkarni,R. B., Finn,F. N.
Keywords:
bridge, design, hinge, earthquake, evaluation restrainers, pavement management, pavement management systems, counties
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