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Seismic Vulnerability Analysis Of Bridges In Mountainous States
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Book Synopsis Seismic Vulnerability Analysis of Bridges in Mountainous States by : Matt Hardman
Download or read book Seismic Vulnerability Analysis of Bridges in Mountainous States written by Matt Hardman and published by . This book was released on 2013 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Depending on the location, highway bridges can often support considerable amounts of traffic. Due to the limitations on current earthquake forecasting techniques, a normal amount of traffic will also typically remain on a bridge when an earthquake occurs. In addition to traffic, scour effects are also a potential hazard to bridge piers that may simultaneously impact the structural integrity of the bridge together with seismic loads. Although a few studies investigating the combined effect of extreme and service loads have been conducted on long-span bridges or in high-seismic zones, the studies on typical short- and medium-span bridges in low and moderate seismic zones are rare. A general dynamic simulation methodology is introduced to study the combined realistic service and extreme loads on short- and medium-span bridges. Following the introduction of the methodology, a numerical study investigating the seismic performance of a typical highway bridge in mountainous states is carried out. The bridge is subjected to different combinations of traffic, seismic, and scour and the effects on the structural performance of the bridge are investigated. The bridge, including both superstructure and substructure, is modeled in detail using SAP2000 to accommodate the goals of this study. The traffic load is considered through dynamic interaction analysis of vehicles in the simulated stochastic traffic flow. Through studying the bridge performance under various combined extreme and service loads, findings are made about controlling cases for different bridge responses and the validity of the traditional superposition approach with consideration to load combinations is also discussed. As the initial effort studied the bridge performance under multiple service and extreme loads, this study sheds some light on more comprehensive studies for the future.
Book Synopsis Transportation Infrastructure by : United States. General Accounting Office
Download or read book Transportation Infrastructure written by United States. General Accounting Office and published by . This book was released on 1992 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Seismic Vulnerability of New Highway Construction by :
Download or read book Seismic Vulnerability of New Highway Construction written by and published by . This book was released on 2002 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: This executive summary gives an overview of the results of FHWA Contract DTFH61 92 C 00112, Seismic Research Program, which performed a series of special studies addressing the seismic design of new construction. The objectives of this project were to perform a series of special studies pertaining to the seismic vulnerability of highway structures, and to develop technical information on which future specifications for the seismic design of bridges could be based. This project divided work into 5 areas and 13 tasks, focusing on the following elements: review of current seismic design criteria, the seismic hazard exposure of the American highway system, foundation design and soil behavior, structural design, structural analysis and response, the relative importance of specific bridges and an assessment of the impact of current and recently completed research. The Seismic Research Program had a national focus, and aimed in part to address the differences in seismicity, bridge types, and typical design details between the central and eastern United States (CEUS) and those previously studied in California and the western United States. In many cases, west coast design practices required considerable modification before implementation in the CEUS. The project resulted in 34 research reports, of which 31 are summarized in this document. Seventeen of the reports have been published as National Center for Earthquake Engineering Research (NCEER) or Multidisciplinary Center for Earthquake Engineering Research (MCEER) reports. The research agencies final reports for the other taks are available from MCEER upon request.
Download or read book Transportation Infrastructure written by and published by DIANE Publishing. This book was released on 1993-07 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focuses on threats that earthquakes pose to the nation1s bridges.
Book Synopsis Seismic Vulnerability Analysis of SR 97/420 Columbia River Bridge, Bebee, Washington by : EQE Engineering Consultants
Download or read book Seismic Vulnerability Analysis of SR 97/420 Columbia River Bridge, Bebee, Washington written by EQE Engineering Consultants and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Quantifying the Seismic Vulnerability of Bridges in Low to Moderate Seismicity Regions by : John Edward Lens
Download or read book Quantifying the Seismic Vulnerability of Bridges in Low to Moderate Seismicity Regions written by John Edward Lens and published by . This book was released on 2019 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Congressional Research Service issued a report for Congress in May 2016, entitled "Earthquake Risk and U.S. Highway Infrastructure: Frequently Asked Questions" which highlighted the absence of a national database on the status of seismic vulnerability of bridges or other infrastructure, and thus no estimate of costs to retrofit vulnerable bridges. Low to moderate seismicity regions exist in each of the continental United States, with over 30 states having mostly or entirely low-to-moderate seismicity. Resources at state transportation agencies and municipalities are focused on higher seismicity regions, creating a gap in quantifying the system-wide seismic vulnerability despite an overall aging bridge inventory, much of which was built before current seismic design standards. This research addressed this data gap and reduces barriers to quantifying seismic vulnerability of existing bridges in low-to-moderate seismicity regions. The work included nonlinear dynamic numerical modeling of typical multiple span bridge configurations in both pristine and deteriorated conditions, by subjecting them to seventy ground motions across four low-to-moderate seismic hazard levels, to evaluate their seismic performance. These typical bridge configurations represent over 160,000 bridges, which comprise 55% of the multiple span bridges nationwide. The research results indicate that there is an overall low probability of significant seismic damage to these typical bridges in such regions. The results also show that current seismic hazard thresholds used for the design of new bridges, and for retrofit of existing bridges, which provide the basis for exempting some bridges from specific seismic analysis and design, can underestimate the expected seismic forces. Those results can be used to refine those exemption thresholds to provide appropriate protection against potential seismic damage in those cases. The study results also formed the basis for a system-wide rapid seismic vulnerability screening algorithm developed for the Vermont bridge inventory, which is applicable to other states with low to moderate seismicity regions.
Book Synopsis Seismic Vulnerability Analysis of WSDOT Bridges, Aberdeen, Washington by : EQE Engineering Consultants
Download or read book Seismic Vulnerability Analysis of WSDOT Bridges, Aberdeen, Washington written by EQE Engineering Consultants and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Seismic Vulnerability Analysis of Scoured Bridge Systems by : Xuan Guo
Download or read book Seismic Vulnerability Analysis of Scoured Bridge Systems written by Xuan Guo and published by . This book was released on 2014 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridges are a vital infrastructure component of the transportation networks in both rural and urban areas. Damaged or destroyed bridges can affect the reliability and resilience of transportation networks that are critical to human life, economical activities, and the social sustainability at large. Understanding how natural hazards affect the life-cycle performance of bridge systems will lead to improved preparedness prior to extreme disasters and benefit the society ultimately. Among many natural events, flood-induced foundation scour has been recognized as a leading cause of bridge failure in the United States. The distinct feature of flood-induced scour is that it may last during the rest of bridge's service life once it is formed around a bridge foundation. Intuitively, the threat may be potentially more severe if the permanent scour is combined with other hazards, such as earthquakes. However, the combined effects of such multiple hazards are not clearly understood to date. It is thus meaningful to investigate the effects of multi-hazard earthquake and scour on the seismic performance of river-crossing bridges. The general objective of this dissertation is to assess the seismic vulnerability of bridge structures considering flooding-induced scour in a general multi-hazard context. To meet this objective, five related research problems are defined in this dissertation. Correspondingly, scientific answers and technical solution frameworks are developed in this dissertation. The dissertation directly contributes to the multi-hazard assessment methodology with an emphasis in flood-induced scour and earthquake hazards. Specifically, the dissertation directly resolves the practical challenge of evaluating the effects of bridge scour on the seismic performance of river-crossing bridges in terms of theoretical frameworks, numerical procedures, and case study-based findings. Future research directions along the line of multi-hazard bridge performance research with an emphasis of hydro- and seismic-impacts are pointed at the end of the dissertation.
Book Synopsis Seismic Vulnerability and Retrofit Recommendations for State Highway Bridges by : Abdollah Shafieezadeh
Download or read book Seismic Vulnerability and Retrofit Recommendations for State Highway Bridges written by Abdollah Shafieezadeh and published by . This book was released on 2009 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of Utah's population dwells in a seismically active region, and many of the bridges connecting transportation lifelines predate the rigorous seismic design standards that have been developed in the past 10-20 years. Other states in the west have instituted seismic retrofit programs in response to damage to transportation networks in past California earthquakes. In a parallel report, seismic retrofit guidelines were developed for Utah based on the Seismic Retrofitting Manual for Highway Structures published by FHWA. In this report, representative case study bridges are evaluated in detail using the guidelines. The case study evaluations include the following for each bridge: 1- selection and presentation of analysis method, 2- development of numerical model in LARSA 4D and/or additional programs as needed, 3- evaluation of the seismic response of the unretrofitted bridge, 4- design of a possible retrofit scheme. The bridges evaluated include a four-span simply supported prestressed concrete girder bridge, a four-span continuous concrete T-beam, and an eight-span curved steel girder bridge with in-span pin and hanger joints.
Book Synopsis Ambient and Seismic Vulnerability Analysis of a Steel Deck Truss Bridge by : Sungyeop Jung
Download or read book Ambient and Seismic Vulnerability Analysis of a Steel Deck Truss Bridge written by Sungyeop Jung and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Seismic Vulnerability Assessment and Retrofit Recommendations for State Highway Bridges by :
Download or read book Seismic Vulnerability Assessment and Retrofit Recommendations for State Highway Bridges written by and published by . This book was released on 2009 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of Utah's population dwells in a seismically active region, and many of the bridges connecting transportation lifelines predate the rigorous seismic design standards that have been developed in the past 10-20 years. Other states in the west have instituted seismic retrofit programs in response to damage to transportation networks in past California earthquakes. In a parallel report, seismic retrofit guidelines were developed for Utah based on the Seismic Retrofitting Manual for Highway Structures published by FHWA. In this report, representative case study bridges are evaluated in detail using the guidelines. The case study evaluations include the following for each bridge: (1) selection and presentation of analysis method, (2) development of numerical model in LARSA 4D and/or additional programs as needed, (3) evaluation of the seismic response of the unretrofitted bridge, (4) design of a possible retrofit scheme. The bridges evaluated include a four-span simply supported prestressed concrete girder bridge, a four-span continuous concrete T-beam, and an eight-span curved steel girder bridge with in-span pin and hanger joints. A variety of different evaluation methods are presented including linear response spectrum analysis for demand assessment, capacity spectrum method and pushover analysis for capacity assessment, and nonlinear response history analysis. A variety of retrofit techniques are presented including column jacketing, cable restrainers, selectively closing pin and hanger joints, and seismic isolation. The varied examples and techniques presented in this report are meant to be representative of assessment and applicable retrofit approaches for many of the bridges in the state inventory that may be seismically deficient.
Book Synopsis Seismic Vulnerability Assessment of Bridges for Retrofitting and New Design by : Pedram Farokh
Download or read book Seismic Vulnerability Assessment of Bridges for Retrofitting and New Design written by Pedram Farokh and published by . This book was released on 2017 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many bridges in North Eastern region of U.S. were designed prior to the adoption of the AASHTO LRFD Guide Specifications for seismic design and may be vulnerable to damage during an earthquake event. This study evaluates the seismic vulnerabilities of those bridges and the structural factors that could affect their performance during a seismic event. The effects of load demands and age deteriorations were also studied. Aging of certain bridge components such as bearings, columns, and bent caps can affect the capacity and demands of these components and accordingly might affect the global behavior and capacity of a bridge during an earthquake event. The concept of fragility curves was studied as a potential tool for evaluating the seismic performance of new bridges, existing bridges and retrofitted bridges for various bridge types subjected to different peak ground acceleration levels. Fragility curves represent the probability of a structure to experience damage levels higher than specific damage state at different peak ground acceleration. Possible retrofit measures for various bridge components were reviewed, and analyzed for their effectiveness. These include superstructure restrainers, stoppers, shear keys, isolation bearings, bent cap strengthening and column jacketing. Existing research shows that the concept of fragility curves can be used to identify bridge vulnerability and level of damage. They can also be used to identify performance and level of damage of various retrofit measures. The effect of aging of certain components such as stiffening and locking of bearings and corrosion of confining steel in columns need to be included when evaluating bridge load demands and capacities. Different types of concrete bridges (typical in North Eastern United States) were analyzed using elastic response spectrum and nonlinear push-over analysis for low, medium-to-high, and high seismicity levels. The effects of pier configuration, continuity between the superstructure and the substructure, and the number of spans were investigated. Analysis results showed that in the longitudinal direction, the displacement demand increased for multi-column bents compared to single-column bents. However, the overall D/C ratio dropped in both transverse and longitudinal directions. The results also showed that in the longitudinal direction the benefit of having multi-column bent over single-column bents in integral bridges is dependent on the seismicity levels. The D/C (demand/capacity) ratio for single column bents in the longitudinal direction was much lower for integral (monolithic) bents compared to non-integral bents. In the transverse directions, the difference in the D/C ratio was not significant. For multi-column bents, the percent change by having integral bents over non-integral bents was dependent on the seismicity levels. For high seismicity zones, the benefits of having Integral bents becomes more significant. This investigation presents guidance on incorporating the effects of aging and retrofitting in the finite element modeling of bridges subjected to various levels of earthquake ground motions.
Book Synopsis Seismic Vulnerability of Timber Bridges and Timber Substructures by :
Download or read book Seismic Vulnerability of Timber Bridges and Timber Substructures written by and published by . This book was released on 2007 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Seismic Risk Assessment of Bridges in Clark County, Nevada by : David Bingham Porter
Download or read book Seismic Risk Assessment of Bridges in Clark County, Nevada written by David Bingham Porter and published by . This book was released on 2006 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridges are a vital connective element in a community's transportation system. In the past, bridges have been severely damaged by earthquakes, but with proper mitigation techniques, such as bridge retrofit, severe earthquake damage to bridges can be avoided. The objective of this project was to perform a seismic risk assessment on bridges in Clark County, Nevada. A seismic risk analysis is the first step to effectively plan for an earthquake. A risk analysis identifies bridges that could be potentially hazardous to the public. There are two key elements of a risk analysis: the importance assessment and the vulnerability assessment. The importance assessment takes into account the number of people that will be affected by a damaged bridge. It considers both immediate and long-term effects of an earthquake. A spreadsheet-type analysis was performed to assess bridge importance. Bridge characteristics such as average daily traffic, detour length, pedestrian traffic, railroad traffic, historical significance, and defense route were used in the analysis. The vulnerability assessment takes into account the behavior of a bridge during an earthquake (i.e., how much damage a bridge is expected to sustain). A GIS-based software called HAZUS-MH was used to analyze the bridges in Clark County. HAZUS-MH takes into account parameters such as bridge material, construction type, skew angle, soil type, and liquefaction potential. The results from the importance assessment, vulnerability assessment, and overall risk analysis can be used to assist pre- and post-earthquake planning organizations in mitigation and preparation efforts for future earthquakes.
Book Synopsis Seismic Vulnerability of Oregon State Highway Bridges by :
Download or read book Seismic Vulnerability of Oregon State Highway Bridges written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Earthquake Risk Assessment of Reinforced Concrete Bridges in Washington State Using Pushover Analysis by : Abigail B. Christman
Download or read book Earthquake Risk Assessment of Reinforced Concrete Bridges in Washington State Using Pushover Analysis written by Abigail B. Christman and published by . This book was released on 2017 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: The average age of reinforced concrete bridges in the state of Washington is 48 years, encompassing more than 100 years of design and construction techniques, which reflect evolving views on seismic risk and mitigation. As such, there is great uncertainty as to the actual seismic resistance of existing bridges. Having a simple and accurate process for assessing the seismic vulnerability of a bridge can help identify vulnerable design details and address them, either through retrofit or replacement. Using pushover analysis to determine the seismic capacity of structures can give an idea of the overall vulnerability of the structure while decreasing the computational power needed to perform analyses as compared to nonlinear time history (NLTH) analysis. Using the finite element program RUAUMOKO-2D, models of existing WSDOT bridges were created and pushover analyses were run. By defining damage states of interest and determining the associated displacement profiles, peak ground accelerations (PGAs) of seismic events were then correlated to the damage states. By combining fragility curves encompassing the probabilistic distribution of the PGA at which a damage state might occur with site hazard risks, Risk Indices were calculated for all bridges considered. The bridges were ranked in order to contextualize the Risk Index values. The results of the assessment process were then verified by comparing them to the results of NLTH analysis.
Book Synopsis Seismic Vulnerability of Bridges in Oregon Highway Network by : Selamawit Tesfayesus Mehary
Download or read book Seismic Vulnerability of Bridges in Oregon Highway Network written by Selamawit Tesfayesus Mehary and published by . This book was released on 2010 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
