Evaluation and Seismically Isolated Substructure Redesign of a Typical Multi-span Pre-stressed Concrete Girder Highway Bridge

Evaluation and Seismically Isolated Substructure Redesign of a Typical Multi-span Pre-stressed Concrete Girder Highway Bridge PDF Author: Brian D. Richins
Publisher:
ISBN:
Category :
Languages : en
Pages : 145

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Book Description
Seismic considerations greatly influence the lateral and vertical design of a structure, often necessitating larger elements than would otherwise be required. Seismic isolation greatly reduces the demands on a structure due to earthquake loading, allowing the use of smaller, more efficient members and foundations. This case study illustrates the theory and procedure of evaluating the response of a recently built multi-span highway bridge using the most recent (2009) AASHTO code. Based on this response, an equivalent structure was designed to incorporate a seismic isolation system, and the substructure of the isolated bridge redesigned to meet the reduced demands more economically. The reduction in demands was quantified, and the member demands and overall responses of the two designs were compared. An overview of isolator design for the common isolator types available in the United States, with examples specific to the isolated structure that was designed, is also included as an addendum.

Evaluation and Seismically Isolated Substructure Redesign of a Typical Multi-span Pre-stressed Concrete Girder Highway Bridge

Evaluation and Seismically Isolated Substructure Redesign of a Typical Multi-span Pre-stressed Concrete Girder Highway Bridge PDF Author: Brian D. Richins
Publisher:
ISBN:
Category :
Languages : en
Pages : 145

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Book Description
Seismic considerations greatly influence the lateral and vertical design of a structure, often necessitating larger elements than would otherwise be required. Seismic isolation greatly reduces the demands on a structure due to earthquake loading, allowing the use of smaller, more efficient members and foundations. This case study illustrates the theory and procedure of evaluating the response of a recently built multi-span highway bridge using the most recent (2009) AASHTO code. Based on this response, an equivalent structure was designed to incorporate a seismic isolation system, and the substructure of the isolated bridge redesigned to meet the reduced demands more economically. The reduction in demands was quantified, and the member demands and overall responses of the two designs were compared. An overview of isolator design for the common isolator types available in the United States, with examples specific to the isolated structure that was designed, is also included as an addendum.

Design, Analysis, and Seismic Performance of a Hypothetical Seismically Isolated Bridge on Legacy Highway

Design, Analysis, and Seismic Performance of a Hypothetical Seismically Isolated Bridge on Legacy Highway PDF Author: Keri Lynn Ryan
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 208

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Book Description
The need to maintain the functionality of critical transportation lifelines after a large seismic event motivates the strategy to design certain bridges for performance standards beyond the minimum required by bridge design codes. To design a bridge to remain operational, one may stiffen and strengthen the load carrying members to increase the capacity, or alternatively use response modification devices such as seismic isolators to shift the dynamic characteristics of the bridge, henceforth reducing the seismic demands. Seismic isolation systems are attractive because they are directly conducive to accelerated bridge construction techniques. The two strategies are compared for a typical Utah highway bridge, using a three-span, pre-stressed concrete girder bridge that crosses Legacy Highway as a case study example.

Bridge Engineering

Bridge Engineering PDF Author: W.F. Chen
Publisher: CRC Press
ISBN: 1420039784
Category : Technology & Engineering
Languages : en
Pages : 479

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Book Description
Mitigating the effects of earthquakes is crucial to bridge design. With chapters culled from the best-selling Bridge Engineering Handbook, this volume sets forth the principles and applications of seismic design, from the necessary geotechnical and dynamic analysis background to seismic isolation and energy dissipation, active control, and retrofit

An Investigation of the Effectiveness of Existing Bridge Design Methodology in Providing Adequate Structural Resistance to Seismic Disturbances

An Investigation of the Effectiveness of Existing Bridge Design Methodology in Providing Adequate Structural Resistance to Seismic Disturbances PDF Author: United States. Federal Highway Administration. Structures and Applied Mechanics Division
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 56

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Book Description


Advanced Models for Sliding Seismic Isolation and Applications for Typical Multi-span Highway Bridges

Advanced Models for Sliding Seismic Isolation and Applications for Typical Multi-span Highway Bridges PDF Author: Murat Eroz
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages :

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Book Description
The large number of bridge collapses that have occurred in recent earthquakes has exposed the vulnerabilities in existing bridges. One of the emerging tools for protecting bridges from the damaging effects of earthquakes is the use of isolation systems. Seismic isolation is achieved via inserting flexible isolator elements into the bridge that shift the vibration period and increase energy dissipation. To date, the structural performance of bridges incorporating sliding seismic isolation is not well-understood, in part due to the lack of adequate models that can account for the complex behavior of the isolators. This study investigates and makes recommendations on the structural performance of bridges utilizing sliding type seismic isolators, based on the development of state-of-the-art analytical models. Unlike previous models, these models can account simultaneously for the variation in the normal force and friction coefficient, large deformation effects, and the coupling of the vertical and horizontal response during motion. The intention is to provide support for seismic risk mitigation and insight for the analysis and design of seismically isolated bridges by quantifying response characteristics. The level of accuracy required for isolator analytical models used in typical highway bridges are assessed. The comparative viability of the two main isolator types (i.e. sliding and elastomeric) for bridges is investigated. The influence of bridge and sliding isolator design parameters on the system s seismic response is illustrated.

Prestress Losses in Pretensioned High-strength Concrete Bridge Girders

Prestress Losses in Pretensioned High-strength Concrete Bridge Girders PDF Author: Maher K. Tadros
Publisher: Transportation Research Board
ISBN: 030908766X
Category : Technology & Engineering
Languages : en
Pages : 73

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Book Description
"The HCM includes three printed volumes (Volumes 1-3) that can be purchased from the Transportation Research Board in print and electronic formats. Volume 4 is a free online resource that supports the rest of the manual. It includes: Supplemental chapters 25-38, providing additional details of the methodologies described in the Volume 1-3 chapters, example problems, and other resources; A technical reference library providing access to a significant portion of the research supporting HCM methods; Two applications guides demonstrating how the HCM can be applied to planning-level analysis and a variety of traffic operations applications; Interpretations, updates, and errata for the HCM (as they are developed);A discussion forum allowing HCM users to ask questions and collaborate on HCM-related matters; and Notifications of chapter updates, active discussions, and more via an optional e-mail notification feature."--Publisher.

Seismic Assessment and Retrofit of Existing Multi-column Bent Bridges

Seismic Assessment and Retrofit of Existing Multi-column Bent Bridges PDF Author: Cole C. McDaniel
Publisher:
ISBN:
Category : Columns, Concrete
Languages : en
Pages : 76

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Book Description
The main objective of this research was to assess the seismic vulnerability of typical pre-1975 WSDOT prestressed concrete multi-column bent bridges. Additional objectives included determining the influence of soil-structure-interaction on the bridge assessment and evaluating the effects of non-traditional retrofit schemes on the global response of the bridges. Overall this research highlighted the vulnerability of non-monolithic bridge decks and shear-dominating bridge columns in pre-1975 WSDOT prestressed concrete multi-column bent bridges as well as the importance of including soil-structure-interaction, calibrating the force/displacement characterization of the columns to experimental test data and detailed modeling of the bridges such as expansion joint/girder interaction. In the end, the seismic assessment of bridges is a cost/efficiency issue. Each bridge is different, therefore, investing in improved analyses up front will enable an efficient use of the limited funds for bridge improvement, resulting in a significant savings overall.

Performance-based Seismic Bridge Design

Performance-based Seismic Bridge Design PDF Author: M. Lee Marsh
Publisher: Transportation Research Board
ISBN: 0309223806
Category : Technology & Engineering
Languages : en
Pages : 138

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Book Description
"TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 440, Performance-Based Seismic Bridge Design (PBSD) summarizes the current state of knowledge and practice for PBSD. PBSD is the process that links decision making for facility design with seismic input, facility response, and potential facility damage. The goal of PBSD is to provide decision makers and stakeholders with data that will enable them to allocate resources for construction based on levels of desired seismic performance"--Publisher's description.

Seismic Vulnerability Assessment and Retrofit Recommendations for State Highway Bridges

Seismic Vulnerability Assessment and Retrofit Recommendations for State Highway Bridges PDF Author:
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 204

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Book Description
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.

Engineering for Structural Stability in Bridge Construction

Engineering for Structural Stability in Bridge Construction PDF Author: Federal Highway Federal Highway Administration
Publisher:
ISBN:
Category :
Languages : en
Pages : 669

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Book Description
This manual is intended to serve as a reference. It will provide technical information which will enable Manual users to perform the following activities:Describe typical erection practices for girder bridge superstructures and recognize critical construction stagesDiscuss typical practices for evaluating structural stability of girder bridge superstructures during early stages of erection and throughout bridge constructionExplain the basic concepts of stability and why it is important in bridge erection* Explain common techniques for performing advanced stability analysis along with their advantages and limitationsDescribe how differing construction sequences effect superstructure stabilityBe able to select appropriate loads, load combinations, and load factors for use in analyzing superstructure components during constructionBe able to analyze bridge members at various stages of erection* Develop erection plans that are safe and economical, and know what information is required and should be a part of those plansDescribe the differences between local, member and global (system) stability