Dynamic Analysis and Testing of a Curved Girder Bridge
Dynamic Analysis and Testing of a Curved Girder Bridge

Author: Matthew R. Tilley

Publisher:

Published: 2006

Total Pages: 38

ISBN-13:

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As a result of increasing highway construction and expansion, a corresponding need to increase traffic capacity in heavily populated areas, and ever-increasing constraints on available land for transportation use, there has been an increasing demand for alignment geometries and bridge configurations that result in more efficient use of available space. As a result of this demand, there has been a steady increase in the use of curved girder bridges over the past 30 years. Despites extensive research relating to the behavior of these types of structures, a thorough understanding of curved girder bridge response, especially relating to dynamic behavior, is still incomplete. To develop an improved, rational set of design guidelines, the Federal Highway Administration (FHWA) initiated the Curved Steel Bridge Research Project in 1992. As part of this project, FHWA constructed a full-scale model of a curved steel girder bridge at its Turner-Fairbank Structures Laboratory. This full-scale model made it possible to conduct numerous tests and collect a significant amount of data relating to the static behavior of a curved girder bridge. However, relatively little information has been available on the dynamic response of curved girder bridges and this type of information is needed before a complete design specification can be developed. The objective of this study was to develop a finite element model using SAP2000 that could be used for predicting and evaluating the dynamic response of a curved girder bridge. Models of the FHWA curved girder bridge were developed using both beam and shell elements and response information compared with experimental data and with analytical data from other finite element codes. The experimental data were obtained during dynamic testing of the full-scale bridge in the Turner-Fairbank Structures Laboratory and analytical response information was provided from finite element models of the bridge using ANSYS and ABAQUS. The primary focus of the study was the prediction of frequencies and mode shapes of the full-scale curved girder both with and without a deck. Both experimental and analytical frequencies and mode shapes were calculated and compared. Although the more refined ANSYS and ABAQUS models provided response data that compared more favorably with the experimental data, the SAP2000 models were found to be more than adequate for predicting the lower modes and frequencies of the bridge.

Guidelines for Analysis Methods and Construction Engineering of Curved and Skewed Steel Girder Bridges
Guidelines for Analysis Methods and Construction Engineering of Curved and Skewed Steel Girder Bridges

Author:

Publisher: Transportation Research Board

Published: 2012

Total Pages: 199

ISBN-13: 0309258391

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"TRB's National Cooperative Highway Research Program (NCHRP) Report 725: Guidelines for Analysis Methods and Construction Engineering of Curved and Skewed Steel Girder Bridges offers guidance on the appropriate level of analysis needed to determine the constructability and constructed geometry of curved and skewed steel girder bridges. When appropriate in lieu of a 3D analysis, the guidelines also introduce improvements to 1D and 2D analyses that require little additional computational costs."--Publication information.

Finite Element Analysis of the Wolf Creek Multispan Curved Girder Bridge
Finite Element Analysis of the Wolf Creek Multispan Curved Girder Bridge

Author: John C. Lydzinski

Publisher:

Published: 2008

Total Pages: 64

ISBN-13:

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The use of curved girder bridges in highway construction has grown steadily during the last 40 years. Today, roughly 25% of newly constructed bridges have a curved alignment. Curved girder bridges have numerous complicating geometric features that distinguish them from bridges on a straight alignment. Most notable of these features is that longitudinal bending and torsion do not decouple. Although considerable research has been conducted into curved girder bridges, and many of the fundamental aspects of girder and plate behavior have been explored, further research into the behavior and modeling of these bridges as a whole is warranted. This study developed two finite element models for the Wolf Creek Bridge, a four-plate girder bridge located in Bland County, Virginia. Both models were constructed using plate elements in ANSYS, which permits both beam and plate behavior of the girders to be reproduced. A series of convergence studies were conducted to validate the level of discretization employed in the final model. The first model employs a rigid pier assumption that is common to many design studies. A large finite element model of the bridge piers was constructed to estimate the actual pier stiffness and dynamic characteristics. The pier natural frequencies were found to be in the same range as the lower frequencies, indicating that coupling of pier and superstructure motion is important. A simplified "frame-type" pier model was constructed to approximate the pier stiffness and mass distribution with many fewer degrees of freedom than the original pier model, and this simplified model was introduced into the superstructure model. The resulting bridge model has significantly different natural frequencies and mode shapes than the original rigid pier model. Differences are particularly noticeable in the combined vertical bending/torsion modes, suggesting that accurate models of curved girder bridges should include pier flexibility. The model has been retained for use as a numerical test bed to compare with field vibration data and for subsequent studies on live load distribution in curved girder bridges. The study recommends consideration of the use of the finite element method as an analysis tool in the design of curved girder bridge structures and the incorporation of pier flexibility in the analysis.

Behavior, Design and Construction of Horizontally Curved Composite Steel Box Girder Bridges [microform]
Behavior, Design and Construction of Horizontally Curved Composite Steel Box Girder Bridges [microform]

Author: Muayad Whyib Aldoori

Publisher: Library and Archives Canada = Bibliothèque et Archives Canada

Published: 2004

Total Pages: 538

ISBN-13: 9780612942684

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Horizontally curved girder bridges have been used considerably in recent years in highly congested urban areas. However, although significant research on physical testing and advanced analysis has been underway for the past decade, the practical employment of many recommendations has not been achieved by the engineering community nor have standards reflecting this work been brought into practice. The design process of curved composite bridges involves tracking the stresses and the potential failure change in the girders during erection, construction and service loading stages. For structural safety and serviceability, the designer estimates the stresses induced within the bridge and assure that they do not exceed the applicable specified limit state as required in bridge design standards. However, the designer may be concerned about the level of approximation that is used in his estimate or even the applicability of the underlying theory. To answer this question and provide the designer with more insight into the behavior of the curved bridges, the field testing during construction and service loading of a curved bridge located near Baltimore, Maryland is re-examined here using linear elastic three-dimensional finite element modeling. Comparisons are made between the finite element results and the measured results. Finally, to facilitate the finite element modeling effort for use by a designer, ANSYS Parametric Design Language (APDL) capabilities are used here to develop an analysis/design tool for "Bath-Tub" style curved steel girder bridges. This tool is then used to evaluate the effects of several important design variables on the response and behavior of the girders during the construction phase. This study demonstrates the ability of finite element modeling to assess the stiffness, serviceability performance, buckling behavior and ultimate strength of curved bridges during construction and it is a major step towards a performance based approach to design for stability. The level of safety or reliability that would be available during the erection and the construction processes of horizontally curved girder bridges represents another major concern for the designer. A three span continuous curved box girder bridge in Houston, Texas is used in this study as an example reflecting current detailing and fabricating practice and it is chosen for a detailed evaluation of the structural safety/reliability during the erection and construction process. This task involves simulating the girder erection and concrete slab placement sequence of the bridge using comprehensive nonlinear three dimensional finite element modeling.

Predicting the Behavior of Horizontally Curved I-girders During Construction
Predicting the Behavior of Horizontally Curved I-girders During Construction

Author: Jason Clarence Stith

Publisher:

Published: 2010

Total Pages: 660

ISBN-13:

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The majority of a bridge designer's time is spent ensuring strength and serviceability limit states are satisfied for the completed structure under various dead and live loads. Anecdotally, the profession has done an admirable job designing safe bridges, but engineering the construction process by which bridges get built plays a lesser role in the design offices. The result of this oversight is the complete collapse of a few large bridges as well as numerous other serviceability failures during construction. According to the available literature there have been only a few attempts to monitor a full-scale bridge in the field during the entire construction process. Another challenge for engineers is the lack of analysis tools available which predict the behavior of the bridge during the intermediate construction phases. During construction, partial bracing is present and the boundary conditions can vary significantly from the final bridge configuration. The challenge is magnified for complex bridge geometries such as curved bridges or bridges with skewed supports. To address some of the concerns facing engineers a three span curved steel I-girder bridge was monitored throughout the entire construction process. Field studies collected data on the girder lifting behavior, partially constructed behavior, and concrete deck placement behavior. Additional analytical studies followed using the field measurements to verify the finite element models. Finally, conclusions drawn from the physical and analytical testing were utilized to derive equations that predicted behavior, and analysis tools were developed to provide engineers with solutions to a wide range of construction related problems. This dissertation describes the development of two design tools, UT Lift and UT Bridge. UT Lift is a macro-enabled Excel spreadsheet that predicts the behavior of curved I-girders during lifting. The derivation of the equations necessary to accomplish these calculations and the implementation are described in this dissertation. UT Bridge is a PC-based, user-friendly, 3-D finite element program for I-girder bridges. The basic design philosophy of UT Bridge aims to allow an engineer to take the information readily available in a set of bridge drawings and easily input the necessary information into the program. A straight or curved I-girder bridge with any number of girders or spans can then be analyzed with a robust finite element analysis for either the erection sequence or the concrete deck placement. The development of UT Bridge as well as the necessary element formulations is provided in this dissertation.