Field Testing of the Wolf Creek Curved Girder Bridge
Field Testing of the Wolf Creek Curved Girder Bridge

Author: Robert S. Turnage

Publisher:

Published: 2009

Total Pages: 64

ISBN-13:

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The Wolf Creek Bridge is a curved, multi-girder three span steel composite bridge located south of Narrows, Virginia, that was completed in 2006. A finite element model of the bridge revealed that pier flexibility may be important in modeling the bridge. In addition, questions have been raised as to the effectiveness of the C15x33 diaphragms in providing lateral transfer of loads between members. This study was conducted as Phase I of a project for which the overall goal was to use field testing to obtain a better understanding of the behavior of multi-span curved girder bridges. An array of vertically oriented accelerometers was located along the inner and outer edges of the bridge, along with radially oriented accelerometers along the outer edge, a tangentially oriented accelerometer on the outer edge, and an additional vertical accelerometer placed in the middle of the center span. Dynamic response data were collected under a variety of excitations, including sinusoidal forcing induced by an electro-dynamic shaker, impulse loadings at various locations, and several different vehicular loads. The dynamic data were transformed into the frequency domain and analyzed using a simple frequency domain algorithm to extract vibration frequencies and mode shapes. The resulting frequencies and mode shapes were compared with the existing finite element model. The findings indicated that not only is pier flexibility important, as had been hypothesized, but also that end constraints imposed by highway guardrails change both the natural frequencies and the mode shapes in ways that had not been anticipated. Frequencies of modes with strong pier participation and modes with strong transverse (hogging) components were lower than predicted by the computer model, suggesting that pier stiffness may be less than the model predicted and that transverse stiffness, to which the diaphragms contribute, may also be estimated. Implications of this study could have a significant effect on future health monitoring applications as they pertain to both curved and straight girder bridges. It is essential that finite element models in such long-term applications be able to reproduce the "as-built" response characteristics of a bridge. The current study raised significant issues about the ability to model the behavior of curved girder bridges correctly. Thus, it will be important to perform subsequent numerical research studies to develop models that will result in more precise predictions and to use these and other methods being developed in any health monitoring applications.

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.

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.

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.