Distortion-induced Fatigue Cracking in Steel Bridges PDF Download

Author: John W. Fisher
Publisher: Transportation Research Board
ISBN: 9780309048590
Category : Technology & Engineering
Languages : en
Pages : 60

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Author: National Research Council (U.S.). Transportation Research Board
Publisher:
ISBN:
Category : Girders
Languages : en
Pages : 0

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Author: Transportation Research Board
Publisher:
ISBN:
Category :
Languages : en
Pages : 43

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Author: John W. Fisher
Publisher:
ISBN:
Category : Steel plate deck bridges
Languages : en
Pages : 68

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Book Description

Author: Mark Douglas Bowman
Publisher: Transportation Research Board
ISBN: 030925826X
Category : Technology & Engineering
Languages : en
Pages : 125

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Book Description
"TRB's National Cooperative Highway Research Program (NCHRP) Report 721: Fatigue Evaluation of Steel Bridges provides proposed revisions to Section 7--Fatigue Evaluation of Steel Bridges of the American Association of State Highway and Transportation Officials Manual for Bridge Evaluation with detailed examples of the application of the proposed revisions."--Publisher's description.

Author: Dmitri Jajich
Publisher:
ISBN:
Category : Diaphragms (Structural engineering)
Languages : en
Pages : 296

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Book Description
This report summarizes the findings of a project with the following goals: to implement a field instrumentation and monitoring program for a typical multi-girder steel bridge on skew supports that may be susceptible to web-gap distortion; to assess the frequency and magnitude of the distortional fatigue stresses at the web-stiffener connections; and to evaluate the impact of these stresses on fatigue life. Measurements from 12 independent strain gauges were continuously monitored and recorded for more than three months on Minnesota Department of Transportation (Mn/DOT) bridge #27734. Truck loading tests also were conducted. Predicted web-gap fatigue life based on the long-term monitoring data from Mn/DOT bridge #27734 ranges from 45 to 75 years. Comparison of web-gap stresses with primary design stresses reveals that web-gap distortional stresses are comparatively high. The report also highlights a detailed finite element study to better understand the web-gap stress mechanism and to compare experimental results with theoretical predictions. Study results have important implications for investigators of distortion-induced web-gap fatigue. They indicate that the actual stress at the so-called hotspot may be as much as twice the stress measured at the strain gauge. The report includes a method for estimating girder deflections and web-gap stress.

Author:
Publisher:
ISBN: 9781109386073
Category : Bridges
Languages : en
Pages :

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Distortion induced fatigue is a common problem for aging steel bridges. The distortion creates secondary bending stresses at web gap locations that are not accounted for in design, thereby initiating fatigue cracks. A large number of such distortion-induced fatigue cracks have recently been found on Delaware Bridge 1-501 in Newport, Delaware. This multi box steel tub girder bridge has cracking that has initiated in the weld which connects the web to the internal bracing via connection plates. To investigate this problem, global finite element models of two of the bridge's spans were created. In order to calibrate the models for use in analysis, a diagnostic load test was performed using strain transducers to measure strains associated with bending of the girders. Once the models were found to reasonably represent the actual response of the structure, the model was then refined for local modeling of the web gap region. As expected, stresses within the gap were found to be large. Reduction of the stresses within these gap locations is required to increase the remaining life of the bridge. Several retrofit methods were designed to accomplish this stress reduction, based on effective retrofits used to correct similar problems in the past. These retrofit methods include drilling holes at the crack tips, positively attaching the connection plates to flanges, increasing the length of the web gaps, and removing the diagonal elements in the diaphragms. The retrofits were modeled and analyzed under fatigue loading and the resulting stresses were compared to the original structure. Of these methods, the positive attachment was found to be most effective in reducing the web gap stresses; however, all of the approaches provided significant reductions in the stress range. Recommendations for applying this type of retrofit detail along with the drilling of holes at the end of crack tips are provided.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 448

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Book Description
The goal of this study was to develop and evaluate the performance of retrofit techniques for existing steel bridges that have already sustained damage due to distortion-induced fatigue, or are anticipated to experience distortion-induced fatigue cracking within their design life. A second goal was to evaluate the use of new technologies and materials for repairing distortion-induced fatigue damage in steel bridges. While a number of retrofit techniques exist for repairing distortion-induced fatigue cracking, many of them require partial or full bridge closure to perform the repair. The retrofits developed under this project are intended to be able to be installed with minimal disturbance to traffic. Four primary subject matters are reported on within this document: (1) the development of the "angles-with-plate" distortion-induced fatigue repair; (2) development of fiber reinforced polymer (FRP) repairs for distortion-induced fatigue and in-plane fatigue; (3) development of Piezoelectric Induced Compressive Kinetics (PICK) technology for treatment of crack-arrest holes; and (4) a series of analytical investigations aimed at better understanding distortion-induced fatigue susceptibility of skewed bridge systems.

Author: F. C. Campbell
Publisher: ASM International
ISBN: 1615039767
Category : Technology & Engineering
Languages : en
Pages : 699

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Book Description
"This book emphasizes the physical and practical aspects of fatigue and fracture. It covers mechanical properties of materials, differences between ductile and brittle fractures, fracture mechanics, the basics of fatigue, structural joints, high temperature failures, wear, environmentally-induced failures, and steps in the failure analysis process."--publishers website.

Author: John W. Fisher
Publisher: Wiley-Interscience
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 344

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Book Description
This book provides a detailed review and summary of twenty-two case studies of fracture and fatigue in bridge structures. Its two parts cover cracks formed as a result of low fatigue resistant details, and cracks resulting from unanticipated secondary or displacement induced stresses.