Enhancement of Welded Steel Bridge Girders Susceptible to Distortion-induced Fatigue PDF Download

Author:
Publisher:
ISBN:
Category : Iron and steel bridges
Languages : en
Pages : 17

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Author: Kasra Ghahremani
Publisher:
ISBN:
Category :
Languages : en
Pages : 134

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This thesis aims to address a number of unanswered questions regarding repair and fatigue design of welded joints in bridges, including developing and evaluating repair methods for enhancing the fatigue behaviour of web stiffeners in steel bridge girders, using local stress-based methods for evaluating the effectiveness of various repair methods and predicting the fatigue life of welded joints, and studying the effectiveness of high frequency mechanical impact (HFMI) treatments under actual in-service loading conditions in the long fatigue life regime. Along with extensive fatigue testing programs and finite element (FE) analyse studies, a strain based fracture mechanics (SBFM) model is used to predict the fatigue behaviour of repaired welds under realistic loading conditions. Through this research, a methodology is developed for generating structural stress design curves for retrofitted highway bridge welds based on small-scale fatigue experiments, relatively simple and inexpensive fatigue tests of smooth specimens, conventional static materials tests, and laboratory measurements. The idea of retrofitting web stiffener ends in steel bridge girders susceptible to distortion-induced fatigue using adhesively-bonded fibre reinforced polymer (FRP) angles is introduced through this research. The proposed retrofit method is relatively cheap and easy to use and does not require deck removal or any other severe modification to the steel girder. Fatigue tests were conducted on specimens designed to model the conditions in the region between a web stiffener and a flange in a steel girder bridge. Fatigue life increases on the order of several hundred percent were achieved by implementing the proposed retrofit. A coarse FE analysis is used to predict the effectiveness of the proposed retrofit methods in terms of the reduction in the structural stress value. A comprehensive variable amplitude (VA) fatigue testing program and analysis was performed to address a number of concerns raised regarding the use of impact treatments for the fatigue enhancement of welds in the high cycle (> 10 million cycles) domain. The test results are then used to evaluate a number of available recommendations for the fatigue design of impact treated welds. The nominal, structural, and effective notch stress approaches are considered. An SBFM model was lastly used to predict the effectiveness of an HFMI treatment applied to welded details. The model is evaluated using the experimental results and found to be capable of predicting the fatigue lives for both the as-welded and impact treated specimens for all of the studied loading conditions. The idea of using the analytical structural stress S-N curves to predict the fatigue behaviour of welded joints with a similar load carrying condition welds was then explored.

Author:
Publisher:
ISBN:
Category : Highway research
Languages : en
Pages : 40

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Author: Mark A. Hurt
Publisher: Butterworth-Heinemann
ISBN: 0128020849
Category : Technology & Engineering
Languages : en
Pages : 350

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Highway Bridge Maintenance Planning and Scheduling provides new tactics for highway departments around the world that are faced with the dilemma of providing improved operations on a shoestring budget. Even after the much needed infrastructure funding is received, the question of which project comes first must be answered. Written by a 20-year veteran with the Kansas Department Of Transportation Bridge Office in design and in maintenance, this book provides Senior Bridge Maintenance Engineers with practical advice on how to create an effective maintenance program that will allow them to not only plan, schedule, direct, and monitor highway bridge repair and rehabilitation projects, but also evaluate all completed work for technical acceptability, productivity, and unit-cost standards. - Provides the tools and methods for building, maintaining, planning, and scheduling effective maintenance - Presents experience-based suggestions for evaluating highway bridges to determine maintenance priorities - Includes methods for evaluating all completed work for technical acceptability, productivity, and unit-cost standards

Author: Jyr-Jong Lee
Publisher:
ISBN:
Category : Girders
Languages : en
Pages : 326

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Author: Wai-Fah Chen
Publisher: CRC Press
ISBN: 1482255030
Category : Technology & Engineering
Languages : en
Pages : 3130

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Over 140 experts, 14 countries, and 89 chapters are represented in the second edition of the Bridge Engineering Handbook. This extensive collection provides detailed information on bridge engineering, and thoroughly explains the concepts and practical applications surrounding the subject, and also highlights bridges from around the world.Published

Author: Wai-Fah Chen
Publisher: CRC Press
ISBN: 1439852332
Category : Technology & Engineering
Languages : en
Pages : 646

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The second edition of this bestselling handbook covers virtually all the information an engineer would need to know about any type of bridge-from planning to construction to maintenance. It contains more than 2,500 tables, charts, and illustrations in a practical, ready-to-use format and an abundance of worked-out examples give readers numerous step-by-step design procedures. Extensively updated and featuring several new chapters, this volume, Construction and Maintenance, covers construction, inspection, bridge management systems, health monitoring, ratings, strengthening and rehabilitation, life cycle analysis and much more.

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

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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: Robert J. Connor
Publisher: Transportation Research Board
ISBN: 0309099374
Category : Transportation
Languages : en
Pages : 140

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Book Description
TRB¿s National Cooperative Highway Research Program (NCHRP) Report 604: Heat-Straightening Repair of Damaged Steel Bridge Girders: Fatigue and Fracture Performance explores limits, based on fatigue and fracture performance, on the number of damage and repair cycles to which damaged steel bridge girders may be subjected using the heat-straightening procedure.