A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Identifying Effective and Ineffective Retrofits for Fatigue Cracking in Steel Bridges using Field Instrumentation
It is estimated that nearly 90% of all fatigue cracking is the result of out-of-plane distortion or other unanticipated secondary stresses at fatigue sensitive details. Interestingly, neither design nor evaluation specifications provide any guidance on how to evaluate the in-service potential for fatigue cracking at these details. Furthermore, the causes and driving forces producing these cracks are typically difficult to accurately characterize using simple design tools. Often, as a result, the effectiveness of various retrofit procedures is often questionable and ill fated. There are many examples where implemented retrofit procedures did not work and fatigue cracking continued. In such cases, details must be re-retrofitted and additional corrective actions taken to ensure a safe structure. Implementation of one or two prototype retrofits is attractive alternative approach to ensuring effective retrofits are developed. In situations where several dozen or even hundreds of details have to be retrofitted due to a common problem, this approach is most practical. The prototypes should be instrumented and the performance evaluated. Field instrumentation and testing has consistently been demonstrated as the most effective means to confidently determining the effectiveness of a given retrofit strategy. Unanticipated effects, due to modification of the detail, are also revealed thereby reducing the chance for future problems. Monitoring for a few weeks to months can also be conducted at little cost to help ensure the longevity of the retrofit and to identify how the retrofitted detail performs when subjected to the variable-amplitude load spectrum. This paper examines examples of where effective prototype retrofit strategies were shown to be effective as demonstrated through performance and field instrumentation.
Identifying Effective and Ineffective Retrofits for Fatigue Cracking in Steel Bridges using Field Instrumentation
It is estimated that nearly 90% of all fatigue cracking is the result of out-of-plane distortion or other unanticipated secondary stresses at fatigue sensitive details. Interestingly, neither design nor evaluation specifications provide any guidance on how to evaluate the in-service potential for fatigue cracking at these details. Furthermore, the causes and driving forces producing these cracks are typically difficult to accurately characterize using simple design tools. Often, as a result, the effectiveness of various retrofit procedures is often questionable and ill fated. There are many examples where implemented retrofit procedures did not work and fatigue cracking continued. In such cases, details must be re-retrofitted and additional corrective actions taken to ensure a safe structure. Implementation of one or two prototype retrofits is attractive alternative approach to ensuring effective retrofits are developed. In situations where several dozen or even hundreds of details have to be retrofitted due to a common problem, this approach is most practical. The prototypes should be instrumented and the performance evaluated. Field instrumentation and testing has consistently been demonstrated as the most effective means to confidently determining the effectiveness of a given retrofit strategy. Unanticipated effects, due to modification of the detail, are also revealed thereby reducing the chance for future problems. Monitoring for a few weeks to months can also be conducted at little cost to help ensure the longevity of the retrofit and to identify how the retrofitted detail performs when subjected to the variable-amplitude load spectrum. This paper examines examples of where effective prototype retrofit strategies were shown to be effective as demonstrated through performance and field instrumentation.
Identifying Effective and Ineffective Retrofits for Fatigue Cracking in Steel Bridges using Field Instrumentation
Connor, Robert J. (author) / Fisher, John W. (author)
Structures Congress 2005 ; 2005 ; New York, New York, United States
Structures Congress 2005 ; 1-9
2005-04-18
Conference paper
Electronic Resource
English
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