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Research for AASHTO Standing Committee on Highways. Task 387. Maintenance Actions to Address Fatigue Cracking in Steel Bridge Structures

项目名称：	Research for AASHTO Standing Committee on Highways. Task 387. Maintenance Actions to Address Fatigue Cracking in Steel Bridge Structures
摘要：	As of December 2013, there were 607,751 bridges in the U.S. national bridge inventory, and 181,095 of those bridges have steel superstructures. Fatigue cracking in steel bridge members is an issue that must be addressed in all structure maintenance programs. If a fatigue crack is allowed to grow and reach a critical length, fracture may occur with the possibility of structural failure of the member. Fatigue cracks may be caused by both in-plane and out-of-plane effects. The vulnerability of a steel bridge superstructure to further damage depends on the loading conditions and crack locations. Immediate replacement of superstructure components with fatigue cracks is often not possible due to funding priorities, access, traffic, and environmental issues. Repair of fatigue cracking has been performed on numerous bridges. Substantial research effort has previously been devoted to understanding the sources of fatigue-prone details and developing engineering solutions to prevent such cracking through enhanced design and construction practices. However, a significant portion of the existing bridge inventory comprises steel structures and systems that contain fatigue-cracked or fatigue-prone elements. Bridge Preservation and Bridge Maintenance Engineers and Practitioners would benefit from a summary of current transportation agency and industry practices and procedures used to repair fatigue cracks in existing steel bridges, and the effectiveness of the various repair methods in mitigating further growth of existing fatigue cracks. This project would support the performance management and research strategic focus areas of the American Association of State Highway and Transportation Officials (AASHTO) Subcommittee on Maintenance Bridge Technical Working Group. The objective of this project is to develop proposed AASHTO guidelines for maintenance actions to address fatigue cracking in steel bridges. The proposed guidelines should cover as a minimum: repair procedures and detailing, and include maintenance and preservation actions to mitigate further growth of existing fatigue cracks in steel bridges. Task 1. Conduct a literature review of relevant domestic and international research, guidelines, and current practices to determine the current state of knowledge on (1) fatigue cracking mechanisms in steel bridges and (2) strategies employed for repair and maintenance actions. This information shall be assembled from published and unpublished reports, contacts with academia, transportation agencies, and industry organizations. The results of this task should be summarized in a tabular form showing the detail, the repair technique, and the success. The survey should include the design stress range at the detail, the type of steel, and service life at the time of the repair. Task 2. Conduct a survey of bridge owners and other stakeholders to collect data related to the research objective. Follow-up with participants as needed. The survey plan, including questions and participants, shall be submitted to the National Cooperative Highway Research Program (NCHRP) for review and approval prior to distribution. Task 3. Synthesize existing repair procedures documenting the repair practice, success of the repairs, and post repair inspection. Prepare an outline of the proposed guidelines, including discussion of the contents and intent. Task 4. Develop a draft of proposed AASHTO guidelines with commentary for maintenance actions to address fatigue cracking in steel bridges according to the approved outline. Submit the draft of the proposed guidelines no later than 3 months after the Task 3 approval. The guidelines should provide detailed repair procedures including post repair inspection recommendations. Task 5. Revise the draft of recommended AASHTO guidelines submitted in Task 4 according to the NCHRP project panel comments. Task 6. Present the recommended guidelines in AASHTO standard interim-revision format to the AASHTO Subcommittee on Bridges and Structures (Technical Committees: T-14 Structural Steel Design and T-18 Bridge Management, Evaluation, and Rehabilitation) and the AASHTO Subcommittee on Maintenance (Bridge Technical Working Group). Task 7. Submit a final report describing the entire research effort with the proposed guidelines. Following receipt of the draft final report, the remaining 2 months shall be for NCHRP review and comment and for research agency preparation of the revised final report.
状态：	Proposed
资金：	100000
资助组织：	Federal Highway Administration
项目负责人：	Dekelbab, Waseem
开始时间：	20150911
预计完成日期：	0
实际结束时间：	0