Reliability-Based Fatigue Assessment of Tube-to-Transverse Plate Attachments in Highway Sign Support Structures
Tube-to-transverse plate stiffened connection details are widely used in cantilevered sign support structures in New Jersey and many other states. The tube wall at the toe of the attachment to tube weld at the termination of attachment is considered a potential fatigue crack location according to the new load and resistance factor (LRFD) Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals (American Association of State Highway and Transportation Officials (AASHTO)-LTS) Specification. There have been several reported cases of fatigue cracking at these locations. Based on recent experimental and analytical studies, the new AASHTO-LTS has updated the constant amplitude fatigue threshold, (∆𝐹)𝑇𝐻 for fatigue design for infinite life. In this paper, a fatigue reliability-based approach is utilized for the potential critical fatigue crack locations. Synthetic analysis of wind data for the State of New Jersey was performed for collected 1-hour averaged wind speed and was then transformed to the transient domain to represent the turbulent natural wind phenomena. Effective stress ranges and number of cycles were obtained using the rainflow counting technique. Existing fatigue test data of these connections were collected, and then a statistical analysis of linear stress-life (S-N) fatigue data is performed to obtain fatigue coefficients. The reliability-based fatigue assessment was used to estimate the probability of crack initiation at that location. Based on the results of the probability of the fatigue crack initiation, inspection frequencies of tube-to-transverse plate connections in these sign structures can be established.
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Supplemental Notes:
- This paper was sponsored by TRB committee AFF10 Standing Committee on General Structures.
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Corporate Authors:
500 Fifth Street, NW
Washington, DC United States 20001 -
Authors:
- Choi, Hyungjoo
- Najm, Husam
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Conference:
- Transportation Research Board 96th Annual Meeting
- Location: Washington DC, United States
- Date: 2017-1-8 to 2017-1-12
- Date: 2017
Language
- English
Media Info
- Media Type: Digital/other
- Features: Figures; Photos; References; Tables;
- Pagination: 17p
- Monograph Title: TRB 96th Annual Meeting Compendium of Papers
Subject/Index Terms
- TRT Terms: Cantilevers; Fatigue (Mechanics); Fatigue cracking; Load and resistance factor design; Reliability; Service life; Sign supports; Statistical analysis; Structural connection; Wind
- Identifier Terms: AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals
- Geographic Terms: New Jersey
- Subject Areas: Bridges and other structures; Design; Highways;
Filing Info
- Accession Number: 01626628
- Record Type: Publication
- Report/Paper Numbers: 17-02075
- Files: TRIS, TRB, ATRI
- Created Date: Feb 27 2017 9:25AM