Skew Detection System Replacement on Vertical Lift Bridges
For a tower drive vertical lift bridge, failure to maintain level operation over its length or width is known as span longitudinal or transverse skew. When occurring, this can lead to jamming of the movable span in its guides and, without adequate protection, can lead to a catastrophic bridge failure. Vertical lift tower drive skew indication and monitoring was historically satisfied with the use of a differential selsyn. However, this legacy technology is nearly obsolete. This study included a review of alternatives for skew control, monitoring, and indication for tower drive vertical lift bridges based on effective management of skew and minimizing advanced electronic equipment. Based on this review, the preferred system for skew control combines the use of direct skew measurement with an inclinometer for skew monitoring and trip indication, and indirect measurement of skew using encoders for controlling skew during operation. To minimize maintenance, mean-time-to-repair, and to limit dependency on Programmable Logic Controller (PLC) systems, control integration should include the use of SMART relays that contains self-diagnostics and may easily be replaced in the event of an issue.
- Record URL:
- Summary URL:
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Corporate Authors:
Wiss, Janney, Elstner Associates, Incorporated
Doylestown, PA United StatesLouisiana Department of Transportation and Development
Baton Rouge, LA United StatesFederal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC United States 20590 -
Authors:
- Rees, Gareth
- Publication Date: 2021-1
Language
- English
Media Info
- Media Type: Digital/other
- Edition: Final Report
- Features: Figures; Photos; References; Tables;
- Pagination: 44p
Subject/Index Terms
- TRT Terms: Bridge towers; Detection and identification systems; Failure; Lift bridges; Skew bridges
- Geographic Terms: Louisiana
- Subject Areas: Bridges and other structures; Highways; Maintenance and Preservation;
Filing Info
- Accession Number: 01835542
- Record Type: Publication
- Report/Paper Numbers: FHWA/LA.17/643, LTRC Project Number: 20-2ST, SIO Number: DOTLT1000343
- Files: TRIS, ATRI, USDOT, STATEDOT
- Created Date: Feb 7 2022 5:26PM