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Live Load Testing of Historic Covered Timber BridgesAuthor(s): Travis Hosteng; James Wacker; Brent Phares
Source: In: Proceedings of the 2nd International Conference of Timber Bridges. September 30 - October 2nd, 2013, Las Vegas, Nevada, USA. (Electronic format without page numbers). Leesburg, VA: American Wood Council – Woodworks. (Peer-Reviewed). ID# 0425. 2013; 11 p.
Publication Series: Full Proceedings
Station: Forest Products Laboratory
PDF: Download Publication (564.57 KB)
DescriptionThe National Historic Covered Bridge Preservation Program (NHCBP), sponsored by the Federal Highway Administration (FHWA), is intended to preserve covered timber bridge structures nationwide. Today, less than 700 covered timber bridges still exist in the United States and of those many are closed to vehicular traffic. Furthermore, a large percentage of the remaining bridges open to traffic are restricted by load postings. Currently, no load rating standards exist for covered timber bridges which often results in overly conservative load ratings/postings. Rating engineers simply do not have adequate resources or background in timber design, especially in covered timber bridge design, for calculation of accurate load postings on covered timber bridges. To better understand the structural performance of covered timber bridges and ultimately develop improved criteria for load rating of these bridges, a series of field tests were performed on eleven historic covered timber bridges. Field live load testing was conducted on three Burr arch truss bridges in Indiana, four Howe truss bridges in Indiana, and four Queen post truss bridges in Vermont. This paper discusses the live load testing of the Cox Ford Burr arch Covered Bridge in Indiana. Included in the discussion is the procedure for installing displacement and strain sensors on the bridge, monitoring those sensors for global displacements and member strains at various cross-sections during passage of a known test vehicle, the results from the load test, and information on how these field tests were used to develop and calibrate an analytical model. The analytical model could then be used for determining more accurate bridge load ratings of the bridge. We believe this work will result in a viable technique for determining reliable load ratings for covered timber bridges using field tests and more accurate computational modeling techniques.
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CitationHosteng, Travis; Wacker, James; Phares, Brent. 2013. Live Load Testing of Historic Covered Timber Bridges. In: Proceedings of the 2nd International Conference of Timber Bridges. September 30 - October 2nd, 2013, Las Vegas, Nevada, USA. (Electronic format without page numbers). Leesburg, VA: American Wood Council – Woodworks. (Peer-Reviewed). ID# 0425. 2013; 11 p.
KeywordsCovered Bridges, Timber, Load Rating, Burr arch, Queenpost
- Simplified Analytical Model for a Queen-Post Covered Timber Bridge
- Live-load performance evaluation of historic covered timber bridges in the United States
- Field testing and structural analysis of Burr arch covered bridges in Pennsylvania
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