NEHRP Clearinghouse
- Title
- Seismic Vulnerability of Timber Bridges and Timber Substructures.
- File
- PB2008105145.pdf
- Author(s)
- Shama, A. A.; Mander, J. B.; Friedland, I. M.; Allicock, D. R.
- Source
- Federal Highway Administration, Washington, DC.; National Science Foundation, Arlington, VA. Earthquake Engineering Research Centers Program., June 7, 2007, 198 p.
- Identifying Number(s)
- MCEER-07-0008
- Abstract
- There is little understanding of the seismic behavior of timber bridges, as historically, little effort has been spent on documenting their performance in past earthquakes or conducting research to develop seismic and/or retrofit requirements for them. This research is devoted towards: (a) documenting the seismic performance of timber bridges in past earthquakes; (b) assessing, from both theoretical as well as experimental perspectives, the strength and ductility capability of timber piled bridges in both the braced in-plane (transverse to the bridge axis) and out-of-plane (longitudinal) directions; and (c) conducting a seismic vulnerability analysis of timber bridges to assess the expected mode of failure. In pursuit of these objectives, theories are developed to predict the performance of timber piles under lateral loading. Theoretical predictions were verified by experimental studies on full-scale timber specimens, and timber pile-to-concrete cap connections. For braced timber pile bents, a prototype timber bridge was used to develop a near-full size physical model that was subjected to shaking table experiments and quasi-static reversed cyclic loading tests on the laboratory strong-floor. A nonlinear force-displacement computational modeling study was also conducted as a companion effort to the experimental investigation. Based on the experimental and theoretical research, the seismic vulnerability study of timber bridges led to the development of fragility curves. It is concluded that timber bridges are inherently robust and have the ability to withstand major earthquakes with minor to no damage. The main issue is in the provision of adequate deck seating on timber caps.
- Keywords
- ; Bridges; Vulnerability; Damage assessment; Substructures; Earthquake damage; Wooden structures; Pile structures; Earthquake engineering; Failure mode analysis; Strength; Performance evaluation; Cyclic loads; Modeling; Retrofit; Seismic effects; Ductility