Seismic Vulnerability of Timber Bridges and Timber Substructures

A.A. Shama, J.B. Mander, I.M. Friedland and D.R. Allicock

MCEER-07-0008 | 06/07/2007 | 194 pages

Cover of Seismic Vulnerability of Timber Bridges and Timber Substructures.

Keywords: Seismic vulnerability assessments.  Timber structures.  Bridges.  Substructures.  Seismic designs.  Seismic performance.  Shaking table tests.  Pile-to-foundation connections.  Cyclic lateral loads.  Predictions.  Fragility curves.  Timber caps.

Abstract: The research is devoted toward documenting the seismic performance of timber bridges in past earthquakes; 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 conducting a seismic vulnerability analysis of timer bridges to assess the expected mode of failure. Theories were developed to predict the performance of timber piles under lateral loading. Experimental studies on full-scale timber specimens and timber pile-to-concrete cap connections were conducted. 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 was used; a nonlinear force-displacement computational modeling study was also conducted. Based on the experimental and theoretical research, the seismic vulnerability study of timer bridges led to the development of fragility curves. Conclusions were 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.