MPC
Project Details

Title:	Rigorous Computer Modeling of Timber Trestle Railroad Bridges
Principal Investigators:	Richard M. Gutkowski and Jeno Balogh
University:	Colorado State University
Status:	Completed
Year:	2000
Project #:	MPC-193

Abstract

Nationally, the structural condition of short span timber trestle railroad bridges is one of concerning circumstances. Reports by the Association of American Railroads (AAR) indicate that degradation has been occurring with material failure evident at some sites. Railway car weights and trainloads have increased considerably. Deterioration due to this heavy, frequent loading and aging and exposure is an important issue. Loosened connections, gaps due to shrinkage to moisture/drying cycles; support movement, differential bearing of members, etc. develop over time and are present in older bridges. These alter load capacity and stiffness from the original condition and significantly affect behavior. To improve understanding of the load paths and structural behavior it is necessary to accurately analytically model the geometry and member condition and properties of actual bridges. A recently developed, leading edge commercial software (Axis VM) will be employed to simulate (model) the standard open deck, timber trestle bridge configuration, including representation of actual condition. The resulting model will be used to predict the displacement response of the bridge under static loadings. Predicted response will be verified by comparison with the results of past load tests of such bridges.