FIELD LOAD TESTS OF OPEN-DECK TIMBER TRESTLE RAILROAD BRIDGES

A field load test program was conducted to evaluate three open-deck railroad trestle bridges. The bridges included part of a 31-span bridge, a four-span bridge with skewed interior bents and a three-span bridge. Plies of the chords of the bridges were evaluated non-destructively for material properties using an ultrasonic stress wave device. The bridges were modeled using typical frame analysis techniques to predict response to loads. Deflection and strain measurements were recorded from the load testing. The responses of the bridges to various loads were compared to the predicted responses from several analytical modeling assumptions. The diagnostic testing used loads applied statically by axles of a test train and ramp loads applied by a specially designed railroad test car. Rolling train loads were conducted using the axles of the test train. Displaced chord ground reference deflections plus some strain measurements were recorded at selected locations. The bridges performed within the expected range of behavior predicted by the analytical models. The chord systems of the bridges performed as beams semi-continuous over multiple supports. Two forms of support motion were observed; motion of the caps and gap closing between individual plies and the supporting caps. Load sharing among individual plies was examined empirically. No definable pattern for load sharing of the plies was identified.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 125 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00823241
  • Record Type: Publication
  • Report/Paper Numbers: MPC 01-125
  • Files: UTC, NTL, TRIS
  • Created Date: Jan 18 2002 12:00AM