STABILITY PROBLEMS OF WOOD TRUSS BRIDGE

THE CASE HISTORY OF STABILITY PROBLEMS AND FAILURE FOR A SPACED-MEMBER TIMBER BRIDGE TRUSS IS PRESENTED TOGETHER WITH THE CAUSE OF FAILURE AND THE CORRECTIVE MEASURES. THE ELBOW GRADE BRIDGE IN THE WILLIAMETTE NATIONAL FOREST WAS A SINGLE LANE THRU-TRUSS STRUCTURE, 120 FT. LONG, DESIGNED TO CARRY LOGGING TRAFFIC ACROSS THE SOUTH FORK OF THE MCKENZIE RIVER. THIS BRIDGE FAILED UNDER NORMAL LOAD 15 DAYS AFTER ERECTED, AND WAS THEREAFTER REBUILT. THE CAUSE OF FAILURE IS IDENTIFIED AS DIFFERENTIAL LONGITUDINAL MOVEMENT BETWEEN THE TWO TIMBERS OF SPACED-MEMBER UPPER CHORD. BOLTED JOINTS PERMIT DIFFERENTIAL LONGITUDINAL MOVEMENT. THIS CAUSES JOINT DISPLACEMENT & STABILITY PROBLEMS. DIFFERENTIAL MOVEMENT MUST BE ELIMINATED TO ACHIEVE STABLE CONDITIONS. THE NEW INFORMATION ON STRESS TRANSFER GAINED FROM THIS EXPERIENCE APPLIES TO THE GENERAL CASE OF WOOD TRUSS WITH SPACED MEMBERS. /AUTHOR/

• Supplemental Notes:
  • Vol 96, No ST2, PROC.PAPER 7095, PP 353-370
• Authors:
  • Hahn, O M
• Publication Date: 1970-2

Media Info

• Serial:
  • Journal of the Structural Division
  • Publisher: American Society of Civil Engineers

Subject/Index Terms

• TRT Terms: Bridges; Failure; Stability criteria; Stresses; Timber; Transfer characteristics; Truss bridges; Wooden bridges
• Uncontrolled Terms: Longitudinal movement
• Old TRIS Terms: Timber (Structural)
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00209169
• Record Type: Publication
• Files: TRIS
• Created Date: May 13 1970 12:00AM