DETERMINATION OF IN-PLACE TIMBER PILING STRENGTH

A nondestructive inspection procedure that uses the ultrasonic technique to determine the material properties of timber piles above and below water is described, and the equipment developed is presented. The technique is suitable primarily for piles such as those on the Denton Bridge (that collapsed in Maryland in 1976) and others that are immersed in fresh water for long periods of time and sustain damage to the wood microstructure, which can reduce pile capacity by actually changing material parameters, such as strength and density, without a loss of cross-sectional area. This type of destructive action cannot be detected by any existing inspection technique. Laboratory testing of a large number of new and old piles from four different bridges in the state of Maryland were used to establish relationships between the pulse velocity from the ultrasonic testing and the crushing strength of the timber piles. Variables that affect the relationships, such as type of wood, degree of decay, moisture content, and treatment of the wood, were also studied. The relationships developed were verified by determining the pulse velocity of in-place piling in a fifth bridge, then removing the piles, cutting them into sections, and axial load testing the sections to determine the strength of the piles. It has been concluded from the favorable comparison of the calculated and the experimentally determined strength that the technique and equipment developed could be confidently used in timber pile inspection. The quantitative determination of the remaining strength of timber piles in service will lead to appropriate judgments as to the ability of the piles to further support the loads imposed on them.

Media Info

  • Media Type: Print
  • Features: Figures; Photos; References; Tables;
  • Pagination: pp 69-77
  • Monograph Title: Bridge maintenance management, corrosion control, heating, and deicing chemicals
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00394972
  • Record Type: Publication
  • ISBN: 0309037182
  • Files: TRIS, TRB
  • Created Date: Jan 31 1986 12:00AM