Synthesis of wood treatment alternatives for timber railroad structures.

Details

• Creators:
  Lombard, Brian ; Kubiczki, John
• Corporate Creators:
  New Hampshire. Dept. of Transportation
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Wooden bridges
  • Timber
  • Wood preservatives
  • Environmental impacts
  • Creosote
  • Specifications
  • Best practices
  • Railroad ties
  • Wood ties
  • Railroad tracks
• Publication/ Report Number:
  FHWA-NH-RD-15680I
• Resource Type:
  Tech Report
• Geographical Coverage:
  New Hampshire
• Corporate Publisher:
  New Hampshire. Dept. of Transportation
• Abstract:
  A wealth of information exists on various wood preservatives, treatment techniques, curing practices, and other engineered ; controls, along with alternative materials for replacement. This study was initiated to review and synthesize available ; information so that future bridge timber work could be completed in a manner that would optimize performance while ; eliminating damage to the environment. This project was triggered by dripping creosote from the Frankenstein Trestle within ; an environmentally sensitive area. ; Of the seven products evaluated, two are recommended for railroad bridge timbers: Copper Naphthenate and Creosote. ; Copper Naphthenate is commonly used in other jurisdictions, especially over sensitive aquatic environments and where ; preservative drippage is a concern. The product has low toxicity, is not listed as a restricted-use pesticide (RUP) by the U.S. ; EPA, and has shown equal or superior performance compared to creosote or pentachlorophenol. State DOTs including Iowa ; and Minnesota specify Copper Naphthenate for replacement and renovation of wooden bridges. Its only disadvantage is a ; limited supply of product currently. Creosote-treated wood has proven its effectiveness and longevity. To minimize potential ; issues, best management practices (BMPs) are required. These include specification of the correct retention rate for the ; wood species and type of use, specification of the empty-cell process, and the use of expansion baths for post-treatment. ; Only straight creosote or a 75/25 creosote/petroleum solution should be specified. ; As a result of this study, the Department’s specifications for railroad bridge timbers have been modified to reflect improved ; standards for preservatives, including treatment techniques and post-treatment procedures. In order to optimize ; performance while mitigating environmental concerns, a series of best management practices (BMPs) covering the design, ; purchase, delivery, handling, installation, and inspection of timbers are also being incorporated into future projects. It is ; expected that these recommendations will be incorporated into wooden highway structures as well.
  More +
• Format:
  PDF
• Funding:
  15680I, X-A000( )
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/27796/dot_27796_DS1.pdf
• File Type:
  [PDF - 917.08 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:80d425a074bf6356c536e46a37d31c6a25a94be667f02f8d46d2ce6b4d034fda