SPACING AND COVER OF EPOXY COATED PRESTRESSING STRANDS. FINAL COMPREHENSIVE REPORT

This report summarizes a two year research effort related to spacing and concrete cover requirements for epoxy coated prestressing strand. Today, prestressed concrete is widely used in the construction industry. Prestressed members are generally smaller than their reinforced concrete counterparts under the same loading conditions. Thus, prestressed members require less concrete and reduce the amount of steel reinforcement needed. However, the smaller amount of reinforcement in prestressed members is more vulnerable to corrosion. Protection against corrosion of prestressing steel is more critical than the non-prestressed reinforcement case since the strength of a prestressed member is a function of the prestressing tendon area. As prestressed structures become older, corrosion of the prestressing steel can become a problem. A prestressing strand manufacturer, Florida Wire and Cable Company, has developed an epoxy coated prestressing strand. This epoxy coating has proven to be effective in preventing the corrosion of prestressing steel. The epoxy coating is impregnated with grit to improve its bonding capabilities in prestress applications. In an earlier research study the splitting at transfer in single epoxy coated strand specimens was observed. This splitting did not occur in uncoated single strand specimens with like dimensions. The splitting problem was attributed to the shorter transfer length of epoxy coated prestressing strand which causes higher bond stresses, and could be even more severe in members with multiple strands at close spacings. This research study was undertaken to investigate the spacing and cover requirements of epoxy coated prestressing strand. By varying the parameters of strand spacing, concrete cover, and number of strands, spacing and concrete cover requirements were determined. These requirements were then compared to existing American Association of State Highway and Transportation Officials (AASHTO) specifications. Also, the transfer length of epoxy coated and uncoated prestressing strand was investigated.

• Record URL:
  http://www.ltrc.lsu.edu/pdf/2008/fr_275.pdf
• 
• Corporate Authors:

  Louisiana State University, Baton Rouge

  Department of Civil and Environmental Engineering
  Baton Rouge, LA  United States  70803

  Louisiana Transportation Research Center

  4101 Gourrier Avenue
  Baton Rouge, LA  United States  70808

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Gopu, VKA
  • Cousins, T E
  • Francis, L H
• Publication Date: 1993-7

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 197 p.

Subject/Index Terms

• TRT Terms: Corrosion protection; Epoxy coatings; Prestressed concrete; Prestressing; Spacing; Splitting (Communications); Time duration; Transfers
• Uncontrolled Terms: Cover depth; Prestressing strands; Transfer length
• Old TRIS Terms: Splitting
• Subject Areas: Bridges and other structures; Design; Finance; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00638792
• Record Type: Publication
• Report/Paper Numbers: FHWA/LA-93/275
• Files: TRIS, USDOT
• Created Date: Nov 15 1993 12:00AM