LRFD DESIGN CRITERIA FOR COTTON DUCK PAD BRIDGE BEARING

Cotton duck pads (CDP) are preformed elastomeric pads consisting of thin layers of elastomer interlayered with layers of cotton duck fabric. CDP are known to be quite stiff and to have large compressive load capacity. Because of this great stiffness, the translational movement and rotational capacity of CDP have been severely limited. Very few tests have been performed on these pads to examine their behavior. Although CDP are permitted significant compressive load capacity in the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) and Standard Specifications, they are allowed virtually no translational movement or rotational capacity in these same specifications. The AASHTO limitation on rotation is very severe, because it makes difficult the accommodation of construction tolerances with CDP applications. The severity of this rotational limit is the primary focus of this research study. The study evaluated existing proprietary data and developed improved recommendations for the AASHTO Specifications. The recommended improvements in LRFD format are included in Appendices A and B.

• Record URL:
  http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w24.pdf
• 
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Corporate Authors:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  University of Washington, Seattle

  Department of Civil and Environmental Engineering, P.O. Box 352700
  Seattle, WA  United States  98195-2700
• Authors:
  • Roeder, C W
• Publication Date: 2000-3

Language

• English

Media Info

• Features: Appendices; Figures; References;
• Pagination: 43 p.
• Serial:
  • NCHRP Web-Only Document
  • Issue Number: 24
  • Publisher: Transportation Research Board

Subject/Index Terms

• TRT Terms: Bridge bearing pads; Cotton; Load and resistance factor design; Recommendations; Rotation; Specifications; Stiffness
• Identifier Terms: American Association of State Highway and Transportation Officials
• Subject Areas: Bridges and other structures; Design; Highways; Research; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00798867
• Record Type: Publication
• Report/Paper Numbers: NCHRP Project 20-07,, Task 99,, Contractor Final Report
• Files: TRIS, TRB
• Created Date: Sep 6 2000 12:00AM