Post-tensioned Tendon Losses in a Spliced-Girder Bridge, Part 2: Analysis of Losses

This paper presents analytical procedures for determining posttensioning tendon losses in a typical spliced, precast concrete girder used in the 4500 South Bridge at Interstate-15 in Salt Lake City, Utah, which is composed of 8 posttensioned, spliced, precast concrete girders with 3 segments each to produce a single clear span of 201.6 ft. The analysis procedure specified in the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications is used and compared with experimental measurements of losses in the posttensioned, spliced, precast concrete girders monitored at the I-15 Bridge as described in the companion paper, "Post-tensioned Tendon Losses in a Spliced-Girder Bridge, Part 1: Field Measurements," in the May-June 2007 PCI Journal. The time-dependent method predicts measured posttensioning losses in the precast concrete girders with sufficient accuracy at the abutments and at midspan. The measured modulus of elasticity of the girder concrete was predicted more accurately by the equation proposed by ACI Committee 363. Concrete shrinkage and creep tests performed on the girders were used to obtain the ultimate creep coefficient and ultimate shrinkage strain. Results were compared with values recommended by ACI Committee 209. Shrinkage and creep tests indicate an asymptotic achievement of ultimate shrinkage strain and ultimate creep coefficient in approximately 8 months, a result supported by strain readings from vibrating wire strain gauges embedded in the concrete of the spliced girders.

  • Availability:
  • Authors:
    • Pantelides, Chris P
    • Saxey, Brandt W
  • Publication Date: 2007-7

Language

  • English

Media Info

  • Media Type: Print
  • Features: Appendices; Figures; References; Tables;
  • Pagination: pp 58-69
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 01054301
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 25 2007 12:42PM