Transfer and Development Lengths of Steel Strands in Full-Scale Prestressed Self-Consolidating Concrete Bridge Girders

Pozolo, Andrew M.

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https://hdl.handle.net/2142/18443 Copy

Description

Title

Transfer and Development Lengths of Steel Strands in Full-Scale Prestressed Self-Consolidating Concrete Bridge Girders

Author(s)

Pozolo, Andrew M.

Issue Date

2011-01-14T22:51:06Z

Director of Research (if dissertation) or Advisor (if thesis)

Andrawes, Bassem

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Self-consolidating concrete
• prestressed concrete
• seven-wire strand
• pullout
• transfer length
• development length
• hollow box girders
• I-girders
• finite element analysis

Abstract

Self-consolidating concrete (SCC) is a workable yet stable concrete which flows easily and consolidates under its own weight. Its unique properties can substantially reduce the labor required to pour complex or heavily reinforced structural members. Over the past decade, the American precast industry has taken significant strides to adopt SCC in commercial projects, though concern about early-age bond behavior has limited the material’s application in prestressed members. A keen understanding of SCC’s bond strength, including its impact on transfer and development lengths in prestressed members, is essential to safely implement SCC in prestressed design. The Illinois Department of Transportation (IDOT) has sponsored a three-phase study exploring the bond behavior of steel strands in prestressed bridge girders. In the first phase, 56 pullout tests were conducted to compare the performance of seven-wire strands embedded in SCC and conventionally-consolidated concrete blocks. In the second phase, transfer lengths of prestressing strands in two SCC hollow box girders and two SCC I-girders were determined experimentally. In the third phase, the development length of strands in the two box girders was determined through a series of iterative flexural tests. This thesis details the three phases of the IDOT study and compares results to industry standards and requirements of the American Concrete Institute and the American Association of State Highway and Transportation Officials. Results are also compared to analytical methods proposed in the literature. Additionally, a systematic method is developed to predict transfer lengths in full-scale specimens using pullout test data and finite element analysis. The proposed method may be useful when large-scale testing is impractical in terms of time or cost.

Graduation Semester

2010-12

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http://hdl.handle.net/2142/18443

Copyright and License Information

Copyright 2010 Andrew M. Pozolo

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