Field Retrofit of Prestressed Concrete T-Beam Using CFRP


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Title: Field Retrofit of Prestressed Concrete T-Beam Using CFRP

Author(s): I. N. Robertson, A. A. Agapay, and L. M. Nakashima

Publication: Special Publication

Volume: 215


Appears on pages(s): 335-348

Keywords: carbon fibers; fiber reinforced polymer (FRP); field application; prestressed concrete; strengthening; T-beam

Date: 8/1/2003

In 1997, a precast, prestressed T-beam in the Ala Moana Shopping Center parking garage, in Honolulu, Hawaii, was strengthened in flexure using carbon fiber reinforced polymer (CFRP) strips epoxy bonded to the soffit of the beam. When the parking garage was demolished in June 2000, this beam and two control beams were salvaged and brought to the University of Hawaii for testing. This paper presents the retrofit procedures used during field application of the CFRP strips. It also describes the beam recovery and preparation for laboratory testing. The test program and results of the flexural testing of both unstrengthened and strengthened beams under four-point loading are presented in detail. The CFRP retrofit significantly increased the flexural capacity of the beam while also increasing its flexural ductility. The failure moment was well in excess of the nominal moment capacity predicted using the strain-compatibility procedure described in the ACI 440R-02 report.