Project Title

Repair of Damaged PC Girder with FRCM and FRP Composites

University

University of Miami

Principal Investigator

Antonio Nanni

PI Contact Information

nanni@miami.edu; 305-284-3391

Funding Source(s) and Amounts Provided (by each agency or organization)

VCTIR (via VATech) $44,800
Structural Technologies $15,932
University of Miami: $59,725
RE-CAST: $120,456

Total Project Cost

$240,912

Matching Agency ID or Contract Number

VATech: Acct# 662720
Structural: Acct# 406203
University of Miami: Acct#169102
RE-CAST: 00042134-04

RE-CAST Grant Award Number

DTRT13-G-UTC45

Start and End Dates

Start Date: January 1, 2014
End Date: December 31, 2016

Brief Description of Research Project

This project is for consideration of the repair of intentionally damaged AASHTO Type III prestressed concrete girders (three locations) to demonstrate the ability of fabric-reinforced-cementitious-matrix (FRCM) and fiber-reinforced polymer (FRP) to restore moment capacity compromised by the loss of four and eight 9.5-mm (3/8-in.) diameter prestressing tendons. In addition, the project includes an extensive material characterization of the strengthening materials.

Describe Implementation of Research Outcomes

Results from material characterization, design guidelines, and experimental tests are used to predict and evaluate the flexural capacity of three girders: one control girder, one FRP strengthened girder and one FRCM strengthened girder. Theoretical, experimental, and design capacities are given in Table 6-2 and Table 6-3 of the final report. Based on the results of the material characterization, theoretical analysis, experimental tests, and design analysis performed on each girder, the following observations and conclusions can be determined:

Material:

• Experimental data are obtained according to the provisions of AC125 and AC434.
• FRCM materials are acceptable from a durability perspective under acceleratedconditions.
• FRP materials are acceptable from a durability perspective under accelerated conditions.
• FRCM test curves show bilinear behavior that is consistent with the hypothesized stress strain behavior given in AC434 Annex
• Increasing from 1 ply to 2 plies for both FRCM and FRP results in an increase in ultimate strength and ultimate strain with a decrease in ductility.
• Early age FRCM bond tests indicate that substantial strength is developed after 7 days of application.

Structural:

• FRP technology successfully restores strength to original capacity
• FRCM technology restored strength to 88% of original capacity, but optimal performance of the FRCM technology was not observed due to the fact that the FRCM strengthened girder was not successfully tested to its maximum capacity.
• Using design guidelines ACI 318, ACI 440.2R-08, ACI 549.4R-13 to predict design strengths proved to be conservative with respect to experimental test results.
• Although ACI 549.4R only addresses to reinforced concrete, it is also applicable to prestressed concrete.

Constructability:

• The FRCM repair has been demonstrated to be very feasible from a constructability stand point (Jones et al., 2015)
• FRCM and FRP repairs take similar levels of effort to install, but the FRCM cementitious matrix is more familiar to construction workers and requires less personal protective gear. (Jones et al., 2015). Further conclusions are given in Jones et al., 2015.

Impacts/Benefits of Implementation

Web Links

Project website: http://recast.mst.edu/projects/repairofdamagedpcgirderwithfrcmandfrp/

Final Report: PDF