Jay Thomas

Performance of Double-T Prestressed Concrete Beams Strengthened with Steel Reinforcement Polymer

In the fall of 2002, a two-storey parking garage in Bloomington, Indiana, built with precast prestrestressed concrete (PC) double-T beams, was decommissioned due to a need for increased parking-space. This led to the opportunity of investigating the flexural performance of the PC double-T beams, upgraded in the positive moment region with steel reinforced polymer (SRP) composite materials, representing the first case study where this material has been applied in the field. SRP makes use of high-strength steel cords embedded in an epoxy resin. This paper reports on the test results to failure of three beams: a control specimen, a beam strengthened with one ply of SRP and a third beam strengthened with two plies of SRP anchored at both ends with SRP U-wraps. Results showed that SRP can significantly improve both flexural capacity and enhance pseudo-ductility. Preliminary analytical work shows that the same approach used for externally bonded fiber reinforced polymer (FRP) can be satisfactorly used for SRP.

THE DEVELOPMENT OF A NOVEL STEEL REINFORCED COMPOSITE (SRC) LINER FOR THE REHABILITATION OF DETERIORATED PCCP

This paper presents details for the development of an innovative steel reinforced composite (SRC) system used for prestressed concrete cylinder pipes (PCCP) remediation. SRC system is a trenchless technology that consists of high strength steel wires continuously wrapped inside the pipe and embedded in cementitious or polymeric matrix. The system was designed to address shortcomings of current PCCP remediation techniques such as replacement, cured-in-place pipe CIPP, slip lining, and jacketing with fiber reinforced polymers (FRP). Full scale pressure testing was performed on two 1676 mm (66 in.) diameter PCCP sections, with and without the SRC system. Part or all of the existing pre-stressing wires in the host pipes were cut to simulate the behavior of a damaged PCCP during the test. Results indicate that while the unstrengthened pipe failed at a low pressure with partial wires cut, the SRC system was able to restore 100% of the original design capacity of the host pipe with 100% of the original prestressing wires cut. SRC design procedure, full scale pressure tests and results, and final conclusions are included in this paper.