RC Slabs Strengthened by Bonded Carbon FRP Plates: Part 1--Laboratory Study


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Title: RC Slabs Strengthened by Bonded Carbon FRP Plates: Part 1--Laboratory Study

Author(s): H. Ichimasu

Publication: Special Publication

Volume: 138


Appears on pages(s): 933-956

Keywords: beams (supports); bending; bonding; carbon; epoxy resins; slabs; fiber reinforced plastics; plates (structural members); strengthening; reinforced concrete; reinforcing steels; tests; Structural Research

Date: 9/1/1993

Reinforced concrete slabs on steel girder bridges on the Tokyo Metropolitan Expressway are generally strengthened by installing additional stringers or attaching steel plates. However, it is difficult to apply such methods to strengthening work in confined box girders or where there are obstructions. Carbon FRP plates (CFRP) have been selected as strengthening materials for their applicability to strengthening work in confined spaces, and because they can be bonded in lattice forms, allowing for bonding condition inspection on the lower faces of the slabs. The aim of CFRP strengthening is to reduce the reinforcing bar stress caused by excessive wheel loads. In Part 1, investigations are conducted on CFRP applicability to strengthening work through static loading and work efficiency tests. Reinforcing bar tensile stress intensity was reduced by 38 to 56 percent of the unstrengthened specimen. The loads at which the tensile stress intensity is 140 MPa (allowable reinforcing bar load) are around 1.3 times that of an unstrengthened specimen. It can be concluded from the preceding that reinforcing bar stress intensity can be reduced, confirming the possibility of strengthening.