Author(s)

F. Ceroni & M. Pecce

Abstract

An experimental program about (RC) beams externally strengthened with carbon FRP sheets is presented in order to discuss strength and ductility performances. The influence of the failure mode due to delamination is evidenced. The evaluation of ductility and plastic rotation is developed. Cyclic behaviour with a low number of cycles also in the post elastic range is examined. Keywords: RC beams externally bonded reinforced, carbon fibres, cyclic loads, bond, delamination, anchorage, ductility. 1 Introduction The strengthening of existing RC flexural members by external FRP laminates is one of the most widely adopted solution for supplying additional external tensile reinforcement. Applications regard shear and flexural reinforcement, confinement of column and joints (Toutanji et al. [2], Antonopoulos and Triantafillou [1]), therefore are now available national and international code indications for the design of elements externally bonded with FRP (ACI Committee 440.2R [3], fib Bulletin 14 [4], Isis Canada [5], Japan Society of Civil Engineers [6], CNR DT200-2004 [7]). However there is still a lack of information and indications about performances of strengthened members in terms of ductility and strength behavior for cyclic load histories, that are both topic aspects for seismic retrofit. About ductility it has to be underlined that FRPs are brittle materials because fibers have a linear elastic behavior until failure. Therefore for elements externally strengthened with FRP laminates, at ultimate condition, in addition to concrete crushing or steel reinforcement rupture, crisis of external reinforcement could happen for FRP debonding. Concrete or steel failure occurs with more o

Keywords

RC beams externally bonded reinforced, carbon fibres, cyclic loads, bond, delamination, anchorage, ductility.