Eksperimentalno-teorijska analiza graničnih stanja armiranobetonskih kontinualnih greda od samougrađujućeg betona ojačanih vlaknima armiranim polimerima (Fiber-reinforced polymer - FRP)

Abstract

The paper presents the results of experimental and numerical investigations of the reinforced (RC) continuous beams made of self-compacting concrete strengthened with fiber reinforced polymer (FRP). Strengthening was performed by mounting glass and carbon FRP bars under the concrete surface (NSM method) as well as by glueing the FRP strips on the tensioned concrete surface (EB method). Six continuous beams were tested during which the deformations of beams and the strains in concrete, steel and FRP reinforcement were recorded until failure under monotonically incresed loading. By strengthening beams with additional glass (Ø10 mm) and carbon (Ø8 mm) FRP bars increasing in bearing capacity was achieved compared to control (unstrengthened) beam of 22% to 82% depending on the type and the position of FRP reinforcement while by strengthening beam with FRP strips increasing in bearing capacity was achieved of 50%. In addition to observed the ultimate strength state, the ultimate serviceability state was verified, while the stress-strain states of the beams and formation of plastic joints were monitored. By using FEM, continuous beams were modelled, and numerical non-linear analysis was conducted using the program ANSYS. The obtained results of numerical analysis correlated very well with the experimental results. Based on the carried out investigation it is concluded that a significant increase in capacity can be achieved by strengthening of continuous beams using reinforcement made of FRP materials, regardless of the type of FRP reinforcement and strengthening method, whereby the NSM method has many advantages compared to the EB method.