Effect of temperature on bond behavior of externally bonded FRP laminates with mechanical end anchorage
The use of mechanical anchorage systems can delay or avoid premature failure of reinforced concrete (RC) structures with externally-bonded fiber-reinforced polymer (EB-FRP) laminates. This work reports the results of an experimental program aimed at studying the bond behavior of a metallic anchorage plate, typically used for pre-stressed EB-FRP systems. The overall experimental program comprised 17 concrete prisms with carbon fiber reinforced polymer (CFRP) laminates externally bonded to the concrete with mechanical anchorage at the end and where different levels of normal stress were applied. Direct shear tests were carried out using two configurations: (i) the steady-state tests, where the laminate was pulled out from the block with increasing force and constant temperature (20 ºC, 60 ºC and 80 ºC); (ii) and the transient tests, where the laminate was pulled out with constant force (0.36%, 0.45% and 0.54% of strain) and the temperature was gradually increased. Experimental results showed that the ultimate capacity of the mechanical anchorage can decrease by 44-59% depending on the temperature and level of normal stress. ; This work was supported by FEDER funds through the Operational Program for Competitiveness Factors – COMPETE and National Funds through FCT (Portuguese Foundation for Science and Technology) under the project FRPLongDur POCI-01-0145- FEDER-016900 (FCT PTDC/ECM-EST/1282/2014) and partly financed by the project POCI544 01-0145-FEDER-007633. The first author wishes also to acknowledge the grant SFRH/BD/98309/2013 provided by FCT. The second author acknowledges the Spanish Government (Ministerio de Educación, Cultura y Deporte) for the grant José Castillejo ref. CAS16/00288. Finally, the authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: the S&P Clever Reinforcement Ibérica Lda. company for providing the laminates, the epoxy adhesive and metallic anchorage plates; the Hilti Portugal-Produtos e Serviços, ...