Flexural Behavior of Concrete Beams Internally Prestressed with Unbonded Carbon-Fiber-Reinforced Polymer Tendons

Modelling of load–deflection of concrete beams internally prestressed with unbonded CFRP tendons

“…In a previous study by some of the current authors (Heo et al, 2013), six simply supported concrete beams post-tensioned with unbonded straight CFRP tendons were tested. The main parameters were the reinforcement ratio of the unbonded prestressing CFRP tendon, the magnitude of the initial prestrain and the section shape (rectangular or T-section).…”

“…As the beam fabrication, loading and measurement, as well as the experimental results of the overall flexural behaviour of the tested beams have been reported in detail elsewhere (Heo et al, 2013), the discussion here is focused mainly on the load-deflection properties of the tested beams observed in the previous research. Table 3 summarises the mechanical properties of the CFRP tendons, the non-prestressed auxiliary bonded steel and the CFRP reinforcements and stirrups used in the test.…”

“…Although much experimental and theoretical research has been conducted for characterising the flexural behaviour of concrete beams prestressed with bonded FRPs (Burke and Dolan, 2001;Dolan and Swanson, 2002;Ehsani et al, 2001;Naaman et al, 1993;Yonekura et al, 1993), fewer studies have been conducted on concrete beams prestressed with unbonded FRPs (Grace et al, 2006(Grace et al, , 2008Heo et al, 2013;Kato and Hayashida, 1993;Maissen and de Smet, 1995). To gain a better understanding of the flexural behaviour and practical application of such beams, it seems necessary to develop a theoretical model that can incorporate the properties of both concrete and reinforcing materials and member-dependent tendon strains in the simulation of the non-linear flexural behaviour of these beams.…”

“…Specifically, the model was developed for a simply supported concrete beam prestressed with internally unbonded straight tendons and subjected to symmetric four-point loading. show the load-deflection curves of two typical unbonded CFRP prestressed concrete beams tested by Heo et al (2013). Both beams were post-tensioned with straight CFRP tendons but reinforced with different types of auxiliary bonded bars -CFRP bars for beam TB45 (Figure 1(a)) and steel bars for beam RU50 (Figure 1(b)).…”

Prestressing Concrete with CFRP Composites for Sustainability and Corrosion-Free Applications

“…The results showed that the calculated ductility overestimates the measured ones and need further refinement. [8] Braimah et al tested five unbonded post-tensioned concrete beams with two different prestressing reinforcement types (prestressing CFRP and steel) under fatigue flexural loading. The steel post-tensioned beams had bonded non-prestressed steel reinforcement, while the CFRP post-tensioned beams had bonded nonprestressed GFRP rods.…”