Nonlaminated FRP Strap Elements for Reinforced Concrete, Timber, and Masonry Applications

Abstract

Advances in material technology allow for the exploration of new structural forms and systems. In recent years, fibre reinforced polymers (FRPs) have emerged as candidate materials for civil engineering applications and the use of FRPs in construction has been an area of growing interest. Unidirectional high strength FRPs are well-suited for use as tensioning elements but anchorage details present a challenge. An alternative is to self-anchor the FRP tensioning element by winding thin layers of material around supports and then laminating all the layers together (a laminated strap) or by securing only the outermost layer to form a closed outer loop while the inner layers remain non-laminated (a non-laminated strap). Non-laminated FRP straps have been found to have higher efficiencies than equivalent laminated straps which is advantageous in high tension applications. The suitability of non-laminated FRP straps for use as unbonded tension elements provides scope for usage in new construction and for the strengthening of existing structures. A review of non-laminated carbon FRP strap system properties and applications in the context of reinforced concrete, timber and masonry structures is presented.

Advanced fibre-reinforced polymer (FRP) composite materials in bridge engineering: materials, properties and applications in bridge enclosures, reinforced and prestressed concrete beams and columns

“…It was concluded that this method would be more effective for large-span beams, and it was recommended that the sum of the initial and additional shear stress from loading between the CFRP strips and the concrete should be limited to the shear stress given in Approach 3 in fib (2001). Lees and Winistörfer (2011) reviewed the non-laminated CFRP strap systems and their potential for the use of self-anchored FRP tension elements with a variety of civil engineering materials. It was shown that when the strap is non-laminated, as opposed to laminated, higher efficiencies can be achieved.…”

Experimental Study of Fatigue and Fracture Behavior of Carbon Fiber-Reinforced Polymer (CFRP) Straps

“…Winistoerfer et al [ 18 , 19 ] studied the pin-loaded looped CFRP strap and suggested it can be used as practical tensile elements since the load can transfer through the pins without the requirement of additional anchoring systems. Lees et al [ 20 ] and Hoult et al [ 21 , 22 ] conducted experiments to analyze the enhancement of shear capacity of reinforced concrete due to CFRP strap. Fan et al [ 23 , 24 ] investigated the distribution of stress, failure mechanism and bearing efficiency by finite element (FE) models.…”

Precracked Reinforced Concrete T-Beams Repaired in Shear with Prestressed Carbon Fiber-Reinforced Polymer Straps

“…The prestressed carbon FRP (CFRP) straps 6 used in this study consist of unidirectional carbon fibers embedded in a thermoplastic resin to create a 12 mm (0.47 in.) wide by 0.16 mm (0.0063 in.)…”