Flexural Strengthening of RC Slabs Using a Hybrid FRP-UHPC System Including Shear Connector

Abstract

A polymeric hybrid composite system made of UHPC and CFRP was proposed as a retrofit system to enhance flexural strength and ductility of RC slabs. While the effectiveness of the proposed system was confirmed previously through testing three full-scale one-way slabs having two continuous spans, the slabs retrofitted with the hybrid system failed in shear. This sudden shear failure would stem from the excessive enhancement of the flexural strength over the shear strength. In this study, shear connectors were installed between the hybrid system and a RC slab. Using simple beam, only positive moment section was examined. Two full-scale RC slabs were cast and tested to failure: the first as a control and the second using this new strengthening technique. The proposed strengthening system increased the ultimate load carrying capacity of the slab by 70%, the stiffness by 60%, and toughness by 128%. The efficiency of shear connectors on ductile behavior of the retrofitted slab was also confirmed. After the UHPC top is separated from the slab, the shear connector transfer shear load and the slab system were in force equilibrium by compression in UHPC and tension in CFRP.

Design Optimization of Explosion-Resistant System Consisting of Steel Slab and CFRP Frame

“…In addition, there is also a demand for lightweight materials for lighter, faster and safer military vehicles. Recently, an efficient material substitute for steel has been carbon fiber-reinforced polymer (CFRP), which contains numerous unique characteristics such as high strength-to-weight ratio and high strength [ 2 ], high energy absorption capacity, and corrosion resistance [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Moreover, the tensile strength and stiffness of steel structure were improved significantly by CFRP [ 11 ].…”

Load-deflection behaviour of hybrid concrete flat slab

“…Strengthening structural members based on layers of several concrete types to produce hybrid concrete gets more interest by researchers in recent years (Kang, Hong & Kwon, 2017;Moon, Reda Taha & Kim, 2017). Hybrid concrete, in addition to the normal strength concrete, may include fi brous concrete, high strength concrete, ultra high performance concrete or any concrete types have special characteristics (Annadurai & Ravichandran, 2016;Kang et al, 2017;Moon et al, 2017).…”

“…Strengthening structural members based on layers of several concrete types to produce hybrid concrete gets more interest by researchers in recent years (Kang, Hong & Kwon, 2017;Moon, Reda Taha & Kim, 2017). Hybrid concrete, in addition to the normal strength concrete, may include fi brous concrete, high strength concrete, ultra high performance concrete or any concrete types have special characteristics (Annadurai & Ravichandran, 2016;Kang et al, 2017;Moon et al, 2017). High strength concrete gets more signifi cant role when it needed to be used within the structural systems that have certain properties such as light weight parts, special architectural requirements or economic considerations (Annadurai & Ravichandran, 2016).…”

Arching in concrete slabs strengthened with near surface mounted fibre reinforced polymers

“…However, the use of advanced materials and innovative methods of analysis can provide engineers with an opportunity to deliver greater material efficiency and provide end users with a sustainable alternative to demolition and new construction. In recent years [7][8][9][10][11], the use of fibre reinforced polymers (FRPs) in retrofitting existing reinforced concrete structures has increased in popularity. This has typically been employed in strengthening highway bridges [12] due to the resistance of FRPs to corrosion from road de-icing salts.…”