TY - GEN

T1 - Prestressing systems for strengthening of concrete and metallic structures

T2 - 8th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering, CICE 2016

AU - Motavalli, M.

AU - Ghafoori, E.

AU - Shahverdi, M.

AU - Michels, J.

AU - Czaderski, C.

PY - 2016

Y1 - 2016

N2 - Carbon fiber reinforced polymer (CFRP) materials have been used for strengthening of concrete and metallic structures. There are several differences between the behavior of bonded joints in CFRP-strengthened concrete and metallic members. One of the main differences between CFRP–concrete and CFRP–metal bonded joints is that in the latter, failure will likely occur in the adhesive layer and in the former failure is expected to occur in the concrete. Furthermore, in the concrete girders, cracks are often initiated at low load levels in the tension face, and the bonded CFRP strip tries to close the crack, and consequently increase the stiffness and cracking load. Nevertheless, metallic girders do not crack even after yielding and the effect of having adhesive between the CFRP laminate and steel substrate is limited to transferring the shear stresses from the steel substrate to the CFRP laminate along the connection. Because of these differences, the strengthening concepts for steel and concrete are different, and, therefore, different CFRP prestressing systems are required. This paper provides a short review for different CFRP retrofit systems that have been recently developed at Empa for concrete and metallic members. Details about strengthening of a concrete and a metallic bridge using prestressed CFRP strips are given. At the end, a novel pre-stressing system, which is based on iron-based shape memory alloy (Fe-SMA), is presented.

AB - Carbon fiber reinforced polymer (CFRP) materials have been used for strengthening of concrete and metallic structures. There are several differences between the behavior of bonded joints in CFRP-strengthened concrete and metallic members. One of the main differences between CFRP–concrete and CFRP–metal bonded joints is that in the latter, failure will likely occur in the adhesive layer and in the former failure is expected to occur in the concrete. Furthermore, in the concrete girders, cracks are often initiated at low load levels in the tension face, and the bonded CFRP strip tries to close the crack, and consequently increase the stiffness and cracking load. Nevertheless, metallic girders do not crack even after yielding and the effect of having adhesive between the CFRP laminate and steel substrate is limited to transferring the shear stresses from the steel substrate to the CFRP laminate along the connection. Because of these differences, the strengthening concepts for steel and concrete are different, and, therefore, different CFRP prestressing systems are required. This paper provides a short review for different CFRP retrofit systems that have been recently developed at Empa for concrete and metallic members. Details about strengthening of a concrete and a metallic bridge using prestressed CFRP strips are given. At the end, a novel pre-stressing system, which is based on iron-based shape memory alloy (Fe-SMA), is presented.

KW - Carbon-fiber-reinforced polymer (CFRP)

KW - Iron-based shape memory alloy (FE-SMA)

KW - Prestressing

KW - Reinforced concrete

KW - Steel structures

KW - Strengthening

UR - http://www.scopus.com/inward/record.url?scp=85049922980&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:85049922980

T3 - Proceedings of the 8th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering, CICE 2016

SP - 1118

EP - 1125

BT - Proceedings of the 8th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering, CICE 2016

A2 - Dai, J.G.

A2 - Teng, J.G.

Y2 - 14 December 2016 through 16 December 2016

ER -