Seismic behaviour of RC columns retrofitted with textile-reinforced mortar (TRM) optimized by short PVA fibres

Abstract

Textile-reinforced mortar (TRM) optimized by short polyvinyl alcohol (PVA) fibres was used as a strengthening material for seismically deficient reinforced concrete (RC) columns. Seven RC columns, including a reference column, a column strengthened with the inorganic matrix added short PVA fibres, and five columns strengthened with the optimized TRM, were subjected to low-frequency cyclic loading. The influences of the reinforcing ratio of carbon textile and axial load ratio on the seismic performance of the jacketed columns were studied. The results showed that the shear capacity and deformability of RC column respectively increased by 54.3 ∼ 55.2 % and 40.34 ∼ 78.62 % after strengthening with the optimized TRM system. Increasing the reinforcing ratio of carbon textiles in the strengthening layer, the displacement ductility and energy dissipation of the jacketed column were further enhanced. As the axial load ratio increased, the shear capacity of the jacketed column increased; however, the corresponding ductility and energy-dissipation ability decreased. The relationship between the shear contribution and material configuration of the TRM was established. The shear capacity of the TRM-strengthened columns can be estimated by a modified shear model considering the reinforcement ratio of textile and the volume content of PVA fibres.