Effect of eccentric compression loading on the strains of FRCM confined concrete columns

• The strains of eccentrically compressed columns strengthened with FRCM materials have been analysed.
• The value of compression strains depends on the construction method and the strengthening intensity.
• The value of hoop strains depends on the effort of concrete inside the jacket, the strengthening method and eccentricity.

The paper describes the effect of eccentric compression on the strains of RC columns, reinforced with FRCM (Fibre Reinforced Cementitious Matrix) composites. Over the span of a dozen or so years, many research studies have been dedicated to the learning of the behaviour of FRP confined concrete elements. The comprehensive test results of axially and eccentrically compressed elements as well as numerous theoretical analyses provide an opinion on the effectiveness of FRPs (Fibre Reinforced Polymers). Under the FRP system, the bonding of a composite material with concrete is made using epoxy resin, on the other hand, under the FRCM system, a composite material is bonded with concrete using a mineral mortar. The FRCM strengthening is relatively poorly recognised, and the research studies presented aim at the widening of the knowledge acquired to date. The testing was performed on 15 slender reinforced concrete columns that were strengthened longitudinally and/or transversally with a composite mesh under the FRCM system. The elements were subjected to axial compression and on the eccentrics: h/6 and h/12. The paper presents the testing preparation and performance method. The description of the strengthening effectiveness was made basing on the values of the energy of destruction. On the grounds of the analysis of the Poisson’s ratio value, the impact of the strengthening method and of the eccentric on the state of stress of the material being tested was reviewed.