m. patel

The presents study numerically investigates the fiber-reinforced polymer (FRP) retrofitted short-damaged reinforced concrete (RC) columns subjected to axial compression load. The main parameter considered to evaluate the effectiveness of FRP retrofitting on circular columns with different aspect ratios, concrete grade, and FRP material. To simulate the behaviour of a short RC column under a uniaxial compression load, a finite element model of the column was developed. The model was then modified to simulate the various level of damage to the column and the behaviour of the column under uniaxial load. The effectiveness of FRP retrofit was studied comparing the behaviour of the retrofitted column to the damaged column. For M20 concrete column retrofitted with carbon fiber reinforced polymer (CFRP) showed a higher strength (2 to 3 times) than glass fiber reinforced polymer (GFRP) retrofitted columns. For M30 concrete, the range is quite similar (1.5 – 2.3 times more). The effectiveness of both FRPs retrofitted columns increases with increasing aspect ratio from 2 and 3, but slightly decreases for an aspect ratio of 4 compared to the damaged specimen. The maximum effectiveness achieved for CFRP retrofitted columns is of 19.45% and for GFRP retrofitted column is of 10.71%, and the other grade of concrete (M30) followed a similar trend. The load-bearing capacity of columns has no significant effect by the increase in aspect ratio from 2 to 4.

The predictive accuracy of the finite element (FE) based packages are broadly based on the compatibility of adopted non-linear numerical procedures and incorporated material models. However, the routine way to define concrete material is not applicable to the concretes containing substitute materials in place of conventional concrete ingredients. Therefore, in this work, appropriate definition of materials in terms of stress-strain relations have been utilized to simulate the experimental work of RC beams containing coarser fractions of recycled concrete aggregates (RCA). The entire work has been carried out into two phases; an experimental work and the simulation of experimental work using FEA package, ABAQUS. In the experimental part, three number of full-scaled beam specimens were tested to failure through four-point monotonous loading. The replacement level of natural coarse aggregates was taken as 0.0, 50 and 100% by direct substitution. In the simulation phase, in addition to laboratory evaluated properties like compressive stress, tensile stress and elastic modulus, the measured stress-strain relationship for reinforcing steel and constitutive relationship for recycled aggregate concrete (RAC) reported in the literature have been considered as an input. The stress-strain relationships of RAC selected from the literature has been treated as user defined model. Besides the strength, serviceability in terms of deflections, crack patterns and load deformation characteristics of simulated beams have been investigated and compared with those of laboratory tested beam specimens.