Structural Behavior of Reinforced Hybrid Concrete Columns under Biaxial Loading

Abstract The study aims to investigate the behaviour of reinforced hybrid concrete columns consisted of two fully-bonded concretes subjected to biaxial loading. Experimental tests were conducted on 5 square columns of 200mm side dimensions. Two columns were cast from one type of concrete but with varied strength. The other three specimens were cast by hybrid concrete with different hybrid’s ratios. The study also comprised the derivation of an analytical model, simulating the behaviour of the tested column by numerical models, and statistical evaluation. Whereas a computer program was constructed to evaluate the ultimate strength of hybrid columns and finite element models were executed for the numerical analysis. Both results were compared with the experimental outcomes and good agreement was observed. The results revealed an increase in the ultimate load of hybrid columns by 33.5% as compared with conventional columns. Also, the ultimate load increased by 38% with decreasing the hybrid’s ratio to 0.16. It was concluded that hybrid columns with small hybrid’s ratios sustain higher loads, moments and exhibited fewer axial strains.