Experimental and theoretical study on coral concrete filled steel tube

The feasibility of using coral concrete in CFST was studied based on the reinforcement corrosion mechanism of chloride iron. The theoretical analysis shows that, filling coral concrete into the inner tube can effectively avoid the problem of corrosion of chlorine ion. In order to examine the bearing capacity of coral-CFST, using coral reefs and sand to substitute conventional coarse and fine aggregates, three groups of nine coral-CFST short columns were tested under axial compression. The tests mainly focused on the influences of coral origin (Bohai Sea, South China Sea) on the mechanical properties of coral-CFST and the difference between coral-CFST and plain CFST. The experimental results show that the load-displacement curves of the three groups of coral CFST column are basically the same with very close maximum capacities. The coral origin doesn't cause significant difference to the mechanical properties of the coral-CFST specimens. According to the test results and the finite element analysis results, the paper gives the coral-CFST capacity calculation formula based on ordinary CFST design method, which is useful to practical engineering.