Abstract: Based on the uniaxial compression acoustic emission (AE) test of concrete-filled steel tube (CFST) columns with different reinforcement ratio and wall thickness， the AE signal characteristics of each specimen in the whole failure process were analyzed. The test results show that the entire failure process of the specimen can be divided into four stages: elastic section， elastoplastic section， strengthening section and failure section. The change of AE characteristic parameters shows a good corresponding relationship with the failure process of the specimen. The AE cumulative energy and AE cumulative impact number rise with the load increases. The b value has experienced a slow rise， steady fluctuation， and rapid decline， reflecting the gradual expansion of the internal cracks of the specimen; through the analysis of the RA value and AF value of AE， it can be seen that the failure process of the CFST column generates both tensile and shear cracks. With the increase of load， the proportion of shear crack in failure increases gradually. The results show that the AE method can effectively monitor the damage status of CFST columns under uniaxial compression.

Key words: acoustic emission(AE); uniaxial compression; concrete-filled steel tube(CFST); damage evolution; failure mode