DAMAGE EVALUATION AND PROTECTION TECHNIQUE OF RC COLUMNS UNDER IMPULSIVE LOAD

Damage evaluation and protection technique of reinforced concrete RC column subjected to impulsive load are studied through numerical simulation of collision between a rigid ball and the RC column. On the basis of the bond-slip model for the RC column,a damage criterion is put forward to determine the damage degree of the RC column under impact based on the residual axial load-carrying capacity of the RC column. And correlativity between damage degree of the RC column and mass,initial velocity of rigid ball is studied qualitatively. Dynamic response and damage of RC columns before and after protection are analyzed,and the protective effects of strengthening with externally bonded steel plate and foamed aluminum are compared. The results indicate that: the damage degree increases faster than the mass and initial velocity of the rigid ball when the mass and initial velocity are in a low level,and the damage degree enhances fastest as the mass and initial velocity increase simultaneously; when the mass and initial velocity of rigid ball reach a certain value,the growth rate of damage degree will be lower than the mass and initial velocity’s. Moreover,the two protective measures externally bonding steel plate and foamed aluminum can effectively reduce the mechanical response and damage degree of the RC columns; and the protection can also transfer the global failure mode of the RC column from bending-shear failure to bending failure.