1.Reasons for insufficient bearing capacity of concrete columns:

(1) poor design or error;

(2) poor construction quality;

(3) quality accidents;

(4) the management of the construction site is not good;

(5) uneven ground subsidence;

(6) the damage of fire, charge, external force and so on.

2. Reinforcement method of concrete column:

Enlarging section method, steel jacketing method, pre-stress CFRP method, unloading external loading method and increasing support method.