As for the limit bearing capacity formula of the concrete filled steel tube long column subjected to axial compress, we lead to the tangent modulus and the conception of metal material.
As the existence of inner stress of steel decreases the bearing capacity of steel, which may lead to unpredictable accidents, therefore it's practically significant to test the inner stress of steel.
钢件内应力的存在使钢件的承载能力下降，常常带来难以预料的事故。
3
Thus, the stresses of the steel increases while the stress of the concrete decreases, which will lead to a reduction of the bearing capacity of components.