the stiffness centers in frame-shear wall structures have been located by the structural torsion stiffness.However
the results are illogical owing to the difference between the distortion character and the shears distribute mechanism of the frames and shear walls.In this paper
a new formula for calculating story stiffness is introduced
which can consider the stiffness of the frames and shear walls at the same time.The structural stiffness centers
the torsion eccentric distances and torsion effect are calculated
and the stiffness of elements is considered also.It is shown that the concept of the presented stiffness model is clear and the results are reasonable
which can be used to calculate the appreciative torsion effect.