Inelastic rotational response of single story lateral load resisting structures

The rotational response of inelastic asymmetric systems is the objective in this paper. As building structures of low or medium height are usually designed by a pseudo-static approach using a base shear much lower than that predicted from an elastic spectrum, the question which arises is what element strength assignment provides the minimum rotational response in the case of a strong ground motion. Several single story structural models are examined subject to six different ground motions and it is demonstrated that any strength distribution which produces low values of strength eccentricity and strength unbalance results in a low or moderate torsional behavior. A convenient method to achieve such reduced parameters is to apply a static analysis assuming that the design shear is passing through the center of mass, neglecting the existence of the orthogonal elements into the torsional stiffness of the system.