PREDICTION OF THE TORSIONAL RESPONSE OF MONO-SYMMETRIC MEMBERS WITH REGULAR PERFORATION SYSTEMS

Perforated cold-formed steel members are commonly used in logistic for storage solutions. Generally, these profiles have a mono-symmetric cross-section characterised by a relevant eccentricity between the shear center and thee cross-section centroid and are interested by non-negligible torsional effects. The design approaches currently adopted derive from those developed for solid bi-symmetric cross-section steel members. As a consequence, this could reflect in an un-optimal design for the use of the components and/or for the effective level of reliability required by standard provisions. The paper is addressed to the torsional response of mono-symmetric perforated members, which are currently used for the columns (uprights) in storage racks. In detail, attention is focused on the evaluation of the warping constant, which is of paramount importance to appraise the distribution of the normal stresses associated with the bimoment and to appraise warping torsion. A model based on the theory of elasticity is proposed in order to account for the sequence of solid and perforated cross-sections along the longitudinal axis of the member. Numerical applications are related to two different open cross-sections and the proposed research outcomes underline the errors associated with a warping constant defined by neglecting the presence of regular perforation systems.