Improvement of stressed skin design procedure based on experimental and numerical simulations

Abstract

Lightweight roof and wall structural systems are widely used for cladding of steel portal frames. It is a well-known fact, that assembled systems of profiled sheeting and purlins show significant stiffness to in-plane loads, which action is referred to as stressed skin effect. This research aimed to investigate the influencing parameters of stressed skin effect in those nonstandard diaphragm constructions, in which seam fasteners are omitted.The focus of this paper is on the results of an experimental test programme, that investigated the stiffness of nonstandard, 3.00 × 3.00 m sized diaphragm configurations for in-plane static load. The experimental results are compared against analytical results derived from calculated shear flexibilities according to current ECCS formulae. Upon experimental test results, a verified and validated numerical model is developed, and the range of experimental tests is extended by numerical simulations. The conclusions of numerical analyses demonstrated, that the effect of purlin section height and thickness is not followed by current ECCS provisions.The intended purpose of the research is to develop the current ECCS stressed skin design formulae to incorporate nonstandard diaphragm constructions, which are commonly used in industrial practice in Europe. The innovative feature of formulae improvement is to comprise the effect of those parameters, which are influencing shear flexibility and are not addressed in the current ECCS design methodology. Upon experimental, analytical and numerical results a modification is presented to current formulae of shear flexibility, which gives a better approach in nonstandard cases.