The Influence on Portal Frame Buckling of Different Cladding Systems – A Comparative Numerical Study Considering Stressed Skin Effect

In 2016 the authors investigated the stressed skin effect of trapezoidal steel sheeting and of deep deck sheeting as roof cladding on the pitched roof portal frame structure, in terms of buckling modes and the load multiplication factor, by comparing the results of a traditional design model with the result of a numerical model including the diaphragm stiffness of the considered claddings. Later, in 2018 the influence of the purlin-to-beam connection stiffness on the stress skin action of trapezoidal steel sheeting was investigated. The study of stressed skin action was further extended by the authors to the effects given by sandwich panels in 2019, where a methodology was presented to including the stressed skin effect of sandwich panels in a simple and time effective way into the day-to-day design methodologies of common engineers. In 2021 the procedures were improved to present a comparison between different cladding types in terms of sway displacement of the frame structure with semi-rigid joints and load transfer by applying the developed methodology to a reference building. The purpose of the current paper is to compare and to estimate in a numerical manner the influence of the cladding type on the sway stability indicators of the structure, such as buckling modes and critical load multiplication factors cr. The paper presents comparative results obtained in terms of stabilization effects given by trapezoidal sheeting and mineral wool core sandwich panels supported by Z purlins applied on the reference cold-formed steel structure.