Experimental full-scale tests on steel portal frames for development of diaphragm action - Part I experimental results

Previous studies on stressed skin effect of industrial steel buildings showed discrepancies between the ECCS formulae and experimental results. To clarify the discrepancies full-scale experimental test program was planned and executed by the Budapest University of Technology and Economics, Department of Structural Engineering. The aims of the full-scale tests were to refine the stressed skin design method and to adjust it to the nonstandard cladding structural system applied by an industrial partner. During execution of the full-scale experiments the shear flexibility of those industrially applied nonstandard diaphragms were examined, where the application of seam fasteners were rejected. Next to the building section a loading frame was built, so that tension and compression force could be applied to each frame, in order to examine the in-plane shear flexibility of the whole nonstandard diaphragm assembly, including the shear flexibility of the portal frame. In the test series four purlin and two trapezoidal sheeting height configurations were combined in more than 100 tests. This paper, denoted as Part I shows the test setup and introduces the results derived from the ECCS formulae, underlining the importance of extending the applicability of the current design formulae to nonstandard cases, which are often applied in industrial practice all over Europe. A companion paper (Part II) presents the comparative results between the various cladding configurations, also the main conclusions regarding the stiffening effect of the applied diaphragm configurations, and reports the effect of change in section size to shear flexibility. Besides this in Part II the effect of different structural components in regards to shear flexibility is underlined.