Untersuchungen zum Rotationsverhalten von Traegern aus Hohlprofilen

Modern design rules in steel construction are based on limit state design where limit states of serviceability, ultimate limit states and fatigue limit states are considered. The design models for these limit states in general are derived from tests. The ultimate limit state of the structure in general is attained when in these load or deformation controlled tests the maximum of the load deformation curve is reached. An important analysis method for determining the resistance of frames is the plastic hinge method basing on the plastic resistance of hinges and the rotation capacity on the plateau of these resistances. For hollow sections so far sufficient test data and behaviour models for plastic resistance and rotation capacity to permit the application of plastic hinge methods were not yet available. The objective of this work is therefore to carry out such tests to obtain the moment-rotation-curves of hollow section beams, to explain the behaviour with theoretical models and to draw conclusions for the resistance and rotation capacity of hollow sections in dependence of the geometry, the steel grade and the production method. In the first part of the work the rotation requirement for hollow sections used as statically indeterminate beams is calculated and presented showing the influence of various parameters of the frame topology, cross sections and the material. A maximum rotation requirement R = 3.0 has been derived. For rotation capacity that must be greater than the rotation requirement when the plastic hinge method shall be used the planning, execution and evaluation of tests is first described. The influence of the production method being either hot- or cold-rolling on the moment-rotation-behaviour has been clarified. For the engineering application a simplified model was developed on the basis of plastic folding mechanisms, the free parameters or which have been calibrated by tests. The results of the work allow to apply the plastic hinge method for hollow sections in the design. (orig./HK)SIGLEAvailable from TIB Hannover: RO 205(31) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman