Experimental tests of steel unstiffened double side bolted end-plate joints have been presented. The main aim of the conducted tests was to check the behavior of joints in an accidental situation and possibility of creating secondary mechanism, i.e. catenary action in the scenario of column loss. Two types of end plate joints were tested: flush end-plate (FP) and extended end-plate (EP) with different thickness and different number of bolt rows in each. The tests were carried out on an isolated cross beam-column-beam type system until joint failure. During tests the available moment resistance and rotation capacity of bending joints and also values of tension forces in the beam were determined. The joints with extended end-plate have demonstrated higher bending and rotational capacity than flush end-plate. Significant deformation of column flanges, web and end plate were observed. The fracture of bolts was the failure mode of joints. Obtained results of axial force values in beam exceeded standard requirement what confirmed that the joints with unstiffened web column, flush or extended end-plate possess the ability of development the catenary action.

No abstract

No abstract

The research project was carried out to estimate the robustness of flat steel-framed structures in a selected accidental situation. For this purpose, a multistage approach based on experimental tests and numerical analysis was performed. As the main objective of the work, a numerical dynamic analysis of the steel frames was performed under a sudden and gradual internal column loss scenario. FEA models were created in Abaqus software using solid and shell elements. Computer analyzes were carried out in a number of different cases, taking into account the size of the structure, the type of joints, and the method of removing the column from the structure. Detailed results on the axial forces and rotation of the joints under analysis are presented, and the robustness of the structures is estimated. In all cases of frames with flush end-plate joints, an insufficient level of robustness was observed and failures of the structures were obtained. In the cases of application of extended end-plate joints in frame analysis, the required level of robustness was reached in all cases and the stop of collapse was obtained. Finally, practical recommendations for designing robust joints and the whole frame structure are presented.

No abstract