Parametric analysis of blind-bolted connections in a moment-resisting composite frame

This paper presents a detailed parametric study on the behaviour of blind-bolted curved endplate connections to concrete-filled circular hollow sections. A detailed finite element model was developed and compared with the results from a full scale T-stub connection test. Comparisons between numerical and experimental data for tensile behaviour of the connection show satisfactory agreement. The models take into account material nonlinearities, geometrical curvature, and complex contact interactions between the blind bolt heads, circular tube wall curved endplates and nuts. The various effects of tube wall thickness, endplate thickness, and anchorage extensions in the tubes on the connection behaviour have been explored using the developed finite element models. A moment-rotation curve has been derived based on the analysis. The favourable strength and stiffness of this innovative connection utilising one-sided fastening blind bolts with anchorage extensions showed that it could be an attractive solution to the conventional welded moment connections in a composite structural frame. The cogged extensions to the blind bolts are very effective in relieving the stress concentration on the thin tube wall.