Seismic performance of innovative flexural bolted connection of portal steel frame made of cold formed members

One of the most exciting developments in structural steelwork during recent years has been the widespread and increasing use of cold formed members as main structure in the construction of steel framing. Their strength, light weight, versatility and non-combustibility and ease of production have encouraged architectures, engineers and contractors to use cold formed steel products which can improve structural function and building performance. This paper presents a numerical investigation on cold formed steel moment frames made of lipped channel sections one way screw connected front to front. The current study, in fact, tries to show the superior performance of the introduced moment resistance cold formed frame in terms of strength and ductility against cold formed steel strap-braced frames, which was previously tested in lab by authors on scaled size 1500×1300 mm specimens, undermonotonic and cyclic loading. Managing to attain moment resistances which are closeto the results of connected sections, it was proven that the proposed connections werestructurally efficient. Finite element models were established in ABAQUSenvironment with the use of shell elements to model the sections while bar elementswere used to model the bolted fastenings for the purpose of examining the structural behaviour of the beam-column connections. Incorporation of material non-linearity and comparison between the experimental and numerical results were presented. It was found that the stiffness and performance of the beam-column connections had significant effect on structural behaviour of the frames. The predicted failure loads are in close agreement with those measured in experimental approaches. In the extended numerical simulation lateral load were applied, with two kinds of cyclic hysteresis and monotonic push over fashions, to the lateral resistance frame in the presence of vertical gravity load.

Keywords:

Cold-formed steel , Bolted moment connections , Stiffness , Beam-column connection , Lateral performance