• Steel and Composite Structures
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• v.6 no.1
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• pp.71-85
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• 2006

This paper presents the results of a series of tests carried out on cold-formed steel rectangular hollow and concrete infilled beam to column connections and frames. A stub column was chosen such that overall buckling does not influence the connection behaviour. The beam chosen was a short-span cantilever with a concentrated load applied at the free end. The beam was connected to the columns along the strong and weak axes of columns and these connections were tested to failure. Twelve experiments were conducted on cold-formed steel direct welded tubular beam to column connections and twelve experiments on connections with concrete infilled column subjected to monotonic loading. In all the experiments conducted, the stiffness of the connection, the ductility characteristics and the moment rotation behaviour were studied. The dominant mode of failure in hollow section connections was chord face yielding and not weld failure. Provision of concrete infill increases the stiffness and the ultimate moment carrying capacity substantially, irrespective of the axis of loading of the column. Weld failure and bearing failure due to transverse compression occurred in connections with concrete infilled columns. Six single-bay two storied frames both with and without concrete infill, and columns loaded along the major and minor axes were tested to failure. Concentrated load was applied at the midspan of first floor beam. The change in behaviour of the frame due to provision of infill in the column and in the entire frame was compared with hollow frames. Failure of the weld at the junction of the beam occurred for frames with infilled columns. Design expressions are suggested for the yielding of the column face in hollow sections and bearing failure in infilled columns which closely predicted the experimental failure loads.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1049-1052
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• 2008

Coupling beams have been used in bearing wall system during last decades. Practically their sectional effects are fully considered in analysis stage to control lateral displacement because they have good contribution to the stiffness of bearing wall system. But the high resultant forces of coupling beam are not fully satisfied in design stage because coupling beams are restricted in sectional size. In this paper the performance of bearing wall system with coupling beam has been evaluated based on improved equivalent linearization procedure of FEMA 440. 15 storied building is selected for analysis. Variables for performance evaluation are natural period, degree of coupling and soil site. To evaluate performance, demand capacity spectrum is calculated based on KBC 2005. As a result, for the most of the cases the life safety limit of chord rotation of coupling beam is less than the performance point of system for soil site $S_D$. That means that the coupling beam can be severly damaged before the system reaches at performance point.