Large inelastic cyclic testing of the gusset-plate brace member assemblies in ultra-low cycle fatigue regime

In this paper, the test results of four gusset plate-brace member assemblies in the ultra-low cycle fatigue regime (less than 20 cycles) is presented. Square hollow sections (SHS) of four different cross sections (i.e. 60 x 60... [ view full abstract ]

In this paper, the test results of four gusset plate-brace member assemblies in the ultra-low cycle fatigue regime (less than 20 cycles) is presented. Square hollow sections (SHS) of four different cross sections (i.e. 60 x 60 x 4-2591mm, 80 x 80 x 4-2591mm, 80 x 80 x 4-2526mm, 100 x 100 x 4-2526mm) were employed as the brace members in conjunction with gusset plates that have two separate sizes (i.e. 200 x 300 x 5mm, 266 x 292 x 5mm). The test setup and details of the assembly are described. The tests were carried out under the loading protocol recommended by the European Convention for Constructional Steelwork (ECCS) for the structural testing. The results show that the assembly tends to develop significant strength and stiffness (buckling in compression and yielding in tension) from the brace under cyclic loading when end connections are rigid or substantially rigid. A stiff type connection tends to develop when the gusset plate is thicker and stockier than the brace member in the assembly; however, it does not imply that a large, thick, and highly stiff gusset plates should be employed in practice, as this may lead to uneconomical material costs and over-conservative member design. The global and local brace slenderness is found to be another factor that affects the response features of CBF system significantly.