| Steel tubular structures has been widely used in construction projects because of its beautiful appearance, fabric concision, light weight and superior mechanical properties. T-type RHS joints is a very common type of structure in the steel structure.When the branch tubular under axial load, upper surface and side wall of main tubular tend to appear deformation of the intersection between main and branch tubular, the intersection between main and branch tubular is a weak site, so it is necessary to reinforce the joints. The arrangement of the inner stiffened plate can enhance both strength and stiffness of the joints and keep the appearance in the meanwhile. Experts and scholars at home and abroad have made a lot of theoretical analysis and experimental research on T-type RHS reinforcement joints, and achieved a lot of results. However, at present, the research results of the intersecting joints at home and abroad belong to the study of the static load carrying capacity of the joints. The research results on the hysteretic behavior of the stiffened joints under cyclic loading are limited. Therefore, this paper studies the hysteretic behavior of T-type RHS joints.In this paper, two T-type RHS joints with no stiffened plate and four T-type RHS joints with stiffened plate were tested by low-cycle tension and compression test. The failure process of the specimen was observed. The failure mode, hysteretic behavior, seismic behavior, carrying capacity, ductile deformation capacity, energy dissipation and local stiffness of joints are analyzed according the data gained from the tests. The results showed that:(1) Under the action of cyclic load, the two welds of the unstiffened specimen cracked along the length of the main tubular, and the upper wall of the main tubular was sheared. The bearing capacity of the non-stiffened specimen was low, the ductility was poor and the energy dissipation was not obvious.(2) After the single stiffened plate is installed inside the main tubular, it is possible to avoid the problem of the earlier cracking of the joints at the intersection between main and branch tubular when the load is repeated, and increase the ductility and energy consumption of the joints.(3) The carrying capacity of the stiffened specimen is better than the unenhanced specimen; The hysteresis curve of the stiffened specimen is more full and the hysteresis loop area is larger, therefore, the inner stiffened plate reinforcement joints can improve the seismic behavior of the joints. The deformation ability of the stiffened specimen is improved obviously. The energy dissipation of the joints is better than that of the unenhanced joints. The local stiffness of the joints is obviously improved compared with the non-stiffened joints.(4) Through the comparison of the data of the stiffened specimen, it is found that the joints with larger β value has better seismic performance, bearing capacity,ductility and dissipation behavior than the joints with smaller β value. When the size is the same, the small hole of the stiffened plate enhanced the behavior of joints to a greater extent. |
