Search Results (3)

In this paper, the quasi-static reciprocating loading test was carried out for the T-stub steel middle column joints with blind-bolt connections. As the thickness of the T-stub steel increased, the damage failure modes were different. The load–displacement curve, cumulative energy dissipation, equivalent viscous damping coefficient, damage index and other characteristics of the joints were analysed. When T-stub steel was used as a connector, its thickness affected the damage development mode. As the thickness of T-stub steel increased, the bearing capacity and plastic displacement were improved, the energy dissipation capacity was significantly increased, and the rotational stiffness retention ability of the joint was improved, but the damage index value was not significantly increased. Finally, the damage index and the rotational stiffness degradation coefficient under each loading level were numerically fitted, and the polynomial and exponential rotational stiffness models were established, taking into account the damage index. These two models took into account the reduction in rotational stiffness caused by damage under each level of load, and the rotational stiffness under each loading level could be obtained from the damage index and the initial rotational stiffness. Full article

The quantitative calculation and evaluation of seismic damage play a crucial role in ensuring structural safety, conducting performance-based structural analysis, and implementing seismic strengthening measures. However, there is limited research on the damage performance of blind-bolted T-stub steel connections used extensively in prefabricated buildings. In this study, the tensile sub model of a blind-bolted T-stub steel connection in a beam–column joint is investigated. The influence of the flange and web thickness of the T-stub connector, as well as the shear-loaded connecting bolts on the web of the T-stub, on the tensile performance of the sub model are considered. Four tensile destructive tests are conducted on a T-stub connector connected to a hollow section column using blind bolts. The experimental results, including failure modes, force–displacement curves, and strain development in the hollow section column and T-stub, are discussed and analyzed in this study. The test results reveal three main failure modes for this tensile substructure: the plastic deformation of the hollow section column, the bending fracture of the T-stub flange, and the fracture of the T-stub web bolt holes due to compression. Furthermore, a ductile damage finite element analysis method is employed to simulate the fracture damage process of the substructure, and the corresponding damage index is calculated using the typical Park–Ang damage model for evaluation, showing good agreement with the damage classification levels specified in FEMA. Full article

The steel frame-reinforced concrete core tube structural system is widely used in mid-rise and high-rise buildings due to its good seismic behaviour and high construction efficiency. Since the steel frame and the reinforced concrete core tube are supposed to deform synergistically under earthquake action, the steel beam-concrete wall joint (SBCW joint for short) will be subjected to a significant pull-out force. Therefore, the pulling resistant capacity of the SBCW joint is quite important for the seismic performance of the overall structure. In response to the shortages of the existing SBCW joint types, a new SBCW joint with a T-stub connector was proposed and studied. The experimental and analytical research has indicated that there are different failure modes and force mechanisms of the SBCW joint under pull-out load, and further studies are required for the pulling resistant capacity. On the basis of recent research findings, a numerical investigation on the pulling resistant capacity of the joint is conducted in this study. An elaborate 3D finite element model of the SBCW joint is proposed, and the load performance, strain and stress development, deformation characteristics and failure modes are analysed in detail. Then, a series of parametric analyses are carried out based on the finite element model, indicating that the length and the web height of the T-stub connector, the number of shear studs on the connector and the reinforcement ratio of stirrups have an obvious effect on the pulling resistant capacity. Finally, the critical value of the embedded depth of the connector, which is found to be one of the most important parameters for the failure mode and pulling resistant capacity of the joint, is determined, and design recommendations are proposed for the SBCW joints with T-stub connectors. Full article