Study on a new type of beam-column joint equipped with inclined tapered steel plates

Abstract

To avoid the sudden brittle failure at the beam-column joint and improve seismic resilience (i.e. low damage and repairability) of the steel frame structure, this study proposes a new type of beam-column joint equipped with inclined tapered steel plates. The steel plates are tapered-shaped to concentrate plasticity at the reduced middle section for efficient energy dissipation, and they are placed inclined to take full advantage of the joint rotation and can be replaced easily after being damaged. Firstly, based on the plasticity theory, the mechanical property of the proposed joint is analyzed in detail. To validate the theoretical analysis and seismic performance of the proposed joint, three joints with different dimensions and combinations of tapered plates installed are designed and tested under quasi-static cyclic loading. Test results show that the stiffness, moment bearing capacity, and energy dissipation of the joint are enhanced with the addition of tapered plates. Both dimensions and the number of plates influence the hysteretic behavior of the joint. By tuning the parameters of the dimensions and the number of the tapered plates, the joint can be designed to meet the required demands of strength and stiffness. A refined numerical model of the new joint is built, which simulates reasonably well the hysteretic behavior of the joint. Lastly, parametric analysis is carried out to investigate the contributing factor influencing its hysteretic behavior. Parametric analysis results show that the flexibility in connection has a much greater influence than the initial imperfection, and a more rigid connection and smaller initial imperfection give a larger initial stiffness and moment bearing capacity.