Numerical simulation and experimental study on mechanical behavior of the gusset for nuclear power plant containment

The gusset of a nuclear power plant containment, which serves as the junction between the shell and the raft foundation, is a critical area that poses a significant challenge due to its irregular shape and complex mechanical properties. Studying the stress mechanism of this area is crucial to understanding the overall structural performance of the containment. To achieve this, ABAQUS software was used to simplify the containment model and develop a gusset model, which was validated by comparing it with a fan-shaped containment model. Two 1:3 scale specimens were then designed and fabricated based on the gusset model to conduct static tests under two loading combinations. The effectiveness of the finite element model (FEM) was verified by comparing the failure mode, load-strain relationship of the rebars, and load-displacement relationship with that of the test. Through finite element parameterization analysis, the effects of reinforcement ratio and thickness on the mechanical performance of the gusset were investigated. The results showed that tripling the reinforcement ratio in rows H1 to H3 and column S1 or increasing the specimen thickness by 500 mm significantly improved the tensile damage of concrete, yield of rebars and structural displacement. Additionally, removing rebars from columns S8 to S13 had little effect on the structure. The findings of this study can guide the optimization of containment structural reinforcement and provide essential data support for FEM.