Seismic impact resilience assessment of aqueduct structure based on stochastic dynamic coupling probability density evolution mode

In response to the insufficient consideration of the collision effect of expansion joints in the current seismic research of aqueduct structures, this study focuses on the seismic collision resilience assessment of aqueduct structures and proposes a comprehensive evaluation method for the seismic resilience of aqueduct structures that considers the composite randomness of seismic motion and structural parameters. The constructed technical framework includes: finite element model considering three-dimensional collision effects, probability density evolution analysis method, vulnerability analysis of double random variables (seismic motion and structural parameters), and component system two-level resilience evaluation model. Input the amplitude modulated random seismic motion into the finite element model of the random structure of the aqueduct considering the three-dimensional collision effect, focusing on the displacement response of the main seismic components. Based on the probability density evolution theory, calculate the seismic vulnerability of the main seismic components, and then comprehensively evaluate the seismic resilience of the components at the system level. The study revealed the seismic damage evolution law of aqueduct structures considering the collision effect of expansion joints. The main research results show that within the range of 0.2–0.7 g PGA, the collision effect of expansion joints leads to a sharp change in displacement response, and the seismic vulnerability curve exhibits a clear S-shaped nonlinear characteristic. Compared to trough piers, the probability of failure of bearings is generally higher at each stage of failure, and after the PGA exceeds 0.6 g, the collision effect causes a significant increase in the probability of moderate, severe, and complete failure of the bearing in the range of 0.7–0.8 g PGA. The resilience assessment results show that the seismic resilience of the system significantly decreases from 0.9548 to 0.1344 as the PGA increases from 0.1 g to 1.0 g. Among them, the reduction in bearing resilience is as high as 99.2 %, which is the dominant factor leading to the overall seismic performance degradation of the aqueduct structure.