Seismic Response Analysis of Dual-Chamber Aqueduct Structure with Fluid-Structure Interaction Based on CC-SFSM

Addressing the computational inefficiency and limited adaptability of existing methods for aqueduct seismic analysis, this study proposes a novel Curvature-Continuous Spline Finite Strip Method (CC-SFSM) for high-precision fluid-structure interaction (FSI) modeling of large-scale aqueducts. The CC-SFSM integrates bending and plane-stress spline rectangular strip elements to discretize the aqueduct body and incorporates Housner’s equivalent spring-mass model for fluid sloshing effects. Validated through shaking table tests and benchmarked against theoretical solutions and conventional finite element software, the method demonstrates ultra-high accuracy (critical displacement/moment errors <5%) and exceptional computational efficiency (40–66% faster than spatial beam element modeling). Application to the Laozhang Aqueduct (Middle Route, South-to-North Water Diversion Project) reveals that: (1) Natural frequencies decrease stepwise with rising water levels, while frequency order dominates modal characteristics; (2) Critical displacements (midspan, pier tops) and expansion joint relative fold angles increase nonlinearly with water level, peaking under full-trough conditions due to fluid inertia; (3) Expansion joint angles at pier 3 exceed those at pier 2 by 88.58%, with timing fluctuations attributed to post-impact fluid vibrations. The CC-SFSM uniquely enables direct calculation of joint fold angles, bypassing error-prone transformations in existing approaches. This work advances seismic reliability assessment for hydraulic thin-walled structures and establishes CC-SFSM as an efficient, high-fidelity tool for complex FSI analysis.