Axial compressive behavior and design method of corrugated double-steel-plate composite shear walls under long-term loading

The design of corrugated double-steel-plate composite shear walls (CDSCWs) is mainly based on their short-term behavior, while their long-term performance remains understood, posing potential safety risks. This study investigates the axial compressive behavior of CDSCWs under long-term loading. A refined finite element model incorporating creep effects (ACI 209, EC2 models) is developed, and a parametric study is conducted considering loading duration, creep load level, aspect ratio, wall thickness, concrete confinement coefficient, and steel plate type. Results reveal that creep-induced stress redistribution transforms the failure mode from localized stress concentration to a more distributed global failure involving multiple load-carrying mechanisms. Long-term loading reduces peak load (up to 23.91%) and axial initial stiffness (up to 42.99%), while significantly enhancing ductility (up to 111.78%). The creep load level, wall thickness, and aspect ratio are identified as the primary parameters governing the peak load, initial stiffness, and ductility, respectively, under long-term loading. A modified calculation formula for predicting the axial compressive capacity of CDSCWs under long-term loading is proposed, based on CECS provisions.