Displacement Distribution of Prestressed Square Concrete-Filled Steel Tubular Cantilever Columns under Lateral Impact at Any Point

Abstract

Prestressed concrete-filled steel tubular (CFST) cantilever columns can delay cracking in steel tubes and enhance their impact resistance. However, existing theoretical models lack the capability to efficiently and analytically predict the displacement distribution along the column height under arbitrary impact locations. This paper conducts theoretical analysis based on d’Alembert’s principle, considering the influence of inertial forces, to derive the displacement distribution of prestressed CFST cantilever columns under lateral impact loads. The theoretical derivation divides the deformation of the cantilever column after impact loading into four stages: the first two stages represent the short-term effects of the member; while the latter two stages represent its long-term effects. The deformation caused by long-term effects is significantly greater than that induced by short-term effects. Comparisons between the theoretically derived values and experimental/simulation results show that the theoretical values can effectively predict the deformation of the member at each stage. However, when the impact height is relatively low or the impact mass is large, the long-term effects significantly exceed the experimental and theoretical values, resulting in conservative (safer) predictions. Additionally, the theoretical calculation formulas qualitatively indicate that the final lateral displacement of the prestressed member is smaller.