Numerically efficient analysis of concrete-filled steel tubular columns under lateral impact loading

Abstract

Concrete-filled steel tube (CFST) columns have been gradually used as an alternative to conventional reinforced concrete columns because of their excellent vertical and lateral bearing capacity, particularly when columns have a high risk of impact loading. Three-dimensional detailed finite element (FE) models are usually employed to estimate the impact-resistant performance of CFST columns under impact loadings. However, detailed FE models are typically complex in modeling and low in calculation efficiency as well as require high performance in computer hardware. Hence, this paper aims to develop an alternative modeling method that can predict the impact behavior of CFST columns with high efficiency and low requirements in computer resources. The developed method includes a contact model using mass-spring-damper elements to describe the contact behavior between the impactor and the impacted CFST columns and a nonlinear fiber-based beam-column element model to simulate the behavior of CFST columns under impact loading. The accuracies of fiber-section beam-column elements are carefully examined for CFST columns based on quasi-static test data reported in the literature. It is found that the fiber-based elements considering confinement effects induced by steel tubes can accurately predict the force versus deformation relationship of the CFST columns under monotonic loading. By incorporating the strain-rate effects of concrete and steel materials, the validated fiber-section elements are employed to simulate thirty-seven impact tests on CFST columns. Good agreements are observed between the results obtained from the developed models and the experimental data. The computational efficiency can be significantly improved by using the developed model.