Investigation into the Nonlinear Time-History Analysis of CNT-Reinforced Concrete Column by a Multiscale Approach

Many concrete structures have been damaged during recent earthquakes due to the low ductility of their columns. Hence, several recent research contributions have been dedicated to producing high-performance concrete materials. Among these contributions, carbon nanotubes (CNTs) are of superior mechanical properties and can be used as additive in concrete. In this research, a sequential multiscale method, including nano-, micro-, meso- and macro-scales, is used to investigate the cyclic and seismic responses of concrete columns through numerical simulations. The aim of this research is to investigate the load-carrying capacity and energy absorption of CNT-reinforced concrete columns under cyclic loading. The results of the current research indicate that both of these properties improve significantly in the presence of CNTs. Furthermore, the results of fragility analysis reveal that for similar damage states, a CNT-reinforced column reaches the specified damage state at higher peak ground motion acceleration than an ordinary concrete column. Hence, the use CNTs in concrete structures may prove beneficial for high-seismic risk areas.