Multi-scale numerical simulation analysis of CFST column-composite beam frame under a column-loss scenario

Abstract

Experimental studies are costly for human and financial resources, while numerical simulation studies can further amplify the conclusions based on experimental results. The conventional numerical model based on brick elements and beam-shell elements is computationally inefficient and inaccurate, respectively. It is advisable to develop a simplified simulation method that ensures computing efficiency while not losing computational accuracy. Consequently, this paper innovatively proposed a numerical simulation method that integrates multi-scale elements modelling and simplified non-essential components, significantly increasing the computing efficiency and accuracy. Subsequently, the concrete-filled steel tubular (CFST) column-composite beam frame models based on the previous tested specimens were numerically developed and studied, considering different simulation methods, column-loss scenarios, and number of storeys. The numerical results identified the cantilevered deep beam effect in a multi-storey composite frame under an edge column-loss scenario, and the simply supported deep beam effect under a penultimate column-loss or a middle column-loss scenario, both reasonably represent the internal force pattern. Furthermore, to enhance the capacity of composite frames to resist progressive collapse, two improvement alternatives were proposed, i.e., fully bolted connection and pre-stressed strand device.