Progressive Collapse Mechanisms of Brittle and Ductile Framed Structures

TL;DR

This study investigates how brittle and ductile 3D reinforced concrete framed structures undergo progressive collapse after a column loss, focusing on the influence of structural features and reinforcement on collapse mechanisms and outcomes.

Contribution

It introduces a simulation approach using the Discrete Element Method to analyze collapse initiation, propagation, and final damage in structures with varying geometric and mechanical properties.

Findings

Collapse mechanisms depend on cross-sectional size and reinforcement ratio.

Plastic capacity influences the extent and nature of collapse.

Reinforcement symmetry affects damage response and failure modes.

Abstract

In this paper, we study the progressive collapse of 3D framed structures made of reinforced concrete after the sudden loss of a column. The structures are represented by elasto-plastic Euler Bernoulli beams with elongation-rotation failure threshold. We performed simulations using the Discrete Element Method considering inelastic collisions between the structural elements. The results show what collapse initiation and impact-driven propagation mechanisms are activated in structures with different geometric and mechanical features. Namely, we investigate the influence of the cross sectional size and reinforcement $\alpha$ and of the plastic capacity $\beta$ of the structural elements. We also study the final collapse extent and the fragment size distribution and their relation to $\alpha$, $\beta$ and to the observed collapse mechanisms. Finally, we compare the damage response of structures with symmetric and asymmetric reinforcement in the beams.