Hierarchical structures for a robustness-oriented capacity design

TL;DR

This study investigates how hierarchical 2D framed structures respond to sudden column removal, focusing on their residual strength and collapse mechanisms, using simulations to compare different structural configurations and design principles.

Contribution

It introduces a simulation-based analysis of hierarchical versus homogeneous frames, revealing how structural hierarchy influences robustness and collapse behavior after damage.

Findings

Hierarchical frames show enhanced residual strength compared to homogeneous frames.

Collapse mechanisms depend on the mechanical hierarchy between beams and columns.

Principles of robustness-oriented capacity design differ from traditional anti-seismic approaches.

Abstract

In this paper, we study the response of 2D framed structures made of rectangular cells, to the sudden removal of columns. We employ a simulation algorithm based on the Discrete Element Method, where the structural elements are represented by elasto-plastic Euler Bernoulli beams with elongation-rotation failure threshold. The effect of structural cell slenderness and of topological hierarchy on the dynamic residual strength after damage $\ROne$ is investigated. Topologically \textit{hierarchical} frames have a primary structure made of few massive elements, while \textit{homogeneous} frames are made of many thin elements. We also show how $\ROne$ depends on the activated collapse mechanisms, which are determined by the mechanical hierarchy between beams and columns, i.e. by their relative strength and stiffness. Finally, principles of robustness-oriented capacity design which seem to be in contrast to the conventional anti-seismic capacity design are addressed.