# Lateral Impact Performance of Cold-Formed Steel L-Shaped Built-Up Columns

## TL;DR

This study examines how cold-formed steel L-shaped columns resist lateral impacts, identifying key factors that influence their performance.

## Contribution

The paper introduces a validated finite element model and parametric analysis to optimize the impact resistance of cold-formed steel columns.

## Key findings

- Peak lateral impact force increases nonlinearly with axial compression ratio, with an optimal ratio of about 0.3.
- Higher impact velocity significantly increases both peak force and displacement responses of the specimens.
- Increasing cross-sectional dimensions and steel thickness, and reducing screw spacing, enhances impact resistance.

## Abstract

Blasts, vehicle collisions, and other unexpected incidents may cause lateral impacts on building structures, which threaten their safety. This paper investigates the impact resistance of cold-formed steel (CFS) L-shaped built-up columns (LBC). Firstly, a finite element model (FEM) was established and validated through experiments conducted by the authors. Then, a parametric analysis was conducted to quantify the effects of axial compression ratio, impact velocity, and dimensions on the impact response. The results indicated that: (1) The peak lateral impact force of the specimens presented a significant nonlinear trend with increasing axial compression ratio, and an optimal axial compression ratio was found as about 0.3. (2) Higher impact velocity intensified both force and displacement responses of the specimens, and both lateral impact peak force and maximum displacement increased significantly with the impact velocity. When the impact velocity rose from 3.13 m/s to 6.26 m/s, the peak force and maximum displacement increased by an average of 38.2% and 96.5%, respectively. (3) Increasing the cross-sectional dimensions and steel thickness, and reducing screw spacing, could significantly enhance the impact resistance and deformation capacity of the specimens. This study reveals the failure mechanism of such members and the laws of parameter influence, which can be used for impact design of CFS-LBC.