Torsional instability in suspension bridges: the Tacoma Narrows Bridge case

TL;DR

This paper introduces a new nonlinear model for suspension bridges, demonstrating through numerical experiments that torsional instability thresholds align with the Tacoma Narrows Bridge collapse, offering a novel explanation based on structural nonlinearities.

Contribution

The paper proposes a new nonlinear model for suspension bridges and shows it can explain torsional instability without aeroelastic theories.

Findings

Thresholds of instability match observed collapse conditions

Nonlinear behavior alone can explain torsional instability

Provides a new perspective on bridge collapse mechanisms

Abstract

All attempts of aeroelastic explanations for the torsional instability of suspension bridges have been somehow criticised and none of them is unanimously accepted by the scientific community. We suggest a new nonlinear model for a suspension bridge and we perform numerical experiments with the parameters corresponding to the collapsed Tacoma Narrows Bridge. We show that the thresholds of instability are in line with those observed the day of the collapse. Our analysis enables us to give a new explanation for the torsional instability, only based on the nonlinear behavior of the structure.