New Formula for Calculating the Vertical Natural Frequency of a Suspension Bridge

Abstract

Long-span suspension bridges are flexible structures that are easily vibrated by external load changes. Their vibration characteristics are related directly to the safety of the structure. Although the free vibration characteristics of the structure can be calculated accurately by numerical simulation with mature commercial software, the practical and straightforward approximate formula still is of considerable value. The existing theoretical results of the vertical symmetrical frequency calculations are excessively complex and thus cannot be applied. Herein, a simpler formula, obtained via a reasonable mathematical derivation, is proposed. This formula can directly reveal the mechanism of vertical vibration in suspension bridges.