Gravity Stiffness of Classical Suspension Bridges

Abstract

Although classical suspension bridges have been designed for over 70 years using the deflection theory, it is difficult to obtain from literature a clear understanding of their structural action. The all‐important “gravity stiffness” is isolated from the modifying effects due to cable extensibility, tower stiffness, and deck bending stiffness. Graphs of maximum gravity stiffness deflections and changes of slope due to concentrated and distributed loads are presented, and formula for the modifying effects are given. It is found that with flexible decks simple formula exist for the maximum bending moment and shearing force in the deck due to concentrated and distributed loads.