An Analytical Algorithm for Estimating the Deck’s Maximum Deflection and Deck-End Rotation Angle of a Suspension Bridge under Live Load

Abstract

With the appearance of large-span and heavy-duty high-speed railway suspension bridges, their deck deflections and deck-end rotation angles (DERA) under the live load became very topical indicators of bridge safety and stability. In contrast to multiple studies of the deck deflection, quite a few were devoted to the DERA. Based on the deflection theory, the continuous functions of deck deflection and DERA with the uniformly distributed load of any length acting at any position were introduced in this study. The method of finding the maximum value by derivative was performed to find the maximum DERA, maximum deck deflection, and its position. The proposed analytical algorithm was applied to a calculation example. The results were compared against those obtained by a trial-and-error method based on the finite-element method, which verified the feasibility and accuracy of the proposed analytical algorithm. Besides, the effects of several design parameters on the maximum DERA and maximum deflection of the deck, including dead load, span length, bending stiffness of the deck, and axial stiffness of the main cable were analyzed via the proposed method. It revealed that adjusting the main span length, dead load, and deck bending stiffness value was the most effective way to control the maximum deck deflection and maximum DERA.