Analysis of Accurate Dynamic Responses on Orthotropic Steel Deck Based on Multi-scale Time-Varying Boundary Approximation Method

Abstract

Accurate evaluation of dynamic effects on critical components of orthotropic bridge decks is of great significance for structural damage identification and fatigue life prediction, especially for long-span cable-stayed bridges. However, the prohibitive computational cost of the traditional finite element (FE) method makes it unfeasible for this problem. Therefore, based on dynamic balance equations and FE strategies, multi-scale time-varying analysis approach is proposed and derived theoretically in this paper. Unlike most of the existing methods, the dynamic effect of the refined model is easily solved by repeated iteration by using the dynamic responses of a relatively large-scale model as boundary conditions. As a case study, the whole segment model of an orthotropic bridge deck is established and performed via two refinement processes at the complex junction area between the plate and the longitudinal ribs under the track. A similar and sufficiently accurate model is also analyzed using ANSYS package in general FE method, and the comparison is made. This study can be considered as an attempt to provide a brand-new high-efficiency analysis framework for accurate solution of local vibration problems. Under relatively small and easily manageable calculation conditions at each cross-scale processing, not only the requirement of global design for actual engineering applications can be met, but also the aim of further in-depth analysis can be achieved as well.