Hybrid Bem-Fem Assessment on the Dynamic Behaviour of Integral Bridge

Abstract

One of the most important steps in the design of dynamic-resistant structure is the identification of the natural frequencies of the structure which are the representation of the dynamic behaviour. In integral bridges, the omittance of joints and bearings leads to substantial soil-structure interaction, thus increasing the sensitivity of the dynamic behaviour of the bridge to the underlying and backfill soil characteristic. As a result, accurate identification of the natural frequencies can be a profound problem for integral bridges when encastre grounding or frequency-independent spring-damper system is utilized in the numerical model. Considering the current trend of infrastructure development, this situation can lead to the increase of the economic cost of infrastructure. In this article, steady-state dynamic assessment of phenomenon at hand is presented by utilizing hybrid method of an in-house BEM for describing the semi-infinite part of the geological region and the commercial FEM software, ABAQUS for modelling the finite part of the soil-structure system. The retained flexibility and versatility of FEM and the capability of satisfying the Sommerfeld's radiation condition of BEM make it possible to approach the problem in a more realistic and accurate manner without losing practicality. The influences of the bridge geometry and the soil condition on the natural frequencies of the structure are investigated and comparison to the conventional results are presented.

The Dynamic Characteristics of Railway Portal Frame Bridges: A Comparison between Measurements and Calculations

“…Furthermore, only 3D models can adequately capture relevant bending and torsional modes. Nevertheless, the use of high-fidelity and complex hybrid models (see Figure 2a) requires significant computational resources and expertise, as highlighted in [12,[34][35][36]. Although this method provides the important representation of the SSSI under discussion, its practical implementation is associated with several challenges and has not yet become established in construction practice.…”