engleski

Spectral method in realistic modelling of bridges under moving vehicles

This paper develops techniques for application of spectral method in dynamics of structures, particularly bridges under the moving loading. Spectral method is formulated in terms of matrix operators capable of discretizing and combining Kirchhoff-Love plates and Bernoulli beams. The boundary conditions have been imposed using Lagrange multipliers and is capable of dealing with various boundary conditions like combinations of Dirichlet and Neumann conditions. The proposed method allows a bridge to be modelled as a 3D structure with realistic cross-section (ribs, box girders etc.). Moving loading can be any realistic model of a vehicle like standard European three-axle road vehicle with 9 dynamic degrees of freedom. Vehicle behaviour is described with an additional system of differential equations that has to be solved together with a partial differential equation of the structure. Two different formulations and the corresponding methods of solution are presented: i) formulation suitable for direct solution, ii) formulation suitable for semi-direct (staggered) solution. The proposed approach based upon the spectral matrix operators is sufficiently general to be suitable for dealing with strong form of any structure analysis problem. Example of dynamic analysis of a real bridge in Croatia illustrates the proposed method.

dynamic structural analysis; realistic bridge analysis; moving vehicle; spectral method; matrix operators; strong formulation

Special issue: Engineering Structures : Modelling and Computations (IASS-IACM 2012) ; Adnan Ibrahimbegovic, Herbert Mang (ur.).