Damage effect on the nonlinear dynamic responses of a bridge
Thiago de Oliveira Abeche1; Roberto Dalledone Machado2; João Elias Abdalla Filho3; Fernando Luiz Martinechen Beghetto4; Luiz Antonio Farani de Souza4
1 Pontifical Catholic University of Paraná (PUCPR); 2 Pontifical Catholic University of Paraná (PUCPR), Federal University of Paraná (UFPR); 3 Pontifical Catholic University of Paraná (PUCPR), Federal Technological University of Parana (UTFPR); 4 Federal Technological University of Paraná (UTFPR)
doi:10.20906/CPS/CILAMCE2015-0720
Resumo
The constant movement of vehicles on bridges can, over time, affect the structural integrity and compromise its service life. The lack of supervision allows overloads that can damage the pavement and the bridge. The lack of maintenance and conservation of the structures do not guarantee safety and structural health. When crossing a bridge with constant speed, the vehicle is subjected to the effects of track irregularities, represented by sinusoidal harmonic functions. The irregularities of the track dynamically excite the vehicle which in turns provokes additional vibrations in the structure of the bridge beyond those produced by their own movement, increasing the degree of damage of the structure. The approach developed in this study treats this phenomenon uncoupled. The damage modifies the dynamic responses of the bridge structure, increasing the magnitude and the oscillations within the same time interval especially at critical speeds of the vehicle, capable to provoke some resonance. Apart from changing the responses in terms of displacements, velocities and accelerations, the damage alters the natural frequencies of vibration of the structure. Such effects are not possible to be analyzed with linear dynamic models. In this sense, this work aims to evaluate the nonlinear dynamic effects produced in a reinforced concrete bridge through the Finite Element Method, on which the degree of damage is altered over time through the stiffness loss of the structure by Damage Mechanics. The damage model used is the Mazars Damage Constitutive Model implemented with the condition of stress inversion due to vibration. In the bridge model are used Euler-Bernoulli beam elements, with Hermite cubic interpolation functions. The structural damping is defined by the Rayleigh method with the updated coefficients. Effects of nonlinearities occur by the fact that the forces no longer linearly depend from the displacements when damage occurs. The continuum damage mechanics is considered dynamically, requiring to evaluate the damage i
Palavras-chave: Damage Mechanics; Dynamic Interaction; Finite Element Method; Computational Modeling