Publications

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Thesis
Long-term Behaviour of Railway Transitions under Dynamic Loading. Eds. Manuel A. G. Silva, and Paul Hölscher. Universidade Nova de Lisboa. Lisbon, 2013.
Modelling dynamic superficial excitation of subsoil (in Portuguese). Eds. Bilé J. P. Serra. Instituto Superior Técnico da Universidade Técnica de Lisboa. Lisbon, 2005.t_mestrado_jnv_versao_definitiva.pdf
Report
Varandas, J. N., and J. P. Bilé Serra Relatório 151/97 - NF, Equipamento para realização dos ensaios segundo as normas ASTM D 4253-93 e D 4254-91. Lisbon: LNEC - Laboratório Nacional de Engenharia Civil, 1997.
Journal Article
Dimitrovová, Z., and J. N. Varandas. "Critical velocity of a load moving on a beam with a sudden change of foundation stiffness: Applications to high-speed trains." Computers & Structures. 87 (2009): 1224-1232. Abstract

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Varandas, J. N., P. Hölscher, and M. A. G. Silva. "Dynamic behaviour of railway tracks on transitions zones." Computers & Structures. 89 (2011): 1468-1479. Abstract

{{\textless}p{\textgreater}{\textless}br/{\textgreater}Transition} zones between structures as bridges or box culverts frequently present higher degradation rates compared to the remaining railway. This paper presents a numerical model for the dynamic loads on the ballast caused by trains passing a transition. The model was validated with field data obtained from an extensive field survey conducted in two transition zones in the Netherlands. Results show that the forces on the ballast vary significantly both in time and space on a transition, especially with the appearance of voids under the sleepers. Implications of the results on the long-term behaviour of transition zones are presented.{\textless}/p{\textgreater}

Varandas, J. N., A. Paixão, E. Fortunato, P. Hölscher, and R. Calçada. "Numerical Modelling of Railway Bridge Approaches: Influence of Soil Non-Linearity." International Journal of Railway Technology. 3.4 (2014): 73-95.
Varandas, J. N., P. Hölscher, and M. A. G. Silva. "Settlement of Ballasted Track Under Traffic Loading. Application to Transition Zones." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. 228.3 (2014): 242-259 . Abstract

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Conference Paper
Bilé Serra, J. P., and J. N. Varandas. "Estimativa da Curva de Dispersão de Rayleigh por Sobreposição Modal." Congreso de Métodos Numéricos en Ingenieria . Granada, Spain 2005.
Dimitrovová, Z., J. N. Varandas, and M. A. G. Silva. "Ground Vibrations Induced by High-Speed Trains in Regions with Sudden Foundation Stiffness Change." Proceedings of the 11th International Conference on Civil, Structural and Environmental Engineering Computing. St. Julians, Malta 2007.
Varandas, J. N., R. Silva, M. A. G. Silva, N. Lopes, and P. Hölscher. "The Impact of Rail Corrugation on the Degradation of Ballast." Proceedings of the First International Conference on Railway Technology: Research, Development and Maintenance. Ed. J. Pombo. Las Palmas de Gran Canaria, Spain: Civil-Comp Press, 2012. 543-546. Abstract

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Varandas, J. N., and J. P. Bilé Serra. "Modelação da excitação superficial do terreno e sua utilização na estimativa de perfis de módulos de corte através da análise espectral de ondas de superfície." 6º Congresso Nacional de Sismologia e Engenharia Sísmica. Guimarães, Portugal 2004.
Varandas, J. N., A. Paixão, E. Fortunato, P. Holscher, and R. Calçada. "Non-linear Elastic Behaviour of Unbound Aggregates in FEM representing Railway Transition Zones." Proceedings of the Second International Conference on Railway Technology: Research, Development and Maintenance. Ajaccio, France: Civil-Comp Press, 2014.
Dimitrovová, Z., J. N. Varandas, J. R. Almeida, and M. A. G. Silva. "Sensitivity Analysis of Track Vibrations due to Vertical Stiffness Variation in High-Speed Railways." Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN. Rethymno, Crete 2007.
Varandas, J. N., P. Hölscher, and M. A. G. Silva. "A Settlement Model for Ballast at Transition Zones." Proceedings of the Tenth International Conference on Engineering Computational Technology. Eds. B. H. V. Topping, J. M. Adam, F. J. Pallarés, R. Bru, and M. L. Romero. Valencia, Spain: Civil-Comp Press, 2010. Abstract

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