Page 312 - 360.revista de Alta Velocidad - Nº 5

Balmaseda, Lucía. Gallego, Inmaculada. Sánchez-Cambronero, Santos. Rivas, Ana.

4. Conclusions

The calculations performed on the 3D numeric model of the rail track proved the following
conclusions:

• The dynamic stiffness is always greater than the static stiffness and the difference between
them decreases as the static stiffness increases.

• For structures with very elastic infrastructures, the dynamic stiffness is greater than the
dynamic stiffness by 18%. However, for rail track structures with rigidities of approximately
50 to 70 KN/mm, the dynamic stiffness is greater by approximately 2%, which is an almost
negligible value.

• The stiffness of high-speed infrastructures needs to be greater than 60 KN/mm, and values
between 70 and 80 KN/mm are recommended. In these cases, the difference between static
stiffness and dynamic stiffness is very small. Therefore, use of the simplifying assumption
that the static stiffness is equal to the dynamic stiffness seems reasonable.

• The dynamic amplification coefficient is the result of relating this dynamic loading to the
static value of the load. The comparison of the analysis of the coefficient values obtained
using Prud'Homme with the analysis obtained using the Eisenmann formula reveals the
limitations of the latter formula.

• Is a good approach to use Eisenmann for stiffness superiors to 80 KN/mm, but for more
flexible compositions we would be overdesign the infrastructure.

• In addition, the formulas converge in zones of transition where appear the MGT, reason why
doesn’t seem suitable to use it to determine the embankment on the rest of the high speed
line.

5. References

• Comité D-71, (ORE), (Office de Recherches et d`Essais de l`Union Internationale des Chemins
de Fer), (1970), Sollicitation de la voie du ballast et de la plateforme sous l`action des
charges roulantes, RP1.

• Comité D-117, (ORE), (Office de Recherches et d`Essais de l`Union Internationale des
Chemins de Fer), (1983), Adaptation optimale de la voie classique au trafic de l’avenir,
Rapport nº 28 - Abaques de comportement du système voie/fondation-.

• Gallego, I. y López, A. ,2009. Numerical simulation of embankment–structure transition
design., Proceedings of the Institution of Mechanical Engineers, PartF: Journal of Rail and
Raspid Transit, Vol. 223, pp. 331-343.

• Gallego, I, et al., 2011. Vertical track stiffness as a new parameter involved in designing
high speed railway, Journal of Transportation Engineering (ASCE), Vol.137(12), pp. 971-979

• Gallego, I. Heterogeneidad resistente de las vías de Alta Velocidad: Transición
terraplénestructura. Editorial Academica Española, 2012

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