Mass-Spring System - Railway Pro

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4DesignVariantsA number of different designs havebeen developed by European railwaycompanies for mass-spring systems inrecent decades. For instance, thereare designs with either in-situ castedor prefabricated concrete slabs aswell as combinations of the two, bothwith and without ballast beds.In designing an elastic support formass-spring systems, the selectedconstruction method is also importantfor the functionality and economicefficiency of the overall system.Whether full-surface, linear or pointlikesupport – Getzner’s know-howensures technically faultless, economicallysustainable and functionalsolutions.8
Full-surface support Linear support Point-like supportFull-surfacesupportDepending on the specific application,a full-surface elastic supportachieves natural frequencies in therange of 14-25 Hz. This corresponds toan achievable structure-borne noisedamping of up to 30 dB in the supercriticalfrequency range.A full-surface elastic support fromGetzner offers advantages in thefollowing areas:— Simple, fast and inexpensive constructionmethods— Low risk of construction errors— Wide-area load distribution in thesubsoil— Damping of structural vibrations ofthe track support elements— Low number of installation joints— High horizontal stability of the entiresystem— Economy of the entire systemLinearsupportLinear supports are preferred inmass-spring systems that make useof prefabricated elements or combineprefab with in-situ casted concrete. Thehorizontal forces that arise both in thedirection of travel (braking and accelerationforces) as well as perpendicularto the track axis (e.g. centrifugal forces,side forces resulting from track geometryerrors) can be handled well by therelatively large support surfaces.With linear support, it is possible toachieve lower support structurenatural frequencies (8-15 Hz) than withfull-surface support while keepingexpenses reasonable. Overall, linearsupport achieves a higher damping ofstructure-borne sound.Point-likesupportThe selected construction methodfor the track support slabs or tracktroughs determines the type ofpoint-like support. Generally it is usedwith track support slabs created usingsite-mixed concrete and lifted intoplace after hardening. The supportsare inserted through openings in theplate.Since train operations give rise tohorizontal forces, attention must bepaid to the transmission of these forcesduring dimensioning of the generallyrelatively small support surfaces. Inorder to limit the horizontal deflectionsin line with the requirements, theoptimal values for shear modulus,support layer thickness and supportarea are used in practice.The lowest natural frequencies areachievable with point-like supports(5-12 Hz). This type of support satisfiesthe highest requirements forstructure-borne sound protection.Structure-borne sound damping of30 dB and more can be achieved withthis type of system.9
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Page 6 and 7: 3How a Mass-Spring SystemFunctionsE
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Page 14 and 15: 8Finite ElementAnalysis14
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Page 18 and 19: 10InternationalReferencesTokyo rapi
Page 20: Getzner Werkstoffe GmbHHerrenau 567

Mass-Spring System - Railway Pro

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